[img]i/expressions/face-icon-small-disgusted.gif[/img]Heya, new to board so if I screw up set me straight. Looking for a little help in getting my 03 kodiak 450 started. Problems first started in fall while high speed trail riding. Ran at 3/4 to full throttle on sled trails for prolonged period of time when i lost high speed rev. Would run fine at 5-10 mph but bog as soon as I hit throttle. Drained 1/2 tank of gas and added dry gas and worked fine. Week later while doing work it just wouldn't start. I pulled and cleaned carb twice seating all jets but one, pulled that back out 2 turns. Checked spark on head, appeared to have good spark but replaced plug and 2 year old battery anyway. Starter motor is turning flywheel but makes an odd scraping sound if I give it throttle and then let off starter(may be normal). Checked and cleaned air filter. Put starter fluid in plug but still couldn't kick over. Quad has a history of false overheating, temp light will go on at startup from cold (temp sensor?). Change oil and filter regularly and do not ride hard except 1 or 2 riding trips a year on fast trails. I have not checked/adjusted the valves or checked compression which are my next steps but i'm hoping someone might have some input on other possibilities. The bike was idling rough when i turned it off last and couldn't start it but to me valves being off would make it run rough not just stop working all of the sudden?? Any thoughts would be appreciated.

 

i thinkn a valve adjustment is, as you said, the next step. idk if the valves being off alot would cause an engine to completly stop running, but ik if you turn off the engine off adjustment valves may not let you get it started agean. a scrapring noise when you let off the starter can be the starter brushes still engadgeing...or somehting els.

it dose point to a heat problem, since you where rideing at 3/4 throttel alot. if you could start the ATV, but would not runr well at higg rpms that might be a sign the CDI is going out...but you say you have good cranking spark... could also be something electrical...stator or ect.

sorry im could not be to specific, just throwing out thing

 

Thanks for the input. I agree, if intake valves are off I may not be getting full compression but should still get enough to atleast try to start, it doesn't even come close. With good spark, fuel in cylinder and clean air filter, I don't see what could stop it from igniting. I guess I don't know how to gauge a good spark though. The bog at higher speed seemed to be water in the fuel but I will look into the CDI. I drained fuel tank, cleaned filter and added fresh gas since then. As long as i'm getting spark at the plug, is it safe to assume that it's not an electrical problem? Is there a way to verify that the piston is actually moving?

 

if you see a nice blue spark time after time its good. really the easiest-and most expensive-way to diagnois a CDI problem is to replace it. especally if you only have trobel with it running at diffirent rpm ranges.

you can take out thr plug, hit the kill switch, and place your finger over the plug hole while hitting the starter. if you feel lost of pressure your piston is moveing.

#1 thing is to check the valves, and see if the cam lobes are worn down. not very common to have cam lobes worn on a low-hour mechine. and check the timeing chain for tightness and movement. even turn the engin over with pull starter slowly to amke sure everything in the head is working correctly

 

The bog at higher RPM's only happened the one time back in early fall and hasn't happened since, I do think that was bad gas. It ran fine after that for a month until it started sputtering then stalled while parked. I thought it may have had some water in gas again so added a litttle dry gas but still wouldn't start and hasn't since. I'll check valves and timing chain and see where that takes me. Thanks for the help bud.

 

Could it be your rubber boot that goes between your intake and carb that is loose . I had that happen once and bike wouldn't start unless I held my hand over the carb and she would back fire and rev but then die and wouldnt start . Everything looked great but I had to loosen clamp and then make sure boot went over carb then retighten . No issues since . Worth a real close look anyhow . Mine would just whirl over but not start .

TD

 

Had the same thing happen twice on my 06 Kodiak 450. Without warning it started to sputter and quit if I went more than 10 mph. Tried choking and made it worse. Then 8 mph then 6 mph and could barely keep it running so I strapped to another bike and kept it running to help as much as I could to get up the steep hills and after about 15 minutes it suddenly cleared up and ran fine the rest of the day. My first thought was a clogged fuel line or jet, but don't know.

 

Check the vent tubes for both the carb and the tank. They could be clogged or kinked.

 

I'm getting gas to the carb just fine but haven't checked vent tubes, hopefully a reasonably simple fix like that. I got ahead of my self pulling jets when I cleaned carb and didn't count turns on pilot jet. When I reassembled I bottomed it then backed out about 2 turns. I can't find anyplace the spec on the turns or is it specific for each quad?