Bike won’t start

auldblue · Jul 10, 2019

The 750 has been off the road for a new box and it started up and ran fine then gave a cough cut out and refused to start. Changed the plugs checked for a spark it was fine , turned it over checked the EI rotor, all good still no start, it tickled fine but not even like firing ,put a drop of petrol in the plug holes and it started up ran and stopped. Had the carbs to bits , bowls were full of fuel and pilots were clear, what am I missing here?

comnoz · Jul 10, 2019

Probably plugged idle circuit from being parked with fuel in the bowls.

acadian · Jul 10, 2019

comnoz said:
Probably plugged idle circuit from being parked with fuel in the bowls.

that, or you need a new johnson rod...

sorry, couldn't resist

auldblue · Jul 11, 2019

I’ve got her running but it takes a handful and it fires and runs with no strange noises.

Torontonian · Jul 11, 2019

auldblue said:
I’ve got her running but it takes a handful and it fires and runs with no strange noises.

Have you tried cleaning up the fuse contacts , the kill switch , the ground(s) ?

auldblue · Jul 11, 2019

Yep I have , I did notice my ignition light go out and I may have to replace the switch and or barrel but I’ll go through the wires and contacts again for peace o’ mind.

Fast Eddie · Jul 11, 2019

If it runs ‘with a handful’ it does seem to support the idea of the pilots being blocked (fuel circuit blocked but air circuit open perhaps?) as, by giving it a handful, it’s no longer trying to run on the pilot circuit.

auldblue · Jul 11, 2019

Yup , yer right basically over riding the pilot circuit, I'll have the carbs off again Nigel as I don't think I did a proper job the first time.

Torontonian · Jul 11, 2019

A fine guitar string or Banjo works well with some cleaner spray.

Fast Eddie · Jul 12, 2019

auldblue said:
Yup , yer right basically over riding the pilot circuit, I'll have the carbs off again Nigel as I don't think I did a proper job the first time.

Jimmy it’s very easy to blow the carb pilot circuit out with air and think they’re free, but actually all you’re doing there is confirming the AIR circuit is free, whereas the pilot jet is the metering for the fuel circuit.

Also, just coz it’s not blocked doesn’t mean it’s completely clear and operating according to its proper size and flow rate etc.

auldblue · Jul 12, 2019

Cheers Nigel and Toronto, I did the pilots with a strand of wire brush and air. But I’ve a feeling it’s still not 100%.

kommando · Jul 12, 2019

#78 or 16 thou drill is the only 100% reliable method, even if you can clear it with the correct sized wire all you are doing it pushing the dirt back into the feed gallery and leave it free to move forward and reblock the pilot.