FAQ: Unable to shift with engine running

After successfully installing an engine upgrade using our installation kit, some customers may encounter a common issue: difficulty or inability to shift gears while the engine is running. Fortunately, this problem can be easily resolved with a few simple steps.

Verify Engine Idle RPM: To ensure smooth gear shifting, it's crucial to maintain an idle speed UNDER 1200 RPM. You'll need a tachometer, which can be purchased here. If you find it challenging to reach the recommended RPM range, you may have an air leak after the carburetor. In some cases the carburetor may need to be re-jetted. (Carb Tuning is beyond the scope of our tech support as it is very advanced, there are many resources on YouTube that will help educate you, just search "GX390() Carb Tuning" or "Predator Carb Tuning" if you have a V-Twin.)

Confirm Belt Tension: Proper belt tension is essential for smooth gear transitions. Ensure there is at LEAST 1.5" of slack in the belt. You can test this by LIGHTLY pressing down on the belt, it should move down 1.5" minimum. If you have to add ANY pressure, its too tight!

Adjust the engine's position as needed to achieve the correct tension. 

In general, you want the belt as tight as you can get it while still being able to shift, so if you cannot shift, loosen the belt as much as you can, verify it can shift and then tighten it up until you cannot shift, then back it off enough to where you can.

If you still cannot shift after following these steps, theres a possibility one of your clutches or transaxle is damaged, take a video of your clutches with the engine idling and send it to info@vegascarts.com so we can put eyes on it.