Cbr600 cutting out when pulling away...

[BuzzBravado]

....and it is doing my tits in. Any pointers on where to start? If I rev it harder when pulling away it lowers the chance of it cutting out, instead it might drop a cylinder until it clears its throat. Also cuts out if I try to very quickly blip the throttle. Increasing the throttle at a regular pace is fine. Idles fine at 1k. It's the last of the carb models.

[BuzzBravado]

Yeah the "fy fx" model

[BuzzBravado]

Steve Bass said:

Carb overhaul time I'd say. Sounds like it's passing enough fuel for tick over but not enough for load.

Time for a new bike you say. Well if needs must

[BuzzBravado]

On closer inspection it idles at 1300 and sounds happy there. This morning filtered right to the front, no doubt ruffling some feathers, where i prompted stalled the bike twice taking away and holding people up. Felt like a right plum.

[BuzzBravado]

Yeah it looks that way. A pain because it is my daily, and will likely be off the road for some time. If the carbs are coming out, i may as well do the valve clearances at the same time.

Its now on 13k miles, with no evidence of any real servicing beyond oil/air changes.

Sigh!

[BuzzBravado]

The mileage works out less than 1000 miles per year, so it is could be gunked up. But this is a new issue, and it had been doing 250 miles per month since April. I'll run a bottle of seafoam or the like through it just in case, but that tends to be wishful thinking.

I'm thinking it could one of the plugs breaking down?

Edited by BuzzBravado on Tuesday 3rd November 12:34

[BuzzBravado]

Prof Prolapse said:

If the engine is only on 13K does it need the clearances? I know in an ideal world etc, but is the mileage indicated by the service interval not double that?

I did them on my CBR600FX and I wish I hadn't and it went without issue. Fiddly fking stty job.

Then again some people like that sort of thing.

There is a light tick, which could be normal, i have nothing to compare it against as its my first bike. A little online reading suggests the "F4" gets the clearances done around 16k.

[BuzzBravado]

Steve Bass said:

Not knowing the history of the Plugs, it'd be worth changing them out as it's a quick and easy fix. Fingers crossed that'll sort it but it might also be gunk from the tank in one of the carbs. Have you checked the fuel filter to see if there's signs of particles or gunk in there??

I'm willing to bet the plugs have never been changed. I haven't checked anything yet.

[BuzzBravado]

UPDATE:

I thought i should post the fix since so many OP's never come back to say what the issue was..... I taken the plugs out which looked perfectly fine, but changed them anyway. Now runs so much nicer and doesn't cut out. Start with the obvious eh.

[BuzzBravado]

Mines was coils straight onto the plugs, so no HT leads. On one plug there was corrosion on the plug where it connects to the coil so that may have been enough to cause an issue. Although my plugs looked fine and were still gaped correctly, i would guess they were original so 15 years old and that was enough to warrant replacement.

I also opened the bleed screws on each carb bowl to empty any water that might have been floating on the fuel. No idea if it helped any though.

I'm still waiting for the issue to re-appear as i cant believe the plugs could have caused all those symptoms, especially the revs dipping with a sharp throttle blip, but there you go.

Edited by BuzzBravado on Monday 23 November 12:07

[BuzzBravado]

Prof Prolapse said:

Just a thought, but did you check the resistance across the coil packs? I think a comparison would have been useful to rule them out.

Nope, i didn't think about them to be honest. Still going well so far.