Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: ebmbiker on February 09, 2022, 01:35:52 PM
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Good afternoon chaps,
Newbie member JB here,
I've bought a 500K2 project bike that's already been dismantled by the previous owner 10 years ago. Including the engine.
I know I need new main crank shells as I've only got 4 of the originals, the rest are missing. Besides seals and gaskets, what else am I going to need whilst I'm doing it? It's been decades since I've done any engine building, and those were 2 stroke singles. So what's the list of 'whilst you're in there' things to do?
Cheers, JB
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Apart from the piston/rings checking (cruzinimage on ebay are quality/cheap) change primary chain/rubber dampers (kawasaki chain is same and cheaper) (http://www.sohc.co.uk/index.php/topic,25977.msg238189.html#msg238189). Camchain (DID) and use genuine camchain train rollers/tensioners. Check gearbox bearings but generally serviceable. Check clutch pushrod as they are known to break (NurseJulie usually stocks them)
Check cams/rockers/bearings for wear.
Ex Honda technicians will be along shortly with detailed advice
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Phil pretty much nailed it.
Buy a set of JIS screwdrivers, most important thing. Also see if you can find them in socket version.
Camchain, genuine no longer available unless your lucky, I'm looking into whether you can use a DID 219FTH chain instead as it's stronger than the standard DID chain and cost is very low considering. Check tensioner blade, guide is usually ok, check tensioner adjuster screw slot, see if it's mangled.
Primary chain, buy the Kwack chain it's 92057-1011, half the price of Hondas and the same chain. Check the oil gallery running under the chain to see if the chain has been hitting it, replace the damper rubbers inside the primary drive hub, you'll need an impact driver to open that.
Check all roller bearings for notchiness and general motion. There are only 4.
Replace all o-rings and seals if possible, you'll need a rotor tool to remove the rotor to replace the one behind it or borrow one.
Check camshaft for wear on lobes and wear on journals, check the head for the wear as well. Check cam followers for wear, if in doubt post a pic on here for advice.
DON'T use an impact driver to remove the tacho drive housing, especially the one holding the cable in, you'll break the housing most likely, check to see if it comes out intact, a lot don't.
Check sump bolt thread in oil pan.
If in doubt, take a picture before dismantling, remove in sequence then reassemble after removal to make sure you know how it goes, use elastic bands if possible to keep things together. Watch when removing the gearbox from the cases, the ends will fall off if your not careful meaning you can't be sure how they went on.
Sounds like a handful but TBH these engines are easy to work on.
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estamos ansiosos esperando.
lo primero que necesitas es el manual de servicio
y revisar todo completamente
we are anxiously waiting.
the first thing you need is the service manual
and check everything out completely
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Phil pretty much nailed it.
Buy a set of JIS screwdrivers, most important thing. Also see if you can find them in socket version.
Camchain, genuine no longer available unless your lucky, I'm looking into whether you can use a DID 219FTH chain instead as it's stronger than the standard DID chain and cost is very low considering. Check tensioner blade, guide is usually ok, check tensioner adjuster screw slot, see if it's mangled.
Primary chain, buy the Kwack chain it's 92057-1011, half the price of Hondas and the same chain. Check the oil gallery running under the chain to see if the chain has been hitting it, replace the damper rubbers inside the primary drive hub, you'll need an impact driver to open that.
Check all roller bearings for notchiness and general motion. There are only 4.
Replace all o-rings and seals if possible, you'll need a rotor tool to remove the rotor to replace the one behind it or borrow one.
Check camshaft for wear on lobes and wear on journals, check the head for the wear as well. Check cam followers for wear, if in doubt post a pic on here for advice.
DON'T use an impact driver to remove the tacho drive housing, especially the one holding the cable in, you'll break the housing most likely, check to see if it comes out intact, a lot don't.
Check sump bolt thread in oil pan.
If in doubt, take a picture before dismantling, remove in sequence then reassemble after removal to make sure you know how it goes, use elastic bands if possible to keep things together. Watch when removing the gearbox from the cases, the ends will fall off if your not careful meaning you can't be sure how they went on.
Sounds like a handful but TBH these engines are easy to work on.
Cheers Oddjob, exactly what I wanted to know. Unfortunately, the engine was already in pieces when I bought the bike so I didn't have the opportunity to photograph and label things. The cam lobes, followers and journals are all smooth with no visible damage. I can see that the primary chain has marked the case, but not much. I'll post a photo of it once I'm back in the workshop.
Cheers, JB
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Here's a photo of the marks in the lower case from the primary drive chain. Thoughts?
Cheers, JB[attachimg=1]
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Thats about as bad as it can be, its the groove at the topp right in the angled bit that is the problem.
Will be OK with new chain and damper rubbers.
