Post by: royhall on May 15, 2017, 03:21:24 PM
Post by: hairygit on May 15, 2017, 03:36:19 PM
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Post by: royhall on May 15, 2017, 04:16:15 PM
Post by: hairygit on May 15, 2017, 04:29:53 PM
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Post by: hairygit on May 15, 2017, 04:33:22 PM
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Post by: royhall on May 15, 2017, 04:39:31 PM
Post by: hairygit on May 15, 2017, 04:50:06 PM
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Post by: royhall on May 15, 2017, 04:57:08 PM
Post by: Trigger on May 15, 2017, 05:53:50 PM
Post by: royhall on May 16, 2017, 07:54:24 AM
Sounds like you have a little bore polishing going on. Hairy is right, take it out, get it hot and give it a few revs.Cheers Trig. What causes the bore polishing?
Post by: Bryanj on May 16, 2017, 08:03:33 AM
Post by: royhall on May 16, 2017, 08:22:37 AM
Riding it too gently and infrequentlyToo many bikes versus too little time. The age old problem.
Post by: Clem2112 on May 16, 2017, 08:56:38 PM
I put this down to slight exhaust valve stem wear and there being no seals on the exhaust stems.
The green o rings (under the valve guides?) were not replaced either.
Post by: royhall on May 17, 2017, 07:47:24 AM
Post by: paul G on May 17, 2017, 08:17:22 AM
Both the ones I have done did not have them on the exhaust and both gasket sets only had four in them.
Post by: hairygit on May 17, 2017, 08:22:05 AM
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Post by: royhall on May 17, 2017, 06:01:48 PM
Post by: royhall on March 14, 2018, 03:27:48 PM
Now the GS1000 is out of the way I decided to strip the top end to have a look, and I'm glad I did.......I stipped it down to the crankcases to look at the pistons. When the head came off all four piston crowns were covered in oil. On checking the gaskets and mating surfaces there was clear evidence of head gasket failure. There was hard burnt on oil deposits behind the head gasket metal sealing ring on all four pots and the gasket was very oily.
I had initially suspected that when the rebore was done it had been bored to a loose tolerance. On measuring the bores and piston skirts the clearance is 0.0008" which is bang on the money for Cruzinimage pistons. Checked the top rings in the bores and the ring gaps are between 6 &8 thou which is also spot on. The new bores appear to have run-in well with a slight glaze but the honing still visible. Strangely each bore has some light vertical scoring that appears to be from the ring ends as they are spaced about 120 degrees apart. Is this scoring normal, its not deep and can barely be felt with a finger nail. I have a new set of plus 1mm Cruzinimage pistons on the shelf, that due to a wrong delivery I got for free, and am toying with the idea of having it bored again just to be sure.
On the head, I tested for valve leakage with the old fill with petrol trick and all is good. That said though, whilst the head is off I am going to replace all eight valve stem seals again just to be sure, and also re-check the valve guides for wear whilst they are out. I solved the mystery of the exhaust stem seals, they had all eight fitted for the first 9 months (approx) of production then further models had the exhaust seals removed. Mine is a very early 1972 model hence the 8 seals. I have checked both barrel top and head for flatness (they were both skimmed at rebuild) and they are spot on.
The questions are how far do I go putting it back together, and clearly I won't be using any more Cruzinimage gasket kits. I have an Athena set for the rebuild (not sure how good the quality of those are) but now I have found that the head gasket was the culprit, should I search for a genuine NOS Honda head gasket? Also what about the rubber seals around the dowels, are they up to the job. I am assuming they are the same items on the 400/4. And how much should the honing be glazed, and what about the vertical scoring is that the cheap Cruzinimage pistons or is it normal.
There are quite a few documented head gasket failures on the USA site but these are mainly leaks to the outside from the edge of the head gasket around the oil control jets. Mine appears to be similar but leaking into the cylinders instead. I had no show of oil at all on the outside of the engine.
Sorry about the long post and the endless questions, just don't want to have to go down this route again. Cheers all.
Post by: Bryanj on March 14, 2018, 04:53:36 PM
Post by: royhall on March 14, 2018, 05:01:29 PM
Post by: kevski on March 14, 2018, 08:52:02 PM
http://forums.sohc4.net/index.php/topic,111517.msg1369678.html#msg1369678
Post by: royhall on March 14, 2018, 08:58:44 PM
Post by: Seabeowner on March 14, 2018, 09:38:05 PM
http://forums.sohc4.net/index.php/topic,165714.0.html
Cheers
Post by: royhall on March 15, 2018, 06:55:03 AM
It would be this on. I think he has given up at the moment and will pick up later.That looks like the thread, will take a while to read right through it though. Thanks for that.
http://forums.sohc4.net/index.php/topic,165714.0.html (http://forums.sohc4.net/index.php/topic,165714.0.html)
Cheers
Post by: MrDavo on March 15, 2018, 07:24:46 AM
The Athena head gasket from the set I bought is still on the garage shelf. It’s free if anyone wants it, but I wouldn’t bother.
