Honda-SOHC
SOHC.co.uk Forums => Project Board => Topic started by: taysidedragon on May 23, 2020, 10:59:25 AM
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I bought a spare engine to overhaul or use parts from for my main engine.
It was reasonably cheap and you can see why from these photos! The tappet covers have been chiselled so hard that one has a hole in it. There's an awful lot of orange silicon gasket on the crankcase join.
I wonder what horrors I will find inside? 😳☹
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Ohhhh, what horrors lurk inside? If it’s just chiselled tappet covers and a bit of orange gunge on the oil filter and joints , ho hi, you’ve got a great spare. Have fun.
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I bought a spare engine to overhaul or use parts from for my main engine.
It was reasonably cheap and you can see why from these photos! The tappet covers have been chiselled so hard that one has a hole in it.
That one on the right looks ok - hopefully you didn't end up buying the world's most expensive used-but-good tappet cover... ;D
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Just take the cam cover off, you will know immediately if its a boat anchour
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Ewww. Not much expertise in evidence.
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Some good news, some bad.
The cam, followers and bearing faces are good. Plenty of oil in evidence. The valves look like new.
The engine hasn't run since being assembled. Combustion chambers and pistons are as clean as a whistle.
However, original Honda pistons look like they've been scraped with a knife, badly scratched crowns.
The bores are smooth and clean but no sign of any honing. The rings look new and the camchain tensioner horseshoe is free.
I'll get measuring in my next visit.
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Could have new rings but not been glaze busted, you can do that with an appropriately sized flap wheel
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Didn't do much today, I had an essential trip to Durham! 🤣
I did find this though. I guess they didn't have a clutch nut tool. 🤨[attach=1]
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Some people should not be allowed to even touch a motorcycle, let alone work on one
Sent from my Moto E (4) Plus using Tapatalk
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I must admit to having had to do similar, but not that bad, back in early 70's when special tools just were not available to buy unless you were a franchised Honda dealer and they would not order the "special" tools for you even if you were prepared to pay the high price
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This is brutal
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This is what was behind the oil pump. 😫
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This is what was behind the oil pump. 😫
Is that yellow mastic 😥😥😥😥
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Orange Heretite silicone i think Julie
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Orange Heretite silicone i think Julie
It could be Bryan. We have found bathroom sealant, white and clear, gutter sealant in black and grey and a green substance which was unidentifiable whilst stripping customers engines. Its always a mystery what we are going to find next 😁😁😁 Unfortunately, the use of these types of goo usually indicate what has not been done correctly within the engine itself by some previous owners.
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Hermatite Bryan, or Instant Gasket as it was named then.
Worst basket nut I've ever seen.
If you need some new points screws I've just got some, come with captive flat and spring washers. £2 for the 6 needed inc P&P.
Thanks for the points screws offer. I'll let you know if I need them. 👍
I'm going to split the cases tomorrow, so far not a single stripped thread!
I hope I haven't put the fluence on it now. 😕
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Thats my damn dyslexic fone again Ken i meant Hermetite.
Julie the green stuff, if it was hard and flaked off was probably Green Hermetite, fairly common on the old Brits along with Red
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Ken you are mixing eras there
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This engine has had a chequered past! It's been opened at least twice before. There is red Hermetite in a lot of places, then some black engine paint remnants on top of the Hermetite. Some of the engine paint even got inside the cases. 😯
The Orange silicone sealant was used the last time the engine came apart, it's horrible.
The primary chain guides had washers underneath them between the guide and the case. These aren't shown on the parts diagram so I assume they shouldn't be there.
Was this an attempt to 'raise' the guides and take up some slack in the worn primary chain? The guide fixing bolts were mostly non standard.
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Just out of interest, the manual says to replace camchain if 6mm longer than standard, but I can't find the standard length published anywhere.
I'm not going to use the old camchain but curious about how worn it was.
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Just out of interest, the manual says to replace camchain if 6mm longer than standard, but I can't find the standard length published anywhere.
I'm not going to use the old camchain but curious about how worn it was.
Lift the chain off of the cam sprocket and if you can see a gap between the top of the sprocket and the underside of the chain, it's well beyond spec. But to answer your question, I have no idea where it says in the shop Manual or Haynes just how long it should be 🤔🤔🤔
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I did that before dismantling and there was some play, but I didn't pay much attention to that because there was no tensioner clamp bolt and the horseshoe was stuck.
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I had a happy ending over the weekend, no, not that kind of 'happy ending!' 😁
I was preparing the cylinder head for painting and had to remove the rock hard carb rubbers from the inlet stubs. The screws would not budge. JIS screwdriver bits, releasing oil, impact driver, heat. None of them would budge the screws so I had to drill the screw heads to remove the rubbers. That left the threaded stubs sticking out of the inlets. I thought they would be a challenge to remove, but they came straight out, threads clean as a whistle!
The screw heads must have been 'welded' to the rubbers and that was the only thing stopping them coming out. I was very relieved. 👍
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Bullet dodged! 8)
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After dismantling and inspecting my spare engine I found that it needs nearly everything replaced. New pistons, rings, rebore, conrods, shells, primary and cam chains and at least one gear so it's been put back on the shelf.
