Sensible engine decision (now top end refresh)

jetmechmarty

jetmechmarty

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This engine came out of my 1983 XS650SK. It came out of the frame for an oil change. I broke a pan bolt and had it repaired by a machinist. While the bottom case was off, I replaced the transmission because I broke a dog off more years ago than I can remember.
OK, this engine runs fine. It pulls just fine. It smokes. It has 57,372 miles on it.
So, first thing I did was put an engine in the frame that I bought in 2003, condition unknown. It runs fine, but the fwd cam chain tensioner foot has lost the plastic bit and must be replaced. So, I have to pull it and take it apart to fix that. I operated it for 1.4 miles and it ran fine.
I just discovered the thread on replacing valve seals without tear down.

So, what would you do? Replace the foot and go, or replace valve seals and go? I would prefer to put off restoration of this motorcycle and just keep riding it. I have others I wish to resurrect first.
 
Stand.... open the carbs....... if it runs.... do a cold and a warm..... toss in some light oil.... see if it comers up.. if it does.. usually indicate rings..... with that much mileage.... it's due for some attention.
 
motormike said:
Stand.... open the carbs....... if it runs.... do a cold and a warm..... toss in some light oil.... see if it comers up.. if it does.. usually indicate rings..... with that much mileage.... it's due for some attention.
Click to expand...
I realize that, but I want to put it off. I have some other bikes I have more interest in right now. First on the list is an XS650E. The '83, I'd just like to ride as is a bit longer.
 
Jeez, Marty, if you have to pull the head to replace the tensioner anyway (and you really need to do that before something unfortunate and costly happens to the ancient cam chain), why not save time and effort and do the needful while you're in there? At that mileage you already know that the cylinders need rings and honing at least, and maybe a bore job for oversized pistons. If you want to check compression on the stand, clip the negative terminal of a battery to a fin and jump the positive terminal to the starter motor. Of course doing the top end would ruin the motor for doing double duty as a mosquito fogger, which could be especially important in your neck of the woods....Hope to see you and Robin in 2021--stay well!
 
grizld1 said:
Jeez, Marty, if you have to pull the head to replace the tensioner anyway (and you really need to do that before something unfortunate and costly happens to the ancient cam chain), why not save time and effort and do the needful while you're in there? At that mileage you already know that the cylinders need rings and honing at least, and maybe a bore job for oversized pistons. If you want to check compression on the stand, clip the negative terminal of a battery to a fin and jump the positive terminal to the starter motor. Of course doing the top end would ruin the motor for doing double duty as a mosquito fogger, which could be especially important in your neck of the woods....Hope to see you and Robin in 2021--stay well!
Click to expand...
Dick, you misunderstood. I have two engines and I want to put off the inevitable and devote the time to something else right now. I replaced the engine in my Special. It has a bad tensioner. The original engine is just tired. I'd just as soon make the smoke go away and drive a while longer. Doing it the right way probably won't happen right now. I would rather spend the time and money on something different. So maybe I'll just mothball the bike since it looks like there may not be any rallies anyway. It may be the best option.
 
Sorry, Marty, I didn't read carefully enough. Re. the smoke, if it's smoking all the time, not just on startup or under engine braking, it's probably troublesome oil rings, not just valve stem seals. Oil rings can cause grief even if compression rings are good. Yep, with the virus on a tear, there probably won't be any rallies; there for sure won't be any for me, Ann and I staying home. We feel really lucky to have 16 acres of woods to isolate on, can't imagine what folks in city apartments are going through.
 
Tsubaki makes a more durable cam chain than DID (thicker pins). The Tsubaki "peanut" cam chain offered by 650 Central is stronger than the OE DID. Michael got a batch of them cheap and is passing along the savings--$39 plus the ride. It's designated an "endless" chain, I don't know why. I bought one, and it's an open chain with a rivet master link, just like any other.
 
