Engine cutting-out problem

[L.L. Cool M]

Hello,

I was recently at the Taupo track day. On three or so occasions, when pushing hard around a corner, when I took the accelerator off my revs dropped right off to nothing and it was almost like the bike had stalled and was coasting and I had to pull out of the corner. This did not happen on every corner, but about three times over the whole day.

The local guru said something like (okay struggling here) "It's too rich, too much fuel is going into the carbs." <- that may be wrong.

He suggested always having the accelerator slightly on around a corner, but this goes against how I would like to corner.

As mentioned, this doesn't happen on every corner, but it's also not very confidence inspiring when you don't know if your bike is going to cut out around a corner that you are taking at speed.

Any suggestions?

[F5 Dave]

Before I start throwing things around the description needs some clarification.

So you shut off the throttle, braked, changing down, turning in and it dies? Do you have the clutch fully in? Engine braking will have the revs up a bit.

Or (more likely) as you are about to accelerate out it is like it is out of gas?

Also do you have a fuel filter fitted?

About the advice some people like to raise the idle speed to force the revs to not get too low making it easier to get back on the revs & keeping the front wheel unweighted, by that I mean not having too much weight on the front. Sounds counter intuitive, you're trying to slow down to as fast as you can manage, not be sped up, but with the correct application is the way forward.

[L.L. Cool M]

Thanks for the reply.

Attempted clarification of when this happened:
I am already half-way round a corner at good speed. I shut the throttle off as I feel I am carrying a little too much speed. The bike revs drop to zero, I get no throttle response and it's almost like the bike has stalled, yet the engine is still going. As I'm mid-corner and need acceleration to help me round, I end up having to stand the bike up, clutch in, change down the gears, stop. I then check the track is free, and pull out again. At no point do I actually need to restart the bike, the engine is going the whole time.

There is no clutch in and changing down and then this happens. It's throttle off, then it happens. I don't notice it like it's out of gas, eg: the whole thing is smooth.

I do not know if I have a fuel filter fitted.

[Max Preload]

The bike revs drop to zero, I get no throttle response and it's almost like the bike has stalled, yet the engine is still going.

That's a contradiction. Do you mean the tachometer needle dropped to zero? Or are you saying the engine stops producing power and the wheel is turning it over?

[skidMark]

it's getting no fuel when leaned over...buy a inline electronic fuel pump....

[xwhatsit]

Yeah, if the clutch is engaged and the bike is still in gear then the revs can't drop to zero if you're moving in the corner. The engine is attached to the rear wheel.

However if the tach drops to zero... hmm... electronic tach?

[skidMark]

Yeah, if the clutch is engaged and the bike is still in gear then the revs can't drop to zero if you're moving in the corner. The engine is attached to the rear wheel.

However if the tach drops to zero... hmm... electronic tach?

all zxr250's have an electronic tachometer correct....which goes off cdi so has nothing to do with rear wheel etc..... sounds like hes actually loosing it all together.

hmmmmm.....could be the earth wire to the cdi is loose...sounds like a dodgy electrical connection to be honest....maybe not fuel pump as i suggested earlier... hmmmmmmmmmmmmmmm

[skidMark]

He suggested always having the accelerator slightly on around a corner, but this goes against how I would like to corner.

man you have to keep power on through a corner

you cant not well you can but your cornering speeds will be stuffed....

you must keep the power on for the speed you are doing...

hell i would never not do it...rear goes all over the place...

you dont have to be accelerating,though it is ideal to be to keep revs up through apex due to the edges of your tyre being smaller diameter than the middle...thus you go slower through the corner the more you lean over so u gotta keep the power on....

but at least hold the revs even with the speed you are doing

if you keep the power on you can go through the corner at higher speed as it significantly increases the turning ability of the bike and you will be able to take corners alot tighter, with little or no gas you will run wide like mad.....

where as if you can keep the power on it can push you (and obviously the bike) through the corner.....i aint no physics man so i dunno the details...but it means u can turns sharper and ant higher speed

as you were.

[skidMark]

i think it's just his tachos crapping out i mean if it's running at all it's gunna register something....maybe when tacho doesnt work the cdi gets confused and cant increase revs....check out ur tacho connections fella.

[cowpoos]

Yeah, if the clutch is engaged and the bike is still in gear then the revs can't drop to zero if you're moving in the corner. The engine is attached to the rear wheel.

However if the tach drops to zero... hmm... electronic tach?

yep...my gut feelings telling me that also!!

[xwhatsit]

Yeah that's what I was thinking. If the tach is going to zero, and now it's confirmed it's an electronic tach, maybe there's a complete electronic failure that is affecting the ignition too. Hell, it's even connected to the CDI. Of course it's hard to tell without more information.