When trying to adjust idle, the plastic screw snapped by the head. Any recommendations on replacement ? The Spring seemed too strong for the plastic. Why use plastic anyway. Very frustrating.

Old

Jitsie do an aluminium idle screw. Most people fit these. I think its more the plastic is too tight in the threads rather than the spring, and i think they use plastic to reduce the likelihood of drawing air, but still crap design.

Sounds logical

If the broken section is still stuck in the carb, heat up a small flat screwdriver and melt a slot into the remaining piece, let it cool, fingers crossed! you'll be able to unscrew it.

1st thing I do with a Keihin carb is change to alloy idle and air adjusters. Jitsie, S3, CSP etc are just some of the brands that do them.

Just replaced the plastic with jitsie alloy one. The plastic one was stuck and after using a plier it snapped flush with the carb body. Used duggan's trick. Took 3 tries as the plastic melted and went deeper. Wheww! Thanks Duggan. The new screw is still very extremely tight but does turn. My next question is what size is the fuel line and carb vent hoses. Also noticed the main fuel tap is larger diameter?

Thanks