Confused about valve clearance adjustment method

[nyitguy]

Having recently acquired my '81 850, I've begun acquiring various tools, documentation, and parts that I'll need to perform a number of basic procedures. One of these will be a valve adjustment. One guide I downloaded from BikeCliff's site (http://members.dslextreme.com/users/bikecliff/images/16valve_adjustment.pdf) mentions nothing about using shims, just loosening locknuts and using a homemade tool to make the adjustment. Can someone give me a clue about which method I should expect to use on my bike? Shims seem to be expensive, for a simple slug of metal, so the prospect of a simple adjustment certainly sounds preferable.

Thanks,
Greg

 

[Brendan W]

That guide is for a sixteen valve motor. You have an eight valve with shims over buckets.
Try this one http://members.dslextreme.com/users/bikecliff/images/gs850valve_adjust.pdf

 

[JJ]

The adjustment method you are referencing is for the 4-valve engines. Your 850 is a 2-valve engine. It uses shims.

A valve check/adjustment is one of the first things you should do to one of these old bikes. Most have suffered from lack of maintenance, and the valve clearance gets smaller over time, leading to low compression, hard starting, burned valves and worse.

 

[rudeman]

Your bike uses shims to alter valve clearances. The reference to locknuts as related to valve clearance adjustment is for 16 valve engines.

You need a tappet depressor and a set of shims (or membership in the shim club) to be properly equipped.

 

[nyitguy]

Duh! The shim club sounds promising, I'll look into that.

Thanks, guys.

 

[Big Rich]

In regards to the shims just being a simple metal slug..... don't cheap out and get off brand shims. There is at least one GS500 on the Twins site that had a K&L shim crack under load, basically destroying the engine.

Shims might not be all that cheap for what you might think, but they prevent some expensive repairs later on. And besides, you really shouldn't have to swap them all out every couple thousand miles anyway.

 

[nyitguy]

I was looking at OEM Suzuki shims on ebay. I'll probably go with the club. What's awkward about the whole process is that unless you have a wide variety of shims on-hand at the moment you're checking the clearances, your bike will sit there with the valve cover off (or loose) until your shims arrive in the mail. I don't suppose that was something Suzuki could foresee back when they came up with this design, the assumption probably being that the Suzuki shop your bike was in would have them in stock. Are these the kind of part one can get from a local shop or a decent parts store?

 

[Brendan W]

Which is why this time out measure and record what shim is in what bucket. Next time you can just measure clearances, figure what if any swapping around could be done and then order new shims. Don't trust the thickness stamped on the shim. Between wear ( slight) and people grinding them down , best get a vernier caliper and double check.

 

[allojohn]

Which is why this time out measure and record what shim is in what bucket. Next time you can just measure clearances, figure what if any swapping around could be done and then order new shims. Don't trust the thickness stamped on the shim. Between wear ( slight) and people grinding them down , best get a vernier caliper and double check.

+1, measure the shims!

 

[Nessism]

Steve will be along shortly to provide you with a spreadsheet which will help you inventory your shims and keep track of the valve clearances. Once you do this you can order up some shims and anticipate your next couple of changes. Z1 Enterprises sells shims for decent prices. The clearance always goes down, not up. So, for example, if your bike has a bunch of shims in the 2.60 range you should purchase a handful of 2.55 & 2.50 shims so you can be ready for next time. The shim club is great and all, but having an inventory on hand before you begin saves a bunch of time.

 

[nyitguy]

Good advice, as usual. The Z1 prices are very reasonable. And there's other stuff there I'd like to order...better check my bank balance.

 

[hannibal]

I ordered shims from the shim club, then Z1 because I messed up the measurement. Went to install and realized I messed up again. My local dealer let me swap out my wrong shim for the correct one at no charge.