Author Topic: Smokey rebuilt 350  (Read 7843 times)

Offline Nurse Julie

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Re: Smokey rebuilt 350
« Reply #60 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.
« Last Edit: April 13, 2018, 02:25:18 PM by Nurse Julie »
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline royhall

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Re: Smokey rebuilt 350
« Reply #61 on: April 13, 2018, 02:30:48 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.
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.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)


Offline royhall

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Re: Smokey rebuilt 350
« Reply #63 on: April 18, 2018, 11:32:49 AM »
Thanks for that. Unfortunately I am now way over stock bores so cant use them.

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.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

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Re: Smokey rebuilt 350
« Reply #64 on: April 18, 2018, 12:26:35 PM »
It sounds like he's on the ball with measuring each one.

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.

Offline Trigger

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Re: Smokey rebuilt 350
« Reply #65 on: April 18, 2018, 08:21:30 PM »
0.0005" differences on pistons is standard, that is unless you are buying top quality race pistons. Same as weight differences  ;)

Offline royhall

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Re: Smokey rebuilt 350
« Reply #66 on: April 19, 2018, 08:19:57 AM »
Another potential culprit in the smoke problem is the exhaust valve guides....... The valves measure up bang on the money but they feel loose in the guides........ When I originally built the engine I checked all this, even turned some bar in 0.001" steps to check the wear from both sides. Some wear was found (3.5 thou) but it was well inside Honda's specified service limits which are stated at over 11 thou........ That can't be right, thats a back alley.......... The exhaust ports were spotless 280 miles ago now they are caked in thick black sticky carbon, that's got to be oil passing the guides. The cylinder head domes and piston tops are spotless, though very oily........ The new guides and o-rings are ordered and will be fitted by the same engineer that does the re-bores......... Also found a tiny nick (looks like a screwdriver scratch, not me) in the head face ironically between the oil feed and cylinder 4 (the really smokey cylinder). Can that be a coincidence? Going to have the head skimmed a few thou to get rid of it anyway...........I guess it's time to stop using Honda's specified wear limits as they are way too lenient, an example of which is maximum piston ring gap at 24 thou. I don't think so. No stone will be left unturned this time around, all limits will be returned to production line spec..........Whilst I'm on about sticky carbon deposits, what's the best way to remove it without damaging the paint?
« Last Edit: April 19, 2018, 08:22:11 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline Seabeowner

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Re: Smokey rebuilt 350
« Reply #67 on: April 19, 2018, 08:53:41 AM »
Lots of silly mistakes in Honda manuals.
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.
Phil
1971  CB500K0  Candy Jade Green or Candy Gold
1973  CB500K1  Candy Ruby Red
1975  CB550F1   Shiny Orange
1978  CB550K     Excel Black

Offline royhall

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Re: Smokey rebuilt 350
« Reply #68 on: April 27, 2018, 09:32:41 AM »
Been undecided what to do about the exhaust valve guides.

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.
« Last Edit: April 27, 2018, 10:48:09 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline royhall

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Re: Smokey rebuilt 350
« Reply #69 on: May 18, 2018, 03:14:14 PM »
The mystery continues.

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.
« Last Edit: May 18, 2018, 03:20:38 PM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline hairygit

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Re: Smokey rebuilt 350
« Reply #70 on: May 18, 2018, 03:36:40 PM »
Give it a while to settle down Roy, it's possible that number 4 exhaust has residual oil in it that will take a while to completely burn away, but it will still smoke while it burns it all away, it needs to get the pipes really hot for some time to remove all traces.
If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline royhall

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Re: Smokey rebuilt 350
« Reply #71 on: May 18, 2018, 03:45:18 PM »
Possibly, as I have only been around the block a few times. It's not legal until Sunday as the MOT ran out whilst it was apart. Will take it a good run next week to see what happens. It will get used a bit harder this time as the bottom end should be loosened up by now.

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.
« Last Edit: May 18, 2018, 04:24:30 PM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

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Re: Smokey rebuilt 350
« Reply #72 on: May 18, 2018, 09:44:38 PM »
What a pain Roy,  but hopefully you're closer to eliminating all the things until you get on top of it.

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?

Offline flatfour

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Re: Smokey rebuilt 350
« Reply #73 on: May 19, 2018, 12:38:01 PM »
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.

If you need them, let me know.

Offline royhall

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Re: Smokey rebuilt 350
« Reply #74 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.

If you need them, let me know.
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.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

 

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