Whats the difference and why with these 2 types of carbs?

[mharrington]

I have a 79 XS1100 and Im working on a 79 GS 1000. Whats the functional differences? Why used on one and not the other?
What our XS1100s use:




1979 Suzuki GS1000:

[TopCatGr58]

The XS11 uses vacuum actuated slides, whereas the Suzuki used mechanically actuated slides. Both need to be balanced, but I think the vacuum style provides a more precise supply and demand function and may also be more fuel efficient? Hopefully Steve or others more knowledgeable and familiar with the Suz. carbs will chime in.

T.C.

[ManagerMike]

Supplier politics maybe??

[James England]

The Suzuki ones are a lot taller? Would they actually fit into the available space on an XS1100? If so, it could be an option to avoid replacing those expensive diaphragms. The Suzuki ones are less sophisticated but I don't think that's necessarily a bad thing!

Are the mouth diameters the same on both sets of carbs? And the length of the carb from front to back?

[crazy steve]

It's usually impossible to know 'why' a manufacturer uses a particular carb on a given bike. Which carb manufacturer can supply them, how much they cost, how well that carb can meet performance/emission/mileage expectations, packaging problems (will it fit on the bike), there's a ton of variables that goes into those decisions at that level. But generally, a manufacturer will have a 'preferred' vendor (Kehin, Mikuni, Hitachi) that they'll go to first, if they can't get what they need they'll look further.

An example of this is what the 'Big 3' (GM, Ford, Chrysler) did until carbs disappeared on cars. GM pretty much stuck to Rochester carbs, Ford used Holley (or in-house-built Autolite which was a cheaper-to-build version of a Holley), and Chrysler used Carter. There was some cross-breeding (mostly on high performance models, where Holley was the preferred carb) if their 'preferred' vendor didn't have what they needed, but they would usually make whatever they had work.

[mharrington]

I have fixed up my 1979 XS1100 and now I am fixing up a 1979 GS1000 for my brother. Its neat to have my hands on two heavy hitters from the 70s! I have not rode the big GS but Im know it didnt run like it should. Clutch springs wore out, 2 valves to tight (lash) bent front fork, tweaked triple tree and bent front axle bolt..... The XS1100 is physically a bigger and heavier bike than the GS. In addition to my 1100 Id love to own a GS1000 and a KZ1000.

My 1100




The GS1000 Im working on

[DGXSER]

The GS are Keihn carbs, interestignly enough, a Honda I am looking into has Keihn on it.

Also the CB650 had Keihns on it in the earlier years, later years look to be Mikuni.

[trdriver71]

I could be wrong but didn't the later gs1100 use the bs34 as well.

[mharrington]

I know the Mikuni CV carbs on our 1100s by design are not an all out performance carb but a carb that does everything good. That being said I cant imagine my 1100 running any better. Its spot on and instant no matter the RPM.

[mharrington]

The carbs for the Suzuki- someone mentioned those are Keihns but they are actually Mikunis. So 2 bikes of same year, similar power and displacement, both have the same emmissions standards to meet (assuming?) but the Yamamha uses Mikuni CV and the Suzuki use Mikuni...non CVs. Interesting.

[bikerphil]

Not positive, but those carbs look like Mikuni flatsides, higher performance carbs that were probably added by some PO.