I run 27" mudlites and need some springs to help power these tires.
I have the white secondary and don't know what color primary to run.

 

Call EPI. Almost noone I know of has an aftermarket drive spring in their 400.

I put a white driven spring my bro's 400. It worked wonders for it. I noticed that you can adjust the spring. Did you adjust yours all the way to the setting for higher RPMs? I think it is A1. I did not adjust mine all the way, but I am only using 26" tires. It runs great, my bro loves it.

If you have any other good ideas for power in the 400, spit them out, let us know.

If you every find a way to unlock the full time 4x4, spit that out too.

 

I am also interested in findind out performance tips for this quad.

where did you get that white spring? does a after market exhaust help these quads? how about belt life? what should the stock compression be if/when we test?

My bro has one of these quads,and he is going to give it a good tune up. and I want to help him do it right.




Bigger.

 

Thanks Nyroc


Will your exhaust mod work on the 400. And will
it help enought to make it worth while.

 

cylinder compression measurement
warm the engine attach compression guage hold the throttlewide open and crank the engine with the electric starter or the recoil starter several times
when the guage stops raising stop cranking and read the gauge
usable range electric starter---57-97psi@500rpm
recoilstarter----60-100psi@5times
thats according to the manual i have
hope it helps you out

 

If the compression test shows low compression, pretty much all it will do is make it hard to start and maybe even hard to idle when cold.

You guys should look into finding out what the timing is on the 400. If it is retarded at all, you can get an offset key for the flywheel to get more advance.

You can raise the compression ratio and port the heads.

Mickey Dunlap has a 500cc kit for the Prairie 400. That will wake it up.

See if Mickey can help with a campshaft too. If you can't get a better cam, see if you can degree the stock one.

I don't know if you can drill the muffler out.

 

Thanks nyroc


Mickey doesn't make the 500 kit anymore because thats the
way i would go.