Post by: kevski on March 15, 2018, 08:24:22 AM
Post by: Nurse Julie on March 15, 2018, 01:23:51 PM
Post by: K2-K6 on March 15, 2018, 08:04:24 PM
That says to me that the piston rings are not round when compressed into the bore, else the ring's ends would not protrude further than their outside diameter (and make the marks you can see) that is not right. His question about black ring coating, and should it wear, shows that the rings are not touching the bores where the coating remains. They are, in effect, elliptical in shape. That will not seal the bores either oil going up, or compression going down. It should be getting to something like 175 psi, it's nowhere near.
Leakdown testing is only going to show efficiency in holding compression, it'll not show oil retention ability as that's the opposite direction.
Exhaust valve guide leaking doesn't usually affect combustion chamber as it's introduced after the cylinder. It'll smoke yes, but just from passing oil into a hot exhaust system.
Inlet guides leaking usually show with throttle shut on overrun, inlet vac goes high and pulls in oil, when you get back on the throttle it'll puff out a single-ish cloud of blue smoke.
Looks like the rings aren't working as they should, whether they'll bed in if they're not touching in the first place I doubt it. You'd, in effect, have to wear all of the "touching" parts of the ring down first before that process could even start to take place.
But as the first example of massive ring gap, that's what you'd get by the time you had achieved the above. There's lots of evidence in that thread but it's not being connected.
Post by: royhall on March 15, 2018, 10:54:05 PM
I fitted extra 'O' rings around the end studs on my 400 rebuild, as suggested by Trig.More information if you would Julie. Cheers
Post by: Nurse Julie on March 16, 2018, 05:46:41 AM
Post by: royhall on March 16, 2018, 08:46:23 AM
Post by: royhall on March 16, 2018, 09:05:31 AM
I've read through that thread on net site, and something they are missing which may have a parallel here is those ring markings vertically in the bores.That jumped out at me straight away after taking it apart, but seemed secondary to the head gasket issue. Have got some time today so am going to probe deeper. Just how good are these Cruzinimage piston kits, they look well made but it's concerning me now as the Cruzinimage gasket set was shite. Would like to find a +.25mm OEM piston set and rings for my spare barrel but that does not seem likely. Does anyone make quality piston rings that will fit the Cruzinimage pistons?
That says to me that the piston rings are not round when compressed into the bore, else the ring's ends would not protrude further than their outside diameter (and make the marks you can see) that is not right. His question about black ring coating, and should it wear, shows that the rings are not touching the bores where the coating remains. They are, in effect, elliptical in shape. That will not seal the bores either oil going up, or compression going down. It should be getting to something like 175 psi, it's nowhere near.
Leakdown testing is only going to show efficiency in holding compression, it'll not show oil retention ability as that's the opposite direction.
Exhaust valve guide leaking doesn't usually affect combustion chamber as it's introduced after the cylinder. It'll smoke yes, but just from passing oil into a hot exhaust system.
Inlet guides leaking usually show with throttle shut on overrun, inlet vac goes high and pulls in oil, when you get back on the throttle it'll puff out a single-ish cloud of blue smoke.
Looks like the rings aren't working as they should, whether they'll bed in if they're not touching in the first place I doubt it. You'd, in effect, have to wear all of the "touching" parts of the ring down first before that process could even start to take place.
But as the first example of massive ring gap, that's what you'd get by the time you had achieved the above. There's lots of evidence in that thread but it's not being connected.
Post by: Nurse Julie on March 16, 2018, 09:16:05 AM
Post by: AshimotoK0 on March 16, 2018, 10:04:55 AM
[/quote]
Hmm Crap gaskets ! ..crap inlet rubbers ! (I saw your horrid images of them !) ..the jury's out on those rings. "Spoiling the the ship for a ha'peth of tar" springs to mind ;D
Post by: royhall on March 16, 2018, 11:00:43 AM
That jumped out at me straight away after taking it apart, but seemed secondary to the head gasket issue. Have got some time today so am going to probe deeper. Just how good are these Cruzinimage piston kits, they look well made but it's concerning me now as the Cruzinimage gasket set was shite. Would like to find a +.25mm OEM piston set and rings for my spare barrel but that does not seem likely. Does anyone make quality piston rings that will fit the Cruzinimage pistons?
