Member 5twins has another good phrase, "false economy". Avoid reusing questionable parts, avoid bypassing simple tasks, like decoking and valve lapping.
There's several threads in here where the owner discovers the unexpected...
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timing troubles and identification help
- Thread starter kawabunga
- Start date
Member 5twins has another good phrase, "false economy". Avoid reusing questionable parts, avoid bypassing simple tasks, like decoking and valve lapping.
There's several threads in here where the owner discovers the unexpected...
Tearing the topend down on one of these isn't that difficult but there is quite a bit of work involved getting to it since the motor must be pulled. For that reason, it's best you do all that needs doing while in there. Typically, when I go into one, I replace the cam chain, the front guide, and the valve guide seals. I lap the valves back in too because you will pretty much always find some leaking, usually the exhausts. I check ring end gaps and replace them if out of spec. If the cylinders are worn beyond spec then an over-bore will be needed. Luckily, a source of good, reasonably priced pistons and rings has been found .....
https://www.ebay.com/itm/76-82-YAMA...BPR-/141204444852?vxp=mtr&hash=item20e070d6b4
https://www.ebay.com/itm/YAMAHA-XS6...S-1-/131956383746?vxp=mtr&hash=item1eb936a002
In your research on topend work, you're going to discover that the front cam chain guide is the part that fails most often on these. It's not a mileage thing, it's due to age. The glue bond between the rubber strip and aluminum base is failing. Mine was still attached but just barely. On several others I took apart, the rubber strip had fallen right off. I've yet to find one still 100% intact. I've never found one worn through the rubber, they just fall apart .....
In order to properly replace this part, the cylinders have to come off. The guide sticks out the top and bottom of the cylinder block and there is play in the mounting holes. It's possible to mount it crooked or off center. You need to be able to measure the gap, top and bottom, between the guide and the sides of the cam chain tunnel to insure it's straight and centered .....
https://www.ebay.com/itm/76-82-YAMA...BPR-/141204444852?vxp=mtr&hash=item20e070d6b4
https://www.ebay.com/itm/YAMAHA-XS6...S-1-/131956383746?vxp=mtr&hash=item1eb936a002
In your research on topend work, you're going to discover that the front cam chain guide is the part that fails most often on these. It's not a mileage thing, it's due to age. The glue bond between the rubber strip and aluminum base is failing. Mine was still attached but just barely. On several others I took apart, the rubber strip had fallen right off. I've yet to find one still 100% intact. I've never found one worn through the rubber, they just fall apart .....
In order to properly replace this part, the cylinders have to come off. The guide sticks out the top and bottom of the cylinder block and there is play in the mounting holes. It's possible to mount it crooked or off center. You need to be able to measure the gap, top and bottom, between the guide and the sides of the cam chain tunnel to insure it's straight and centered .....
Lately, I've been getting my cam chains right from Yamaha. They seem to have about the best deal unless you happen upon a bargain on eBay. This is a Tsubaki chain which is reportedly a little better than the D.I.D. offering. It is split and comes with a master link .....
http://www.boats.net/parts/detail/yamaha/Y-94500-02106-00.html
The front guide can be a little bit more difficult to decide on. MikesXS sells a repop but there have been reports of poorly threaded mounting holes that easily strip out. I've used them in the past and had no problems but I guess I got good ones. Also, last spring I had occasion to tear down a motor we put one of the Mikes guides in about 6 years ago. Happily, it was pristine with the rubber strip still firmly attached. So, it seems the guide portion on these repops is fine, there just may be an issue with the mounting holes.
Originals are, of course, best, but they are getting hard to find, and the price has shot way up, probably because of that. The MikesXS repop is about $35. A couple years ago, originals were about $65. Now they've shot up to about $115, if you can even find one. Many sites list it as no longer available.
http://www.boats.net/parts/detail/yamaha/Y-94500-02106-00.html
The front guide can be a little bit more difficult to decide on. MikesXS sells a repop but there have been reports of poorly threaded mounting holes that easily strip out. I've used them in the past and had no problems but I guess I got good ones. Also, last spring I had occasion to tear down a motor we put one of the Mikes guides in about 6 years ago. Happily, it was pristine with the rubber strip still firmly attached. So, it seems the guide portion on these repops is fine, there just may be an issue with the mounting holes.
