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[Jim]

My 2010 500 Bullet is a closet 2 stroke, it insists on fouling spark plugs:-) This happens always under the same circumstances.

When I haven't used the bike for a few days I start it up on the kickstart and leave it idling for a few minutes without any problems.

I can pull away and run for about half a mile OK and then I get misfires, popping through the exhaust and the exhaust note goes flat. There is no acceleration when I open the throttle.

Usually I can limp home if not too far away and, when I remove the plug, it's sooty black (carbon not oil). A quick clean up and everything is right again. It started it again this morning but I was able to give it some welly and it seemed to clear the problem because it never missed a beat afterwards.


The plugs I'm using at the moment are NGK BP6ES although it has done it with the original 3 electrode plug that came with the bike.



Do the cognescenti have any ideas on this? It's still under warranty so I can take it back if needs be.

Ta

[MadMike]

Jim it's a no brainer this one. TAKE IT BACK. You paid hard earned money for it and if it doesn't work properly simply take it back........my oft quoted washing machine comes to mind yet again. £250 for a wsashing machind and if it doesn't work you would have no hesitation in getting it sorted by Curry's or whoever sold it to you, your wife wouldnt have it any other way would she. Take it back Jim.

[Alan R]

----------yep, I'd second that !!

[Jim]

Thanks for the good advice guys and it will be going in shortly for its second service but I would just like to know any possible causes before I take it in. I have a feeling that it may be a battery low condition as the last time it wouldn't engage the starter motor.


If it's a sensor problem there's nothing showing on the engine management light.

[Jim]

Just been on to Watsonian Squire regarding this problem. They are of the opinion that it's a fuel enrichment problem and I tend to agree, given the symptoms. They asked me to check the manual bi-starter (why can't they just call it a choke?) for sticking and to see if there was a click when the valve was closed.

Bit difficult for me as I have some hearing damage but I did notice that the cable was bundled with others using a cable tie. This caused the bi-starter cable to loop round in a very tight turn and it's possible that movement of the handlebars has been causing the enrichment jet to lift off its seat.
I've removed the tie and eased the loop and I think I can hear a click as the lever is closed.

It will have to wait until tomorrow before I test it weather permitting.

[Paulk]

Jim,

They don't call it a choke because it isn't a choke. A choke restricts the flow of air, you have a valve to introduce more fuel to enrich the mixture for starting. Similar effect for different reasons. Bit like calling a Dyson a Hoover, wrong but many do it.

[Jim]

Thanks Paul. Same end result but approached from a different direction.

[Jim]

Paul


I have the EFI workshop and service manual and, while there's quite a lot of good information in it I wouldn't like to rely on it for a strip and rebuild. There's too much confusion with a heading saying one thing while the pictures are of something totally different and the text describing something else.



Interestingly I have just found this in it...Manual Bi Starter Helps in providing additional air into the engine during cold start, for better idling RPM, till the engine operating temperature is attained.[/b]



So, is it an enrichment jet or a choke? I'm totally confused now. Incidentally, the bi starter fiddling didn't cure anything so it's back onto WS on Monday.

[Paulk]

Jim, I’ll do my best to shed some light, btw I’m no expert.
A choke works by restricting the airflow into the carb with the combined effect to increase the fuel/air mix ratio that a cold motor needs to run when cold. One drawback is to prevent the motor from stalling whilst warming up is the throttle valve needs to be raised slightly.
More recent designs of carb (like ours) have a cold start system (or what anyone wishes to call it) that on operation an extra path of fuel and air (in the much greater fuel/air ratio) delivered on the engine side of the throttle valve allowing the motor to idle with having to be baby sat for the first few minutes.
The term choke has been adopted by many to mean any cold start system but you wouldn’t expect a technical publication (like a workshop manual) to be technically wrong, would you, or is that asking too much.
Paul.

[Paulk]

Please substitute "without having to be baby sat"