Bike won't start - suggestions please.

[einsteingarage]

I had a 05 250 and did some top end work, put it together and no spark, just the funny back fire thing. Thought maybe the kill switch was stuck, coil, stator,etc. Pull the plug and it was wet but didn't seem to get spark. Messed with it for hours and finally decided to buy a brand new plug and bam started right up.

Go back to the plug that worked when it ran the race. Plugs usually don't just die so you know that one works.


I would stick with looking at your carb and then use a new plug. I get the feeling that it's in your carb. Air screw backed out too much, choke blocked, blocked hoses on the outside, you could also have a sand pebble in the pilot and it looks clear but isn't(I have had this before).

[stay_upright]

I bought a new plug with the plug cap - but no spark now...

Also tried the plug I was using in the race - that would spark OK but the bike wouldn't fire.

My symptoms sound like yours einstein except i've tried the new plug and no good.

[einsteingarage]

Could you try the trials carb?

as far as the spark. I had problems with the yellow wire and the yellow with green stripe. Also the connection with the white plug in the upper right.

[stay_upright]

OK thanks I'll have a closer look at those wires, I've gave them the once over and they looked OK but I'll check in a bit more detail.

[seitz64]

try acouple shot of starting fluid if it trys to start its probably a fuel problem if not its a good chance its a stator, take flywheel off [need puller] look at stator for burn marks! u could try and bump start also , if it starts or trys to start its the stator! good luck

[stay_upright]

Got the spark back - was some of the connectors under the seat were just a bit dirty it looks like.

Still no luck starting it.

Could a crankseal have failed since the rebuild - could one side let air into the cylinder?

Is there any way to test this?

I've got spark, fuel and compression but it won't go

Will try to find some easy start today despite a friend warning me it blew the engine on one of their works trucks (though I'm wondering if it was diesel now)

[einsteingarage]

Hold that baby wide open and kick it like mad.


Also, do you tip your bike on it's side prior to starting until fuel comes out the bottom of the carb hose? Usually results into a one kick start.

I am dying to find out what the problem is.

[stay_upright]

Already tried kicking at WOT can try again kicking more aggressively...

I've never tipped the bike over but I'm willing to give anything a try.

I was going to go and get some easy start next plus some carb cleaner to submerge the carb in overnight in case blowing it out with a air line is not clearing something.

Also what is the brass cylinder near the front of the carb - long thing the bottom must sit near the bottom of the float bowl. That's the only think I've been able to check I get airflow through 'cos I don't know where it goes.

I've also asked a mate to borrow his 300 to try swapping parts, hopefully he will say yes. I've got 10 days off and really want to ride the stupid thing!

I may also cut the centre electrode off a plug to see if the spark can jump right across in case maybe the spark's too weak to jump when there's compression in the cylinder.

[stay_upright]

wow found the problem, no wonder it wasn't easy.

I tried the easy start and that just made it more likely to go bang without turning the engine round, felt the exhaust it got warm so I'm thinking maybe the timing's out.

I push the engine to before TDC with the kickstart where the compression starts to make it hard to push around and the raised section for the ignition timing is about 120degrees away from the pickup. It should be very close at TDC.

So I remove the generator cover and find the culprit - a sheared woodruff key.

So the timing was miles out hence why most of the time it wouldn't fire and when it did it was burning in the exhaust.

I've got a 12oz FWW fitted also I guess that adds to the stress on the key quite a lot so probably more prone to failure.

Anyway I'm really happy, if I can get a key tomorrow I could be riding tomorrow night.

[einsteingarage]

That's great news! let us know how the ride goes.