Amyh76, The crankshaft keys have been known to just go away. When you figure every time you give it gas, or let off, you are subjecting that piece to a shear load. I would however, try the easier tests first. None of us are there, so we can only go by what you tell us. Heck, it could even be a broken reed. Like Walexa and Bubba suggested, those are probably the easiest ways to elminate a couple of components. Have you ever had your airbox off? To go with Walexa's idea, if you could wrestle that unit off, and using a spray bottle, give it a couple of sprays of pre-mixed fuel/oil, then give a pull. Maybe even before you do this, you could perform Bubba's suggestion since accessing the sparkplug is easy. Also, I would strongly recommend getting yourself a $20 maint. manual. Simple preventative jobs like changing out your in-line oil and fuel filters, along with lot's "O" other stuff can save you time and money.

 

When is the last time you changed your air filter? If you have a K&N what i'm about to say is probably not applicable because of the increase in air flow they provide. I was riding my 2000 Scrambler 400 all day and on the ride home it started backfiring and craping out. I could not figure out the problem for the life of me. I checked everything including the stock air filter. The stock filter looked totally fine but was shot. My machine would idle fine but not run above an idle. If your filter is so clogged turning over the motor will not produce enough vacuum to pull fuel into the motor. Try this, remove your air filter and try to start your quad(do this only in NO DUST condition, in a garage etc. ) this will allow your motor tons of air to pull fuel in. If you have spark but the plug is not wet when using the FULL choke and it won't start you have a fuel problem. Even with a worn cylinder the plug should still get wet. A worn cylinder will also produce very little vacuum which will in turn not draw fuel into the motor. Try the air filter it might be simpler than you think. After I got a new filter my problem was solved. The stock filter is absolutly crap and should be the first thing upgraded on any polaris quad. Live and learn I guess. Good luck

 

A lot of great advice guys. I won't have a chance for a day or two to do more tests due to work. I'm planning to get a compression guage and check that next.
I do have a k&n air filter, and I actually tried starting it with the whole airbox off of it. I also took out the reeds, and for what I know they looked fine.
I guess I need to check my compression!
Thanks for all of the advice guys. It's very much appreciated!

Colin

 

Hey, if you have your carb and reed cage off, you can look right in on the piston. Still a great idea to run a compression check. But take a look inside.

 

Modquad, I believe he will only be able to look at the intake side of the piston.......not the top. Anyway, let us know what the problem was.

Waylan

 

I guess maybe I'm spoiled with all the stuff removed off mine. If you can, shine the light in the intake, and use a mirror to look down the plug hole, improvise when needed. [img]i/expressions/face-icon-small-smile.gif[/img]

 

amyh76,check the on/off fuel switch on the left front end.