1977 XS650D Top End Noise

[zoomoto]

hey fam!

I’m posting a video of how my bike is currently running. I know these bike are notorious for being noisy but I feel like mine has gradually gotten louder over the last 500 miles I put down since buying the bike.

Like I mentioned, 1977 XS650D. Just adjusted cam chain tension flush with adjuster at full extension when warm (I may readjust), cold set intake valves to .002 (going to reset to .003 probably after more research) and exhaust are set to .006 per my Clymer Manual. I just did an oil change as well.

Oil level was a little low and I noticed a carb boot leak. So i took off the airbox, carbs, and boots. I cleaned everything, set cam chain tension, set valve clearance, changed oil, etc.

Any input would be incredibly valuable and I’m happy to provide any additional information. I just wanna ride out the rest of the season before it ends! Thanks!

 

[zoomoto]

Also. I noticed this was made as a thread and not a post. Sorry to an admin’s out there! Getting used to the site.

 

[MaxPete]

Oooooo.....that sounds like a toasted front timing chain guide to me - rather than the cam chain tensioner which is on the rear of the timing chain.

The tensioner seldom ever seems to give any trouble, but perhaps I'm a little over-sensitive after my recent experience.

Pete

 

[zoomoto]

Oooooo.....that sounds like a toasted front timing chain guide to me - rather than the cam chain tensioner which is on the rear of the timing chain.

The tensioner seldom ever seems to give any trouble, but perhaps I'm a little over-sensitive after my recent experience.

Pete

Yeah dude, I’m like 4 pages into your thread right now, hahah. That was my thought upon further reading. I put a few miles on it this morning to diagnose a few things. I’m gonna sift my old oil and check for plastic from the guide. Recheck clearances and tension and keep trying to check more things off the list.

Is there an easy way to confirm that is the issue?

 

[nj1639]

The bike sounds great, aside from that noise.
Check for aluminum bits in the side strainer......behind the round section on the right engine case.

 

[5twins]

How did you adjust the cam chain? By the book method with the motor off? It's easy to screw it up that way and get the chain too loose, in which case it can rattle like loose valves. Best, easiest, and most foolproof method to check/set the cam chain tension is to do so while the engine sits there running at idle. Remove the acorn cover nut on the adjuster and observe the plunger in the end of the adjustment bolt. Properly set, it should bounce in and out a little, maybe a MM or so. If it's not moving at all, the tension is too tight, if bouncing in/out more than about a MM, it's too loose.

You can tighten the adjuster up real tight momentarily so the rod virtually stops moving, then back it off to get the little bit of movement you want. You can also demonstrate to yourself what a too loose adjustment sounds like by loosening the adjuster way up until you get increased topend clatter.

You should probably pull the adjuster screw and rod out and check to see if the copper damper washer is there. It'll tick without it. I don't know what happens to them but many seem to go missing.

Unfortunately, there's really no way to inspect the front guide while the motor is still assembled. Your idle speed seems a bit high, maybe lowering it to around 1100 would quiet things down some.

Also be aware that your '77 most likely has the notorious type D cam chain adjuster assembly, the one with no lock nut. If that's true then I would put upgrading to the later type E tensioner on your "to do" list.

 

[zoomoto]

How did you adjust the cam chain? By the book method with the motor off? It's easy to screw it up that way and get the chain too loose, in which case it can rattle like loose valves. Best, easiest, and most foolproof method to check/set the cam chain tension is to do so while the engine sits there running at idle. Remove the acorn cover nut on the adjuster and observe the plunger in the end of the adjustment bolt. Properly set, it should bounce in and out a little, maybe a MM or so. If it's not moving at all, the tension is too tight, if bouncing in/out more than about a MM, it's too loose.

You can tighten the adjuster up real tight momentarily so the rod virtually stops moving, then back it off to get the little bit of movement you want. You can also demonstrate to yourself what a too loose adjustment sounds like by loosening the adjuster way up until you get increased topend clatter.

You should probably pull the adjuster screw and rod out and check to see if the copper damper washer is there. It'll tick without it. I don't know what happens to them but many seem to go missing.

Unfortunately, there's really no way to inspect the front guide while the motor is still assembled. Your idle speed seems a bit high, maybe lowering it to around 1100 would quiet things down some.

Also be aware that your '77 most likely has the notorious type D cam chain adjuster assembly, the one with no lock nut. If that's true then I would put upgrading to the later type E tensioner on your "to do" list.

It totally does have the good ol’ Type D tensioner. Hahah it’s officially on my list of updates, hahah

I set the cam chain tension with engine on the bike, engine warm but not running. I’ll reset that per your recommendations here when I get home. I’ll check for the copper spacer as well.

The bike doesn’t like idling that low at the moment. I was going to address that in order of chain tension, valve clearance, timing, and then carbs to see if I can’t figure that out. For now I’m not passed the first two

Thank you so much for the help. It’s very encouraging to find an active forum with passionate members.

Updates to follow

 

[zoomoto]

Turns out the spacer was left behind on my work bench. Ooooops. Takes ya once to learn, hah.

 

[zoomoto]

I popped it in and now my adjustment rod barely moves at all compared it how it used to. Is that correct??

 

[5twins]

Yes, that looks better, sounds better too. No need to pull the whole housing off like that to check things, you can just remove the screw/plunger/spring parts from it.

 

[zoomoto]

Yes, that looks better, sounds better too. No need to pull the whole housing off like that to check things, you can just remove the screw/plunger/spring parts from it.

Awesome! Super helpful to know.

Yeah this is so quiet compared to before. I honestly thought I had made it too tight or something, hahah. Alright! Now onto ignition timing! Thanks Twins

 

[MaxPete]

WOW - what a huge difference in sound!

Congrats zoomoto - that is a great outcome from what could have been a long expensive fix! My bike definitely had a pooched front guide, but yours appears to be in great shape now just by adding in that little copper washer.

Awesome!

Pete

 

[zoomoto]

WOW - what a huge difference in sound!

Congrats zoomoto - that is a great outcome from what could have been a long expensive fix! My bike definitely had a pooched front guide, but yours appears to be in great shape now just by adding in that little copper washer.

Awesome!

Pete

Yeah, man! The more I get into vintage bikes and cars the more I learn about their mechanics and tolerances. Funny what 2mm of copper will do! Hahah.

I appreciate you documenting and sharing your journey with the fam. I already have learned so much from it.