Hello all, i am new to the forums. i have searched the forums and had not found anything i was looking for. i just bought a 1996 polaris scrambler 400cc 4x4 and am needing some help with it. when i bought it the guy said he had just rebuilt the top end less then 20 hours ago and that everything works good. well i notice that when you run it it runs fine but to me it smells like it is running a little too rich and stumbles just a little bit when you give it the gas from a dead stop. it is also throwing out more smoke then a 2 stroke should be throwing out. is there a way to adjust this easily or not? Thanks

 

the boring on rebuild may have been sloppy. it should be bored over .020" if not more.

try full synthetic 2 stroke oil.
carb adj may be nessesary, check the plug color.
clean air filter and check spark plug wire for tightness on plug.

Jim

 

the amount the engine was bored over has nothing to do with it. If the previous damage cleans up with a .010 piston. and proper clearances a obtained. then the top end will be fine. these bikes tend to be jetted to rich from factory. look into that.

 

I agree the bore size don't matter as long as its cleaned up but i believe the next size up Wiseco offered is .020" over.

Jim

 

Hi: might just have extra oil with the gas for a new break in.

 

extra smoke could be a few things,,,

your oil pump could be malfunctioning, and letting in too much oil. you should inspect it closely inside. the spring in there is known to break.

if you have the oil pump blocked off, and are running premix gas, you might empty it out and remix the gas to the proper ratio. i think most use 40:1?

change the plug too.

the 400 motors are sensitive to outside temperature changes. they require proper jetting for the correct temperatures to run right.

X

 

ok, before i bought it the guy installed a brand new spark plug in the machine. I have ran a full tank of just regular gas through it and just filled it back up with regular gas yesterday. i have not premixed the gas at all in this thing. Now as far as adjusting the carb and things. Does anybody know about how much the screws need to be turned? Also, on the oil pump do you have to take the cover off to inspect it/adjust it or can you just adjust it from the outside of the oil pump on top where the cable goes? Thanks

 

the srew might be around 1 1/2 turns. turn it all the way in easy and dont bottom it out while counting your turns to see what it is now. should be in that ball park. im not sure if there is an adjustment on the cable or not where it pulls the arm for the pump. i know on some sleds theres marks to incate proper line up. how is the plug look, was it back and wet from gas then its running too rich. does this have a reg air filter or a oil type w/ too much oil in it to make it run rich.

 

On my 400 Explorer I run the fuel srew 1 and half turns out with a 210 main jet and the needle clip raised one position from the middle. The factory Polaris manual has a lot of good info to help you work on your Quad.

 

wiseco does now sell .010 and .030 not sure if they do .050 and .070 or not maybe just the half mills after that