Hmm Crap gaskets ! ..crap inlet rubbers ! (I saw your horrid images of them !) ..the jury's out on those rings. "Spoiling the the ship for a ha'peth of tar" springs to mind ;D
Your probably right Ash. That's why it's going back together with all genuine gaskets and stem seals etc. Am looking for genuine pistons and rings also. Been bitten enough on this bike with pattern parts. The new front mudguard from Silvers is gently rusting away whilst the genuine re-chromed rear is still perfect.
Post by: AshimotoK0 on March 16, 2018, 11:18:04 AM
Post by: Nurse Julie on March 16, 2018, 02:19:44 PM
Post by: royhall on March 16, 2018, 02:50:30 PM
Should the clearance on Cruzin pistons / rings not be 1 thou Roy?. I know the genuine Honda pistons can go down to 0.0008 thou but I thought a tad more clearance was needed on the Cruzin kits. I can't ask Trig, I am not allowed to mention, Honda, bike, work or Forum whilst on our travels ::) ::)Leave it until you get back Julie. Am going to PM Trig about a rebore anyway so will go through the possibilities then. Enjoy your holiday.
Post by: royhall on March 16, 2018, 04:30:12 PM
The vertical scores on the bores are no more than marks, cant feel them with a scriber or a finger nail. I have checked all the top rings in the bores and all gaps are 7 to 8 thou. The rings appear to have run-in evenly all the way around and do not have any damage or scoring, nor could I find any protruding ring ends. Don't know if it's worth checking the second and scraper rings as I don't want to risk damaging them getting them off the pistons, but I will check that they are all fitted the correct way up.
From what I see, I would say the barrels are good for re-assembly. Before then I am going to "engineers blue" the barrel top to head mating surface to check how they go together. Have already checked both are flat.
The problem I think, from the evidence left behind, was the Cruzinimage gasket set being rubbish, allowing oil to escape around the control jets then under the head gasket, there is quite a bit of oil pressure at that point. I don't think the two forward drains have caused any issues as there is no pressure there.
On next assembly only genuine Honda parts will be used, plus Trig has a trick with extra o-rings that hopefully he will chip in about on his return from India.
Post by: MrDavo on March 16, 2018, 04:51:14 PM
Didn't we have an issue with this company's rubber camchain tensioner wheels in the past?
The words don't, touch and bargepole spring to mind.
Post by: mart on March 16, 2018, 09:22:17 PM
Post by: Rozabikes Tim on March 16, 2018, 09:36:50 PM
If the smoke is Black it my be over fueling /Flooding on the cylinders of which you speak . turn of the fuel tap and as the Fuel level lowers in the Carbs see if they stop smoking ..Possibly a bit difficult with head and barrels off ;)
Post by: royhall on March 17, 2018, 09:10:01 AM
If the smoke is Black it my be over fueling /Flooding on the cylinders of which you speak . turn of the fuel tap and as the Fuel level lowers in the Carbs see if they stop smoking ..Thanks for the input. All the possible scenarios were checked out before the strip down, carbs and ignition were eliminated at that point. The problem is head gasket failure, plus some other minor issues.
Post by: Trigger on March 31, 2018, 11:43:26 AM
We should hire an Indian to follow Trigger everywhere on a Honda so obviously sick that eventually he has to take a look to see what's wrong with it... 8)
Didn't we have an issue with this company's rubber camchain tensioner wheels in the past?
The words don't, touch and bargepole spring to mind.
why hire a Indian when you can hire a Enfield ;D ;D ;D
Post by: royhall on April 13, 2018, 09:30:47 AM
Post by: Nurse Julie on April 13, 2018, 09:45:10 AM
Post by: royhall on April 13, 2018, 09:58:29 AM
Post by: Nurse Julie on April 13, 2018, 10:03:55 AM
Post by: royhall on April 13, 2018, 10:17:01 AM
Post by: royhall on April 13, 2018, 11:14:38 AM
Post by: AshimotoK0 on April 13, 2018, 11:29:09 AM
The rings are marked "T" and the oversize on all three rings, no signs of an "R".......... I have a set of Cruzinimage +1 pistons and the rings on that are marked the same. What make would they be.
No copyright on marking rings ..you can stamp what like on them. I have Honda CB250K rings from the far east in red Honda packing with the Riken marks on them but they are definitely copies. Buyer beware, spoiling the ship ...blah blah blah. I would go for Genuine, Riken or NPR from a reputable source.
Post by: royhall on April 13, 2018, 11:35:15 AM
Do you have a reputable source Ash? Could do with sending them a piston so they can match them up.The rings are marked "T" and the oversize on all three rings, no signs of an "R".......... I have a set of Cruzinimage +1 pistons and the rings on that are marked the same. What make would they be.