I took my fitted engine out and dismantled it to find it is in better condition overall and just needs new rings, primary and cam chains. New parts to be ordered and engine re-assembled.
I wish I'd started with the fitted engine first, but it was easier to start work on the engine that was already out and on the workbench.
One thing I found on both engines was the pistons had been numbered backwards with numbers scratched inside the piston skirts. Now I know that as long as the components were put back in the same cylinder they came from it doesn't really matter, but it worries me that they might not have been put back right. What else was done wrong? Is this something that is often found when opening these engines? It really bothers my OCD! :o
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I forgot to mention the camchain tensioner. The horseshoe was stuck and the loose camchain was grinding on it quite badly. Luckily I have a good one to replace it with. 👍
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"I had a happy ending over the weekend, no, not that kind of 'happy ending!' 😁"
;D ;D ;D
Helping a friend with making a patio once, his diy instructions called for "4 yards of well rammed aggregated hard-core" to which I thought, that's certain to make someone's eyes water! :)
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"I had a happy ending over the weekend, no, not that kind of 'happy ending!' 😁"
;D ;D ;D
Helping a friend with making a patio once, his diy instructions called for "4 yards of well rammed aggregated hard-core" to which I thought, that's certain to make someone's eyes water! :)
Ouch! 🤕🤕🤕
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There is quite a lot of play on my Countershaft bottom gear and a small amount on Mainshaft top gear.
Is this normal or do they need replacing/rebushing?
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There is quite a lot of play on my Countershaft bottom gear and a small amount on Mainshaft top gear.
Is this normal or do they need replacing/rebushing?
Can anybody give me some advice on this? New gears are available from CMSNL but over £200 each! Any idea how much it's likely to cost to get the bottom gear rebushed?
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I can't really offer any advice other than I thought it was common on most Jap bikes of that era to have a lot of backlash, I certainly remember it was mentioned a lot it road tests at the time.
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On the notes I got with my 400, the previous owner but one mentions fitting a new bush to first gear. Unfortunately there is no receipt for this and I can't get hold of him. So not much help except it can be done.
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Ok. Thanks for the replies. Ive checked several gearboxes and first gear is the same on all of them
so I wanted to check if that was excess wear or not. The bushes don't look very worn so it may be ok.
I don't suppose anybody has the bore size of a new gear do they?
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Difficult, without being there, to accurately feel what it's like.
As Dave mentioned, there's a fair amount of movement in gearboxes but in the right direction. They are after all fairly crude, but effective, by nature of design.
What shouldn't happen is for you to move the gear radially as the teeth would vary in mesh to it's pair, which is not acceptable.
Because of their compact nature, some gears are in effect stabilized by it's neighbouring gear which is moved into "dog" engagement with it. Left in neutral, you can't fully see that support, but of course the gear takes absolutely no torque load until it's in use for that ratio.
Also a straight cut gear imparts no sideways loading to the gear itself, so no inherent drive to push it out of alignment.
To summarise, you shouldn't be able to take one individual gear and move it radially on it's shaft so that it goes away from running concentric. That's worn, but slight wobble will be present for many.
A bit long winded, but hopefully give you a little help to check.
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Difficult, without being there, to accurately feel what it's like.
As Dave mentioned, there's a fair amount of movement in gearboxes but in the right direction. They are after all fairly crude, but effective, by nature of design.
What shouldn't happen is for you to move the gear radially as the teeth would vary in mesh to it's pair, which is not acceptable.
Because of their compact nature, some gears are in effect stabilized by it's neighbouring gear which is moved into "dog" engagement with it. Left in neutral, you can't fully see that support, but of course the gear takes absolutely no torque load until it's in use for that ratio.
Also a straight cut gear imparts no sideways loading to the gear itself, so no inherent drive to push it out of alignment.
To summarise, you shouldn't be able to take one individual gear and move it radially on it's shaft so that it goes away from running concentric. That's worn, but slight wobble will be present for many.
A bit long winded, but hopefully give you a little help to check.
Thanks. There's no noticeable movement radially but I can rock the gear on the shaft, worse on the large 41 tooth gear, but that might seem worse because of the bigger diameter.
I'll try to take a video later.
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There's a consideration too about where the load travels if you want to look while in there.
The "bushed" gears only ever run on their bushes by rotating on the shaft when NOT in use as a ratio. Once you select that gear to use it in drive train then either it or it's neighbouring gear slides to connect via the face dogs. Then the torque passes through the teeth and as far as the dogs, then divert into that paired gear and so onto the gearshaft to give output.
It doesn't much matter with some free play as it'll orient itself on the dog faces once changed, it's initial alignment comes from it's opposing gear, and it, having straight teeth that take out misalignment when spinning together.
If you put it in the gear ratio in question, then look at the load path it'll show this.
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There's a consideration too about where the load travels if you want to look while in there.
