Putting it back together....1981 GS750

**TheNose** · 08-27-2003, 07:46 PM

The best advice that anyone could give you is to buy a manual. They are invaluable. You will be able to find the answer to this question and all the others that will arise. A good deal for less than $20. But, if you don't want to buy one, then go to your local library and check one out.

I'd tell you what you want to know, but I don't have a manual for your bike. Just for grins, put your hometown on your profile. Maybe another member lives close to you and would be willing to help you.

Terry

**Anonymous** · 09-04-2003, 04:35 PM

well, after lurking, (and waiting for gaskets, darn the budget thing anyway) I have decided several things. Oh, and by the way, my bike was built in 1980, but is an 1981 model

1. The little hole I covered on my #2 carb was there for a reason, looks like the guy who had the bike before me had some issues
2. there is a lot to get this back on the road.

List of what I think I'm going to do..

1. Clean the carbs (did it a bit last year, but not taking it ALL the way apart and soaking it) and replace any bad rubber parts
2. Clean the petcock (and replace, cause I think the vacuum thing is bad, as it was DISCONNECTED when I go the bike, gonna strip it down and see tonight.)
3. Reshim the Valves and check to see how they are seating (will gas in the top of the head work to see if it's leaking?)
oh, and my valvse dont' seem to have "shims", they seem to have a little bolt you can turn to adjust the way the valve go up/down a small amount...is this normal?
4. Oil my chain (old shafty here, that's all I've really ridden up till now....too bad I didn't think about it before buying it, my knees already hate me)

anything else I should do with the head off the bike, and trying to get it back into good running condition?

**daveo** · 09-04-2003, 06:31 PM

Originally posted by nweaver

3. Reshim the Valves and check to see how they are seating (will gas in the top of the head work to see if it's leaking?)

yes but be careful!

oh, and my valvse dont' seem to have "shims", they seem to have a little bolt you can turn to adjust the way the valve go up/down a small amount...is this normal?

Yes, no shims, be careful to not strip the adjuster with the locknut though

anything else I should do with the head off the bike, and trying to get it back into good running condition?

The valve stem seals aren't a bad idea

**Anonymous** · 09-04-2003, 11:52 PM

Update from night number 1...

printed Carb cleaning guide, started cleaning carbs (number one finished, not goint to start 2 till one is assembled again), picking up dip in the morning (live out of town a ways). stripped Petcock down, darn guy had the vaccume disconnected, and the petcock on "prime" with another shutoff switch just below that main one.....

How can I test the petcock valve? I stuck a tube on the fuel outlet, and sucked, but got air no matter what position the petcock was in. Shouldn't It stop if it's "On" or "Reserve" cause I don't have a vacuum?

I was unable to get the "Air Screw" out of the number one carb, I sprayed cab cleaner in there, and gave it a few minutes, but it just stripped a bit. How crucial is it to get that air screw out? I would prefer not to have to tap it out, if it will be ok. Will dipping the body while it is in hurt the O ring in that?

Thanks for the Help

Nick Weaver

**daveo** · 09-05-2003, 08:28 AM

try heating up around the screw with a heat gun or hair dryer then soaking down the screw in liquid wrench, let set awhile before trying again,the 0-ring will not take kindly to the dip

**Anonymous** · 09-05-2003, 09:10 AM

I am having a hard time putting my petcock valve back together, and can't seem to find my manuals (I have one for 550, and one for 850-1100, but not for the 750) :roll:
I was armed with my digital camera, but was to anxious to get pictures before ripping into it, and I'm not sure if it was assembled correctly in the first place. I am looking for an exploded view of one. Is the petcock mostly the same setup for all the GS's around then?

**daveo** · 09-05-2003, 09:51 AM

Hope this helps....

**TheNose** · 09-05-2003, 10:05 AM

Dave, I think the drawing you posted is for a 1980 petcock. It is different from other years. At least all that I have seen, which is not that many though. I'm glad you posted it, because I did not know the correct position for prime and ON and was going to ask for help.

Terry

**daveo** · 09-05-2003, 10:33 AM

Originally posted by TheNose

Dave, I think the drawing you posted is for a 1980 petcock. It is different from other years. At least all that I have seen, which is not that many though. I'm glad you posted it, because I did not know the correct position for prime and ON and was going to ask for help.

Terry

actually the 81s had that one too,my 82 is different(guts are the same though) but it's in the 82-83 factory manual?

**Anonymous** · 09-05-2003, 05:51 PM

hoping I can get that screw out...the head is stripped some, and the screwdriver wasn't wanting to bite much...would an impact driver work still? If I can't pull this out, should I tap it and replace the screw?

I really don't wanna be tapping the thing out, if I sprayed the inside of the carb and cleaned it really good, and left that one alone, would it really hurt the bike much? Is that a screw I need to adjust?

**daveo** · 09-05-2003, 06:35 PM

Originally posted by nweaver

hoping I can get that screw out...the head is stripped some, and the screwdriver wasn't wanting to bite much...would an impact driver work still? If I can't pull this out, should I tap it and replace the screw?

I really don't wanna be tapping the thing out, if I sprayed the inside of the carb and cleaned it really good, and left that one alone, would it really hurt the bike much? Is that a screw I need to adjust?

Heat it up and let soak in liquid wrench,for a hours, then heat it again and try, you need to be able to adjust it

**Anonymous** · 09-05-2003, 07:32 PM

anyone got valve clearence for this year? book is on it's way, but I can't wait

**TheNose** · 09-07-2003, 03:00 PM

Originally posted by nweaver

anyone got valve clearence for this year? book is on it's way, but I can't wait

Intake 0.025-0.052 mm
0.0010-0.0020 in

Exhaust 0.040-0.067 mm
0.0016-0.0026 in

For a TSCC Engine GS750

Terry

**Anonymous** · 09-08-2003, 01:28 PM

Thanks....I got the petcock back together, not sure if the vaccum will work, but it doesn't let me suck air through it on res or run, so I think that is a good sign.

2 carbs cleaned, 2 stripped and uncleaned air screws...I am debating about getting new air screws, or just letting it go...I know that could be bad, but I am trying to get the bike running again, and at minimal cost. I have tried the liquid wrench/heat stuff, but no luck. Can I buy just the airscrews from somewhere?

One more question, I cleaned up the underside of the head really good with a soft wire brush/dremel. I couldn't compress my valves to get the seat at all. I poured some gas into the top, but it's hard to get it on just the valves. It seemed to have a little bit of leakage, should I pull out the valves and use grinding compound on the seats/valves to get a good fit? are valves inexpensive for these bikes? 16 valves can get spendy real quick. I want to do this right, but I don't wanna spend hundreds doing stuff like valves unless I have to to make it run fairly well. It was running ok before, but the carbs needed cleaned/sync a bit, and the head gasket was leaking oil.

Putting it back together....1981 GS750

Putting it back together....1981 GS750

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