The carb on my son's 250 tends to spill gas out of the overflow. Every YouTube video I've watched for setting float height on these Mikunis has them measuring up from the bowl mounting surface to the tang ( with the carb inverted), but according to the image in the service manual, it "appears" that they are measuring down from the main jet tube. However the graphics are so poor that I'm not 100% sure. Anyone know for sure what the proper measuring points are?

 

Does it flood when sitting or riding?

 

It will sometimes spill through the Overflow and he usually has to hold the throttle wide open while he kick-starts it to get it to fire. I have replaced the needle and seat and installed a fuel filter just Upstream of the carb which is squeaky clean so I know it's not a needle and see tissue

 

I'll take that as a "when sitting" answer.. I think..
Who said anything about a needle and seat issue?
But seeins you mentioned it, I wonder just why it is leaking fuel by the needle and seat and flooding the carb?? Hmmmmmmmmmmm..

 

Yes it is while sitting. I mentioned needle and seat because that is the first response I seem to get. The fuel sits too high. The previous owner had messed around with it and the tangs don't measure within specs using either method.

 

Sorta weird eh. I suppose in that case I'd just drop the float height till it stops at the correct level. I'm certainly no Q-racer carb expert.
Now onto what I was going to get around to, I certainly won't argue the fact that needle seat looks clean and such. My idea to mention is: Ethanol fuel. Many needle/seat problems caused by it. Only thing I can think of is that it sorta gums the needle/seat up.
If running ethanol fuel, you must shut the petcock off and run dry/drain the carb when done riding for the day. Next time riding you turn the gas on and it washes the
needle/seat area.
If you're not running ethanol, then I've wasted your time and mine trying. Could be worse, right?? lol
Maybe try the guys at: suzukiquadracerHQ.com.

 

At the very least, it might help someone else who wasn't aware of this, right? Ya, I always do my best to run non-ethy. Don't think engineers in 1986 expected this when they designed these things. 😁