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Posted

The website i found list the style of main-jet that is needed http://www.pjmotorsports.com/street-bikes-fitment-list.html (bottom of page). But does not list the style of pilot-jet that is needed. http://www.pjmotorsports.com/mikuni-jets.html#piolot/slow%20jets I don't want to have to tear my bike down just to see what parts i have to buy.

 

I'm riding an 07 RSTD

 

Any information would be greatly appreciated.

Posted

Perhaps you overlooked it but the 1st link listing the Yamaha jet fitments does say main jets as being Mikuni N102/221. Mains are the small round head types. Using your 2nd link that would be the 4th set of mains down the page shown. I measured extra mains I have here at the house to also verify the size/type.

Keep in mind that each cylinder has a different sized main. #1 & #3 being larger. Been a while since I've been into the carbs so don't remember the exact #'s used per cyclinder.

Larry

Posted

It looks like #1 & #2 mains are a 122.5

 

#3 main is a 117.5

 

#4 main is a 120

 

Trust, but Verify

 

I would be interested in logic behind these.

 

I can see a front to rear difference possibly due to heat, but what about side to side difference?

 

Gary

Posted (edited)

I did find the main jets. My question was what style of pilot-jets do i use? I want to up the main and pilot jets by one size

 

 

I got this info from a thread on this site

I am gonna buy 2 #125 main jet for Cylinders #1 and #2 and 4 # 17.5 Pilot Jets. I am gonna reuse the jets i already have for Cylinders #3 and #4.

Cylinder #1 and #2 will use the #125 jets that i buy

Cylinder #3 I will reuse the #120 jet from cylinder #4

Cylinder #4 I will reuse the one of the #122.5 jets

 

And im going from a #15 Pilot-jets to #17.5 Pilot-jets

Edited by littlebitcrazy
Posted

OOPs my mistake in reading it all. Ok you need the N224.103 pilot jets.

I did what you're planing on doing several years ago. Bumping all pilots & mains up 1 #.

I found that bumping up pilots was very helpfull in low end & inital throttle response. As for the mains they were running to rich causing the spark plugs to turn black. Also at times under a load pulling a trailer I was getting black exhaust soot on the cooler. Once I changed back the mains to their orginal postions my spark plugs were once again a nice clean brown/tan on the tips. No more problems with exhaust soot either. I did leave the pilots bumped up one number. At the time I was using H-D mufflers but that was the only change from stock. I'm now back with shortened stock mufflers since converting to a trike.

Good luck doing you mods and let us know what your results are.

Larry

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