"stuttering" power at high revs?

[XmisterIS]

My SV is currently restricted to 33bhp.

It has a stop on the throttle and washers in the exhaust ... I think ... or perhaps its just a stop on the throttle, I'm not sure.

Anyway, even restricted it accelerates like a little blue lightning bolt and can easily leave pretty much anything on four wheels looking like a dot in my wing mirror (which is why I went for a lightweight V-Twin on a restricted licence!).

Anyway, the acceleration is strong and constant all the way up to about 10K (it redlines at 12k), then it stops accelerating and starts "stuttering" - the engine isn't intermittently cutting out or anything like that, but it feels like it's hit an acceleration "wall" (i.e. suddenly won't accelerate anymore) and it feels like the power is on/off - like it's bouncing in and out of neutral (which clearly it isn't, but that's what it feels like).

When it starts "stuttering" like that, I kick it up into the next gear until it starts stuttering again, then up again, etc.

This only affects me when I am trying to get it to accelerate as hard as possible and I don't do it all that often - normally I have more than enough acceleration at my disposal.

Do you think this is due to the 33bhp restriction or a problem with the engine?

[jamesw]

I would say that is down to your restriction. At high engine speeds the airflow through the engine is much greater. The washer in the exhaust narrows the passage for exhaust gasses, which in simple terms stops the exhaust gasses from exiting the engine at the speed with which they want to exit the engine.

If that makes sense?

[Pete]

Naughty boy! Your poor bike Like James says, it's probably just your restrictor.

[XmisterIS]

Lol! Will it damage the engine if I do that to it?

[Guest akey]

Its down to the restriction mate, best method would be to change up a gear just before you hit the 'wall', or even a good way before the wall.

While in itself it shouldnt damage the engine, it will be putting more strain on all the components including gearbox and final drive, its also actually slowing down your acceleration.

Watch how a racer does it, they rarely hit the rev limiter and when they do its usually a concious decision to hold that gear for benifit a little later (i.e. half a second later so they dont need to change down again).

Even once unrestricted this is good advice, most bikes hit peak power before they hit the red line or rev limiter so its pointless going passed the peak power point.

[MtotheJ]

My Kwak i restricted too and also hits a wall at around 10k revs. Not very pleasant but just need to shift up quicker.

[XmisterIS]

Thanks for the tips, I'm now kicking it up at around 9K, which does actually seem to make it accelerate quicker! Very useful for getting up to speed on very short dual carriageway entry ramps! There's a notoriously short one coming out of a petrol station on the A27 towards Chichester - I can only just get up to 70 in time to join the carriageway, so goodness knows what cars and lorries have to do. I think its dangerous myself, very short entry ramp, straight after a blind bend. Clever road planners ...