i'm anxiously awaiting the arrival of a Yosh RS-3 slip on, Dynojet satge 2 kit, K&N filter w/adapter plate for my 02 raptor. My question is with regards to the jet sizes in the dynojet kit. Yoshimura recommends 150-150 jets but the biggest jet in the dynojet stage 2 kit is a 150. From other posts, it seems dynojet recommends using jetting in the range of 146-148. Am i missing something here or is there a legitimate explanation to clarify my confusion.

 

The jet sizes recomended by Yosh are Mikuni factory sizes. They are not the same sizes as Dynojet's sizes. I.E. a Mikuni 150 is not the same size as a Dynojet 150. The 146-148 Dynojet should be a good baseline for your setup.

 

I am running the same Yoshi and airbox setup with dyno jet 146 148 and it runs perfect!! I also have a whole draw fulll of stock jets but i m done with them. all you need to do is follow the dynojet instructions and you should be alll set. make sure you install the entire kit including needles..............

 

Tank you for the replies. Everyone on here is always helpful. If Dynojets mains are 148-150, what size would the mikuni jets be? Joed, how do you like your set-up. Did you notice a drastic difference?

 

One more question for you guys. What are your recommendations as far as the pilot jet is concerned. Would a jump up to a 25 or 27.5 be wise ?

 

oh i forgot to say that i have a complete Yoshi system..but even with the jet and airfilter alone you should notice a dramatic difference..it reallly wakes up the RAPTOR big time...i have 6 uni vents in my airbox but taped up 4 of them ,,you really shouldn't have to change your pilot jets..i didin't and she runs like a monster now...its really one of the best things you can do to your raptor...don't forget to trim your snorkle also.

its like night and day..the one thing i notice is that its like an immediate ssurge ..no waiting

 

jet sizes are based on flow rates, a 150 is a 150 no matter who makes it (yoshi, mikuni, dynojet or anyone else), the differences are in the flow characteristics, dynojet claims they put extensive research into this to get better flow but the volume is still the same, dont believe me? call dynojet they will tell you the same thing, for a good explanation on jetting see the april dirtwheels pg 162 great article on jetting

 

Vraptor, there was a post in the Bombardier forum that had a link to a site that contradicts that statement. To sum it up, the post stated that Dynojet's sizing is based on flow rates and Mikuni's sizing is based on the actual diameter of the opening in the jet. I don't know if this is true or not, but it would seem to make sense based on the differences between the Mikuni and Dynojet sizes that work for the same setups.