Motor dying

[Butcherbird]

The motor has started dying on me every now and then, it gets unresponsive to the throttle first then a few seconds later it just dies and wont fire again even if I have a bit of speed on and can keep it turning over but after a few of mins it usually fires up with a couple of kicks, sometimes about half choke seems to help if it doesn't fire at first.
As you might expect with an intermittent fault, everything seems OK when I get back in the garage and try to find the problem.
Any ideas ?

[Mezo]

So when its cold it fires up no problem? just when its warm it plays up? coil perhaps?

Mezo.

[Butcherbird]

That's right, the coil tests OK according to the clymer manual I have but been trying to think of some way I could test the coil straight after it has died as it normally takes a good few mins to get at it. Guess I'll have to get another one to try and hope it's not the CDI unit.

[Mezo]

Well Karl had a problem & it was his pick ups, but your problem sounds different? if its playing up when it gets hot its normally an electrical component that`s shagged out, id go with a plug first & then the coil, then finally the CDI (cheap first to expensive).

Don`t suppose you have access to a spare working CDI?

Mezo.

[Butcherbird]

Tried a plug and tested all the stator coils and ignition coil, they all test a few ohms higher than the manual says but I'm guessing that is probably my meter, and no spare bits to substitute so it's off to fleabay and google!

[ActionManMelb]

The motor has started dying on me every now and then, it gets unresponsive to the throttle first then a few seconds later it just dies
Any ideas ?

Electrical problems usually stop the motor dead.
"Unresponsive to the throttle" sounds like a fuel starvation problem.

[Butcherbird]

Thanks for the suggestion, will investigate. When it starts to do it if I try to open the throttle it runs roughish and won't rev up then just dies after a few seconds of this. I have checked and it has plenty of fuel in, I did run it out of juce once and it gave a lot more warning of what's coming, coughed and splutterd for quite a while, though it was doing the refusing to rev properly bit then.

[Mezo]

So possibly sucked some shit from the tank? are you using an in line fuel filter between the tank & carbie?

Mezo.

[MaltaBike]

Does this happen around the same revs or happens in a completely random manner, because if you notice a pattern with revs there may be some issue with the carb rubbers.

I had a problem with mine: it used to stall whenever I reached 3500rpm. At this rev the secondary carb starts coming in and its rubber was completely thorn from the inside, which was messing the whole fuel/air ratio and stalling the engine everytime.

[Butcherbird]

Got the carb off and dismantled, can't see any problem with the rubber mounts and can't really find anything wrong with the carb. There didn't seem to be a lot of fuel in the float chamber when I opened it up but the needle and floats don't seem to be sticking or anything, there was no rubbish in the bottom and fuel is coming through OK, checked the float level using the method in the manual and it seems to be about right.
I have always used an in-line fuel filter but recently fitted a new one, the large type with a replaceable element.
So better put it all back together and see what happens.