Originals are, of course, best, but they are getting hard to find, and the price has shot way up, probably because of that. The MikesXS repop is about $35. A couple years ago, originals were about $65. Now they've shot up to about $115, if you can even find one. Many sites list it as no longer available.
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kawabunga
XS650 Addict
Thank you for the info and links, 5twins!
Does the engine need to be pulled in order to remove just the cam cover and replace the cam chain?
Interesting. Good to know. I'm assuming this is why Gary had asked about cleaning the oil screens in the beginning of the thread. To see if there were pieces of the guide. I should look into that, I'm curious now.
Now I need to decide how far I want to take this. Like I said, I don't want to do more than is needed currently. I'm still not entirely sure what I'm going to do with the bike yet, but I do want to get it up and running. So, at a minimum, it's a new cam chain. I really didn't want to pull the head or cylinders if I don't have to.
Does the engine need to be pulled in order to remove just the cam cover and replace the cam chain?
Interesting. Good to know. I'm assuming this is why Gary had asked about cleaning the oil screens in the beginning of the thread. To see if there were pieces of the guide. I should look into that, I'm curious now.
Now I need to decide how far I want to take this. Like I said, I don't want to do more than is needed currently. I'm still not entirely sure what I'm going to do with the bike yet, but I do want to get it up and running. So, at a minimum, it's a new cam chain. I really didn't want to pull the head or cylinders if I don't have to.
You can't take the top cover off with the engine still in the frame. You can't lift it up high enough to get it off the studs before it hits the frame. If you don't do all the stuff I've mentioned now, you'll be back in there in a year or two doing it, maybe sooner. Especially if the rubber has completely fallen off the front guide. Then the chain will be running against the guide's aluminum base and grinding into it. When you change the oil, it will look like it has metal flakes in it because, well, it does, lol. You won't get chunks of metal from the guide, just ground up aluminum bits. Think of the particles produced when you file something. That's what's happening in there, the chain will be acting like a file against the bare aluminum guide.
kawabunga......................You're heading into winter. This is the perfect time to re-build the top end.
Procrastination is not your friend!
Procrastination is not your friend!
kawabunga
XS650 Addict
Yeah, I hear ya... But I need to evaluate what I want out of this bike. It's not the only project I have going on and I need to keep the budget in mind.
That's lame. I can pull the cylinders off my CB550 with the engine in the frame in about an hour. Good thing it's basically just an engine in a frame at the moment anyway. Shouldn't take much to get it on the bench.
Is it possible to inspect the state of the guide without removing the head and/or cylinders?
You could remove the sump cover and look for bits.
But can't really see much up in there.
More info in here:
http://www.xs650.com/threads/engine-noise.38994/
kawabunga
XS650 Addict
Prior to pulling the engine I figured a compression test would be nice to at least know where it was at. A bit low but at least they're pretty even.
Cold = 100/102
Warm = 113/114
One thing was odd, though. I got higher readings when I closed the throttle. The warm compression number is actually an average of open and closed throttle. The difference between the two was less than 10 psi but I thought it was peculiar...
Also drained the oil after warming it up. It was as you expected, 5twins, full of fine metal shavings.
Ive got a cam chain on order already. We'll see what I find when I get it opened up soon.
I was pleasantly surprised by how easy was to pull the engine. So that's a plus!
Cold = 100/102
Warm = 113/114
One thing was odd, though. I got higher readings when I closed the throttle. The warm compression number is actually an average of open and closed throttle. The difference between the two was less than 10 psi but I thought it was peculiar...
Also drained the oil after warming it up. It was as you expected, 5twins, full of fine metal shavings.
