Expert: Bill Silver - 10/27/2009

Question
As you know from answering previous questions i am making a dune buggy with this street bike engine.  Tell me what you think.  It has a new carb that i am trying my best to tune.  Could you give me some tips on how to tune and jet is correctly.  When you hit the gas it studders a little and sometimes dies.  Also the time has come to change clutch plates.  I took the side cover off along with the plate that covers the springs, and finally the springs. Holding the clutch basket on is this strange looking nut.  It is round all the way around.  Then there are 4 half of a square intentions on the outside of the round nut.  If you will give me your e-mail I will send you a picture that I drew up on the computer.

Answer
Erick, with a non-stock intake and/or exhaust system, you have to find your way to success with the carburetors. I would try raising the needle (lowering the clip, if possible) one notch and put in one size larger main jet. If it still is flat, put in the next bigger size main jet after the first change.

There is a special 2 prong tool for these kinds of nuts, plus you may need to rig up or buy a clutch holder tool to keep it from spinning when you are loosening the nut. The tools usually have a 3/8 or 1/2" square drive so you can insert an extension from your socket set. Using air tools will make it easier. You have to measure the width of the nut, as the 4 prong tools come in different widths.

I don't see the special nut on these diagrams, however.

http://www.cmsnl.com/honda-cm250c-custom-1982-us_model1045/partslist/E++07.html


Bill Silver