I noticed the stock Raptor comes with a 140 / 145 jet combo (5 number increment in between).

I installed a White Brothers R4 Silencer (only) and increased my jets to 145 / 150.

I see a lot of folks only have 2 or 2.5 between their main jets. As an example, I noticed kyraptor23 has a combo of 148 / 150.

Why do some folks have 5 numbers between and others have 2 or 3 numbers in between?

Does my 140 / 145 combo sound right for a new Raptor with a WB Silencer, stock airbox and no other mods? I ride at sea level.

Thanks!

 

Rob- the 148/150 are dyno jet numbers. Dyno jet uses a different system than mukuni dos. You can get the factory jets in 2.5 increments up to 190. They do not make a 197.5 or a 192.5 jet size anymore. You can not mix dyno jet jets with mukinus or the needels

 

Thanks....I was not aware of that!

So, if I wanted to increase my jets one size, and use Mikuni jets, I would jump to a 145 / 150 combiniation?

Does this seem enough for my conditions?

 

good info 14, i learned the hardway..

 

What do you mean...the hard way? Did you combine the jets? What happened?

 

well i had a shop do the work the first time, and trusted the mechanic judgements and he was wrong..

the dyno jet kit jets stop at 150 and i needed a 155 so he assumed a makuni would work,well it did fine and for at least 4 trips it ran fine. then all of a sudden it started running like crap and I couldent ride it at all, so i had a friend help me and he figured it out ,and said it was funny that the guy dident even put the parts from the jet kit into the bike except the diffrent jets..(pilot,no fuel mixture turns,and difrent jets) and he said my valves were ready to go..anyways i switched to a GYT-R jet kit and the bike runs solid and i have no problems like ,backfiring,any stutter in the throttle at anytime,and no popping on deceleration,also went with the pro design airfilter and that helped..

 

A Mikuni 150 main is not the same as a Dynojet 150 main and a Mikuni needle is not the same as a Dynojet needle.

Dynojet 146/148 main and Dynojet needle combo has similar flow to Mikuni 160/165 main and Mikuni needle combo.

if you have Mikuni jets and add Dynojet needles you will fow more because the Dynojet needle in narrower.

 

Raptor03- I learned the really, really hard and expensive way. When i did my first 686 the shop and i spent 4 hours trying to get it to run with the jets provided. The shop that i sent my stuff out to sent me mukuni jets. When i placed my oder for the kit I TOLD THEM I HAD A DYNO JET KIT IN IT AND NEEDED THE JETS. They overlooked it and sent me regular jets no knowing they would not work. I did get it to run on dyno jet nedels and mukinus. Of course i misplaced my original needels and BOB Craycraft loan me his for a bit. Man those stock needels cost a bundle. 21 dollars each.

 

Rob with just a slip on and no air box mods your 145/150 mikuni jetting should be fine.