Thanks Hick

Well, so far this is the best it has been.

Pilot: #38 @ 1 1/2 out

Needle: EJR clip #2

Main: #162

Acc. Pump Duration: One full turn out from .3 seconds

I made the last adjustment to the acc. pump on the trail, so I was not able to time it.

I am not the best tester, but I can't tell you how many corners I overshot on yesterdays ride. I have a 30 mile loop out my back door that I do 3-5 times a week, and I know every inch very well. Coming out of several corners I found myself panic braking to make the next turn. The same ammount of throttle for the same ammount of time (as yesterday) resulted in much more acceleration.

Once or twice I wicked it wide open instantly from a very low rpm. This resulted in a pop through the carb, then instant acceleration. That is when I added the extra turn out (more fuel) on the acc. pump. That seems to have cured the pop, but I did not really test it thoroughly.

I feel I still need to do a bit more fine tuning, but now it truly is awsome.

I might want to try the EKR, Where does it end?

Important notes; all testing done at 7-8000ft, '01 yz426 with Big Gun SDS (single,dual,single) pipe. Big gun claims this pipe makes 1 full HP more than thier others at the bottom.


Rick Fuller

'01 yz426

'00 yz426 destroyed by fire in desert race 4/22/01

'81 490 Maico



I assume you already rode it some with EJR #3??

Because it sounds like it MAY want to be a tiny bit richer on the clip (the cough when you wick it, if more juice from the pump doesn’t get rid of this).

You may also try a few roll-on tests with the pump turned off altogether. For me that really made it obvious where my clip position needed to be. I keep track of the # of turns out on the pump, you need to have the cover off to see exactly where zero pump travel is (stop screw just touches cam with throttle closed), I’ve never bothered to time the squirt.

I’m glad you liked the R needle, maybe EKR #3 (equivalent to EJR # 2.5) is that last 1%.

If you are having fun messing with this stuff I really think you should get the adjustable Pilot Air Jet from Sudco, like $15 w/ shipping, the smaller sized pilot should work better with a smaller PAJ and the infinitely adjustable kind is only a few bucks more than buying a WR # 75 fixed-size PAJ. I’m somewhere around 80 or 90 on the PAJ with a 40 pilot down here at 4k ft. You can jet for this by trying small throttle openings to neutral throttle and back. This sort of overlaps the straight portion of the needle, you are now two sizes leaner there (R vs. stock P), and with the smaller pilot the only thing missing then is a smaller PAJ.

Worth a try for fifteen bucks anyway.


I'll be in Tonapoh this weekend for course marking and the North/South State Championships will be in two weeks, so I'll be back down there Sept. 8,9.

I'd like to check out your scoot when your settled on the setting. I changed to YZ timing after the grey wire mod and am thinking about going back. I just miss the low end punch. I'm really more of an open bike style, although I have to admit for wide open desert is seems to be better mid to top. If the Big Gun has more bottom, that might be the ticket.

Give me a call when your ready, I'd love to see your loop.



Is the Big Gun SDS a spark arrestor? I am looking a putting a spark arrester silencer on my 00 WR400, but haven't decided which one. I like the FMF IV2 with the power bomb head pipe, but have also liked the dyno curves for the Big Gun. My head pipe doesn't need replacing, yet. But I like the heat guard and might get a 01 head pipe for oil filter clearance.

The bike came with a Pro Circuit 304 series, but no spark arrestor is available for it. I have considered taking a small add on sparky and trying to adapt it to the 2" Pro Circuit exaust port. Don't know if it would even work, just hard to shell out 3-4 hundred when I have this other pipe already.

So, any way you sound happy with the Big Gun?



The SDS is a header, no longer in production. I also have the Big Gun silencer with S/A.

I like the system, but it is all I know. I tend to lug it from time to time, and rarely use the top end.

I have your phone number, just been to busy.


Rick Fuller

'01 yz426

'00 yz426 destroyed by fire in desert race 4/22/01

'81 490 Maico


A friend of mine is in the process of modifying his 304 muffler with a Pro Circuit R4 endcap/spark arrestor. Since I have the same pipe, I'll let you know the result.



01' WR426

99' YZ400

87' FZR1000

Uh, like twist the throttle...

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