My bike started running rough, bogging quite badly. Took it to a professional who said the rubber joint between the carb and engine neeeded replacing. Picked it up and it seemed to be running okay when I started it before leaving. Tried taking it out for a ride a couple of weeks later and it started fine on the choke, rode it for a couple of minutes to get it warmed up but then it died while idling and wouldn't start with choke on or off. Tried bump starting it but no luck either. Put it back in the garage and tried again a week later but wouldn't start with the choke on or off.
Here's what I've done so far to diagnose:
- checked there's a spark. Pulled the plug out and checked there's a visible spark when earthing it and hitting the start button and there is a nice strong spark. The plug did look quite black, and it was dry which I thought might be unexpected given that I'd been trying to start the bike a bunch immediately before pulling it? Should there not have been unburned fuel on it?
- cleaned, oiled and re-fitted the air filter.
- dissassembled bottom half of the carb, cleaned out and blew through the jets. It wasn't dirty at all and all the jets / holes were clear already. The one way "check valve" was very hard to blow / suck through but maybe that's normal?. It has a 142 main and a 48 pilot fitted which seems like stock for my bike's year.
- removed the carb diaphragm, cleaned it up and reinstalled. The rubber disk part looks fine, but the metal surface on the carb it sits against was quite rusty so I cleaned that up with some very fine wet and dry sand paper.
- checked the operation of the accelerator pump. I can see a decent squirt of fuel being sent from it when operating the throttle.
- partially dissassembled the top of the carb, I stopped at the point I would have removed the circlip from the throttle shaft as it looked tricky as hell and I didn't trust myself to get it off without damaging something, never mind getting it back on. The top of the carb all looks fine internally though and I can see the choke is working as it should.
- checked fuel is flowing from the tank into the carb. Opened up the drain screw on the carb and fuel flows out continuously. Double checked that fuel is making it out of the tap from the tank and it is.
- cleaned the air filter box out. Probably uneccessary but whilst I had it off the bike to work on the carb I thought I might as well.
- new battery installed. Not going to be the cause of the issues, because the old battery wasn't completely dead and the bike started fine on it so long as I charged it before hand.
I'm at a bit of a loss in terms of what to check next, would appreciate any suggestions!
I'm 99% sure he did - he said he had, he charged me £68 for the part and it's on the invoice with the correct part number (4GY135860000).
Just tried to start the bike again and looked at the plug - it actually is getting a bit wet and smells of fuel so I think I was wrong earlier when I said it was dry.
