1977 GS 750 mutt..Carb problem/identification.

[banshee]

Picked up this thing on a trade. I am a two stroke guy and a total newb when it comes to 4 strokes and street bikes for that matter. Yes I did use the search function.

This gs750, was allegedly bored to a 1000. It does appear to have larger carbs from another application. Also looks like the previous owner thought he had a speed demon on his hands and replace the entire swing arm and I believe front end, with street bike swinger, forks. Anyways first post so there is a little about my bike.

I am having some type of carb issues. The bike starts and idles very high 5,000 rpms. After 30 seconds or so the idle slows down and the bike dies. The bike will rev all day if you stay on the throttle, the rpms are very slow to go down after revving... The plates dont expire on the bike for awhile, so I don't think it has set for very long. I was thinking a clogged piolit jet causing a lean condition at idle? Anyone have a similar problem?

While I am posting these carbs have some type of diaphragm deal. The slides are slow to fall due to a vacuum. Carb #2 falls quickly. I inspected it and it seems like the diaphram is not making a good seal on this round plastic doo hicky...Its just held together by these two plastic notches that go into holes, does not seem air tight..is there some type of sealant that is used do these?

Here are some pictures of my pile..also posting pictures of the carbs if someone can tell me what they are from exactly and or what model number that would be great.

[Octain]

Someone find this man a correct set of carbs!!

[chuck hahn]

If it truely has been made over to be a 1000, then the CVs will be ok. However, I would go back to the stock VM26s jetted for the 1000 specs. Then again thats just my personal preferrence. I think VMs are just easier to sync and fine tune myself. And..replace the orings in the intake boots ( between the flange and head ) Hanging idles are usually indicitive of air leaks and lean conditions.

[banshee]

So what are the carbs on there now from? What are they worth ebay value? How much am I looking at to put the stock carbs back on?

[chuck hahn]

They are probably BS32s..they are worth about 100.oo tops. Vm 26s will cost you about the same. Then you gotta rebuild them to be sure they are good and have the stock 1000 jets in them. Maybe someone here can do a package deal for you. Clean up a set and jet them for a trade on your BS carbs and a few buck for labor and parts. Start asking around and make some deals.

[Octain]

Looks like some kinda mucked up intake boots as well.
I seriously doubt that engine is anything beyond stock.

At some point someone thought putting a later model set of carbs was a good idea.
They actually look like Honda Carbs.

[banshee]

Wish I had some way to verify it really was 1000cc's. Could I just richen it up with the needle fuel/air screw and go from there?


Confirming these are the carbs I need

http://www.ebay.com/itm/Carbs-Carburetors-Suzuki-GS750-/190627338415?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item2c624658af

Seems like a pretty good deal to

[koolaid_kid]

IDK about displacement, but I agree those boots look really bad, and those certainly do not look like GS carbs. It would be much easier just to start over with the correct carbs. I have no love for VMs, but that is what came on it and would be the easiest to get tuned correctly because the correct settings are well documented.

[koolaid_kid]

Wish I had some way to verify it really was 1000cc's. Could I just richen it up with the needle fuel/air screw and go from there?


Confirming these are the carbs I need

http://www.ebay.com/itm/Carbs-Carburetors-Suzuki-GS750-/190627338415?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item2c624658af

Seems like a pretty good deal to

That is what they look like. You'll certainly have to do a complete and thorough cleaning, but the procedures are on BassCliff's website.

[chuck hahn]

Good eye guys. Those intake manifold all need to be replaced. WTF was the PO thinking there??? Dont get all flustered though..we can fix that bike for you. I will dig thru my stashes and see if I can come up with 4 intake boots. I will aslo probably kick myself for this later, but i have 2 sets of the VMs. Tell you what. You get me a set of orings from Cycleorings.com ( Robertbarr here on the forum ) and give me 75.00 and those carbs I will rebuild a set and send them to you. Youll have to do the valves and then vacuum sync the carbs to your engine.

[banshee]

Could someone link basscliffs website..Also are there a better set of carbs out there for the money?

[banshee]

Good eye guys. Those intake manifold all need to be replaced. WTF was the PO thinking there??? Dont get all flustered though..we can fix that bike for you. I will dig thru my stashes and see if I can come up with 4 intake boots. I will aslo probably kick myself for this later, but i have 2 sets of the VMs. Tell you what. You get me a set of orings from Cycleorings.com ( Robertbarr here on the forum ) and give me 75.00 and those carbs I will rebuild a set and send them to you. Youll have to do the valves and then vacuum sync the carbs to your engine.

Thats a deal for sure. I'd rather let someone else do it that is already experienced. I'm know to break things 2-3 times before I get it right. But when you say I'll have to do the valves you mean adjust them right? Also I am Keyser Soze on www.bansheehq.com I am a moderator over there and have great buyer/seller feedback

[TheCafeKid]

Those aren't BS32s. If they're even Mikuni they'll be from a later model, maybe small gixxer/katana/bandit.

But they're not right for the bike, even with a 1000cc bore kit. However, with the manifolds changed, you may not be able to go back without buying new manifolds.
I saw this bike for sale on here, or someone posted a Craigslist link for it. Got a lot of upgrades on it, but it's gonna need some serious work to get it right. You're in for a project for sure, but once you get the mechanicals, maintenance and such sorted, you'll have one of those "upgrade" projects people spend lots of time and money on even after they deal with getting it going. But you'd better go through it all with a fine tooth comb and be skeptical of anything that doesn't look safe, because unfortunately when people "modify" to try to make it something it isn't and wasn't supposed to be, they often get in over their heads and make a cock handed mess of it...

[banshee]

Those aren't BS32s. If they're even Mikuni they'll be from a later model, maybe small gixxer/katana/bandit.

But they're not right for the bike, even with a 1000cc bore kit. However, with the manifolds changed, you may not be able to go back without buying new manifolds.
I saw this bike for sale on here, or someone posted a Craigslist link for it. Got a lot of upgrades on it, but it's gonna need some serious work to get it right. You're in for a project for sure, but once you get the mechanicals, maintenance and such sorted, you'll have one of those "upgrade" projects people spend lots of time and money on even after they deal with getting it going. But you'd better go through it all with a fine tooth comb and be skeptical of anything that doesn't look safe, because unfortunately when people "modify" to try to make it something it isn't and wasn't supposed to be, they often get in over their heads and make a cock handed mess of it...

Do you know for sure what was done to it? I checked the compression and I got between 165-175 PSI on all 4...Seems high to me, maybe the head was milled? . My compression gauge is accurate, I cross checked it with my 4mil banshee after to ensure it was still on point. To me it looks like someone loved it, then someone started jacking around. As far as I can tell the swing arm was done right. The gauges and signals are all modern, but they are all functional and correct. Someone fabbed some nice looking exhaust brackets to worth with the aluminum
swinger, and some nice brackets for the modern gauges.

[chuck hahn]

Just came in from the shed..Heres your carbs and newish intake boots. Should i verify the jetting for a 750 or 1000????