Peugeot Kisbee 50cc 4 stroke Pulse air valve - engine won't rev up!

I recently had a fault with my Peugeot Kisbee 50cc 2013 4 stroke whereby it would not rev up properly, so it was only working at low revs and riding very slowly.

I checked various things, compression, valve clearances etc but nothing seemed to be wrong.

Turns out after a while, the part which was faulty is the pulse air valve, this valve is not mentioned in the factory manual and it's only touched upon in the Haynes manual briefly, but it's not made clear that if it's faulty it will stop your engine revving up normally. The pulse air valve is located in the emissions system, which is part of the engine valve rocker cover. If you remove the larger of the two pipes that connect into the air filter, and if then, with the pipe removed, your engine revs up normally again, you will know that the pulse air valve is faulty.

You can buy a new pulse air valve, but an easier fix is to delete out the emissions system, you can buy a blanking plate (that covers part of the emissions system on the cylinder head) for a few pounds online to do this, then remove the larger rubber pipe that runs from the air filter to the rocker cover and blank the larger pipe off at the air filter. There are videos about removing the emissions system on the GY6 engine on youtube too.

The point here is this fault can be hard to find and the manuals aren't making it clear it can be a problem, so hopefully my thread will help a little.

 

Thanks for this. Solved my issue after a lot of faffing about. I've just unplugged the pipe for now.