broken

[MotionBlur]

Hey guys, long time reader first time poster. I frequent these forums alot and you guys all really seem to know your stuff so i firgure you guys are the right ones to ask.

So i only ran my quad once this winter.. the battery was dead so we towed it behind another quad to start it. It started pretty rough but smoothed out and i rode for a half hour or so though i noticed on full throttle it seemed to be struggling a little. thinking it was old gas or some other menial reason i parked it and left it until yesterday.

Yesterday i went and tried to fire it up to take it to the track, but a no go. even with a boost from a quick pack it is struggling to turn. Feels and sounds like a compression problem. it has gas, its getting to the engine, it has spark and air and everything is moving through and out the exhaust. after about 6 hours of pulling things and checking it i decicded to try pull starting to see if it would go.

Well it fired, sounded a pretty rough ran for about 15 seconds and died. got it going again and gently played with the throttle to feel it out. struggling and mild backfires..

My initial guess is that the timing chain skipped a little and the valves are just off time with eachother so its not sealing. And this brings me to my 2 questions:

-Can i work on the timing while its on the quad or do i have to pull the engine off?

-Any thoughts on what else the problem might be, what might have caused this, other things to look for/inspect/try etc...

[otownrider]

Not too familiar with these 450's yet, coming off a kfx 400, but it sound like a valve clearance problem that I had on my 400. You should be able to check clearances without removing the engine. I don't know on these but I'm guessing that it is an automatic cam chain tensioner, so if it is it shouldn't be able to jump, even if that somehow is the case somewhere there should be a TDC mark that you can find and with the valvecover off you could check the timing by cam markings and counting the chain...AGAIN THIS IS BASED OFF INFO FROM MY 400, SO DON'T DO ANYTHING UNTIL YOU GET BETTER ADVICE. I do have a manual so when I get a chance I can check for you and see.

[ononewheel]

well 1st whats mods do you have if any?
if your running a pc3 or other programmer could be a map issue!
as for cam chain jumping i would think probably not unless its super old but you can check your tensioner to see how far out it is!
as for compression you can do a test to check your rings!
and yes to adjust cam chain/valves/piston it can be done with the engine in place!
these bikes can also have electrical issues also id check all your grounds and also look for corrosion too!hope this helps!

[MotionBlur]

No mods whatsoever. All the electrical looks solid to my inexperienced eye. I don't think it's the Piston rings but will do a test. I'm just waiting for my new head cover gasket to come in before I open up the top. Will post again when I open up the top and see what's going on. Thanks guys. Btw ononewheel your machine looks awesome. I want those wheels

[ononewheel]

Originally Posted by MotionBlur

No mods whatsoever. All the electrical looks solid to my inexperienced eye. I don't think it's the Piston rings but will do a test. I'm just waiting for my new head cover gasket to come in before I open up the top. Will post again when I open up the top and see what's going on. Thanks guys. Btw ononewheel your machine looks awesome. I want those wheels

thanks!ebay keep your eye out!i stole these there tech 3's along with brand new tires 650.00 i bid at the last 30 minutes and won!keep me posted!also get into kfx450hq.com its a bit busyer than this forum and alotta people there no there stuff!
i no one kid had a bad ecu which was makin his bike run like crap so idk the olny bad thing with these bikes is if its electrical its a bitch to figure out!

[MotionBlur]

well i opened up the top and everything is god. timing and clearance are all fine and everything turns normally. this leaves me now to think it is an electrical issue as you suggested. my main suspects are the ignition coil, the ecu and the startermotor. time to bvreak out the multi tool and see what i can find.

[wmfw]

i faced similar problems
i had to replace injector on my bike
you can check the resistance on the injector

[MotionBlur]

haha well i figured out the problem. feel rather dumb. i went through everything and i still cnt figure out where the drain is coming from but i did fix the running problem. the battery was so dead that it couldnt complete the circuit to run the ecu. i didnt put my new one on cause i didnt want to waste another battery before i fixed the problem. i used the new one however to try and pinpoint the electrical issue. At some point i decided to try the key with the new battery. fired up first turn. couldnt believe it. runs great. so weird. still havent figured out where th drain is but atleast its running again!!

[DEVIN56]

i HAVE "HEARD" the drain is off the stock ecu... but that is just what I have heard, I myself have not had this problem.

[ononewheel]

ya lots of the 08's do this with the bike off the ecu still draws power sometimes minimal other times itll kill your battery!more than a few people have had this problem with my 09 ive never had this happen!i guess a few things to try and do is park the bike in neutral a battery tender is a good idea too!maybe consider getting an after market ecu but thatll run you around 200 bucks!kawi hasnt recalled this yet theyre holding out but think they may have changed somthin in the 09/10 bikes!