No copyright on marking rings ..you can stamp what like on them. I have Honda CB250K rings from the far east in red Honda packing with the Riken marks on them but they are definitely copies. Buyer beware, spoiling the ship ...blah blah blah. I would go for Genuine, Riken or NPR from a reputable source.
Post by: AshimotoK0 on April 13, 2018, 12:30:30 PM
Do you have a reputable source Ash? Could do with sending them a piston so they can match them up.The rings are marked "T" and the oversize on all three rings, no signs of an "R".......... I have a set of Cruzinimage +1 pistons and the rings on that are marked the same. What make would they be.
No copyright on marking rings ..you can stamp what like on them. I have Honda CB250K rings from the far east in red Honda packing with the Riken marks on them but they are definitely copies. Buyer beware, spoiling the ship ...blah blah blah. I would go for Genuine, Riken or NPR from a reputable source.
Not really ..they seem really rare NOS and hence very expensive. I have no experience with IMD but perhaps someone on here has, and if they are good quality then worth a try. I notice originals are one piece oil control rings. Perhaps there is a later bike which may fit uses 3 -piece or IMD would probably supply 3-piece. (e.g one model CB125 single rings fit a CB500/4)
Post by: paul G on April 13, 2018, 12:36:42 PM
I had a set off them for the Z650 about 2yrs ago and all seems well at the moment.
Not the cheapest but seem good quality.
Post by: AshimotoK0 on April 13, 2018, 01:01:39 PM
Hmm think C90 may be 50mm bore ...ST70 is 47mm though.....Hairy ?????
Post by: paul G on April 13, 2018, 01:16:57 PM
IMD don't list them . I think C90 is 47mm bore size though or possibly C70 or both. Hairygit will know. I may have some sort of Honda 90 rings at home ..will check tonight.They do carry a lot more stock than just what is on the web site give him a ring.
Hmm think C90 may be 50mm bore ...ST70 is 47mm though.....Hairy ?????
Post by: royhall on April 13, 2018, 01:34:58 PM
Post by: hairygit on April 13, 2018, 01:43:13 PM
Post by: K2-K6 on April 13, 2018, 02:01:16 PM
Like anything manufactured, you can get a problem occur which is why you'd try to have batch identifications to help pull the affected parts from giving the supplier a poor reputation. If the company policy effectively locks that route off its a catch 22 for the client and you're left to express your findings freely to others.
It shouldn't be like that as other stuff appears to have reasonable views for similar items. They'll shoot themselves in the foot by sticking to that method of selling.
Obsolete pistons and rings are often made in batches to best support slow sales, it's possible that it could be a substandard batch of rings in supply chain, but if they won't look at it then not much you can do.
As you say Roy, to go toward a rebuild with the effort, cost and anticipation that entails, then it's a real pain with a poor outcome.
Post by: Nurse Julie on April 13, 2018, 02:18:35 PM
Just dug out of the pile a new set of Genuine Honda 350F rings, and they have a "T" and the oversize stamped on exactly the same as Cruzin. I guess the Genuine's I have are fake..... They mike up exactly the same size as well, and they look the same.The thing is Roy and it's well advertised all over internet, Riken make piston rings for Honda. I can't imagine Riken making 'to spec' piston rings for Honda and sub standard rings for every other supplier that sells them as Riken, including Cruzinimage. Now, I can understand a pattern part maker making parts that look identical and selling them as such and there is no way we will ever really know if what we are buying really is 'Genuine' or not. It also doesn't mean that the more we pay, the more chance of the product being truly 'Genuine'. Those days are long gone. Agree with Nigel though, could be a sub standard batch.
Edit...as an example we buy OEM indicator stems direct from the same supplier that Honda buy them from in Malaysia. Honda put them in Honda bags with a part number and then charge $$$$$$ more. They all come off the same production line.
Post by: royhall on April 13, 2018, 02:30:48 PM
Cheers Julie and all who contributed. Am going to PM Trig about some rebore and skim work. About time the experts had a look at this.Just dug out of the pile a new set of Genuine Honda 350F rings, and they have a "T" and the oversize stamped on exactly the same as Cruzin. I guess the Genuine's I have are fake..... They mike up exactly the same size as well, and they look the same.The thing is Roy and it's well advertised all over internet, Riken make piston rings for Honda. I can't imagine Riken making 'to spec' piston rings for Honda and sub standard rings for every other supplier that sells them as Riken, including Cruzinimage. Now, I can understand a pattern part maker making parts that look identical and selling them as such and there is no way we will ever really know if what we are buying really is 'Genuine' or not. It also doesn't mean that the more we pay, the more chance of the product being truly 'Genuine'. Those days are long gone. Agree with Nigel though, could be a sub standard batch.
