Struggling under load

Hi everyone

Just had a new crank and top end in my aerox. Brand new standard top end with a pm crank. It's got a Doppler s3r and a 17.5,m carb with a 92 jet (jetting was perfect before the rebuild).

I have run it in through a whole tank of petrol so far. I know it's not run in yet, but to run it in properly I need to vary the engine revs and load on the engine. So, whilst it was still warmed up, I thought Id see what it was like under heavy load by doing a few wheelies. I did what I usually do; slow dowto like 5mph, and pin it, sliding back as the power comes in.

It comes up for a few seconds and revs up nicely, then it just bogs down and loses power. If I keep the throttle open it will just rev up again after a second or two.

Any ideas?

 

Is it a 70 top end and are you running without a filter ?

 

Standard 50cc top end with brand new standard airbox mate

 

Sounds like your overjetted hence the bogging , a main jet around 80 should do it.

 

I have just done a plug chop so I'll see what it's like when it's cooled down.

I since its only when I whack it open quick, maybe I can just richer the needle a bit? It's not doing it as badly now though