Honda ATV Forum banner

2007 honda rancher 420fm wont start, spark plug is dry

3847 Views 5 Replies 3 Participants Last post by  misterclean59
hello, this is my first time posting in this forum, i have been searching for a few days and haven't ran across one with my symptoms. i apologize for the long description i'm just trying to be very thorough

i recently bought a 2007 honda rancher 420 4x4 from a family member of mine. knowing that is had been sitting for a while i knew i would have a little project on my hands but i am stumped. i got it and right away i had to replace the ignition switch because it had been cut and re spliced the start and light switch wires on the handle bars because he had cut them. then i cleaned the fuse panel with electric clean and replaced all fuses good or bad because of corrosion. then replaced fuel pump once i found that it had power going to it but not turning on.

hear is where is gets tricky. i sent the throttle body to a guy to get cleaned and checked(don't know him that well, was referred to him by a friend). i have good spark coming from spark plug, and i know i am getting fuel to the throttle body because i pulled off fuel line on it and turned it on. but i still cant get it to run. also none of the light on dash come on at all. i've checked all connections and everything seems good and clean. the fuel pump relay makes some very quiet clicks when i turn the key on. i also tried starting fluid and after about 5 to 10 seconds of turning over is will backfire and shoot a flame out of exhaust pipe. i also swapped pgm-fi off of my uncles bike which is a 2010 420es but i don't think it would have helped because the model numbers were different, i just wanted to try. mine wouldn't start his and his didn't help my problem. also swapped rectifier to a known good one with no change.

i am completely lost with the fuel injection bikes, and i am contemplating rigging up a carb and deleting everything or at least trying. so any information would be great full
See less See more
1 - 2 of 6 Posts
thanks for the reply. i started this morning by digging around and found my compression tester. and it turns out that i have major problems on the top end. gauge wouldn't get over 30 psi. i went off my cousins word when i got the bike from him when he said he parked it because he ran bad gas in it and couldn't get it to start the next day after riding about 5 hours. i don't believe it would have been sunk but i may be wrong. so i will be tearing the top end off when i get back from offshore in 2 weeks. with that low compression i am thinking that the damage is going to be sever and will most likely be replacing the cylinder and piston as well. as far the wiring problem, sorry i should have mentioned that i am an I&E tech offshore(instrument, electrician) so i am pretty confident in my wiring. not saying that i didn't overlook anything, that a lot of wiring for a bike.

also, if i do end of having to replace everything, has anyone ever put the 500cc big bore kit in and did they like the extra power it provided?
See less See more
1 - 2 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.