Hey guys, hope everyone is getting in some good riding weather and plenty of miles. I need some expert opinions on a jetting matter. I have the '94 250R with Yoshi pipe installed. I don't know if the previous owner jetted the carbs or not so I'm gonna do it. As far as I know, the stock main jets are 105's and i'm gonna go up to 110's. Now the pilot im not sure about. I think they come with 38's ???? anyhow, im gonna put in 35's.. anyone familiar with what is working on this set-up??? Also, on the 250, both carbs should be jetted the same, correct?

 

where is your manual morey? I am not sure on the pilots or on the mains for your elevation, humidity, riding expectations, etc.

 

Unfortunately I don't have a manual yet...its on order. I do know that i am about 1,000 ft above sea level, humidity is very high here, and I commute with the bike 26 miles round trip everyday (about half highway, half stop-n-go), but I still like to give it some hard acceleration from time to time. Don't know what else is figured in this equation, I've just read time and time again that with that pipe the carbs have to be rejetted and it seems to be running pretty lean gauging from the intermittent backfires and the fact that it seems to run better after its gotten hot rather than when its cold. When I changed the plugs out they werent totally white but there was some buildup on the electrode.
It's been quite a few years since I rebuilt the carbs on my volkswagon bug when I was 17, and man I dont remember it being this technical LOL.. Guess I have more to learn than I thought. Thanks for the help!

 

Why do you want to re-jet? Is the bike running too rich or too weak, and in what part of the throttle range?

The answer to that will tell you which way you need to go with the jets.

If the bike is running OK you probably have the correct jets. If so, any change will adversely impact on performance.

Plug chop.

Rob

 

Rob is right....

If it ain't broke, ride it.
If your hell-bent on jetting, got to the dealer and get a "Stage 1" jet kit.
It's specific to the bike, comes with all the necessary parts, and instructions.

The instructions will ask about plug burn, so don't use new plugs until the kit is in.