2002 yzf jetting for wr?

I am thinking about changing my carb settings to the 2002 yzf specs. I have opened up the exhaust, disconnected grey wire, lid removed, and yz throttle stop so far. From reading some of the past posts I think I would be a good candidate for this because of the mods done. I ride in Michigan and was wondering if anyone has any suggestions or tips before doing this. Also does anyone have the carb specs for the 2002 yzf 426. From past posts I have seen some info on the air cut valve and understand that the yz does not have this. Does the 2002 wr have it and will I have to plug it when changing to yz carb specs. Any info will be greatly appreciated.

wr 2002 has the ACV and you have to desable it, if you want to replicate yz jetting. Try a search on ACV and you will find many information on the subject. yz jets that are different from wr's are:

MJ: 162 (4MX-14943-90)

PAS: 100 (7A9-14943-27) needed if ACV disabled

OBEJP needle (5JG-14916-JP)

Starter jet(for chock):72 (3TJ-1494F-16)

I think that's all you have to change. I will advise you read the "Jetting Qs" tread (here). It's great info that TT best jetting gurus gave us all, and it's FREE :)


[ September 09, 2002, 12:02 AM: Message edited by: sabin ]

On my 02,I left the acv as is. The original 42 pilot jet and 75 pilot air jet seemed to be the best combo. Do the BK mod and cut the squirt down to 1 second or less. I used the OBELN(clip 3) from the 250F.Increase the main jet to a 168. These settings and YZ timing has my 02 just flat out ripping.

Good Luck...

as harem says "yz timing ...."


Harem, at what elevation/humidity are you riding?

200' - 1700'

high humidity and temps in the 90's.

tweek the fuel screw a little to adjust for different conditions.

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