Help re engine problem needed

[starmist]

Just recently my Griff 500 has started to go flat at around 3200 rpm onwards. There's no popping and banging which would indicate a sparking problem, and to start with it seemed to cure if I planted my foot.

More recently even this does not help. Even if I toe it, it pauses, pulls, hesitates again... It seems like some kind of fuel starvation.

Can anyone tell me what to start looking at, i.e. duff connection to fuel pump, injectors, etc. Or is this typical of another well documented problem? It just seems strange that everything is okay below 3200, even with a bootful.

Thanks in advance...

[Heliox]

Fuel filter need changing?

h

[starmist]

Hadn't thought of that one! Thanx. Where is it? Under the bonnet somewhere?

I wondered if the tank might be filling up with crud.

[mongoose]

fuel pump and filter are easily accessed after jacking up the n/side rear.

[siwes]

What year is your Griff?
If it is a 95 onward check the coil amplifier, does it feel like a rev limiter is coming in ? mine used to do it around 4000 rpm took a lot of finding.little solid state box of tricks next to the coil .
good luck
Simon

[starmist]

I'll have a look at both of thes (today if I have time). Thanks for that.

Given that everything is fine under 3200rpm I can't help but think it's an electronic thing, where something's supposed to happen, like altered ignition timing and it isn't. If it was fuel starvation you would expect this to happen on throttle application, rather than revs alone, surely?