FZR600R Rev Limiter.

[Alex.]

Hi Chaps,

I had my bike on the Gibson dyno last Saturday and came away with the curve below:-

The engine is a 1994 FZR600R Foxeye, with some suspected mods.

It is a nice smooth curve, but I can't help noticing that the curve is still going up when the rev limiter is hit.

Do you think that there would be any benefit from raising the rev limit? Perhaps by sourcing a race CDI of some description?

Alex.

[Marb]

That is a curve you can be proud of.

Over on the dutch FZR forum some of the racers are using http://www.ignitech.cz/ ignitions and speak highly of them.

[Andy J]

The trouble with raising the rev limit is that you stand a greater chance of the engine shitting itself. You may need to think about stronger rods, different valve springs etc. Im not saying its not possible but the limiter is there for a reason.

[Alex.]

My thinking is that if previous work has been done and it includes electrics to raise the rev limit, then some internals will probably have been modified to cope.

It is currently only 3bhp down on Monty's superspert tuned FZR6 3HE, so something must have been done.

It was just the curve that suggested to me that the bike was expecting to rev higher...

Alex.

[lorenzo]

I wonder how different the cdi on the 400 is? Didn't they have a higher rev limiter? And yes, it'd be a laugh, but I wouldn't spend very long up above the usual redline unless you were friendly with an engine builder.

[Kayla]

I wonder how different the cdi on the 400 is? Didn't they have a higher rev limiter? And yes, it'd be a laugh, but I wouldn't spend very long up above the usual redline unless you were friendly with an engine builder.

The 400 cdi has a restriction built in that's a bit of a bugger to get around*. I think you'd need the clocks and stuff to get it to work properly. They rev to 14,000 ish.

* Having said that, my li'l FZR400 (running no clocks other than a Vapor thinger) seems to rev out ok without any of the restriction wiring actually present

[Alex.]

I know that the 3HE 600 engine will run in a 3EN 400 using the 400 electrics, with a higher rev limit.

But I don't think it is the case with the 4JH 600 and 3TJ 400. Usually, when this conversion is done all of the 600 electrics are used.

I have been looking around for a race CDI, but can't find anything! Probably because not many people raced these in the 2 years they were around...

Alex.

[fran9r]

That is a curve you can be proud of.

Over on the dutch FZR forum some of the racers are using http://www.ignitech.cz/ ignitions and speak highly of them.

Mmm that stuff sounds good...

[Evilchicken0]

Looking at the speed of the bike on the graph I'd suggest you change into 6th !!!

You "might" want to over rev the engine on a straigh, on track instead of changing up ... but then you might want to short shift. Chances are you'll only very rarely use the extra and as pointed out that would come at the cost of engine wear.

Fit a turbo

[Alex.]

As the bike is a road bike, I would very rarely use the extra.

But my train of thought is such that if the engine had been tuned by a previous owner, but put back with a standard chassis/electrics, then maybe I am missing out on some easy and cheap power.

Besides, I'm an incurable mechanical fiddler...

Alex.

[Evilchicken0]

power schmower

Once your up that high on a motor the extra will only be a number and not usable. Torque is what you want