me and a friend built a side by side with parts from a trail boss 350 and a snowmobile engine et540 for an engine. the prob is either secondary clutching or poor jetting.it climbs rpm good spins the tire and all but when the secondary shift she bogs hard. so we tried dif spring tensions but didnt get a real improvement so im here for help

 

Have you tried a bigger sprocket or smaller tires, smaller front sprocket?
Change the gear ratio.
The spring tension in both clutches should be about the same.
Maybe drop the needle in the carb a notch or two to lean out the engine.
Good luck.

 

there are definetaly a few issues with the unit when the secondary shift open it boggs the machine down, plus the only way the engine runs good is the air fuel screw all the way out. the secondary seams like maybe the spring is too weak and the clutch opens too quick changing it to too high of a ratio to quick i will try the needle position good call bud im not afraid to screw around i think since i need a the air fuel out i might need a bigger main

 

1. If it is not idling right without the air jet screwed all the way out, it has to much fuel. It needs a smaller idle jet in the carb.
2. If it is bogging on the top end the main jet is to big. Go with a smaller main.
3. Repositioning the needle setting: the higher the needle sets, the faster fuel will dump into the carb. The lower the needle sets the slower the fuel will dump. Needle setting will affect the response on low to mid throttle.
4. Top end RPM is determined by

If the engine is hard to start your reed plates could be weak and holding open, creating problems.

Check the plug (in motion) running the engine at 3/4 throttle for aprox. 100 yards and shut off engine without letting the engine idle back down (shut off engine at 3/4 throttle and slow to a stop). Pull the plug and check the color--If the plug is a nice beige you have the proper mix. If the plug is dark brown/black, it is to rich. If the plug is white it is too lean.

 

the old mukuni carb it has is a butterfly type carb so there no needle to raise or lower and i thought since the air/fuel screw is at the front of the carb or venturi as they say that this screw regulates fuel and it being all the way out would be making it rich so maybe i would need a bigger main? it idle fine i guess could maybe be a little higher but i could just ajust the cable. the throttle does seem to have the best response at 1/4 to half throttle though so idk any help would be appreciated

 

maybe some help from a sled mechanic eh