Edit...as an example we buy OEM indicator stems direct from the same supplier that Honda buy them from in Malaysia. Honda put them in Honda bags with a part number and then charge $$$$$$ more. They all come off the same production line.
Post by: K2-K6 on April 18, 2018, 10:14:55 AM
Any use?
Post by: royhall on April 18, 2018, 11:32:49 AM
Decided to go with the Cruzinimage piston kit I got for free and rebore the cylinders to the full +1mm.
Took it to the engineers yesterday and by chance he was just starting a rebore on a 400F so he said he would do them straight after whilst he was set up. Anyway 24 hours later I have picked them up, top service. He has matched the pistons to the bores individually as the Cruzin pistons have 0.0005" differences, good job he checked. He said the 400F before it had NOS Honda pistons and they were way worse. So heads up if you having a rebore, get them to bore each cylinder to a specific piston.
More learning curve, and possibly a contributor to the smoke who knows.
Post by: K2-K6 on April 18, 2018, 12:26:35 PM
Years ago someone who just specialised in rebores said to me, the golden rule is to never machine until you have the piston in front of you, and to measure every piston as it's not often they're the same!
Unsure how familiar you are with this area of engineering. If you put the new piston and rings in the bore before assembly of the engine, it should sound and feel as if the rings are running over emery cloth. It's this action that "cuts" material off the rings to make them fit the bores during run in process.
Hopefully you'll have covered off all your issues leading to the rebuild.
Post by: Trigger on April 18, 2018, 08:21:30 PM
Post by: royhall on April 19, 2018, 08:19:57 AM
Post by: Seabeowner on April 19, 2018, 08:53:41 AM
My Haynes book states max stem to guide clearance for CB350 as .003 inlet, .004 exhaust. Same as 500. And I like to stay a way inside that.
Post by: royhall on April 27, 2018, 09:32:41 AM
Some engines (mine included) had stem seals on the exhaust side and some had unsealed guides that are machined to a point to shed the excess oil. According to some on the internet the excessive wear is due to the stem seals on this engine and the lack of oil on the valve stems, and they should have the other type. Many others disagree and say to fit the 400 type with the seal (which as we know should be designed to leak slightly).
I even checked the ones on Yamiya's site for the 400 and if you buy the full set they all have seals, if you buy the exhaust guides separately they don't have seals? All the guides on CMS for the 350 are without seals except for the French bikes. This is all a bit weird.
I rang CMS with my engine number and they say the non sealed version so that is what I have gone with (even though seals were fitted in my engine). On top of that there are 4 different versions of unsealed guides so I went with the latest version. Just hope it's the right decision as I have fitted them now.
This is not usual Honda and is very confusing.
Post by: royhall on May 18, 2018, 03:14:14 PM
The 350F is now rebuilt again with all genuine Honda parts except for the +1mm Cruzinimage pistons. The pistons were supplied with exactly the same rings as my Genuine Honda set.
The barrels were rebored to exactly the right size with each bore individually cut to the relevant piston. The exhaust valve guides were replaced with the correct non sealed versions and reamed to suit. This time around everything was measured and double checked. The rings are all fitted the correct way up and verified twice.
Started the engine this afternoon for the first time, it started straight away on the button with no messing around. Guess what, No.4 is still smoking badly.
That just leaves the carbs that have already been rebuilt twice, once by Gerben and once by Matt Harper. I am beginning to see why the guy on the USA site gave up and sold it on.
Does anybody have a good set of 350F carbs that I could borrow for a short while to eliminate the problem. I'm thinking there may be a small crack somewhere in the No.4 carbs casting causing it to run very rich? Or it may be the Cruzinimage carb kits that were used are duff.
Cheers.
Post by: hairygit on May 18, 2018, 03:36:40 PM
Post by: royhall on May 18, 2018, 03:45:18 PM
But I would still like to borrow a good set of 350F carbs just to eliminate the carbs from the problem. I will gladly pay the postage there and back. I have just checked the new plugs and they are black and No.4 was wet. It smells like petrol but a bit hard to tell. Looks to me like it's running very rich.
I am at least happy now that the engine is back together as well as it can be, it would not have been long before the Cruzinimage head gasket let me down.
Post by: K2-K6 on May 18, 2018, 09:44:38 PM
As Hairy says, it's worth running a bit more to evaluate the pipe and if it will clean up . Although that black plug is worrying and as you say, suggests you've got too much of something burning in there.