You can get the "normal" style (oval side plates) Tsubaki chain from Yamaha cheaper than from Mike's .....

https://www.partshark.com/oemparts/p/yamaha/94500-02106-00/chain

Although not mentioned in the description, the ones I've gotten so far have all been split and included the master link. Take the money you save and buy a cam chain rivet tool off eBay. They can be readily found for less than $20, another big savings over the one MikesXS sells (which is essentially the same thing).

https://www.ebay.com/itm/New-13pc-C...485024?hash=item2f4d11f3a0:g:skIAAOSw7AhfmQ4B
 
Last edited:
5twins said:
You can get the "normal" style (oval side plates) Tsubaki chain from Yamaha cheaper than from Mike's .....

https://www.partshark.com/oemparts/p/yamaha/94500-02106-00/chain

Although not mentioned in the description, the ones I've gotten so far have all been split and included the master link. Take the money you save and buy a cam chain rivet tool off eBay. They can be readily found for less than $20, another big savings over the one MikesXS sells (which is essentially the same thing).

https://www.ebay.com/itm/New-13pc-C...485024?hash=item2f4d11f3a0:g:skIAAOSw7AhfmQ4B
Click to expand...

Regarding chain tool
I fumbled trying to rivet the cam chain. I have done it without a tool many years ago . But not this time
Cant remember how I did it So I ordered a cheap tool. Perhaps this on the link.
The first one I got ..The punch was not in line with the other side.
Got a replacement .. no problems ..and got the job done .. But the quality of the tool was such that if I should do it again I would pay a bit more.
 
Jan_P said:
Regarding chain tool
I fumbled trying to rivet the cam chain. I have done it without a tool many years ago . But not this time
Cant remember how I did it So I ordered a cheap tool. Perhaps this on the link.
The first one I got ..The punch was not in line with the other side.
Got a replacement .. no problems ..and got the job done .. But the quality of the tool was such that if I should do it again I would pay a bit more.
Click to expand...
Yes, that tiny pin is easy to break. BTDT

I’m going to cut the chain and throw it away. The riveter side of the tool is stout enough to do the job. If I were a professional motorcycle mechanic, I wouldn’t have this junk. As often as I need it, it’s fine.
 
Nice, better quality replacement pins are available from Motion Pro .....

https://www.motionpro.com/product/08-0058

I discovered this when I made the mistake of loaning my tool to the ham-fisted kid down the street so he could rivet the master link on his sport bike chain. He buggered the end of the riveting pin all up, lol. But, this really turned out to be a blessing in disguise. The Motion Pro replacement works much better than the original ever did because the rivet tip has a better shape. It's a bit more tapered and flares the link pin ends much nicer.
 
5twins said:
I discovered this when I made the mistake of loaning my tool to the ham-fisted kid down the street so he could rivet the master link on his sport bike chain.
Click to expand...
The first time I did this, I borrowed the tool kit. The tiny pin was broken, so I bought one. Then, I broke it. I bought yet another and returned the kit intact.
Thanks for the tip!
 
Normally, I don't use this tool for breaking chains, just riveting. Yes, the pin for the small sized cam chain is tiny and easy to bend or break. Usually I just grind the chain pins flush with the side plate and then pry the plate off. Grinding the pins flush is a good idea even if you are going to use the breaker tool. It greatly reduces the strain on it. I have a larger chain braking tool I use for drive chains but even with that, I grind the link pins flush first. I learned this lesson years ago because I broke the pin on that larger tool, lol. Luckily, I was able to grind the tip square again and repair it but now I take these precautions to ease the strain on it.
 
5twins said:
Normally, I don't use this tool for breaking chains, just riveting. Yes, the pin for the small sized cam chain is tiny and easy to bend or break. Usually I just grind the chain pins flush with the side plate and then pry the plate off. Grinding the pins flush is a good idea even if you are going to use the breaker tool. It greatly reduces the strain on it. I have a larger chain braking tool I use for drive chains but even with that, I grind the link pins flush first. I learned this lesson years ago because I broke the pin on that larger tool, lol. Luckily, I was able to grind the tip square again and repair it but now I take these precautions to ease the strain on it.
Click to expand...
Yeah, I agree. I always grind to pins first too. It's just easier that way.
 

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