i dropped a new engine in my bike about 3 or so weeks ago, it has 7,000 miles on it and runs strong. Yet the first start-up is rediculously hard. i have to have the choke off and pump the throttle vigorously while turning it over. Sometimes it takes 25-30 seconds to slowly begin to fire up. But after it has started once, i can stop and start it no problem at all. any ideas? thanks in advance

 

plugged fuel filters?

 

Wouldn't plugged fuel filters show signs of issues while running? I would think there would already be gas in the carbs from the last time it was running. I'm asking because I don't know. I'm having a very similiar issue when trying to start my F2 when it is cold.

 

It's gotta be something to do with fuel delivery, could be many things though... carbs would be what I would check first but I cant give youa definitive answer[&:]

 

i would go with plugged pilot jets. i believe the pilot controls fuel from start up to about 4Krpms then the main kicks in. they may not be open all the way.

 

I read somewhere that if the a bike doesn't start when it's cold then it's an ignition issue and not a fuel delivery issue. Don't know if that's true or not.

 

Pilot jet is used for about about 1500 RPM's (call it 1/8 to 1/4 turn of thegrip) then you're on the main jet.

I'd check the choke cable tension to make sure the choke isn't already partially open when the lever's closed, check and/or replace plug boots/ wires if cracked, check and/or replace the plugs, definitelybalance the carbs. If not any of that, I'd be looking into tearing the carbs apart...


FWIW, my '03 FZ1 has done the very same thing since I bought it...hard starting when stone cold but fine after some warm up...even after a pipe and jets.

 

i dont believe its a carb related problem because i used the carbs from my old engine and i never had any problem with it. It may be the plugs, as i didnt swap my olds ones into this engine, i just used the ones already in it...

 

Mmm... straight swap with carbs will require some tweaking, every engine runs differently.

Do you know the jet sizes from your carbs? you got any aftermarket bits like K&N or exhaust?

Did you adjust the pilot settings?

 

Always pull the plugs and go from there.