jetting advice needed/ cuts out at top
Posted April 29, 2000 - 01:51 PM
At top rpm, she now cuts out....studders.
I have a canadian 2000 model with the following:
Air box lid removed.
No throttle restriction.
New fmf power core IV-2 pipe.
I went from 42 pilot to 45 pilot.
Main from 165 to 175
Pilot screw from 1 2/8 to 1 1/2.
I'am at sea level and air temp was 70.
I tried the new pipe with the original jetting and it did not cut out. However, it certainly did not have the same amount of acceleration.
After modifying the carb, it cuts out at top. The rest of the powerband from bottom to near top is good.
Is it overjetted? Maybe I should try the 168 main jet and work it from there? Or perhaps I go down one clip (3) on the needle?
What do you think?
Posted April 29, 2000 - 05:08 PM
Posted April 30, 2000 - 04:27 PM
86TT225, 98CR80, 99WR, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. Odometer and headlight removed. Moose hand and mud guards.
Posted May 01, 2000 - 05:28 PM
While I'm no longer the mechanical moron I claimed to be in the early days of this site, I still am learning the theories of jetting and engine diagnostics.
James and Clark are your best bets here. Good luck.
Dougie, '99 WR400
Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics
Posted May 01, 2000 - 06:01 PM
Posted May 01, 2000 - 07:03 PM
Posted May 03, 2000 - 07:29 PM
Thanks for your advice. It made a lot of sense. I now believe I am hitting the rev limiter. Prior to the new pipe, I never tacked it out. Afterwards, I deliberately wanted to see the performance...naturally it cut out on top. Just to be sure I wasn't fooling myself about it, I rejetted the carb back to original (165 main, 42 pilot, 4 clip down, 1 2/8 screw adjustment). Again, it cut out at top!
Oh, one other thing, I have a different needle on the Canadian. I believe it runs a couple of clips richer than stock. It's last initial is a Q. Instead of richening it, I dropped it to the third clip. It seemed slightly cleaner on top than the second or fourth clip.
Bottom line...I now have a 45 pilot, 175 main, 3 clip and 1 1/2 screw adjustment. It seems to work well with the FMF IV-2, no throttle restriction and airbox lid removed.