Hi Guys, Any help would be MUCH appreciated!!!

PROBLEM: Quad will idle but when you try to give it throttle the machine boggs, backfires through the carb, and dies. Can't even get it going enough to get it to move.
- Started having this problem while my son was moving rock (heavy loads) after about 2.5 hours of work.

HISTORY: I bought this quad new and have always taken really good care of it. I go through the carb every spring but have never checked the valve gap. I did have to replace the bottom radiator hose after finding a leak in March. No leaks since

Trouble shooting steps to this point.
- Checked carb. Cleaned all parts. Verified float position.
- Checked fuel mixture screw position (2.5 turns out)
- Tried several fuel mixture screw adjustment none of which helped the bogging.
-- 1 turn out
-- 1.5 turns out
-- 2 turns out
-- 2.5 and 3 turns out.
- Checked spark and plug condition.
- Checked basic wiring for opens, shorts ect.
- Checked CDI unit. Nothing notable found

Im concerned my son might have over heated the motor and maybe screwed the valves but not sure. I inspected the valves but didn't find any problems.

Does anyone have any ideas? Thinking I might have to take her into the steallership.


Thanks,
Tim from NH

 

im not sure if your 450 uses the same carb as my raptoe (350) the slide had a small hole in the dia fram

 

Check carb and gas tank vent tubes for kinks, blockage.

 

Excellent suggestions. Will check. THANKS

 

On a differant forum someone suggested timing. Gonna check that.

Thanks,
Tim

 

Does your Kodiak have a rev limiter if the parking brake is engaged? If so, and the parking brake switch is engaged, you'll have similar symptoms. I went through this with my 02 Wolverine this spring. Idled beautifully, but as soon as throttle was applied, cough, sputter, backfire etc. I had mine to the dealer, the fiddled with the parking brake lever on the handlebar and voila, problem fixed. The dealer admitted that this is an issue with some models of Yammy ATVs.

I might be way off here, but might be a simple thing to try first. Good luck - frustrating, eh?

 

Finally found the problem. Stupid, stupid, stupid....

Don't know how the quad went from bad to good. IE running fine then bad but I've spent hours tiring to diagnose this problem and finally came up with the fix..

The "Nozzle, main" (refer to parts diagram #16) was installed upside down. This part is located on the bowl side of the carb and where the needle slides into.

It sounds crazy but I couldn't find a breakdown that showed the correct direction of this part. Bought a service manual, NADA. Hours surfing the web. NADA. Mikuni website with the actual OEM part number. NADA..

If you need to know the tapered end of this part should point toward the needle or carb opening.

Tim