78 XS650E, how thick is brass plug over mixture needle ?

[usmc1lt]

Drilling out brass plug over mixture needle & afraid to drill too far. Approx how thick is the plug ? This engine 2FO 002211 and has carbs with no overflow drains on them

[grizld1]

Welcome back!

There shouldn't be a brass plug over the mixture screw in a 78 carb (BS38), so it appears that your E model has been fitted with a pair of later BS34's. The plugs are pretty thick; if you use light pressure and take your time you won't tear anything up. My preferred treatment is to tap the plugs, run in a 4 mm. screw, and pull them out. That way you can reseal the plugs with a dab of silicone and reinstall them to keep out moisture and debris.BTW those "overflows" are float chamber vents, and their primary function is to keep the float chamber at atmospheric pressure. Your carbs have them; your float chambers vent through two big holes in the intake bells, which is why a bad float or float valve will fill your air cleaner with fuel.

[usmc1lt]

I have had a 1980 XS650 so I know they aren't the BS34 carbs. Im embarrassed to even tell you what a dumass I am. What I thought was the brass plug over the mixture screw upon further review is the right end of the throttle shaft. At least I had sense enough to quit before it was too late. So there is no mixture screw at all on these carbs ? Ive got a stock motor with the airbox on and nothing done except a set of the Contenental replica mufflers with all the holes in the ends. The bike has a dead spot right off idle when I take off, after it passes that it runs Ok. What would you suggest ? At least everyone on here can get a good laugh at a senile citizens efforts.

[grizld1]

Yes, there are mixture screws. They're right out in the open on the sides of the carb bodies. They were originally fitted with plastic caps which limit the range of adjustment. If the caps are still there, get rid of them.

[usmc1lt]

mail.aol.com/38683-116/aol-6/en-us/Suite.aspx please show me on this carb where it is, I sure cant find it. If you don't have aol, then email me at [e-mail] and Ill send you pictures of both carbs. Thanks for the help. I managed to insert 1 picture

[grizld1]

Go to www.biker.net and look at the exploded diagram in the parts manual. Your pilot screw is part no. 41.