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salz

'02 WR426 Jetting in the Denver area

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Help! Based on info from a friend, I recently did the following: 38PJ/65PAJ (or 3/8 turn out using a PAS)/EKP#3/150MJ/160MAJ/approx. 1.5 turns out on pilot screw.

Ride mostly 6-10,000 feet: Left Hand Canyon, Rollinsville, and Ward areas. The bike always starts, idles perfect, good acceleration 1/4 to 3/4 throttle. But there are 2 problems: sooty plug after a day of riding, and upon full throttle (and holding the throttle wide open) I get engine "hesitation" or engine "surging" at the higher RPM band.

Any ideas or recommendations would be greatly appreciated.

R Salzwedel

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That is a pretty small Main and MAJ, even at that altitude. I would suggest trying one size larger on each and doing some WOT runs to compare.

Also, it wouldn’t surprise me if clip # 2 was better than # 3 at the higher elevations for your EKP. If I were you I’d also try an EKQ or even EKR (Yamaha PN: 5JG-14916-E1 or 5JG-14916-ER). They are leaner off the bottom and would probably work better with a 38 pilot compared to the EKP.

I don’t pay any attention whatsoever to what my plug looks like. Carb has an accelerator pump that squirts a stream of gas right at it whenever you twist the throttle, so there is always the potential for it to be sooty…

[edited for PN correction]

[ August 01, 2002: Message edited by: Hick ]

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Originally posted by Hick:

That is a pretty small Main and MAJ, even at that altitude. I would suggest trying one size larger on each and doing some WOT runs to compare.

Trying one change at a time, of course, so I guess I'd suggest trying the larger main, then try to dial in the higher rpms by changing the MAJ.

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I agree on you being a bit lean. I run a 158 main at anything over 8,000K, and a 160 main from 5,000K to 8,000K. However, since I don't even know my other jet settings, I'll let the true experts help.

Late

Dodger :):D

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salz, what other mods have you done, if any? That is LarryCo's jetting, and if I remember correctly he is running the stock pipe with another tip and WR timing.

I agree with the suggestions to try moving up on the main jet. I am running the__R needle though and find it too lean with a 42 PJ.

Dodger, are you running a D__ or an E__ needle?

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All I can really say is that this jetting works for me. I would be interested to see if it works for anyone else. Check the sig and let me know if you try and if you find something better.

Jason

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salz,

I ride anywhere from 6,000ft to 13,000ft and my setup (in my signiture) works awesome. My bike runs great through all ranges. When I first got my WR, I had the exact same hesitation and surging problem while holding the throttle wide open, it was way too rich. Also if you haven't already, do the BK mod and the ACV mod, these make a world of difference. Everybody's bike is set up and behaves differently so don't be surprised if your jetting settings are completely different. Just look at this topic, 148MJ to a 158MJ, big difference.

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Salz,

That's pretty much the exact jetting I use out at Rampart and Moab (4K - 9K). Runs fantastic! Let me qualify my statement by saying that I have done the BK mod (0.5 sec squirt) and have a US uncorked stock WR exhaust (no insert). Also have WR timing, which I'm not convinved makes a big difference. May be a difference here between our bikes to account for...

When at higher altitudes (9K - 13K), like out in Rollinsville/St. Mary's glacier area or in Ouray/Crested Butte, I've found that my bike is entirely too RICH with this jetting. I'm getting close to higher altitude jetting by using the following: 38PJ/65PAJ/EKQ#2/148MJ/160MAJ...but it's still hesitating sometimes when whacking the throttle at lower speeds to wheelie stuff. Notice that I'm running clip #2, while you're running clip #3. You might try that to start...and try to lean out a bit your pilot circuit.

Taffy suggested a couple of things (which I havent tried yet) to eliminate that lower-end bog...one was to further limit the accelerator pump squirt (BK mod to about 0.25 sec...just a drizzle), another was to actually RAISE my EKQ needle to #3 while lowering the main jet to about a 145 or 142, and the last was to try another needle altogether (like that EKR for eg.). I was going to start with changing the accel pump squirt and go from there. The bike does run great except for that occasional low end bog...so I'm close.

Like I said, I havent got this jetting down quite yet (havent been out to ride in a while), so experiment a bit. But I CAN SAY that this is normal for the jetting setup that you currently have, in that what you're running is TOO RICH for that altitude.

Let me know how you end up...I've got Moab to Denver to Rampart jetting down...just need a bit more work on that even higher stuff.

Larry

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I figured you would show up on this post sooner or later Larry. :) Whacha been up to?

I tried the shorter duration squirt on the BK mod and it didn't work too well. I finally just ended up tinkering with it while the bike was running to fine-tune it, now I haven't got a clue how long the squirt lasts.

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Originally posted by LarryCO:

Taffy suggested a couple of things (which I havent tried yet) to eliminate that lower-end bog...one was to further limit the accelerator pump squirt (BK mod to about 0.25 sec...just a drizzle), another was to actually RAISE my EKQ needle to #3 while lowering the main jet to about a 145 or 142, and the last was to try another needle altogether (like that EKR for eg.).

Larry,

Keep in mind Taffy is, well, he’s English. And he rides a 400. And he hates accelerator pumps.

Anyway, I just wanted to encourage you to try a different needle. An EKP/EJP is too rich for me down here at 4000+, not a huge amount, but an EKQ is better, and it is actually most noticeable when you are just getting on the gas...

I still can’t believe that tiny main gives you good top end, although I’ve never even tried anything smaller than a 158 main/180 MAJ...

I’ve read that the main jet affects a good portion of the throttle range, but my fanny tells me it doesn’t do much at all. Back in the early days of TTalk somebody, might have been James Dean, removed the main altogether and didn’t notice any difference at all unless it was WOT...

Then Taffy and JD had everybody drilling their MAJ’s larger, then Taff had some sort of epiphany and went the opposite extreme. I can’t keep track.

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Wicked,

How r u amigo? Been doing allright myself. Planning a ride at Rampart this Sat with Dougie if you're interested. Also, we're taking the week after Labor Day to head out to Ouray/Telluride/Crested Butte if that fits into your schedule. Let me know on either account and I'll email you the details.

Hick,

Thanks for the input. Yeah, that "P" needle does get a bit rich at altitude (I've found over 9K ft. I start having problems). Thus, the recent move to the EKQ. It seems to run fine, except for that damn occasional bog when whacking the throttle. I'll get it figured out here. That EKP does run quite well for me with a 38PJ/65PAJ though in Denver...

Yes, I do run lean mains. Probably a bit too lean...but I hate to foul plugs, period! LOL A 150MJ is definitely too lean for Denver riding, but works pretty well when you're up over 9K ft.

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