Ive got a cam chain on order already. We'll see what I find when I get it opened up soon.
I was pleasantly surprised by how easy was to pull the engine. So that's a plus!
kawabunga
XS650 Addict
What are your recommendations for gaskets / gasket kits? I've been looking at MikesXS, DCC, 650 Central, etc. I had some pretty bad experiences with Vesrah gaskets for my CB550, so I'm leery about using them again. Thoughts?
kawabunga
XS650 Addict
Resurrecting this since I finally found some time to get back on this project.
I pulled the cam cover off.
Can anyone verify if this is or is not the original cam chain?
Checking the cam timing.
Set to TDC
Cam sits like this.
Does this verify a stretched cam chain?
Is it possible that the timing is off by one or two teeth? If so, is it possible to adjust the timing by a tooth without breaking the chain?
I already have a fresh cam chain (master link style) from the local Yamaha dealer.
Also, I realize this image doesn't reveal much, but does anyone see any for sure signs of the chain guide being toast from the top view?
I pulled the cam cover off.
Can anyone verify if this is or is not the original cam chain?
Checking the cam timing.
Set to TDC
Cam sits like this.
Does this verify a stretched cam chain?
Is it possible that the timing is off by one or two teeth? If so, is it possible to adjust the timing by a tooth without breaking the chain?
I already have a fresh cam chain (master link style) from the local Yamaha dealer.
Also, I realize this image doesn't reveal much, but does anyone see any for sure signs of the chain guide being toast from the top view?
That's definitely off by a tooth. Looking closely at the 3rd pic, you can see the camchain lifting off the sprocket teeth at the sides of the camshaft sprocket. That would indicate a severely stretched camchain. A way to confirm would be to unscrew, or completely remove the tensioner, to see how much camchain slop there is to allow the cam to freely rotate fore/aft. When new, the camchain is so tight that you can't move the cam.
A bandaid fix would be to pop off the cam bearings, and re-index the cam.
But, don't go there.
The metal flakes in your oil means something else needs work.
A full top end overhaul would be prudent...
A bandaid fix would be to pop off the cam bearings, and re-index the cam.
But, don't go there.
The metal flakes in your oil means something else needs work.
A full top end overhaul would be prudent...
kawabunga
XS650 Addict
I did pull the tensioner out and with it removed I could rotate the cam back and forth quite a bit. I wasn't sure if that was normal or not. Sounds like a stretched cam chain then.
What is the preferred method for removing the cam chain? Is grinding a pin what most people do? Or is it worth it to buy the tool?
What is the preferred method for removing the cam chain? Is grinding a pin what most people do? Or is it worth it to buy the tool?
Most grind the peened ends off the master link like so .....
Then it's just a matter of prying the side plate off or tapping the link out with a punch, or a combination of both. If you've adequately ground the riveted pin heads off, the link taps out easily.
I think you will want the cam chain tool for riveting the new link. That's all I use mine for (not removal). Don't buy the one from Mike's, it's way over-priced. You can get pretty much the same tool off eBay for less than $20 .....
https://www.ebay.com/itm/13pc-Set-C...558162?hash=item1ec2b36f12:g:n9gAAOSwB-1YulV1
I can see that someone's been into your motor before. The red gasket sealer on the top cover joint is pretty much a dead giveaway. Yamaha used their gray colored Yamabond there. Your cam chain is most likely the original. A D.I.D. brand like you have is what is usually found in these from the factory. But I think the last guy split it then reinstalled it with a new master link. The rivet job on your master link doesn't look "factory". Also, it's facing the wrong way. I've always found them with the riveted side facing the left, or points side of the engine. Yours is facing the right or advance side.
Then it's just a matter of prying the side plate off or tapping the link out with a punch, or a combination of both. If you've adequately ground the riveted pin heads off, the link taps out easily.
