Slipping gear? Maybe bad valve adjustment?

[Owen8]

Hi everyone,

I’ve posted before but on a different issue that I have now resolved. Anyways, I ride a 1978 xs650 and have done the following. It’s been completely rewired, full carb rebuild and clean, has been timed, and has new coils and spark plugs.

My most recent job was adjusting the valves. The bike was riding great but I would hear constant valve chatter which I thought was due to my valves being too loose. After adjusting the valves and triple checking if I got my specs right (.004 intake and .006 exhaust) I still run into this same problem. it sounds like a clanking mess and the bike revs around 3-4k in gears 3,4 and 5 even though I’m going max 40mph. I’ve heard this could be dude to a slipping clutch. But it’s hard for me to believe that’s the issue because it ran perfectly find until I messed with the valves. Any thoughts on what could be the issue?

Thank you all for your help,
Owen

 

[jetmechmarty]

Did you adjust the valves with the engine stone cold? It has to be cold.

 

[jetmechmarty]

Does it sound like the video?

Does the engine RPM increase while the speed does not increase? That would be clutch slipping.

 

[Owen8]

Does it sound like the video?

Does the engine RPM increase while the speed does not increase? That would be clutch slipping.

Yes sir sounds just like that! And I did adjust when engine is cold. The speed does increase… however, I’m having to shift through my gears really quick to avoid reving the engine too high and the max I can go is 40-45mph in 5th gear without pushing it past 4k rpm

 

[jetmechmarty]

Yes sir sounds just like that! And I did adjust when engine is cold.

That's the front timing chain guide. See if you can adjust the timing chain. You have to nearly run out of adjustment if it has delaminated.

 

[Owen8]

That's the front timing chain guide. See if you can adjust the timing chain. You have to nearly run out of adjustment if it has delaminated.

Sorry for my lack of knowledge but is that the cam chain? And what do you mean by nearly run out of adjustment? Sorry I’m a beginner!

 

[Owen8]

I also want to add that I just found one of my valve covers is missing a O ring. Could that be the reason for the lack of power?

 

[nj1639]

We need some overall pics of yer bike. It'd be helpful.
O ring missing will just leak oil.
Cam chain gets checked and adjusted if needed and then valves, always.
At high speeds and extended miles I'd probably check those in that order if I was hearing noises.
Good tech menu in the forum with lots of info on cams and adjustment,

 

[jetmechmarty]

Sorry for my lack of knowledge but is that the cam chain? And what do you mean by nearly run out of adjustment?

https://www.xs650.com/threads/cam-chain-tensioners.1056/

 

[Owen8]

https://www.xs650.com/threads/cam-chain-tensioners.1056/

So i followed the instructions on how to adjust the cam chain. Still nothing I also adjusted my clutch just in case my clutch was slipping…still nothing has changed.

Here is how the bike sounds after the cam chain adjustment and valve adjustment. It sounds alright when it is idling but when its time to ride the thing it’s hard to listen to… I refuse to believe it’s my carbs because I’ve rebuilt them twice now and they are extremely clean. Running out of ideas on what it could be.

 

[jetmechmarty]

So i followed the instructions on how to adjust the cam chain. Still nothing I also adjusted my clutch just in case my clutch was slipping…still nothing has changed.

Here is how the bike sounds after the cam chain adjustment and valve adjustment. It sounds alright when it is idling but when its time to ride the thing it’s hard to listen to… I refuse to believe it’s my carbs because I’ve rebuilt them twice now and they are extremely clean. Running out of ideas on what it could be.

I fail to hear the offending noise.

 

[Raymond]

Sounds like a good un in your vid, @Owen8 - can you give us a bit more description of how the sound changes when you're under way? Can you replicate the hard-to-listen sound with the bike on the stand and post a recording?

 

[Owen8]

I fail to hear the offending noise.

Exactly it sounds fine while idling but as soon as it gets up and running it runs like complete shit and sounds like an old sewing machine.

sorry hard to ride with one hand but I have to shift the bike super quickly to avoid redlining it. I would say if I want to get up to 30-40mph I’m shifting the bike from 1st to 2nd when going about 8-10mph then 2nd to third when going 10-15mph then 3rd to 4th when going 20-30mph then 4th to 5th when going max 40mph.

 

[jetmechmarty]

How do you feel about pulling the engine and going in? Before doing that, check both screens for aluminum shavings. Right now, I'm thinking front cam chain guide. It is a job, but not insurmountable for a novice.

 

[Owen8]

I would feel pretty confident, If I wasn’t in college right now and working with a limited amount of tools.

I’ve never taken apart an engine but would I only have to take off the bores to access the cam chain? Is there any videos on how to replace the cam chain? And how much would a cam chain replacement cost in parts?

 

[Its been a long time]

I would feel pretty confident, If I wasn’t in college right now and working with a limited amount of tools.

I’ve never taken apart an engine but would I only have to take off the bores to access the cam chain? Is there any videos on how to replace the cam chain? And how much would a cam chain replacement cost in parts?

Engine has to be removed from the frame.

 

[Owen8]

Would I be able to lift it out myself? I saw a pretty good video on this form of a guy that is doing the replacement for a cam chain. His is on a 1980 mine is a 78 would that change any of the steps? I also just don’t want to get into anything like that until I I can determine that is for sure the problem.

 

[Its been a long time]

Would I be able to lift it out myself? I saw a pretty good video on this form of a guy that is doing the replacement for a cam chain. His is on a 1980 mine is a 78 would that change any of the steps? I also just don’t want to get into anything like that until I I can determine that is for sure the problem.

I couldn't lift it myself. But you might be a lot younger and stronger. I suggest you look at the various write ups in the Technical Reference section of this website. They're excellent. As far as I'm aware, a camshaft job on a 78 and an 80 model are essentially the same if not identical.

 

[jetmechmarty]

I would feel pretty confident, If I wasn’t in college right now and working with a limited amount of tools.

I’ve never taken apart an engine but would I only have to take off the bores to access the cam chain? Is there any videos on how to replace the cam chain? And how much would a cam chain replacement cost in parts?

There are many videos on YouTube covering XS650 engine overhaul in detail. And, you have us. First, pull the screens. There should be debris in there.

 

[Its been a long time]

There are many videos on YouTube covering XS650 engine overhaul in detail. And, you have us. First, pull the screens. There should be debris in there.

+1 definitely this ^^^^