fresh rebuild, ran for 30 mins, now wont start

[Xplorer99]

hey guys, just got the 440 all done, took it for a 10 min ride, changed oil, yesterday i took it out for about 15 mins, be running great. went 1st to 2nd gear, when i went up to 3rd it started bogging so i shifted dosn to 2nd and it died. wouldnt start again. pushed it home and it was getting what i thought was a weak spark, my plug boot fell off, new NGK plug boot and spark plug. still didnt work. had the coil tested today and it is fine,, put a new wire on the coil also. it has spark, the guy at honda shop said to take the plug boot off and hold it the wire itself about 1/4 inch from the side of the head and check spark that way. its deffinately getting good spark when i test it that way.

it still wont start. its getting fuel and air and spark. im going to grab the cdi box off my buddies 400 and try that. any other things that i could check?

thanks! sucks i cant go riding over the holiday weekend now UGH :mad:

[vaget22]

Are you positive it is getting fuel? Is the spark plug wet with gas when you turn it over and over? Can you smell gas in the tail pipe when you crank it? Maybe you should check the timing. Could be the timing chain tensioner didn't get adjusted correctly and it jumped a tooth or two?

[Xplorer99]

took air boot off, and when u push the throttle the carb opens up and it sprays fuel into the carb, can i check the tensioner with out takes the motor back apart? thanks for the fast reply!

[Xplorer99]

ok i couldnt really tell on the new plug since it was so shiny. i put old dirty plug in it. roller it over a few times whilte hitting the gas a couple times. then while off i opened throttle up about 5 times and watched it squirt the fuel in. held hand over the back of carb and rolled it over so it would suck the fuel in. took plug out and it was bone dry.....

[JOHNDOE83]

on off switch?...just an idea?...I still do that once in awhile, im like whats goin on, then notice I hit the switch on accident.

[vaget22]

If you are seeing gas shooting into the engine when you hit the throttle it should at least fire for a second or two if everything else is good. And you say for sure it is getting a spart? Then it comes down to compression or timing. Pull off the valve cover and hand crank the motor to top dead center as per the manual. Then look at the reference marks on the cams.

[Xplorer99]

Originally posted by JOHNDOE83
on off switch?...just an idea?...I still do that once in awhile, im like whats goin on, then notice I hit the switch on accident.


u mean the kill switch? checked that, actually the kill switch doesnt even work lol


i guess im going out to tear the valve cover off and check timing. the valve where tapping pretty loud, but they where dead on when i adjusted them, ill check them too. i have a brand new CRF 450 cam chain. maybe it stretched and the cam chain tensioner is bad and didnt tighten and it jumped a tooth or something... idk where else to start.... thanks

[storms400ex]

before you take cover pour a little fuel down in the plug hole then try to start it, if it starts then you know your not getting gas