GPX 250 problem

Hi all,

I recently bought a GPX and have had it serviced, (new chain sprockets
and tuned etc). However there seems to be a problem. There is a flat
spot in the acceleration at low revs < 5k (it's hard to tell exact;y
as when it happens I don't want to look down at the tacho).... I was
told by the mechanic that I wasn't reving hard enough and the delay
was a rubber shock absorbing mechanism in the drive train. Which may
account for the 'flat spot' sometimes but I don't think all the time.

Also at some times the engine changes it's note and makes a kind of
warbling sound and looses power, I think only when high rev's low
gear. That said I feel I have never gone beyond about 10k and have
been pretty careful.

Any ideas, suggestions would be helpful.

Cheers,

Peter Cupit

 

All Stock Gpx250's have a flat spot in the power from 5-5.5k rpm you can
fix the problem with a rejet but it is probably not worth it as you won't
spent too much time down there anyway.
Robert

98 VFR800
99 Gpx 250

 

The reason for the flatspot would most likely be that that is the point at which the sound reading
is taken for the DB rating of the bike, check the little sticker on the side of the bike specifying
how noisy it is, check the sticker for the revs for the measurement.

Mike.S

 

ridden gpx/zzr250
variety of problems
problems soved when i found workshop that tuened "by the book"
good luck in finding such a white elefant
adrian

 

Keep the revs above 6,000? ;-)

I don't know about the "warbling sound", although the later models
('94 or so on I think) have a rev limiter in the ignition box that
cuts off the spark to one cylinder once you get to 14,000rpm, maybe
that's what the problem is? *shrug*.

Excellent choice of motorcycle, by the way! ;-)


BTH

 

Yeah, changing gears at about 9-11 thou rpm is a decent point to do it, not the 4500-5600
if you were revving a car pretty hard

Mike.S

 

Thanks for the ideas / suggestions. Perhaps my main problem is that by
force of habit I try to keep the rev range to the same as a car...

Btw, I like to do one of my practice rides up and down the road from
Berwick to Emerald, great road (I think). So if you happen to notice
me steer well clear! (I'll probably be the slow one).

Cheers,

Peter Cupit