Not quite right...

[DaveT.]

I have been helping a co-worker get his 1980 GS850G running for the last year. So far, it's not quite right...

Here is the situation. Carbs had green stuff floating in them, so we rebuilt all 4 with new kits. We also replaced the intake boots. Got it running pretty good so we thought. Upon further inspection, I found #1 cylinders exhaust pipe only about 1/2 as hot as the others. Next, my friend said it was like it was running on 3 cylinders.

So today, we did a compresson test on #1 cylinder. Only got 90-100 psi. Hell, I pulled the spark plug (new spark plugs and 1 cap) and it ran the same. I checked the #4 cylinder and we only got 100 psi. We figured out it will not run over 5000 rpm's without the airbox on. I did put on the velocity stacks only, but still would only get up to 5k's. With the airbox and stock foam airfilter in, it runs great, but #1 cylinder still seems suspect.

Checked the plugs, #1 was clean like new, #2 was a perfect tan, #3 was like #1 but with a little tan and #4 is dry with soot. I also check the valve clearance and only found #2 intake was too tight (zero clearance). The rest had around .06 mm.

Anybody have any ideas???

I would also like to get a hold of a Suzuki factory manual for this bike. Is chiltons manual even worth the $20?

Thanks in advance! :-D

[flyingace]

Compression check must be made with engine warm and throttle wide open. If this was the case, then put a tablespoon of motot oil down the plug holes and recheck compression. If compression raises quite a bit, rings are worn and you are looking at a rebore/rering at minimum.

The soot on #4 is a common problem on the 850. I believe it starts with moisture getting into #4 pilot air screw, then people screwing with that carb causing lots of other problems.

[DaveT.]

My friend had an air compressor, so we put the #1 and #4 cylinder @ TDC. Then we put 100 psi of air on each and listened for leaks. #1 spark plug threads in the cylinder head are suspect, so I put teflon tape on the plug. I sprayed some soap around the plug to check for a leak, put didn't see any.

I will try the tablespoon of oil trick next time. My compression tester wouldn't hold @ peak psi, so that has to be fixed too. The motorcycle has only 12500 miles on it..

What I am really looking for is carb information, how all the circuits work and a reference point for the settings. On this bike we found the air screws 3-4 turns out. Is this close?

[5RON5]

Not quit right-Manual!

To your question; Is $20 even worth the price for Chilton manual? HE__ NO! It is not! The Suzuki manual is so much better than anything else! I have a Clymer & it's worthless, other than basic stuff. So I guess it's better than nothing! But if you have a chance of getting the manual from Suzuki, DO SO !

[DaveT.]

I will keep looking for a factory manual.

One other thing; when compression testing, are you supposed to hold the CV valve open with the throttle valve also? Will just opening the throttle valves give a low reading?? 8-[

[DaveDanger]

I've been trying to buy a factory manual for my 81 GS850GLX for several months now, have even gone so far as to already pay for one on my credit card at my local dealer, but he tells me that Suzuki has recently switched publishers for their manuals, and there's a dearth of manuals available at this point.

[thewiz]

Try this.

http://www.repairmanual.com/motorcycles/1980/62/6/5528

[DaveDanger]

Thanks thewiz... Found it, purchased it. should have it in 2 to 3 days I need to remember now to go to the dealer and cancel that order!

[DaveDanger]

Late for an addition to this post, but thought I'd mention the following anyway. I did order the factory manual for my 81 GS850 and received it within about 4 days. Good job I thought. Finally pulled it out and began looking up something specific on my carbs, and turns out the manual is supposed to cover from 1978 through about 1983 850's, but the manual ONLY covers 1979 models. My CV carbs are mentioned nowhere in it. I'm trying now to return it, if they refuse that... I'll offer it for sale here to someone that needs it for that year model.

[mark]

I will keep looking for a factory manual.

One other thing; when compression testing, are you supposed to hold the CV valve open with the throttle valve also? Will just opening the throttle valves give a low reading?? 8-[

Compression testing must be done with the throttle wide open. Also compression can be affected by poorly adjusted valves, so make sure your valves are adjusted correctly as well. Proper valve adjustment is necessary to adjust your carbs correctly as well.

[bwringer]

My friend had an air compressor, so we put the #1 and #4 cylinder @ TDC. Then we put 100 psi of air on each and listened for leaks. #1 spark plug threads in the cylinder head are suspect, so I put teflon tape on the plug. I sprayed some soap around the plug to check for a leak, put didn't see any.

I will try the tablespoon of oil trick next time. My compression tester wouldn't hold @ peak psi, so that has to be fixed too. The motorcycle has only 12500 miles on it..

What I am really looking for is carb information, how all the circuits work and a reference point for the settings. On this bike we found the air screws 3-4 turns out. Is this close?

1-3/4 turns out is a good starting point for the air screws. Mine ended up about 2.25 to 2.5 turns out.

Um, you HAVE seen the carb cleaning series, right?

http://thegsresources.com/gs_carbrebuild.htm