cam chain tension with worn front guide

[XSGLENN]

So I've had my 1980 xs650 for a couple of months, After rebuilding the carbs, replacing coil, spark plugs, caps and wires she's running good still a little tuning but I'll get there. Also I adjusted the valves and cam chain. When changing the oil I noticed the black plastic chunks and a small amount of aluminum shavings from the front cam chain guide. I plan to replace it in a few months, but right now the tensioner is set with the recommended 1-2 mm of movement. Was wondering if it would be smart to loosen it to say 3 mm to help reduce front guide wear? The only concern is jumping timing or the motor running poor with a loose chain. Is this something you would try, or should I just run it as is. Also after aluminum shavings show up how long before it completely destroys the front guide. Is this something that will last a few hundred miles or a few thousand?

 

[jd750ace]

If it's already into the metal, you run the risk of sending a chunk, rather than shavings, careening around in the cases. A chunk can possibly just go to the bottom and rest, or get flung up into a position to possibly break the cam chain or get slammed through your case if it gets into a tight clearance area with a dynamic component. ANYTHING making metal in an engine is a cease and desist for me personally, but especially with this screen equipped motor. You are processing shavings every revolution. Just because we find it all in the bottom does not mean that it falls down there and never gets kicked up through the system.

 

[XSLeo]

I agree, it should be changed soon. It may or may not crumble into chunks but why risk it.
Running the chain loose is never a good thing. Poor running and excess noise result.
Leo

 

[5twins]

Yes, keep the cam chain properly adjusted. If loose, it will rattle around even more against that already worn front guide.

 

[XSGLENN]

Y'all make a good point, and I already hear a metal to metal grinding noise so I'm sure it's long over due for replacement. Looks like I'll be ordering parts this week. What's the chance I can reuse the head gasket? Also what are the must have parts. If it helps i plan to Just remove the head using carpenter shims. I'd like to keep cost down because I plan to rebuild late winter or early spring.

 

[I am Carbon]

What's the chance I can reuse the head gasket? super slim to none.
if it were me
cam chain, guide, cam chain tensinor, lower cylinder gasket,and the orings, head gasket, rings if needed, inspect everything, for wear or damage..Im sure I missed something.

 

[jd750ace]

What's the chance I can reuse the head gasket? super slim to none.
if it were me
cam chain, guide, cam chain tensinor, lower cylinder gasket,and the orings, head gasket, rings if needed, inspect everything, for wear or damage..Im sure I missed something.

+1. Why bust it open twice? It's not exactly a Saturday afternoon job to do it right. More of a weekender. The only other thing I can think of would be exhaust head pipe gaskets. Many people attempt to re-use them, few succeed in getting them to seal a second time.

 

[5twins]

New ones will re-seal multiple times, but not the 30 year old originals, which is what many of these guys choose to use. Buy a tube of silicone sealer. Be sure you use the whole thing on that old head gasket, lol.

 

[jd750ace]

New ones will re-seal multiple times, but not the 30 year old originals, which is what many of these guys choose to use. Buy a tube of silicone sealer. Be sure you use the whole thing on that old head gasket, lol.

Which size JB weld kit should I get when I do this?

 

[Brian902]

New ones will re-seal multiple times, but not the 30 year old originals, which is what many of these guys choose to use. Buy a tube of silicone sealer. Be sure you use the whole thing on that old head gasket, lol.

Will this size be enough for one head?

.

 

[XSGLENN]

Man, ya'll gave a even better ideal..... I've got a gallon of roofing tar and a gasket making kit around here somewhere. If I take my time I think it would work, Hell I could repair the guide with rubber and self tapping screws . LOL
Yeah, I guess it was a dumb ass question about the head gasket Damn I set myself for the kill on that one! LOL! But all jokes aside, For some reason I thought the gasket itself was $50 but looking back I can get the complete kit for that. Guys I know it sounds like it but I'm not the half ass type. I know going in the motor twice will suck, but I don't have the funds to do a complete rebuild right now. Couple hundred I could do. Correct me if I'm wrong but I'm guessing a full top end rebuild would be at least a grand.

 

[Brian902]

Back to business;

Best case, you replace cam chain guide, head gasket, base gasket and possibly valve cover gaskets. Forgot if it has seals or gaskets or both.

Exhaust gaskets, no problem, if they leak after using tons of roofing tar, replace. External repair, easy.
Edit: don't worry about valve cover gaskets, if they leak, just another external repair, easy.

While apart, examine what you have and make the winter list for the complete re-build.

Ride on.

 

[5twins]

If you do the work yourself, about $200 should cover it. That will get you gaskets, front guide, cam chain, and rings. Check the valves for leaks and hand lap them back in if need be. Another guy here recently did a quickie topend job and was back in there about a month later because of the valves. He never bothered checking them the 1st time in there and they were leaking bad. It wasn't too much longer before they were leaking too badly for the bike to run right.