low power at 3000 to 4000 rpm

[lombere]

Hi I've been trying to solve a problem with my 1999 xt600e, at about 3000 to 4000 rpm there is a stuttering and lack of power. This is most noticeable in 4th and 5th gears but also affects 3rd, it seems to improve after 4000-4200 rpm. The carb has been stripped down cleaned and re-built with the pilot screw set at 1.5 turns out and the carb sync has been set to 7mm, the float level is set to 26mm. The air filter is new as is the oil and filter. I'm going to remove the carb again and check the rubber connections for any damage and splits and also remove my inline fuel filter and check the spark plug. The screw for the drain plug is rounded so I can't check the actual level of fuel in the float bowl.
I'd appreciate any more info and advice on this problem, thanks

Owen

[winmac]

I would set the carb sync to 5mm if you cannot find anything else wrong.

[Moto Zulu]

for me it sounds like air filter, mine 1993 did like this with an blocked filter.

Or if you have an BMC or K&N filter with to much oil on will also give problems like that.

Did you test it without airfilter ?

Did you clean the sieve before the needle valve?

Did you check the sieve on top of the fuel tap?

regards

Thomas

[yelotret3]

I was having the same problem with my bike and i tried countless things to fix it, but nothing worked. I read your article this morning and figured what the heck, i'll give it a try...

Took the bike out for a ride with the air filter off and magic. Bike runs perfect. No miss, no sputter, nothing. I just wanted to thank you for the input. I would have been pulling my hair out for weeks if i had not read your article.

I imagine the best thing to do is purchase a k&n or similar aftermarket air filter to increase flow, as cleaning the old one did not seem to work.

Well anyway, thanks agian. Marc

[lombere]

thanks for the suggestions, the bikes ok now, I tried the old air filter and it was running well again so I stripped the carb again and set the primary needle to the factory setting 4/5 and its fine now with the new air filter
cheers all