Mileage before/after BK mod and jetting

Has anyone documented their mileage on a WR before an after the BK mod/jetting/timing changes? I want the performance, but would rather have the range since I don't ride my machine to its full potential as it is. TIA

Fat Matt

Fat Matt,

I couldnt help but think doing the mod would only improve gas mileage, as you're reducing the amount of gas on the accel. pump reduce bog.

Do the mod...and if you do it the "non-permanent" way as described in this forum, you can always go back to the way it was by simply turning the newly-added screw back out.

Red Wings suck!


A loyal Av's fan!

I thought about that also, but, in my experience, more performance always means less efficient. Thanks for your input.


BTW. I have to brag about the Wings. Can you say 8 present/future hall of famers, including 3 600-career-goal scorers? Well, at least the Av's don't have Claude "the turtle" Lemeiux anymore.

Fat Matt,

That's all fine and long as they can last throughout the whole season! I'll give you three things...

1. your team is stacked with older talent.

2. your team so far is kicking the crap out of the rest of the league.

3. the av's are playing with a very serious stanley hangover.

I do miss the good ol' rivalries with the Av's/Wings...but I sure dont miss Bowman and Crawford whining back and forth at one another!

How's Krupp being doing for ya? :)

I would have to back up Matt with what he said:


As for the BK mod, no idea as I've not done it yet.

Hey Matt, are you in Detroit or in the suburbs? I'm in Canton just west of I-275. Do you ride with a group? So far I have been riding alone, luckily without major incident.

Good question!! First we are reducing the squirt of the accel pump..good. To counter the shorter squirt duration we are increasing the size of the pilot good, possibly raising the needle a position or good and finally going up on the main jet a size or good. On the other hand, if it is running better you might not have to be on the gas as much to get the same result.

Based on my riding experience with and without the BK mod, I haven't noticed a difference in fuel consumption.


I generally get the opposite affect. Any performance increase usually comes with a more efficient running motor. My 450 gets way better mileage than a 400 or 426 since I'm not in the main jet nearly as much.

Thanks for the info. everyone. I guess I might be the first to check into the mileage pertaining to these mods. I'm still all stock, panty-hosed modded airbox cover, t-stop trimmed, grey wire snipped. I ride with and without the baffle. I'll do the BK mod first, then work from there. I'll post what I find.

POOLEY, send an e-mail to with your phone number or I'll reply w/ mine. I'd like to talk about doing some serious trail riding. I ride w/ almost all quads right now and need to break free! Thanks.


Originally posted by Matt the Fat:

I ride with and without the baffle.


I would guess that you may have to have two jetting combos as the baffle really chokes down the exhaust. One setting without the baffle and one with it. You'll have to ride it both ways before you'll know for sure.


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