What about getting a emissions test for each pipe once it's warmed up at mot test station. If you can get a decent readout for each then at least you can make a more fundamental judgment as to what's coming out of that cylinder versus the others.
Or, pull the carbs and switch the main jet from that #4 over to another cylinder to see if the problem moves?
Post by: flatfour on May 19, 2018, 12:38:01 PM
If you need them, let me know.
Post by: royhall on May 20, 2018, 10:05:14 AM
I've most of a set of 350/4 carburettors if it helps - some parts (I can't remember which)) were removed from one or more of them long ago, however they are substantially complete with all linkages, springs etc. in place.Thanks for the offer, will keep you in mind. I have contacted Matt at Harpers Ultrasonic and he has offered to take the carbs back for another look. He's a top bloke. Will post what he finds but I am of a mind to get rid of the Cruzinimage carb kits that were fitted. Cheers.
If you need them, let me know.
Post by: royhall on May 24, 2018, 05:56:12 PM
What a pain Roy, but hopefully you're closer to eliminating all the things until you get on top of it.That emissions test at the MOT centre was a very good idea. Tonight I did just that and the readings on 3 pots were pretty high and 1 pot they were low. The readings were as follows: No1-3.002 No2-3.050 No3-0.084 No4-2.800. Neither me or the MOT tester knows what the readings should be but pots 1,2,and 4 appear to be running rich with pot 3 lean. Pot 3 is the only one that does not smoke. I know it's rich as it starts first prod without any choke, very un-Honda like. Does anyone know what the correct emissions should be on a 350F. Cheers.
As Hairy says, it's worth running a bit more to evaluate the pipe and if it will clean up . Although that black plug is worrying and as you say, suggests you've got too much of something burning in there.
What about getting a emissions test for each pipe once it's warmed up at mot test station. If you can get a decent readout for each then at least you can make a more fundamental judgment as to what's coming out of that cylinder versus the others.
Or, pull the carbs and switch the main jet from that #4 over to another cylinder to see if the problem moves?
Post by: K2-K6 on May 24, 2018, 06:36:06 PM
If it's CO, then a good aim point is 1% (it's usually expressed as percentage even if not marked as such on printout) below 1% the exhaust starts to smell more carbon monoxide,eee and much less of unburnt petrol as it's a more efficient burn condition.
I'm trying to find if bikes have a specific level so will post if anything found.
Currently petrol cars pre cat equipped are max 1200 ppm for HC, I'm seeing avg around 100 actual for currently well setup motor.
And for CO, max limit of 3.5% with current avg actual of 0.65% for same engine.
It certainly gives you a lead to get a feel for what your cylinders are doing, and hopefully a path to examine.
Post by: K2-K6 on May 24, 2018, 07:20:17 PM
If it were in front of me I'd try to find what is causing the low number three reading as it looks like the measurements are for CO. You could start by adjusting the idle screw on that carb to see if the idle circuit gives you any response as it looks impaired. Looks like it's burning almost nothing at tickover.
If it's been synced on this offset it can give a overall poor setup. It's this area I'm getting at when discussing syncing as one error here can cause you to put an undesired offset in place.
If you can answer that number three mixture, then get it to parity you could then aim with the idle screws to get it close to 2% at idle for all four cylinders. In other words, untangle the primary error then you've more room to manoeuvre in desirable setup.
If that makes sense.
Nigel.
Post by: andut on May 24, 2018, 08:52:20 PM
Andy
Post by: K2-K6 on May 24, 2018, 10:15:06 PM
My post with current levels of car engine is for fuel injected, although about 28yrs old and fairly crude, it does have the ability to work with a lower baseline setting and still give a stable idle plus additional enrichment when wacking the throttle open. So explains the baseline of 1% versus 2% for carb fed engines.
http://blankeindustries.com/exhauxt-gas-analyzer-products/technical-bulletins/motorcycle-airfuel-mixture-adjustment-guide/
Above link gives a reasonable overview of desired levels and what you are looking at.
Don't know your arrangements with the test station Roy, but if you sort the no3 problem and look at it again it could be worthwhile recording the "turns out" idle screw position to obtain both 2% and 3% readings so you have some scale to play with for setup.
Interesting to judge the higher rev reading and assess the main jet mixtures as well.
I know you have indicated concern about cruzinimage kit before, but those numbers for the three cylinders look impressively accurate in delivering CO readings almost bang on aim and tightly grouped to boot.
