Motorcycle Repair: cold start problem, pilot jet, mikuni hsr42

Question
Johnny

Thanks for your answer, I will double check the timing and plugs later this week. Please double check your pilot jet recommendations for me. The carb came with a 25 pilot jet which, according to the adjustment procedure in their book, seems to be fine. The pilot air adjustment was just about dead on with the original jet. I increased it to a 27.5 because I thought that the bike wasn't getting enough gas, when cold, to start.

Just a little more info, I set the timing to the advance mark on the flywheel, not sure what the degrees are. I have a dyna s ignition with a mechanical advance. I set the flywheels to the right spot and then advance the unit and then adjust the plate so the voltage changes from low to high at the coil. ( It is a single fire unit). I think this is the right procedure. The mark I use on the flywheels is the single dot.

Thanks again and I will let you know what happens in a couple of days.


Jim

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Followup To
Question -
I have a new 99 EVO engine in a custom application. The bike is kick start only and when the weather gets cold the bike won't start.

The engine has about 1000 miles and runs great when warm.

I had a points ignition but changed it to an Dyna electronic ignition this weekend. This didn't help. I have a Mikuni HSR42 carb and using the enrichener circuit it still does't help.

I changed the pilot jet to one that is one size larger to see if a little more gas would help, it didn't.

I have great spark at both plugs (point or electronic ignition).

Can you give me any help?

Thanks

Jim
Answer -
Pilot jet should be a .20 or a 17.5 and main jet should be a 150 to 160 . When using the enrichner you can NOT use any Throttle at all. I use only NGK BPR6ES spark plugs gapped at .040" and torqued to 18-22 ft lbs using anti- seze on threads, I do not know what your timing is but I would set it at 32 degrees full advance,   Johnny..

Answer
The timing mark is a stright line and should be in the center of the timing window, On the front compression stroke, The carb came with a 25 which is to Big. Drop down to a 20 or a 17.5 pilot jet Take all most all the pump OFF. and main jet should be no more then a 160. I think you are timing the bike wrong. It is hard to know some times what other people are saying. But I think I know what you are trying to say.  Johnny 602-705-7474