Searched before posting this but no definitive answer. Only when cold (-5 to +2 degrees celcius etc) the bike doesn't want to start. In neutral, clutch in so no drag, holding in the choke lever, no battery issues, turns over no problem. Wants to fire but doesn't. A couple of fuel pump cycles doesn't help. It's trying to fire and does eventually but something is awry. Changed the spark plug (iridium), and it looked a bit sooty. Changed the water temp sensor for the new one (white). Changed the fuel. Fuel line from the tank and pump are fine, all connections secure. Air filter is clean. I'm out of ideas apart from the valves? Am a little concerned about the sooty plug though. Bike starts fine when warmed up. I'm running a single pipe with one baffle only, opened up airbox, power up kit. Any other ideas fellas?
I'd check the valves, bet something's tight. Easy to put a comp gauge on it also. Could also be too lean at start for those temps. .
Hm. Seems ok now? Weird. Was new fuel too. Still want to get to the bottom of why it seems to be running a bit rich though.
Tight valves tend to be more of a problem hot than cold; still, starting problems are often valve related, so it's worth looking at. Any time a bike is hard to start when it's real cold, it's usually too lean. Be careful about using the plug as an indicator; it could be sooty from normal operation, but lean when trying to start...
Yep point taken. I'll do the valves anyway though I checked them about 600 miles ago and they were absolutely fine.
I'm putting this down to slightly old fuel. I did change it but once the old fuel had gone through the injectors etc, it starts no problem now.