I think you will want the cam chain tool for riveting the new link. That's all I use mine for (not removal). Don't buy the one from Mike's, it's way over-priced. You can get pretty much the same tool off eBay for less than $20 .....
https://www.ebay.com/itm/13pc-Set-C...558162?hash=item1ec2b36f12:g:n9gAAOSwB-1YulV1
I can see that someone's been into your motor before. The red gasket sealer on the top cover joint is pretty much a dead giveaway. Yamaha used their gray colored Yamabond there. Your cam chain is most likely the original. A D.I.D. brand like you have is what is usually found in these from the factory. But I think the last guy split it then reinstalled it with a new master link. The rivet job on your master link doesn't look "factory". Also, it's facing the wrong way. I've always found them with the riveted side facing the left, or points side of the engine. Yours is facing the right or advance side.
kawabunga
XS650 Addict
Tonight I pulled the tensioner out again to verify the cam movement. It moves a lot fore and aft. It spins just about the distance between two cam chain pins.
Thanks for the link, 5t, I’m going to order that.
There’s other signs of someone having been in there too. All the valves are labeled to their corresponding corners with sharpie. I have zero history on the bike so who knows what happened in there.
I haven’t gone past pulling the rocker cover off yet. If I’m going to go through with pulling the cylinders, any suggestions on what else I should be looking for? Common problems? Items to replace?
I’m thinking fresh rings, hone the cylinders, front cam chain guide and maybe lap the valves and new valve seals. And fresh gaskets of course. Anything else? Does the tensioner guide typically need replacing? Other seals or bearings that are worth it? I don’t want to go overboard, just fix and freshen up.
Thanks for the link, 5t, I’m going to order that.
There’s other signs of someone having been in there too. All the valves are labeled to their corresponding corners with sharpie. I have zero history on the bike so who knows what happened in there.
I haven’t gone past pulling the rocker cover off yet. If I’m going to go through with pulling the cylinders, any suggestions on what else I should be looking for? Common problems? Items to replace?
I’m thinking fresh rings, hone the cylinders, front cam chain guide and maybe lap the valves and new valve seals. And fresh gaskets of course. Anything else? Does the tensioner guide typically need replacing? Other seals or bearings that are worth it? I don’t want to go overboard, just fix and freshen up.
Posting good/crisp pics of things, especially wear surfaces, always helps. You've got dozens of eyeballs here ready to point things out...
kawabunga
XS650 Addict
I dug deeper today. To my surprise, somebody prior to me has already done the service in question. Cylinders recently honed, fresh gaskets, valves/head are very clean and what looks to be a brand spankin' new front cam chain guide.
The tensioner guide shows some wear but it doesn't look terrible.
Everything looked pretty good except for these wear marks on one cam lobe and rocker arm. They're pretty aggressive.
I'm thinking a new rocker and cam are in order. I was looking on eBay and found some reasonably priced ones. Are there certain models/years that I should be looking for? Mine is a '79 XSF. Or is there a better replacement option from a different model that is popular?
I don't want to go the performance cam route that I found on MikesXS, that's way more coin than I want to spend on this engine.
Other than the cam and rocker, I think a fresh set of gaskets and the new cam chain are all I should be needing. Unless there's something else that jumps out to anyone... It's hard to know what exactly went on and why the engine was serviced previously, but it appears that a top end refresh was completed, minus a cam chain for whatever reason. I have no idea if it was even run after the rebuild, the guy I bought it from never had it running and claimed the guy before him was doing some tinkering. The metal in the oil could be from prior to the rebuild, perhaps what prompted it, but I don't see anything indicating excessive wear at this point except the cam.
The tensioner guide shows some wear but it doesn't look terrible.
Everything looked pretty good except for these wear marks on one cam lobe and rocker arm. They're pretty aggressive.
I'm thinking a new rocker and cam are in order. I was looking on eBay and found some reasonably priced ones. Are there certain models/years that I should be looking for? Mine is a '79 XSF. Or is there a better replacement option from a different model that is popular?
