timing chain issues

[joker88]

So we get to the next issue with the Slingshot. I have i slight knock in the engine at idle, goes away after 2.500. had a bit of a poke around and found that my cam chain tensioner is wound out as far as it can go, i.e chain has stretched past limits. does anyone have another explanation i might be missing. there doesn't seem to be any excessive vibration that would indicate a big end gone or something like that. the problem, i am unsure of what i'm facing to change it. i have fair amount of experience with most mechanical things but have never had my head in a gs twin engine and don't want to have to pull whole engine down to change the cam chain. would anyone happen to know a few tricks they would be willing to share to make the job a bit easier, and please don't say take it to mechanic, because they over charge and i haven't won lotto yet.

[Big Rich]

Are you sure the chain tensioner hasn't seized? IIRC, they are fairly simple to pull off and replace/fix if needed. Also, I think it was Burning1 that said he has never heard of the cam chain being out of spec. But if it is, you wouldn't have o tear the whole motor down - just take the headcover off. As long as you can get a rivet type chain, you could just cut the old one and fish the new one in.

[joker88]

yeah already had tensioner off and checked it out, it works perfect. spring is still tight and moves along complete lenght easily. it actually doesn't look like it original, it may have been changed by owner??? i also checked it on bike, which is quite finicky, but i wound it loose and slowly let it out and it seemed like it went as far as it could. also a couple of days before tapping started there was a whirring noise coming from bike which both me and mechanic thought sounded like timing chain. so..... i'll replace chain and hope it stops and if it don't i'll look else where i spose, process of elimination

[gsJack]

Infamous GS500 camshaft knock?

Knocks only when hot, only at idle, stops when idle speed is picked up to 2k or so.  Harmless.

Bike year and milage?

[joker88]

this one is knocking even when cold. stops when lifts over 2.5k. she is a 89 bike with a 91 engine with 40,000 km on it.

[adidasguy]

Junior, my red 1992 does the same. Always has. Runs really well and super smooth. Its just that famous GS500 cam shaft knock. Give even a little throttle and it goes away.

[joker88]

i'm gonna change timing chain to be on safe side i think, had some bad experiences trusting that others maintain their bikes the way i do mine. THAT A HUGE MISTAKE IF YOU HAVEN'T DONE IT YOURSELF IT NOT DONE. and i don't have funds to replace pistons and valves if they collide. found oem chain online for 110 to my door.

[adidasguy]

When in doubt, put in new parts (or newer parts). I do the same. When working somewhere, if I can upgrade parts in the same area, I do it - just in case.....  Nothing wrong with that.

When Junior (my cool red 1992 Canadian bike) had a fork leak, I put on 2009 forks. Put in new springs at the same time. And while I was at it with the forks, changed the front brakes to 2009 ones I had, new master cylinder (2009 also), SS brake line and a few other minor things. When something is taken apart, it is easy to do everything at once rather than taking it apart again and again and again.....

I had Junior checked out by Aurora Suzuki (superb mechanics there!) and they said Junior was one of the best running GS500's around. If the knocking at low RPM in neutral was abnormal, they would say.

The knocking is the cam shafts bouncing left and right. In newer models, they added a spring on the end of the shafts to eliminate that. Older bikes can be upgraded with the newer spring loaded end spacers. (Saw that in a service manual, as an addendum, and also said newer bikes can not have the older parts. Makes sense.)