The "bushed" gears only ever run on their bushes by rotating on the shaft when NOT in use as a ratio. Once you select that gear to use it in drive train then either it or it's neighbouring gear slides to connect via the face dogs. Then the torque passes through the teeth and as far as the dogs, then divert into that paired gear and so onto the gearshaft to give output.
It doesn't much matter with some free play as it'll orient itself on the dog faces once changed, it's initial alignment comes from it's opposing gear, and it, having straight teeth that take out misalignment when spinning together.
If you put it in the gear ratio in question, then look at the load path it'll show this.
Cheers. Makes sense. 👍
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Play on countershaft first gear.
https://m.facebook.com/groups/cb400f/permalink/3369540299765998/
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All the parts I need for the rebuild have arrived and the gear bush is sorted.
Primary drive rubbers and gasket set not in picture. Let the fun begin! 😁[attachimg=1]
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All those parts look reassuringly expensive :)
Don't forget the Hondabond for the case joint!
Time to make a cuppa and get started on the adventure :D
Good luck and keep the progress photos coming.
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Luverly..... Enjoy
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All those parts look reassuringly expensive :)
Don't forget the Hondabond for the case joint!
Time to make a cuppa and get started on the adventure :D
Good luck and keep the progress photos coming.
Yep. Got a tube of Hondabond HT. Forget to put it in the pic.
I haven't added up the cost yet, but got the Kawasaki primary chain from MSP, piston set from Cruzinimage
and o-rings etc from Nurse Julie so did quite well on prices. 👍🔧🏍
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All the parts I need for the rebuild have arrived and the gear bush is sorted.
Primary drive rubbers and gasket set not in picture. Let the fun begin! 😁 (Attachment Link)
Eye candy - lovely what make are the pistons and who did you source them from I'm pretty certain I might end up needing some early next year.
?
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All the parts I need for the rebuild have arrived and the gear bush is sorted.
Primary drive rubbers and gasket set not in picture. Let the fun begin! 😁 (Attachment Link)
Eye candy - lovely what make are the pistons and who did you source them from I'm pretty certain I might end up needing some early next year.
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The pistons are unbranded Japanese from Cruzinimage. They seem good quality and a very good price.
They arrived after just 6 days!
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Hope you can post some pictures and details on fitting the pistons to the barrels. In my mind it looks impossibly fiddly presumably having to fit two at the same time then the second pair fighting against the weight of the barrels unless you have the engine on it's side.
It looks as though gudgeon pins just push through the piston & the little ends with a clip on each side or are they an interference fit as well?
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it looks impossibly fiddly presumably having to fit two at the same time then the second pair fighting against the weight of the barrels
Like everything it takes some practice :)
Just cut some wooden blocks to the right size to support the barrels halfway up, and take your time.
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Hope you can post some pictures and details on fitting the pistons to the barrels. In my mind it looks impossibly fiddly presumably having to fit two at the same time then the second pair fighting against the weight of the barrels unless you have the engine on it's side.
It looks as though gudgeon pins just push through the piston & the little ends with a clip on each side or are they an interference fit as well?
Will do - if I've got a spare hand!
The gudgeon pins sometimes need a bit of heat on the piston to slide in or out.
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All those parts look reassuringly expensive :)
Don't forget the Hondabond for the case joint!
Time to make a cuppa and get started on the adventure :D
Good luck and keep the progress photos coming.
Yep. Got a tube of Hondabond HT. Forget to put it in the pic.
I haven't added up the cost yet, but got the Kawasaki primary chain from MSP, piston set from Cruzinimage
and o-rings etc from Nurse Julie so did quite well on prices. 👍🔧🏍
Did a quick add up. Comes to just over £300, a bit more than I thought!
I've still got to get a couple of small things like new Dowty seals for the head.
The ones that were on it are well past it.
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£300 for all those parts, you've done very well.
There was a thread on here about replacements for those dowty washers but I can't find it!
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I'd like to think my inevitable engine rebuild could be done in that budget!
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It would have been a lot more if I'd needed new main or big end shells. 😊
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Finally getting around to reassemble my engine. I've been delayed by the central heating boiler going on the blink, now I have to get a new boiler. 🤨
Anyhow, crankcases assembled and torqued down. Primary shaft and gear fitted then kickstart shaft and spring hooked up. New pistons fitted after checking ring gaps in the bores. Cylinders on, I fed the pistons and rings in by hand, middle ones first. They went in without any bother, one ring at a time, working the cylinders down gradually. I was very relieved when they were all in, no breakages! 🙂
Cylinder head on and torqued down. Making progress, should be finished soon. 👍
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This all brings back memories of my engine, with the exciting stage of getting it all back together. That was 3 years ago, where have they gone 😢😢😢😢
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Time flies when you have fun Julie, or so they tell me! Just got back from 8 days in wet Cornwall and cant figure out where the days went
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This all brings back memories of my engine, with the exciting stage of getting it all back together. That was 3 years ago, where have they gone 😢😢😢😢
Julie, your engine rebuild file has been a great help for me. I've delved into it a few times to confirm something that I wasn't sure about. Thanks. 🙂🔧🔩