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Hello again,

Next problem.... Lol.

Running sweet, had a good couple days, maybe even a week on her. Now this has happened a couple of times.....

This has only ever happened on a dual carriage way at full whack. I'll pin it right up to the speed limit (honest/honest ) then when I roll off the throttle and go to reapply it makes an awful noise and power like it's only running on 2 or 3 cylinders or running out of fuel. It jumps back into life sometimes momentarily but inevitably it will cut out and I'll coast to the side.

Now the first time this happened my fuel was low, I assumed it was out popped reserve on and away she went. Happened a 2nd time and I assumed again. It just happened to me a 3rd time on the way home from work and I thought there is no way I have used that tank already. I pop open the cap and can see plenty of fuel, well above that metal plate (baffle?) you can see.

Flick round to reserve starts only with the choke and away we go.

Now the only think I can think is that I've started using s tank bag and it sits over the fuel cap, do our caps vent? Am I causing a vacuum? Or is this a fuel tap issue?

Anyone experienced anything similar?

Update:

Took the tank bag off.

Ok so it's definitely fuel starvation at high speed....

Did a run down my local bypass with fuel tap on, fuel starvation if I pin it.

Fuel tap to reserve, fuel starvation if I pin it.

So both times after stopping I sit for a minute to see if the fuel catches up with gravity and starts....nothing.

It's only when I flick the fuel tap either way and give it a bucket of choke, she fires, runs like a pig for a second then fine.

If I bimble around like an old lady rubs fine if a little gutless here and there.

It's a brand new fuel pump, fuel lines look good but could be better, will upgrade them to braided hoses to ensure no kinks and chang the fuel filter out.

I have no clue when it comes to carbs so I really hope it's not anything to do with that....

Any bets?

When it comes to problems with a Zxr 400 99% of the time it's the carbs.

Check the easy stuff first, filter fuel lines etc but it probably time to take the carbs off and clean them out, reset the pilot screws and balance them

Miles wrote:When it comes to problems with a Zxr 400 99% of the time it's the carbs.

Check the easy stuff first, filter fuel lines etc but it probably time to take the carbs off and clean them out, reset the pilot screws and balance them

Agree!

I shall do indeed.

Fuel filter ordered along with new hose.

Was having a nose earlier at the fuel cap, I assume it's a pressure cap, much like a radiator. The spring bit is fine but if you look st the opening where the fuel goes there is lots of dried paint where somebody has obviously taken the cap out and painted the tank. It's all under that rubber circle bit. I wonder if some of that has flaked off and got into the tank and blocked a fuel line or the filter.

Would make sense, the amount of time that tank has been on and off lately due to wiring underneath it. Lol

I shall keep you updated!

OK well.... Update.

Went to fit new fuel filter this morning and on removing a notice a kinked hose. Woohoo! Problem solved right?? Wrong.

Hose is all straightened up, I'm currently stood at the side of the r ok ad waiting for a lift lol.

This flipping bike! So fuel hoses are definitely perfect. Fuel filter good, brand new pump. Fuel filter doesn't seem to be filling.

I know you said carbs, but this seems like a problem getting fuel to the carbs....

Can the fuek tap cause any problems? Can it block up?

I guess it would be possible to block the fuel tap. All it is is two 'pipes' one long , On position, & one short, Reserve, position. Fitted too the top of these 'pipes' are a fine mesh. If your tank is seriously full of crap I suppose you could block one or both of the mesh.

I'd still be looking at carbs

too small on the main jets, you need choke (i.e. its running lean) when on full throttle so go up 1-2 sizes and see if that makes a difference - should do.

getting the pilots set correctly, and then balance the carbs can only make it happier as well.