GX 200 Lacking RPM

[aksleder]

I bought a modified gx 200 from NR Racing last year and installed it in a zr 200 snowmobile. Engine has 280 Cam, 27/24 valves, 26lb srings and 10.7-1 head. Governor has been removed.

When I first got it the engine ran great and had tons of power, but then the carb broke (22 mikuni round) from hitting the frame. So I went with a new set up and installed a 26mm pwk. Jetted it to chocolate brown but the engine still wont rev past 3400-3700 rpm. I'm stuck and not sure what to check next.

Could the valves or springs have gone bad or could it be something electrical? Any help would be great.

 

[Flyinhillbilly]

If it was running good until the carb broke I’d suspect a carb problem. I’d drop a few sizes on the main jet and see what happened. Will the jets from the old carb fit the new one?

 

[aksleder]

No it’s a different style carb and I already tried different jets, both leaner and richer.

 

[mckutzy]

Did you install a billet conrod??

 

[Karts of Kaos]

Why not just use the original 22mm. I think they are about 35$ on GPS

 

[aksleder]

It has billet rocker arms i don’t think it has billet connecting rod, I don’t believe it’s a carb problem. I put all new intake manifold, gasket air filter and the carb

 

[mckutzy]

As I understand it...With out that billet con rod... its going to be a block problem... as in a hole in it as something lets go, with that setup...

 

[thedude306]

Does that sled have a rev limiter? I know the polaris 120 throttle flippers do. Messes up the signal from the coil. They even have a statement on unplugging it for an "emergency" to get the sled home in case of a failure. Unplug everything and manually ground the coil to shut off. See if problem goes away.

Oh and pictures just cuz I'm a sled guy.