Rubbers are still available to order from any Honda dealer
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Yep, that's a bad un. Almost through the oil gallery, there are some things you can do.
First replace the chain and damper rubbers, that will stop it rubbing for a good while.
Replace the chain every 30K at least, sooner is better. You can't take a chance anymore as any more damage will mean a new set of crankcases.
Fit a CB650 primary chain tensioner, these can be hard to find but it's a mod worth doing, especially with that damage, you need a special bracket making to fit the tensioner. This is a mod I'm doing on my engine when it's next in pieces, which will be this year sometime. I had 2 of the brackets made as the engineer didn't want to make only one so I had to tempt him with 2. Cost me £50 each but one is spare if you ever go this way.
I'd replace the roller bearings on the primary drive as well, all that alloy flying around is bound to have gone into the bearings and the chain must have really been whipping around to do that much damage and that would have been hard on the bearings, for the cost, replace them.
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Ive always wondered if youcould machine a steel tube to line that gallery and slide it in
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Not sure Bryan, I was cleaning one the other day and I think it goes round a corner so maybe not.
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Blimey, that was a close shave 😱😱😱😱 I think we have had at least one, maybe 2 that have been worse than that but that's up there with them.
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Well I’m glad I showed you guys the damage. Is it worth getting the bad scar over the oil gallery built up with weld?
Oddjob, do you have a drawing of the 650 primary tensioner bracket mod you’d be willing to share? Machining is my background so I’m pretty sure I could make one.
Cheers, JB
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Yeah got it somewhere.
Will post when I find it.
Here you go.
(https://i.postimg.cc/wMKBN7Nx/drawing.jpg) (https://postimg.cc/475Zk4wj)
Would a picture of the finished article help?
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Well I’m glad I showed you guys the damage. Is it worth getting the bad scar over the oil gallery built up with weld?
As long as you don't melt into the tunnel, yep if you can do it.
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Yeah got it somewhere.
Will post when I find it.
Here you go.
(https://i.postimg.cc/wMKBN7Nx/drawing.jpg) (https://postimg.cc/475Zk4wj)
Would a picture of the finished article help?
[/quote]
Interested in a photo please Ken
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Ok here Phil.
(https://i.postimg.cc/hjSYr7z4/IMG-2487.jpg) (https://postimg.cc/B8VNZbBR)
(https://i.postimg.cc/YS7DrmxN/IMG-2488.jpg) (https://postimg.cc/YvXz80Zj)
(https://i.postimg.cc/V6L7MQpd/IMG-2490.jpg) (https://postimg.cc/2qMFRJzD)
(https://i.postimg.cc/nrNT6szD/IMG-2491.jpg) (https://postimg.cc/PvzmD51X)
I've included the 650 primary chain tensioner in the last 2 pics so you can see what to look for. One bracket is attached to it.
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here it is all
http://forums.sohc4.net/index.php/topic,80690.25.html
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Thanks Ken and Murdock
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la parte dificil es conseguir el tensor
the hard part is getting the tensioner
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Indeed it is. I couldn’t readily find a tensioner so decided against the mod.
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Cheers for the drawings and info guys. This really is a very helpful forum!
I’ll try and find a 650 tensioner before I make the bracket. I reckon once everything is replaced in the primary drive it will be good for years to come as I won’t be doing lots of mileage. The one thing that I’m picking up from reading the posts on the forum is regular oil change, and using good quality oil.
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I also think you should consider how your bike will be used and mileage you will be do. My American inport 500k2 (with 11000 miles indicated but not authenticated - so at least that mileage I would guess) had no marks on the cases. I replaced the chain/dampers but I am unlikely to get that mileage on the bike before I snuff it so probably not worth me doing the mod.
There's a few members on here who have done 100,000 plus miles and would be interested to see what their cases are like? I will vary with use and maintenence I suppose
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aqui hay un poco mas sobre el tensor
here is a little more about the chain tensioner
http://www.sohc.co.uk/index.php?topic=11741.0
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Old topic I know but I was looking at some old Kwack primary chains today and noticed that the ZX600 I think it was also had a primary chain tensioner fitted that looks a lot like the CB650 one, it may not be identical but it could be made to work I reckon.
https://www.ebay.co.uk/itm/203865918192?hash=item2f775b0af0:g:JYcAAOSwMS9iLNR~
https://www.ebay.co.uk/itm/373566567673?epid=1323120587&hash=item56fa4d74f9:g:ltoAAOSwFFhgkKt2
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Managed to spot and buy a 650 primary chain tensioner today. It came with a knackered primary chain, of course it may not be knackered but seriously who'd take a chance fitting an old one.
I'll now bung the tensioner and bracket on Ebay unless someone on here wants to buy them both.