Jump to content
Sign in to follow this  

Help with a 28MM PWK on a RM 85

Recommended Posts

Wondering if anyone has some baseline jetting as we are going to try a PWK on our RM 85 with a 95lb rider, V Force 3 Reeds, Fatty Pipe and 13/47 gearing?

Thanks!

Share this post


Link to post
Share on other sites

Havent put it on yet but I do have a couple of kx 85 cables if the RM one doesnt work?

Share this post


Link to post
Share on other sites

I'm not sure, the slide on the PWK I have looks like it takes a coin shaped swedge instead of the barrel style of the RM, I haven't put mine on yet. Plan on doing it next week. Going on a MOD 85 motor with Vforce reeds, R&D EVC(powervalve) FMF pipe.

I found this in another thread.

So I found this in another thread:

YOU move the clip up to lean it out. So if you want to lean it out from 2nd clip, go to the 1st clip to the top. DO this first, and see if that helps.

If youre mainly riding MX, this bike is near perfect for that stock. THe triple taper gives the bike a snap and a hit that even RC would be impressed. If you're going to trail ride you should replace the stock NBKF needle w/ a needle w/ a larger dia. like an NBKG,2ndclip . This leans out the bottom end and works better for offroading, where you're mainly riding in the 1/16 to 3/8 throttle opening. Also helps w/ spooge control too.

YOu can also get 1/2 clip position needles from Yamaha if you want to fine tune the 1/4 to 1/2 throttle, and even though moving the clip up/down using one needle almost gets you there, sometimes a 1/2 clip change makes all the differencee in the world. The 1/2 clip needle that's leaner than the stock NBKF-#2 is NBLF@ #1 cip. 1/2 clip richer than stock is NBLF @ #3. THe 1/2 clip in the NBKG #2 needle is the NBLG #1(lean) or NBLG #3(richer).

You can also use a Kx85/100 needle that's supposed to work pretty well for more bottom end. They use an NAPE needle #3clip and an NAPF #4.

ANd you can also replace the stock triple taper needle w/ a straight taper needle if you want to smooth out the upper band hit that the YZ85 is famouns for, but you would also need to go up two sizes larger on the main because these needles have a sharper taper angle. The SUDCO equivalent to the stock NBKF is the JJF clip#3. NBLF equivalent is the JJG #3. With these straight taper, you'd want to start w/ a 150 main to start w. I wound up w/ a 148 main The pilot size wound up being 50, which I thought was a bit large.

SO to reiterate, change out the needle's diameter for 1/16 to 1/4 throttle, move the clip up/down for 1/4 to 1/2 throttle. ANd go w/ a straight taper needle if you want to tone down the MX hit.

I'm still struggling with determining what needle is a step or two leaner than a NBKF in the #1 position, while still maintaining some adjustability on both sides (i.e. not in the #1 or #5 needle grooves).

Share this post


Link to post
Share on other sites

If you guys are still running the 85cc cylinder, use the KX85 or CR85 jetting. That is if you have the 28mm carb. Jet the carb with the slide needle in the 2nd or 3rd groove. If you have to go to the 1st, 4th or 5th groove to make it run, then your jetting is off. Keep it in the 2nd or 3rd groove or you will fight the jetting every time the temp or humidity changes.

If you have the 29mm carb off a KX or RM100s you will need to jet for the 85cc and it will have a bog in the 1/4 throttle range that is hard to tune out unless your rider is ringing the crap out of the bike all the time. Also with the 29mm the bike will have zero low end pull.

Edited by Padgett

Share this post


Link to post
Share on other sites

The PWK can use the standard jetting from the original carb on the FMF or ProCircut websites. We did the same mod to my RM and only some fine tuning was necessary to make it run perfect. It also uses the same throttle assembly and cable so there is no need for the others.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...