I don't want to go the performance cam route that I found on MikesXS, that's way more coin than I want to spend on this engine.
Other than the cam and rocker, I think a fresh set of gaskets and the new cam chain are all I should be needing. Unless there's something else that jumps out to anyone... It's hard to know what exactly went on and why the engine was serviced previously, but it appears that a top end refresh was completed, minus a cam chain for whatever reason. I have no idea if it was even run after the rebuild, the guy I bought it from never had it running and claimed the guy before him was doing some tinkering. The metal in the oil could be from prior to the rebuild, perhaps what prompted it, but I don't see anything indicating excessive wear at this point except the cam.
Your front guide isn't new, it's been run some. There should be rubber covering both edges on the sides. It's missing on yours and the now exposed aluminum edges look a bit chewed up. The old stretched chain was probably flexing side to side and hitting them. That's probably where the metal flakes in the oil came from. See the 1st pic in my post #22 and make sure your guide still has the rubber strip firmly attached top and bottom. They can look unworn but still be coming apart.
Yes, I think you need a new cam and one rocker arm. Any '74-on cam will work but only ones up to '79 will have the bushings installed to support the advance rod. You can install the bushings in an '80 and newer cam but you must take care. Sometimes the ends of the cam split. Yamaha didn't bother finishing off the holes as well as on the earlier cams because they knew they weren't going to be pressing bushings into them anymore. Personally, I'd avoid the possible hassle and shop for a '74-'79 cam, one with the bushings already in it.
Yes, I think you need a new cam and one rocker arm. Any '74-on cam will work but only ones up to '79 will have the bushings installed to support the advance rod. You can install the bushings in an '80 and newer cam but you must take care. Sometimes the ends of the cam split. Yamaha didn't bother finishing off the holes as well as on the earlier cams because they knew they weren't going to be pressing bushings into them anymore. Personally, I'd avoid the possible hassle and shop for a '74-'79 cam, one with the bushings already in it.
kawabunga
XS650 Addict
Gotcha, I see it now. The plastic part of it looked so good that I thought it was new. My bad, but I’m glad you spotted it. I’ll poke around on it some more and report back.
Thanks for the tip on the cam. Also, are all the rockers the same for the years? Are they specific to intake or exhaust? And is it best to buy a rocker with a pin? Or is it fine to fit a new rocker on an existing pin?
Thanks for the tip on the cam. Also, are all the rockers the same for the years? Are they specific to intake or exhaust? And is it best to buy a rocker with a pin? Or is it fine to fit a new rocker on an existing pin?
I just noticed something else. Whoever installed that front guide didn't center it. Look at your last pic in post #31. The chain was definitely rubbing into the aluminum on one side. You can also see the notch it cut in the first couple pics in post #37. You have to be pretty meticulous with some parts of this motor work. "Slam, bam, thank you ma'am" just doesn't cut it, lol.
Yes, all 4 of the rocker arms are the same, no difference between intakes and exhausts, or any of the 4 for that matter. But, the arms from '72-'73, maybe even into '74, have an extra nub or boss near the adjuster screw. This was for the compression release mechanism to work against on the early electric start models .....
I wouldn't use one of those rocker arms, there's probably a weight difference. It wouldn't be a bad idea to use the original matching shaft with the new rocker arm. Those 2 parts have been run in together. But, as long as the fit was good between the new rocker arm and your existing shaft, there probably wouldn't be a problem.
Yes, all 4 of the rocker arms are the same, no difference between intakes and exhausts, or any of the 4 for that matter. But, the arms from '72-'73, maybe even into '74, have an extra nub or boss near the adjuster screw. This was for the compression release mechanism to work against on the early electric start models .....
I wouldn't use one of those rocker arms, there's probably a weight difference. It wouldn't be a bad idea to use the original matching shaft with the new rocker arm. Those 2 parts have been run in together. But, as long as the fit was good between the new rocker arm and your existing shaft, there probably wouldn't be a problem.
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