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Main Area => General GS500 Discussion => Topic started by: struckjm on September 25, 2020, 11:10:35 AM

Title: Exhaust Valve Shim Buckets WONT rotate
Post by: struckjm on September 25, 2020, 11:10:35 AM
Exhaust Valve Shim Buckets WONT rotate (to access the recess that allows you to pry out the shim and remove)

Any advice on how to get the buckets to spin? The intakes were ok, but these exhausts won't budge.

ALL CLEARANCES WERE ESSENTIALLY ZERO before I began removing shims.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: Sporty on September 25, 2020, 03:16:15 PM
Quote from: struckjm on September 25, 2020, 11:10:35 AM
Exhaust Valve Shim Buckets WONT rotate (to access the recess that allows you to pry out the shim and remove)

Any advice on how to get the buckets to spin? The intakes were ok, but these exhausts won't budge.

ALL CLEARANCES WERE ESSENTIALLY ZERO before I began removing shims.

(https://iili.io/2aYxRf.md.jpg) (https://freeimage.host/i/2aYxRf)
(https://iili.io/2aYzN4.jpg) (https://freeimage.host/)


So with the camshaft in the checking position, there is no clearance and the valve bucket won't spin?

When you rotate the engine, does the bucket follow the lobe smoothly?

If so, with the lobes in the checking position., loosen the camshaft journal caps enough that you get some clearance. Loosen them evenly, half turn at a time, diagonally. Once you have a bit of clearance they should spin.  If not, they have to be sticking in the bores. In which case, you could try spraying some penetrating oil and rotating  the engine to work it in.

If all that doesn't work, remove the  camshaft for better access.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: Joolstacho on September 25, 2020, 04:38:08 PM
Well I would be a little concerned. It could have been running with no clearances meaning a valve might have been held off it's seat, with consequent damage to valve or seat.
(Sorry to be alarmist!). What's the history of the bike? Known? or bought cheap because it wouldn't run - (possibly because of the valve issue?) There's a reason for this, the shim not spinning is probably not THE problem, but a symptom of a bigger problem. I'd certainly pull the head off to check it all.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: HPP8140 on September 25, 2020, 10:00:12 PM
Purchased a 2002 with 14k that valve adjustments had been neglected. Think I dropped down 3 shim sizes to get clearance for left exhaust valve. Bike now has 73K on it and that left exhaust valve has tight bucket.

It can be a pain, here's what I've done:


Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: struckjm on September 26, 2020, 09:51:05 AM
Thanks everybody. I rigged a iron stake into a hook and got it in there and spun it.

Both of the exhaust valve shims were 310. I got one to .10MM and one to .13mm with 255/260 shims. SO YEAH. They were way off.

Now I have about 82 and 99 PSI in the cylinders and I am trying to get it to idle/warm up and https://youtu.be/NfhHSBJIP4g
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: Joolstacho on September 26, 2020, 04:45:10 PM
You've probably got shagged valves/valveseats.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: aconti2 on September 26, 2020, 05:37:36 PM
If you decide to inspect the valves its a pretty simple process and you can pull it right out with the engine in frame. You just have to remove the breather cover to get enough clearance.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: Sporty on September 27, 2020, 05:47:04 AM
I'd recommend diagnosing the problem before tear down. 
A leakdown tester is used for this purpose.
If you don't have a leakdown tester, the compression tester hose can used to put air in the cylinder.
I took the time to write this up in the other thread.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: struckjm on September 27, 2020, 08:08:03 AM
@sporty. THANK YOU. You've been a tremendous help.

https://youtu.be/RP3eCeoiQX0

That's where we are today.
Title: Re: Exhaust Valve Shim Buckets WONT rotate
Post by: Sporty on September 27, 2020, 09:26:04 AM
Quote from: struckjm on September 27, 2020, 08:08:03 AM
@sporty. THANK YOU. You've been a tremendous help.

https://youtu.be/RP3eCeoiQX0

That's where we are today.

My pleasure.

It sounds as it running on one cylinder at lower RPM.  Try running with one spark plug wire off. See if you can isolate the weak one.

  (It should fire with 75 PSI cranking compression, so the low reading isn't the issue)