1981 gs650g tappet clearance, insight needed please

[Guest]

So I have this '81 gs650g that I've slowly been working on, here's the skinny. Bike last saw the road in 2002 and has been in a garage since..... sitting. At at a point now where I decided to check tappet clearances. I have 2 out of 6(one intake & one exhaust) that are coming in at .03mm and the other 6 are <.03mm. Engine has less than 7500mi. on it, all head bolts are torqued to spec, my feelers are good, is there something I'm missing or could this just be possible and it's time to replace shims?

[cowboyup3371]

Yes it is possible and you need to complete the valve adjustment. Check out the Shim Club in the GS Services area for new shims and email Steve (username and real name) for his spreadsheet

[phydeauxmutt]

Very common. With 7500 miles on it, it has probably missed its 600, 1000, 4000 and 7000 mile services. You probably caught it before any major damage has been done.

Do you have a proper service manual? If not, go to BassCliff's site and get one. Follow the proper procedure for checking clearances, the off-brand manuals are rather confusing on how to do that properly. Look up member "Steve" and look at the offer in his signature for a spreadsheet that helps you figure out what shims you will need. Very handy tool, but you need to check your clearances properly for it all to work right.

Clearances will always tighten up, so it's normal for them to get smaller. You will have to inventory your shims, you might be able to swap some around to minimize how many you will need to purchase. When you have your shims inventoried, take the thinnest one out, put a coin (quarter, half-dollar, etc.) in its place and move that shim to the other spaces to measure the clearance. You might get a better idea what shims you will need. Whatever you do, DO NOT ROTATE THE CRANK UNLESS THERE IS SOMETHING IN EVERY SHIM BUCKET. If you leave a shim (or coin) out, the edges of the cam lobe WILL be damaged.

[Duttry98]

Thank you all for the quick responses! Yes I have a factory service manual that I acquired from a shop going out of business. First thing I bought after getting the bike LOL. I also have BikeCliff's site always ready at the helm! I just wanted to make sure this was a normal situation I'm in before dumping loot into a shim tool and shims if they were to do me no good right now.

[SVSooke]

http://members.dslextreme.com/users/...ol_zip_tie.pdf I have used this and it works.

[tom203]

http://members.dslextreme.com/users/...ol_zip_tie.pdf I have used this and it works.

Me too, twice! Buy the tool, but I found its use difficult with just two hands.

[Duttry98]

WOW, that Shim Club deal is awesome! I've currently been in touch with Steve and he's given a copious amount of info.

I'm gonna cup the balls here and just say this site and members are simply outstanding. I appreciate all the useful and friendly insight I've received this far. CHEERS!

[Duttry98]

Here's the numbers I have to share. The first number is what the shim is, the number in parentheses is what it read via my caliper, the third number is the feeler gauge reading. Here we go.....
#1 exhaust.... 2.70 (2.71) .02
Intake.... 2.70 (2.70) <.02
#2 exhaust.... 2.85 (2.87) <.02
Intake.... 2.70 (2.71) <.02
#3 exhaust.... 2.70 (2.58) <.02
Intake.... 2.70 (2.72) .04
#4 exhaust.... ??? (2.78) <.02
Intake.... 2.70 (2.71) .04

Thoughts???

[Nessism]

those valves with less than .02 may need to move two sizes. I'd plan on it even. I'd get a handful of 2.60's, a couple 2.65's, and a 2.75

[1_v8_merc]

I like my valves on the extra loosey side, haha.

[tkent02]

Did you do the "spin the bucket" trick?

From another thread the other day:

The shims only come in .05mm increments, you can't just go .08mm smaller. Do this, see if the shim bucket will spin in it's bore with light finger pressure when the cam isn't depressing the shim. If the bucket will spin easily there is at least some clearance, so go one size smaller, .05mm. Replace the 2.70 shim with a 2.65 for example. This should leave you with something over .05mm clearance.

If it won't spin at all theres less than zero clearance, go two sizes smaller, which is .1mm. Replace the 2.70 shim with a 2.60. This should get them all in the ballpark. This should give you at least .05mm clearance on all.

Might leave you with a few above .08mm clearance, might be up to .10mm, but that's OK. A lot of us go for .05 to .10mm clearance anyway. It works fine.

The ones that won't spin could be so tight that a .10mm thinner shim still doesn't give any clearance, if so do it again. Usually that's not the case on engines that run OK, it they were that tight it likely would have burned the valve.

[Duttry98]

I did not do the "bucket spin" trick, but I did stay at a Holiday Inn Express once LOL! Steve gave me some solid info on what to do last night. Right now I'll just buy a bunch of shims from Z1 Enterprises, jump on board with the shim club later.... when it's time to do the 425 and 650 again later.

One thing I noticed last night when going thru all the shims, #1 intake shim was extremely "blued" compared to the rest. That tells me it was getting hot there! Anything to be concerned about? Possibly burnt valve?

[tkent02]

A burnt valve wouldn't get the bucket hot let alone the shim. What does that cam lobe look like? I bet the blue shim came from a different manufacturer, although I've never seen a blue one.

Z1 will take forever, their service is no good anymore. Ray will send his shim club shims right away.

[Duttry98]

Cam lobe, all of them actually, look great.

[tkent02]

Got a pic of this blue shim?