Suzuki gs 550-650 carbs

[c-west]

Hi,
Im new to this forum.
My name is Helge, a 30 year old guy from Norway.
I have owned a stock 79 Suzuki gs550 for about a year now, and are looking into getting some more
power for it.


Im going to build a gs 650 cylinder and head on my gs 550 bottom end.

Both engines have the same stroke, but the 650 (673cc) has larger bore.
It bolts right on with some minor grinding inside the engine case, and gives me a ligther bottom end with
a 6 speed tranny vs the 5 speed on the 650.

The big bonus is that it gives me about 40% more torque and power compared to the 550



Searching the net I found out that the650 has the Mikuni BS32SS carbs, and my 550 has Mikuni BS32 carbs.

Is it possible to re-jet the 550 carbs (Mikuni BS32) to fit the 650 cylinder?
Can anybody tell me the difference between the two carbs?

 

[Big R]

Somebody here might know....but the folks at the GSResources would know for sure.

 

[AlphaDogChoppers]

The difference could be something as inconsequential as a cable operated choke vs. knob or lever on the carbs.

Probably won't need too much difference in jetting, but those bikes are already lean to begin with. You could probably go up 5 jet sizes if you install a K&N filter and open up the intake snorkel. If you go with pod filters, you may have to go even further up in jet size.

When I say "5 jet sizes," I don't mean 5 points larger on the jet number. These jets are in increments of 2.5. If the stock jet is 115, then 5 jet sizes would be 127.5.

Bonus is that properly jetted, these bikes will get BETTER fuel mileage.

 

[tigerfan474]

​

alphdog is right. These are the same carbs. I got a jet kit through 6sigma because I put k&n's on them. The kit worked great.

 

[c-west]

Thanks alot for your info guys!!

Saves me alot to just re-use the 550 carbs.

Is Dynojet kits the way to go for re-jetting?
Or would you recommend other brands or tuners to re-jet them?

 

[AlphaDogChoppers]

Dynojet kits are good, but a lot more money than just buying jets.