Penton Owners Group

General Discussion => Penton Talk => Topic started by: tomale on March 09, 2003, 09:40:39 PM

Title: Mikuni jetting
Post by: tomale on March 09, 2003, 09:40:39 PM
I have been thinking about setting up my bike with a with a mikuni carb. it is for my 76' KTM 250 has anyone else done this and what jets did you end up with.

Thom Green,I own and ride a 76 250 MC5 MX which I bought new.
Title: Mikuni jetting
Post by: Blue_Dog on March 14, 2003, 11:56:09 AM
Rocket:

 I have a Mikuni on my 250 (other brand) and am running a 210 main. Its pretty crisp you might want start with a 220 to 240.
I guess you just want to try and smooth out the power band?

B_D


 
Title: Mikuni jetting
Post by: [email protected] on March 14, 2003, 12:35:51 PM
Be very cautious on the main jet.Start way big, plugs are cheap, motors are not.My piston port 250's are anywhere from 270 to 330 on the main.On a premix motor when you slam the throttle shut there is no lubication excepting residual.I like an almost chocolate brown plug read.Seizure at speed is exciting,but painful.

 
Title: Mikuni jetting
Post by: john durrill on March 14, 2003, 07:37:57 PM
B_D,
 could you look at your carb and post for us what you are useing for jetting?
the  size and model
the main jet
the pilot jet
the air jet
the needle jet
the needle #
the slide cutaway
if it has a starter jet what the # on it is.
 what year and any mods you have done from stock to you engine.
 we have folks ask all the time on what to get if the go to a Mikuni. if they have to figure out all that from scratch it will cost them a lot of money over the price of the carb unless the are very lucky and get the right needle, needle jet, slide cutaway and air jet when the buy the carb.
 i will save the info to disk and post it in the library.
 I would greatly apprecieate it if you could.
 anyone else that can give us their info on the Mikuni they are useing will really help the folks in POG that want to go with another carb over the Bing.
 John D.
 


 
Title: Mikuni jetting
Post by: tomale on March 14, 2003, 09:46:12 PM
Thanks John that is what I was asking for. My bike might be a bit different because I am not running a stock pipe but we should be able to get real close. I might need to change either or both the main and pilot jet to get mine to run good and clean without causing it to go into self-distruct mode.

Thom Green,I own and ride a 76 250 MC5 MX which I bought new.
Title: Mikuni jetting
Post by: [email protected] on March 14, 2003, 10:17:12 PM
Wrote a small book on the wanted page on this subject.Guess I skip around too much.