jerky throttle

[ac@39]

jerky is about as best i can describe it - have resolved umpteen issues and thought this was possibly down to the gearing i had had chosen, but it would appear not.

while under hard acceleration the bike is fine - if i have to cruise along its almost as if every bump i hit opens the throttle

carbs are all stripped cleaned and balanced - tps is adjusted correctly

i have changed the gearing, loosened off the throttle cable play - no difference made ( throttle cable play now back as was )
i have checked there is enough play on the throttle cable routing so that bumps wont come into play

but basically going into a roundabout is a slightly hairy experience as cannot maintain a smooth throttle

any ideas what i can look at?

[cobbadiggabuddyblooo]

Not much info to go by. What RPM, what gear, what speed, still with std ECU????

[Rod.s]

Did you forget to replace the carb piston dampening springs?

[ac@39]

All gears - all rpms that require a careful/ considered throttle - full chat any gear and no issue whatsoever- just when your trying to cruise
Carbs been apart several times and all present and correct
Running standard Ecu

Chain has been checked for tight spots and whilst there were a couple all appear to have the same play on them now

Have even swapped the needles out for aftermarket ones with 6 settings and thinner taper and made no difference

Doesn’t feel electrical at all just very jerky on - off- on feeling

[Rod.s]

I know this sounds strange, but I've recently helped a chap with a TRX and his carbs were not seated correctly resulting in similar behaviour, secondly what conditioner the carb manifolds? any splits or cracks?

[cobbadiggabuddyblooo]

Vaccum operated fuel tap... Get rid of it.....
Look on my rebuild thread as I just put the link there for the std TRX tap mod...

[Racer-unk]

what cobba said, then spark plug caps, wires, coils? does it happen more when wet?

[dicky]

It really does sound like no slack in the throttle cables, but you've checked that already.
Where did you adjust it, at the carbs or behind the triple clamp?
I had the same problem a while back and found that I had to have a couple of goes at the top adjuster to get it right. Slacker is better.

[ac@39]

Fue Vacuum tap mod was done from the offset

Can recheck carb rubbers easily enough and they look in ok condition -
the throttle slack was adjusted carb end so can see what if any difference when adjusted at the triple clamp end

And can swap out the coils as have a spare pair although I’ve not ridden it in the rain

Will post back the results