Sign in to follow this  
Followers 0
koondawg

hesitation on accell

24 posts in this topic

i was riding my new bike today and it was heistating on accell. even cruisin in 3rd, no accell it would hesitate and hop kind of?? i just cut my gray wire,

any ideas?

Share this post


Link to post
Share on other sites

Do a search in this forum for the TPS (throttle position sensor). It can cause a similar situation to what you describe.

Share this post


Link to post
Share on other sites

The TPS "usually" only causes a miss at constant throttle so i would say jetting as well. But there is an easy test just to make sure. Just unplug the TPS and see if the problem goes away or at least improves.

Share this post


Link to post
Share on other sites

okay, it is more noticable at constant speeds, but it does seem to hesitate right at first on accell, but after that she roars..

thanks, i'll check the tps first.

Share this post


Link to post
Share on other sites

koondawg,

Most of us went thru the same thing, rejetted and took care of the problem.

Do you recall if the hesitation was threre before the grey wire mod? I don't remember with mine because I cut it right away.

Thanks

Share this post


Link to post
Share on other sites
rejet and tune your carb. It's running lean

Wrong way mate! It is rich for sure!

Share this post


Link to post
Share on other sites
okay, it is more noticable at constant speeds, but it does seem to hesitate right at first on accell, but after that she roars..

thanks, i'll check the tps first.

Don't touch TPS, it is there for a reason.

Jet your carb corectly! I suggest drop your needle 1 clip to lean it off.

Share this post


Link to post
Share on other sites

Search about the TPS--the posts appear to be about evenly split. Some say remove it, some say don't.

Share this post


Link to post
Share on other sites

hook the grey wire back up :thumbsup:

See if that what caused it. What other mods you do to it besides the grey wire? After doing mods be prepared to set up your jetting

Share this post


Link to post
Share on other sites
Disconnecting the TPS seems to be a quick 1/2 fix for poor jetting.

Matty, my bike was jetted near perfect and it still had a constant speed miss. I only noticed it when I road it up the street and held a 1/4 to 1/2 throttle which seldom happens with I ride dirt and it went away with the TPS disconnected. Check with the experts like burned and JD and they will tell you a constant speed miss is NOT jetting related. I'm not saying to leave it disconnected but disconnecting it is a quick way to see if it is causing part of the problem.

Share this post


Link to post
Share on other sites

The reason I asked if it did it before the grey wire mod was that I did the mods all at one to a new bike and only rode the unmodded beast once.

Here was my thinking:

The grey wire mod remaps the CDI to the YZ curve. Thei curve advances the timing much sooner than the WR curve. The WR having a heaver flywheel can't 'spool' off the bottom as well.

Advancing timing reduces torque increasing upperend power.

My thought in progress.....

I'm going to do a controlled experiment and try it w/ and w/o grey wire mod and see what the effect is to off idle stumble, hopefully this weekend.

Share this post


Link to post
Share on other sites

well, i cut the wire so hookin back up is not as easy as clippin it back in, i guess i got excited for more umph!

i just drove it with and without the TPS, definately accell a lot smoother without and starting also, but I still did notice the problem, just not as bad.

i was going to cut my Throttle stop, but it appears it has already been done, and it looks a little short??

i just bought the bike, it has exhaust , w race series?, and I thinks thats all the mods.....

Share this post


Link to post
Share on other sites

I didn't see where you said which WR you had.

Be sure to adjust the slop from your accelerator pump linkage. This will help a bunch with the hickup off idle.

Also, I went to a #35 leak jeat that helped a ton. To get the bog I really have to try snapping the throttle hard. At this poing its really no a realistiic problem since there is no reason to snap it like that during riding but I still want to tune it out. I may try a closed off leak jet this weekend. If it still has ANY hesitation I'm trying a Boysen quick shot.

The trouble is that here in PA this time of year we may have a 20 degree night and 30 degree day for only anotehr week then right up to the 50, 60 and 70's and its back to the jetting but once I get rid of the off idle issue I should be able to keep it gone.

Easy starting can be had with better jetting.

The TPS is to help the CDI 'anticipate' where to put the timing bsed on throttle position instead of just using RPM teh CDI uses both.

Share this post


Link to post
Share on other sites
Matty, my bike was jetted near perfect and it still had a constant speed miss. I only noticed it when I road it up the street and held a 1/4 to 1/2 throttle which seldom happens with I ride dirt and it went away with the TPS disconnected. Check with the experts like burned and JD and they will tell you a constant speed miss is NOT jetting related. I'm not saying to leave it disconnected but disconnecting it is a quick way to see if it is causing part of the problem.

Sometimes its hard to determine the miss. But the original post suggested that the miss started after the grey wire was cut. Its kinda of hard to listen to a bike over the internet and determine if the miss is carberation, or ignition missing. The throttle position sensor isnt gonna cause the problem at a steady throttle as its doing nothing.

I personally think it is your jetting. These carbs are crazy.

Im waiting for temperatures to warm up before setting up my carb, so I can run all summer with out tinkering with it :thumbsup:

unplugging your tps is only retarding your vacuum advance, and hiding your problem.

Share this post


Link to post
Share on other sites

Waiting for warm temps is a good idea. I did mine during a 70 deg warm snap two weeks ago. I ran great. Now its 30 and a bit lean. Temps should be back up soon.

Share this post


Link to post
Share on other sites
I personally think it is your jetting.
I agree, but not one person has asked for your jetting specs. I think you should tear into your carb, for a good cleaning at least, and figure out which jets you are running. Post your specs and I'm sure someone can make a much more well informed recommendation.

Share this post


Link to post
Share on other sites

I am goinng to take it apart and clean it up if nothin else.. I will see what I got in there, it was mid 40's and I will be riding in 60's-70's for a few months then 80's, 90's for bit.

I am thinking it was there before I cut the grey wire, just not as bad, it was a lot warmer the day I drove it uncut

Sounds like I am going to get to know this carb pretty good

thanks for your help. If I have more poblems with the warm weather I will start jetting research :thumbsup:

2003 wr450f

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0