alright, it's a good thing I don't get paid for this...

[snowbeard]

because now that all you nice people have found my problem is an intake leak somewhere, the manifold sounds like a logical place as the bike is 23 yrs old and I kinda doubt the O-rings have ever been replaced, but now I realize, I can't identify the damn manifold!!

I looked thru the clymers, and I would guess that the manifold is the boot system that the carbs insert into before the actual engine, but my clymers calls that the "engine flange" am I whacko? what is my manifold???

can anyone point me in the right direction? is there an online diagram I might peruse? a pic in the clymers that I missed?


I think I'm going to have to sell my small engine repair business, I'm a sham...

[Anonymous]

Should be the rubbers between the carbs and the cylinder head.

[earlfor]

This is a diagram of a 1981 GS650G. The "O" ring you need is part 24 in the diaghram. The "O" ring fits in a groove on the face of the boot that mates to the cylinderhead. The other end of the rubber boot clamps to the carb.


Earl

[ZacharyB]

I have an intake leak as well but I heard I should replace both the boots and the o-rings. My boots look ok but the o-rings look melted into a good seal. At $35 each do you think replacing the boots is necessary? I want to avoid it if possible. Can an intake leak come from somewhere else other than the vacuum port screws, intake boots or the intake boot o-rings? I've checked all of them and they appear fine.

[Anonymous]

This might help. It's my standard sermon:

http://www.cycleorings.com/intake.html

[earlfor]

If the intake "O" rings are not pliable with a round cross section they are not fine. If you cannot remove them easily or if they appear flat and hard, they are not fine. If they are more than 2-3 years old, they are not fine. New ones are about $1 each. Go for the gusto........invest the 4 bucks. :-) :-)

Earl

I have an intake leak as well but I heard I should replace both the boots and the o-rings. My boots look ok but the o-rings look melted into a good seal. At $35 each do you think replacing the boots is necessary? I want to avoid it if possible. Can an intake leak come from somewhere else other than the vacuum port screws, intake boots or the intake boot o-rings? I've checked all of them and they appear fine.

[Dark Jedi]

If the intake "O" rings are not pliable with a round cross section they are not fine. If you cannot remove them easily or if they appear flat and hard, they are not fine. If they are more than 2-3 years old, they are not fine. New ones are about $1 each. Go for the gusto........invest the 4 bucks. :-) :-)

Earl

True, dat.

BTW, what's a good source for these o-rings? I lucked in to a set, but our buddy above might appreciate a link. For that matter, I might to for future reference.

[earlfor]

I just buy them through the local dealer. At a couple bucks each, its not a big deal.

Earl

If the intake "O" rings are not pliable with a round cross section they are not fine. If you cannot remove them easily or if they appear flat and hard, they are not fine. If they are more than 2-3 years old, they are not fine. New ones are about $1 each. Go for the gusto........invest the 4 bucks. :-) :-)

Earl

True, dat.

BTW, what's a good source for these o-rings? I lucked in to a set, but our buddy above might appreciate a link. For that matter, I might to for future reference.

[snowbeard]

well I guess I'm not as bad at this as I thought, cause that was my first guess! good to know for sure, I'll get some rings and deal with it soon. Thank yous!!

So another question along these lines, now that I (think I) know the problem, I also find that it is lessened by leaving the second clip off my airbox cover. so is this because I'm lessening the vacuum pulled at the intake by opening the system elsewhere? thereby less of a manifold leak since it can get the more air it wants thru the airbox? is this going to affect my gas flow at idle, or only the air added to the same gas flow? I can definitely say I can fell a difference in power when I leave it open!!

[earlfor]

Leaving the clip off the airbox lid lets a little more air into the intake more easily. That it seems to improve things suggests that perhaps your idle mixture settings are slightly on the rich side, or possibly the the air cleaner element is dirty enough to restrict some flow.

The amount of dirt build up in the element that can cause flow restriction isnt visable. (its that slight)

Earl

So another question along these lines, now that I (think I) know the problem, I also find that it is lessened by leaving the second clip off my airbox cover. so is this because I'm lessening the vacuum pulled at the intake by opening the system elsewhere? thereby less of a manifold leak since it can get the more air it wants thru the airbox? is this going to affect my gas flow at idle, or only the air added to the same gas flow? I can definitely say I can fell a difference in power when I leave it open!!

[snowbeard]

I should probably get a new element soon, as I believe this to be the original. I've washed it well with thinner and dishsoap, even left off oiling it again just to see if it helped (don't have filter oil yet), but clamping it all the way down seems to restrict the flow. do they make a K&N that fits inside our boxes? I have seen the fact that they have replacements for us, but noone has a picture to compare...

my other thought is to clamp a nice big K&N cone shape on the air splitter, leaving out the airbox altogether without filtering each carb separately... course that means some fabrication work to make an oval attatchment...

I've never messed with the mixture as my pipes are still white and I'd rather keep them that way, as opposed to going too lean... at least it runs!

Thanks Earl!!!

[fast eddie]

I admire your candor, and empathize. They should sell modified Haynes/Clymer manuals, where every maintenance item is accompanied by a photo of the entire bike, with a large arrow pointing to exactly where to find the piece. I'd be first in line to buy that!