Vortex mini rok - Slow from a Stop

Hi, My sons cadet vortex mini rok clutch has been slipping on take off but runs fine when he is going, so I have replaced clutch, clutch bell and roller bearings, all fine on warm up when the kart is on the stand :+1::+1: but when he sits in the kart and puts his foot down to go , the kart doesn’t pick up the revs , and only goes at walking pace , any suggestions on what is happening, many thanks

If it doesn’t “pick up the revs” then the clutch is not slipping but rather engaging at a very low speed and causing the engine to lug down to well below a good speed range to make power, causing slow starts.

Try measuring the clearance between the clutch shoe and drum and comparing it to the specification.

Alternately, the compression, carburetion, or ignition could be wrong and that would cause it to be slow at lower speeds.

You can avoid clutch problems by removing the clutch and installing a direct-drive sprocket on the crankshaft. If it still pulls poorly out of slow corners or off the grid when push-started then it’s an engine issue.

1 Like

So I’m not super familiar with the Vortex engines, but if they’re like the IAME Swift equipment, I think that might just be normal for them. I know the Mini and Micro Swift engines don’t get going from a stop very quickly, just because of the low-stall clutch and high rev range. Is his kart taking off significantly worse than the other Mini Roks he runs with?

1 Like

Hi, thanks for your suggestion of the motor, it was even more simple than I could have imagined, due to having a new clutch they are to grippy and a little crc sprayed onto the clutch bell is needed ,until it has a small amount of chain oil etc build up , cheers Andy