Post by: royhall on May 25, 2018, 05:15:41 AM
A brief history: These carbs came as a refurbished set from Gerben in Holland. They gave trouble immediately and were sent back to Gerben who went through them again. They were better but not right so I sent them to Harper's who stripped and cleaned them and fitted the Cruzinimage kits. They were decent for a while then got smokey. At that point I wrongly diagnosed the smoke as an engine issue due to the carbs having been professionally built three times. Problems were found and rectified on the subsequent strip down, so that at least was not wasted. These carbs have been ultrasonic cleaned at least twice by two people that know what there doing and all new internals fitted.
At this point I'm not sure the emissions readings are helping. It starts from cold without choke or throttle and idles immediately. That is not what Honda's do. It runs okay until the engine get properly warm then it bogs down. It is obvious from the symptoms that it's super rich. I am ready to abandon this set of carbs and find some more. I could really do with borrowing a set just to make certain that it runs well on known good carbs before buying any more. Not sure I can do much more with this set. Today however, I am going to make a fitting to check the actual float/fuel levels with a clear tube. Kevski has given me a measurement to set them to that works on his 350.
I think this is why bikes end up dumped under a cover at the back of the garage. Will report back with what I find.
Post by: Laverda Dave on May 25, 2018, 07:31:31 AM
Post by: kevski on May 25, 2018, 07:35:07 AM
Post by: royhall on May 25, 2018, 07:41:26 AM
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Post by: kevski on May 25, 2018, 08:02:27 AM
Post by: royhall on May 25, 2018, 09:20:17 AM
Post by: K2-K6 on May 25, 2018, 02:24:30 PM
Years ago I had a look at a bike that was doing something similar and the air filter, which had just been put in new, was not flowing properly. Never did figure out why it wouldn't flow air at the right volume. It defied logic and was replaced without any further issues.
It doesn't deal with the odd carb on no3 though.
Post by: royhall on May 25, 2018, 02:37:52 PM
Post by: royhall on May 25, 2018, 03:04:35 PM
Checked the float heights with the clear tube method. Pot 1- Can't check (flooding), Pot 2 - On the bowl crease (good), Pot 3 - Top of the screw threads (nearly overflow), Pot 4 - Bowl crease (good). I think Pot 1 is flooding due to it being way too high, and the extra ventilation is allowing it to flood. Stopped doing it when I removed the tube. A mixed bag really, all plugs are black with Pot 4 (the worst one) wet with petrol. Strange how the height on the worst one is correct? Carbs out again time. Matt Harper has offered to ultrasonic them again and check for cracks and corrosion etc. Gerben has sent me some Viton seals and stainless clips. I am also sending my 4 spare carb bodies so he can pick the best of the bunch. I don't think Matt likes to be beaten by carbs, appears to relish the challenge. Well I wish him the best of luck.
Off the road again for now until Matt waves his magic wand. One day you never know!!
Post by: royhall on August 16, 2018, 03:43:17 PM
1. The engine ran fine after the 1st rebuild for 200 miles.
2. At this point cylinder 4 started smoking and it got so bad it wouldn't really run as it was filling the street with smoke.
3. Stripped down the top end as I was suspecting it had been bored to the wrong tolerance.
4. Had the bores re-done to 8 tenths of a thou (although they were okay the first time) that eliminated pistons and rings.
5. Re-did the valve guides that were reamed to new tolerance and the valves checked for wear.
6. Reassembled the engine using all genuine Honda gaskets and seals.
7. Carbs rebuilt again due to leaky float valves, another set of carbs tried. That eliminates the carbs.
Certainly looks like the top end is coming apart yet again unless someone can make a suggestion for something I have overlooked. This time I'm going to have to look for cracks/distortion/holes etc as that oil is getting in somewhere. Any ideas before I get a can of petrol and burn the wretched thing down to the ground. ;D
Post by: Nurse Julie on August 16, 2018, 04:04:13 PM
Although re bored, did the liner clean up 100%, ie no scoring, or rust pockets beyond what what bored ?.
(The reason i say this is because Trig has rebored some barrels to .25 they still showed a minute mark on 1 liner, continued to rebore all the way up to 1.0 and the marks were still there, pushed the liner out and the rust had gone all the way through to the outside of the liner).
Post by: royhall on August 16, 2018, 04:12:19 PM
Just a side issue. I can run the engine with the tappet caps off and I don't get wet. Also there appears to be more oil around the inlet valves than the outlet. Is this correct?
Post by: Moorey on August 17, 2018, 09:55:34 AM
You will need the full kit.
