GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: oldguy on June 25, 2003, 07:43:00 PM

Title: A word of caution...
Post by: oldguy on June 25, 2003, 07:43:00 PM
Just got finished rebuilding the top end of my 1990 GS500E.  The cam-chain tensioner spring snapped at the shaft, and the chain loosened.  The exhaust cam jumped the chain, and both ex valves hit the piston, bending them.

With 21K mi. I decided to put rings in it, and new gaskets.  Parts came to about $225, including a NEW cam chain tensioner($47).

My GS was VERY old, and I SHOULD have replaced the tensioner before this.  So should you.  A very costly PM mistake.

Hope info helps.
Title: A word of caution...
Post by: nsoccer3097 on June 25, 2003, 08:30:45 PM
what does the cam chain tensioner do and how much and difficult is it to replace?  is it "prevenative" maintenance?
Title: A word of caution...
Post by: glenn9171 on June 25, 2003, 09:55:41 PM
Cam chain tensioner (CCT) in layman's terms keeps the chain that makes the valves go up and down nice and tight.  It the spring breaks like his did, the chain could become loose enough to jump off of the sprockets inside the engine.  Nothing but bad news. :cry:

If the spring starts to get slack, you start hearing it knocking inside the engine.  Makes a sort of clicking noise.
Title: A word of caution...
Post by: Mizen on June 25, 2003, 10:10:14 PM
Uh oh....  since my GS is a 91, abused, salvaged title, bought at 29k miles and currently pushing 42k miles....

maybe I should replace the CCT? ;)

It's leaking anyway.... is it a hard job? Can you leave the valve cover on, and just remove the carbs to access the CCT and then swap it out?

Thanks for any input!  :cheers:
Title: A word of caution...
Post by: davipu on May 27, 2005, 12:32:55 AM
good info,  bump
Title: A word of caution...
Post by: dgyver on May 27, 2005, 05:36:55 AM
you must be bored.... bringing up a 2 year old thread
Title: A word of caution...
Post by: cheesy on May 27, 2005, 06:15:16 AM
Quote from: dgyveryou must be bored.... bringing up a 2 year old thread

prolly cause he's awesome at searching.
Title: A word of caution...
Post by: ubul on May 27, 2005, 06:29:26 AM
Yeah, good info. Better than starting a new thread.
I will need to check everything on my GS, since I bought it from a guy who didn't know how to maintain a bike. At least he cleaned it well.
Title: A word of caution...
Post by: sys49152 on May 27, 2005, 07:04:09 AM
Whoa - talk about coincidence.  I bought a cam chain tensioner yesterday for the CBR.  I did a bunch of research before figuring out what the heck the problem was!  I should have just searched this forum :oops: .

On the CBR you get a nasty rattling sound between 3-6K RPM.  Almost like a million ball bearings jumping around inside your engine.  It doesn't happen when the bike is standing still and revved.  Only when it's moving.  Turns out it's a common problem on the pre 2001 CBR's, and Honda had a recall.  The new one will hopefully fix this problem.

From what I understand though, if you've got a manual tensioner, which I believe the GS has, it's highly unlikely that you will ever need to replace it -- it usually outlasts the bike from what I've read.  I contemplated putting a manual tensioner instead of the automatic honda one, but since it was really cheap, I thought I'd give the honda one a try.
Title: A word of caution...
Post by: goat on May 27, 2005, 07:37:30 AM
The GS has an automatic tensioner. You can get manual ones but the stock one is spring loaded.