Wot Help!

[motomike07]

Hi guys

i'm still having trouble with my pitpro 140xr at WOT. pretty much 3/4 throttle and below is perfect, then going past that from 3/4 to WOT and the bike splutters and bogs, it doesn't die though, just won't accelerate anymore...like it's getting too much fuel and not enough air. i had a 105 main jet in there, took that out and put a 102.5, made no difference....i wrote in an earlier post about changing the e-clip position...would this help??? i thought the e-clip is only associated with fueling from 1/2 to 3/4 throttle?

any ideas why the revs aren't cleaning out at WOT? it's really annoying

it's a stock 30mm mikuni carby that comes with an 08 pitpro 140xr. the only mods to the carby that i've done are the 102.5 main jet (on at the moment) and a uni filter.

any help would be great

cheers

Mike

 

[roost666]

ya play with the e-clip im pretty sure thats your problem

 

[thump*140]

when you say splutters and bogs, is it loading up, or is it making a loud, sharp crack when it goes bang?? if it sharp crack, might be too lean on the main jet, not too rich... easiest way to check, is to clean up your spark plug, put it back in, find a decent straight, start it up, (warm), then run it through the gears at full throttle... stop and pull spark plug out... if plug electrode is black and sooty, it's too rich, if it's white or "ashy" it's too lean.... plug electrodes should be a tan colour if it's jetted properly... run a plug chop, and go from there....another way is to raise your needle to the bottom clip, run full throttle.. if it's still blubbery, you need a bigger mainjet..

 

[rumble]

i had the same issue with my 150XR. I had to make the main jet bigger.

As thump said try a lower clip or two, three and if the top end is better you will need a bigger main jet. If you do get the bigger main jet you will have to adjust the e clip again.

By my scetchy memory i think i went to a 110 or 112, thats for a yx150.

 

[thump*140]

having same issue with my LIFAN 140 fitted with 28mm oko flatslide... i've gone from a 130 mainjet (keihin jets, not mikuni, so they're bigger than what you're running) to a 148 mainjet... unfortunately churchill road isnt the best place to tune bikes, so i'm waiting til i can ride the thing before posting results.... Brian from East50's has been incredibly helpful in tuning, and suggested that small steps with main jets MAY not be effective with the problems we both seem to be experiencing... try going from a 102.5 to a 110 mainjet and see if that fixes thing. start with the needle clip on the middle position, run it at full throttle through the gears, and do a plug chop to see if the plug is overly sooty or has unburnt fuel on it... I am having mine dynoed on thursday of this week to tune the carby, float bowl and timing, so once i have results, i'll post them on here as hints for others using a similar setup, as to whether the problem is being too rich or too lean....