Hey: Guys I need help

Last weekend I went ridding and my bike ran very poor from 3/4 to wide open. It had a very hard stumble. It did run ok from idle to 3/4. I know everybody is thinking jetting, but I don't think so. I was ridding in the same pace as I always do. About 3200 feet above sea level. I have not changed my jetting in over a year, it has always run great. The only things that were different were that it was very wet and muddy and I do run an open filter with a outerwear. I cleaned and reoiled the filter today and still no change. I also added a carb adaptor so that I could run a vacumn for my carb vent. I removed it today to see if there was a difference, no better. I checked the plugs and they were both very dark, so I thought weird but maybe rich. I replaced both plugs and jetted the main down because that controls 3/4-full throttle (right). I went down from a 190 to a 185 and still had no change. I again did a plug reading and again they looked black. I checked spark to make sure I did not have a bad coil. Spark was good on both plugs.
It almost feel like a rev limiter kicking in, which I dont have
(Woods box). Do boxes ever fail ??
I do not know what else to check, please help I do not want to go to the dealer and have him tell me it is my carb mount filter and big gun exhaust.

 

a bad battery can sometimes cause symptoms like that. We had that problem with our 01 DS

 

Hey: Jetsnow
When you had this problem did your bike still start ok and run ok until you got to 3/4 throttle. It almost sounds like this could be my problem because I did drain the battery totally a week before that. I did re-charge it, but know that I think of it I have had that problem since.

 

check to make sure that your battery is reading 12.8 volts at least with the engine running.
check your coils to make sure that they are tight. THis will sometimes cause a high end stumble.
If you are at 3200 ft you could possibly go down on your main jet because the higher the altl the less fuel and engine requires.
THis is as far as I can go with out knowing your mods.

 

I would try jetting down, one more time to a 180 before you give up on that idea, that sounds exactly like my bike when it was rich, remeber temp. can make a differance, so going into the summer months can cause a leaner rejet vs the winter....

 

Hey: Guys

Checked my battery to nite and it reads 12.4 not running and 14.3 while running. I even swaped out a battery with another just to make sure - no differance. I checked the connections at the coil and they all seem to be ok.
Is there a way to check the coils(maybe I have a coil breaking up)?
Is it possible for a rev box to go bad ?

Help Help Help

 

How long has it been since you checked the valve clearances? When my intakes tighten up I lose WOT power. The bike starts fine runs great on the bottom, but bad on top. I would call it like a rev limiter kicking in though. But you did say "Almost"[img]i/expressions/face-icon-small-wink.gif[/img]