stupid PO...no timing chain tensioner...

[Guest]

So when I first purchased my GS750EN, I went through and did a valve adjustment, which it needed pretty badly. When the cover was off, I noticed that there were witness marks on the underside of the valve cover from the timing chain hitting it. Everything seemed to check out though, and then it got all wintry out and school got hectic and I put it on the back burner. Meanwhile, I noticed that the tensioner was leaking some oil, so I figured today was as good a time as any to take it apart and fix it. Using the guide created by a GSR member, I bought the seals and spring and such, and when I went to do the first step of tightening the set screw...it wouldn't turn. Not at all, tighter or looser. So I said screw it, I'll pull the whole thing off and then deal with it. Well, I take the tensioner off...and the plunger is in its fully compressed removal position. The set screw was so tight that I had to use a torch and vice grips to get it freed up.

So long story short, my GS has been running for some unknown amount of time with essentially no timing chain tension. It's a miracle it didn't jump time and destroy the engine... Now it's all put back together, and the engine suddenly sounds nice and quiet. Being used to old vehicles, I never realized how much noise it was making. Stupid previous owner... don't start turning the damn screws unless you know what they do!

[sedelen]

Wow, that was a ticking time bomb had you not found it?

[bwringer]

This is quite common -- on about half the timing chain tensioners I encounter, some idiot in the past has tightened the setscrew all the way.

It is sort of a strange mechanism, but why do so many people monkey with it if they don't understand it?

[tkent02]

It is sort of a strange mechanism, but why do so many people monkey with it if they don't understand it?

Same reason they take perfectly good engines apart to fix electrical or carburetor problems:

"I always wanted to fix a motorcycle!"

[sedelen]

This is quite common -- on about half the timing chain tensioners I encounter, some idiot in the past has tightened the setscrew all the way.

It is sort of a strange mechanism, but why do so many people monkey with it if they don't understand it?

Yeah, on the '79 GS1000E owners manual on page 41, it says it's an Automatic Cam chain tensioner, never needs serviced or checked.
Also there's a warning underneath, don't turn the wheel (dial knob).
I've got to believe that's an open invitation to some people to "mess"
with it.

[gearheadE30]

I guess so... I mean, the setscrew on mine was so tight that it actually flared the face of the pushrod slightly, and it took a vise, vicegrips, and a torch to get it out. You gotta try really hard to do that...makes me wonder if the PO or someone in the bike's past thought that that screw actually was the tension or something. On my honda at least, you aren't supposed to leave it backed out. You back it out and let it adjust, and then tighten it again, so who knows. Maybe they thought it was like that.

I took it for a ride today (sunny and 45; about as good as it gets in February) and it sounds way better, but now it's got a bit of a whine to it, mostly at idle. I'm not sure what that's about, but I'll assume it's significantly less of an issue than not having a tensioner, hah.

[sedelen]

I guess so... I mean, the setscrew on mine was so tight that it actually flared the face of the pushrod slightly, and it took a vise, vicegrips, and a torch to get it out. You gotta try really hard to do that...makes me wonder if the PO or someone in the bike's past thought that that screw actually was the tension or something. On my honda at least, you aren't supposed to leave it backed out. You back it out and let it adjust, and then tighten it again, so who knows. Maybe they thought it was like that.

I took it for a ride today (sunny and 45; about as good as it gets in February) and it sounds way better, but now it's got a bit of a whine to it, mostly at idle. I'm not sure what that's about, but I'll assume it's significantly less of an issue than not having a tensioner, hah.

Do believe that was true for Honda's, at least it rings a bell on the CB450 I had. It probably always had that whine, since it's quieter now, you can now hear that.