Post by: royhall on August 17, 2018, 11:27:09 AM
If you pull the engine again try one of these to find a crack. https://www.ebay.co.uk/itm/Weld-Crack-Detector-Aerosols-Penetrant-Developer-Cleaner-or-full-set-of-3/183374704949?hash=item2ab1fbf135:m:m3tzZ_DI3GoC4KBNvH9-WHQ (https://www.ebay.co.uk/itm/Weld-Crack-Detector-Aerosols-Penetrant-Developer-Cleaner-or-full-set-of-3/183374704949?hash=item2ab1fbf135:m:m3tzZ_DI3GoC4KBNvH9-WHQ) We use them to find cracks in leaking vessels and reactors when we cant see the crack with the naked eye. Then when we start welding as soon as heat is introduced the crack opens right up. Maybe yours does not show until heat is involved. It seems like you hav already thrown a shit load of money at it. Good luck with it.That looks interesting. What's the procedure for using it.
You will need the full kit.
Post by: Nurse Julie on August 17, 2018, 12:32:06 PM
Post by: royhall on August 17, 2018, 12:39:08 PM
A cheap simple and quick diagnostic test would be to pop the lines out, swap them around and see if the problem moves cylinders.When you say lines, do you mean the HT leads?
Post by: Nurse Julie on August 17, 2018, 12:41:40 PM
F'kin spell check, LINERS as in barrels.A cheap simple and quick diagnostic test would be to pop the lines out, swap them around and see if the problem moves cylinders.When you say lines, do you mean the HT leads?
Post by: royhall on August 17, 2018, 12:44:56 PM
Post by: Moorey on August 17, 2018, 02:36:16 PM
If you pull the engine again try one of these to find a crack. https://www.ebay.co.uk/itm/Weld-Crack-Detector-Aerosols-Penetrant-Developer-Cleaner-or-full-set-of-3/183374704949?hash=item2ab1fbf135:m:m3tzZ_DI3GoC4KBNvH9-WHQ (https://www.ebay.co.uk/itm/Weld-Crack-Detector-Aerosols-Penetrant-Developer-Cleaner-or-full-set-of-3/183374704949?hash=item2ab1fbf135:m:m3tzZ_DI3GoC4KBNvH9-WHQ) We use them to find cracks in leaking vessels and reactors when we cant see the crack with the naked eye. Then when we start welding as soon as heat is introduced the crack opens right up. Maybe yours does not show until heat is involved. It seems like you hav already thrown a shit load of money at it. Good luck with it.That looks interesting. What's the procedure for using it.
You will need the full kit.
Very simple but very effective. Give everything a good clean with the spray cleaner and dry, then spray on the penetrant which is usually a red dye that works its way into the fault leave a while then clean again, then spray on the developer which is a white powder. If there are any cracks or faults the powder draws out the red penetrant from the crack showing the problem area. Quick and simple to use. I don't envy you, frustingto say the least.
Post by: Nurse Julie on August 17, 2018, 03:15:09 PM
Is the valve stem the correct size, ie, the same as the other valves?
Post by: Laverda Dave on August 17, 2018, 04:20:39 PM
Good luck.
Post by: royhall on August 17, 2018, 04:41:57 PM
Post by: royhall on October 27, 2019, 10:31:02 AM
After pushing the thing to the back of the garage under a sheet for nearly a year I thought I would have another go. This time around I am taking no prisoners so am removing all reproduction engine parts and replacing with genuine.
After stripping the top end I checked the barrels and liners for cracks with Dye-pen. They checked out okay. Unfortunately they were now at maximum bore with Cruzinimage pistons so they are unusable with NOS pistons. They are good though so I will sell them on.
Couldn't Dye-pen the head as the casting inside the ports (where it matters) is just too rough. After sending the head to an NDT specialist who checked it with something to do with Eddy Currents (pass) it came back with the problem marked. It appears that after changing the valve guides the casting had a small crack on No.4 inlet that had slowly propagated along until neat oil was being pulled into the cylinder. Bingo, problem found.
After weeks of looking I finally sourced replacement head, barrels, and pistons. The head was like new and required nothing but a clean up, painting, and valves lapped in. The barrels went off to Trigger (thanks for the great work Trig) who replaced some liners then rebored for the NOS pistons. All went back together with NE gaskets.
Only done a few miles on her, but the engine is smoke free and runs superbly. Guess it will have to wait until spring now to run her in properly. Thanks to all members that helped (or tried to help) with this problem. It can feel like a hopeless case but every problem has a cause, it just has to be found.
I treated her to a Spa day and polished everything to within an inch of its life. She looks a real lady now.
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Post by: hairygit on October 27, 2019, 10:49:49 AM
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Post by: royhall on October 27, 2019, 10:54:10 AM
Post by: hairygit on October 27, 2019, 10:59:35 AM
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Post by: Moorey on October 27, 2019, 07:26:41 PM
Post by: Rob62 on October 30, 2019, 01:07:17 PM