Potentially damaged cam chain tensioner

[divlukic]

I brought my 1978 XS650SE into my mechanic to fix a charging issue, and they told me they heard a noise that they didn't like and tried to diagnose that instead. They also noticed some plastic and metal debris in the oil filter. They think the issue is the cam chain tensioner, which they told me they adjusted, but quoted me $1800 to tear it down and inspect/replace the cam chain tensioner entirely. They're recommending that I do not ride the bike at all. I'm not sure how much they actually believe that it is in unridable condition versus how much they just want to get another job from me. My plan is to change the oil and the oil filters to get rid of the metal bits and ride it around the city at low to medium speeds for the next week or so and then change the oil again to see if there's more metal in the new filter / oil that would indicate there's still something grinding away at the tensioner or something else.

Does this sound like a good way to diagnose this issue myself without spending all that money on a tear down? Is this an incredibly unsafe plan? Have any of you had similar issues? Worst case scenario, does anyone have experience changing a cam chain tensioner themselves and if so, how arduous was that process?

The bike also is only at 13,000 miles, so I'm skeptical that it would need a full engine tear down at such relatively low mileage, I thought the big draw of these engines was that they were reliable for much longer distances without such intensive maintenance / rebuilds.

I've attached a video of the engine running while warm, just in case anyone can diagnose something based off of the sounds. The RPMs hang up a little when I rev it so I know I need to mess with the carbs a little too, but I'm including the video just in case it helps anyone help me.

https://imgur.com/72oImoP

 

[Jim]

That whine is typical of what it sounds like when you "scissor" (bend) the crank. Easiest way to check is pull the right cover and look at the end of the crank as you spin it. You'll see the wobble.

 

[divlukic]

That whine it typical of what it sounds like when you "scissor" (bend) the crank. Easiest way to check is pull the right cover and look at the end of the crank as you spin it. You'll see the wobble.

Do you mean the round oil filter cover on the right side? If it is wobbling, does that indicate a problem with the crank shaft as well as the cam chain tensioner guide?

 

[divlukic]

Update to the original post: I believe it’s the cam chain guide that they think needs to be replaced, not the tensioner itself, since that’s one of the only plastic pieces that would’ve been grounded away and collected in the oil filter

 

[Jim]

No, the large cover over the clutch.
Fwiw, the chain guide is a known issue related to the age of the bike more so than the milage. If your '78 hasn't been replaced, then yes, it's likely bad. That requires pulling the engine and rebuilding the top end.
Having said that, when the plastic's gone off it, it sounds like badly adjusted valves. That's not your sound, yours is a whine... almost like a gear whine... and as I said, it's usually associated with a scissored crank.

 

[divlukic]

No, the large cover over the clutch.
Fwiw, the chain guide is a known issue related to the age of the bike more so than the milage. If your '78 hasn't been replaced, then yes, it's likely bad. That requires pulling the engine and rebuilding the top end.
Having said that, when the plastic's gone off it, it sounds like badly adjusted valves. That's not your sound, yours is a whine... almost like a gear whine... and as I said, it's usually associated with a scissored crank.

Ah, thanks for the clarification. Hate to hear that about the scissored crankshaft, really hope it's not that. If I do see a wobble like you said, how would you recommend to proceed from there?

 

[Jim]

If the crank's scissored, your options are to buy a second hand crank or have somebody rebuild that one.

 

[Jim]

really hope it's not that.

So do I... just callin' balls and strike here as I see (hear?) 'em.

 

[Its been a long time]

And while you're doing the crank, it's time to do the cam chain guide and all the other stuff that you do while the engine is apart.

 

[JJames]

Exactly what Jim Says. That sounds horrible. Yes, the cam chain guide likely is bad, but definitely not the cause of that noise. I'd be a bit skeptical of a shop that missed that one. What were they going to do after the $1800 repair and it's still jacked?

 

[cra-z1]

Time to get a manual, pull up your big boy pants and dig into it yourself. Builds self esteem and very gratifying when done. Cranks are out there but you still have to be careful as the used one can be bad also. These guys can recommend shops who do the work. Or cut your losses and sell it as is if you're not mechanically inclined. I would not pay a shop as most of them are incompetent to say the least, unless you want to go down that rabbit hole.

 

[JJames]

Adding my 2cents
If you want to own an XS or any (older) motorcycle. You're going to have to learn to work on it yourself. Even if you don't consider yourself mechanically inclined, if you can follow directions, have a manual and some basic tools, you're on your way. As cra-z1 says, very gratifying. Granted. The deeper you get into the engine, you will need a few more tools and hopefully but not absolutely necessary, a covered space to do repairs. All of this may cost less than a single shop visit where IMO they are as likely to break it as fix it. Last but not least. Don't underestimate the wealth of knowledge and experience found on this site. Doing some homework here will pay off in spades as there is basically no aspect of XS repair that is not covered here in detail, with photos by folks who know there stuff. Anyhow, if you're up for it, the XS is a great bike to learn on and a hoot to ride once you get it sorted. Have fun.

Time to get a manual, pull up your big boy pants and dig into it yourself. Builds self esteem and very gratifying when done. Cranks are out there but you still have to be careful as the used one can be bad also. These guys can recommend shops who do the work. Or cut your losses and sell it as is if you're not mechanically inclined. I would not pay a shop as most of them are incompetent to say the least, unless you want to go down that rabbit hole.