03 450fse starts cold, but not hot. Need help.

Zanderson

New member
So, I just got a 2003 450fse, and it fires right up when cold, but it warms up it will hardly idle and if it dies its basically impossible to start again. I though it might be the valve clearances, but i checked them this morning and they where right on the money .15mm intake and .25mm exhaust with the engine cold. The spark plug was a step hotter (NGK CR7E) and had to big of a gap. Re gapped it and still having issues. Just tried the normal spark plug (NGK CR8E) it calls for but still only slightly better if at all.

when its running its fine as long as i say in the throttle when stopped. I really want to make the bike street legal and commute with but not till it starts consistently and idle when hot.

it does backfire when it wont start as well, i think either there is a temp sensor problem or the fuel injection system needs to be re calibrated. If so anyone in my area have the software because i dont have the money right now to buy it myself.
 
Last edited:
Update

So I'm barely getting 13v at idle and higher rs and it gets lower as the bike warms up. Had the bike hooked up to a fully charged car battery and it started and idled for over and hour with no problems. What's the best way to test my stator and voltage regulator?
 
I have one with the same problems. I hope someone has a solution. Fully charged, the bike will start and run. Shut it down, and it won't re-start. I left the battery in it and not on charge and it was completely discharged and dead in a week. The guy gave me a new starter and gaskets with it, but I'm not entirely sure that is it.
 
update

So upon further inspection of my wiring harness found high resistance in multiple circuits, two in particular, my coolant temp sensor ground and one leg of the startor to the voltage regulator. Purchased a new harness and a lithium ion battery, hopefully it will be back to running next week!
 
Back
Top