Finally have my GK73 on the road. Having stripped the carbs i noticed all four had rubber bungs over the pilot jets which don't appear on the parts list. Does anyone know if these are standard or have i got carbs fitted off another Suzuki 400? Bike runs well and will do 14500rpm in top so can't be much wrong with it

They are from the bandit 400.
Same body with very slight difference in jetting, main difference as you note is pilots having rubber bungs to make them get their fuel from the emulsion tube, supposed to stop them going lean under heavy acceleration.

Variablevalves suck wrote:They are from the bandit 400.
Same body with very slight difference in jetting, main difference as you note is pilots having rubber bungs to make them get their fuel from the emulsion tube, supposed to stop them going lean under heavy acceleration.

Thanks! Thought i hadn't seen them on a 73 before but it's been 15 years lol.

Can i junk the bungs next time the carbs are off?

The SP 73A is meant to have the rubber bungs over the pilots. It runs too rich on the mains otherwise (as the main jet sucks fuel through the pilot apperture.
I've had one very new one 20 years ago which had them in, and was 100% standard, and another one I have now I've just bought the bungs for from Suzuki. I raced the bike in F400 for a few years.

For example
with 102.5 mains and a Yoshi race system and the bungs it was really lean
with 102.5 mains and a Yoshi System without the bungs it was about right on the dyno
with 128 mains, bungs re-fitted, same Yoshi system it was 13/1 and made 64 rwhp Dynojet hp.

I'm not sure about the regular GSXR400, I think it does without them, but that has 32mm carbs not the 33's the SP 73A has.
Hope that clears some of the doubt up. Nick.

They are shown on the parts diagram for the 73aSP. Item 53.
Nick.

Great post.
My sp ain't got them so you forget they are oe.

The only thing that I wonder about is how they don't fall out, as the float assembly doesn't quite touch them!
IF you run without the air restrictor and have a fancy 4 into 1 you need to get somewhere near 130 MJ with the little guys in there.

I think they swell slightly when immersed in fuel.

Are you referring to the air restriction as the rubber flap behind the rad and where you still running the stock air box and filter?

The air restrictor that sits in the top of the air filter. Nick.