HL 388B Carburettor

M

Miknrod

New member
Hi All,
I have 2 Yamaha motors and have decided to run the Burris HL 388B Carbies but I just cant get them to idle.
My boys 12 & 14 run clutches and we do standing starts so I need them to idle without the boys having to keep on the accelerator all the time.

Any ideas, Burris said to drill a hole in the butterfly to get them to idle.

Any information will be greatly appreciated.

Thank you.
 
That may work . It lets some air through .
Location would be centered above the idle holes .
I've also seen v notches cut in them .
Did they offer a recommended Size .
Stock kt's on gasoline.
 
Didnt recomend a size.
Sorry should have said Yamaha YF 200 from burris, slightly modified for racing at Ipswich dirt karts here in Australia.
 
Ten 4.
When you turn the idle speed screw in. Will it idle up ?
I assume it will , only too high.
Start small 1/8" .
 
It will, but I ended up at 3/4L and 3/4H and then it wouldn't rev. That's too low on the low jet and It had a massive flat spot and wouldn't rev.
I am going to try at 11/2 on the Low and try to work it from there before I drill any holes.
I am trying to get it to idle at 2100 rpm.
 
Don't idle the carburetor; close the butterfly completely. Keep the engine running with your throttle, and try the needles 2-2.5 on the low and one on the high. Idling a diaphragm carburetor on a 4-cycle engine is the number one problem when tuning them.
 
Seems like I am going to have to do some practise with the boys on how to keep them going without an idle.
 
Burris's recommendation will work, put it at rhe bottom of the butterfly away from the fuel ports. Start about 1/8 inch, now let the shutter fully close.
 
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