Valve clearance drift

[Guest]

Just trying to get a feeler from some of the experienced members here.

How often are shim changes required? I know to check every 4-5000 miles, but how often does a shim change?

I ask because my most recent clearance adjustment, just after I got the bike, was a pretty big range of shims from 2.30 to 2.75.

If the clearance changes every couple of times, and the thinnest shim is a 2.20, theoretically, I can only get another 10-20K miles out of this cylinder head before a rebuild.

I sometimes commute on the bike, and my commute is 120 miles round trip, so I can burn miles quick doing that.

[bwringer]

I check my valve clearances every 4,000 miles, and the usual pattern is that I need to change one or two shims every other check. My bike sees a LOT of high-rpm use.

The experiences of other 8V owners I've talked to are about the same.

[Steve]

The last check of the valves on my wife's bike showed that only one valve needed a shim change, and that was only one size. And, that was after about 20,000 miles of no changes.

The difference in shim sizes in interesting, but if that's what it takes to get proper clearances, so be it.

Here is where I make an unashamed plug for my spreadsheet. You already have a copy, it is easy to look at the records to see what has changed, and how often. Generally, they will change the most right after any head work has been done or new valves installed (which might explain the different shim sizes), then will "settle in" and not require much attention for quite a while.

.

[86turbodsl]

Ok, this lends me a bit of comfort. I don't have any history with GS's. This 850 is my first. I just wanted to get a feel of how long I can expect to go between major head rebuilds.
Very helpful. Thanks!