my 8yr old sons brand new py90 starts to smoke from the front of engine.(dont know what its called, Its the bit just behind front mud guard.) its fine for five or so minutes whilst I let it warm up but then it starts to smoke, lose power and sounds rough. Its got oil in Castrol 0w-40w. I put the oil in where the dipstick is. Is this correct?? it kickstarts fine and sounds sweet as a nut until this smoke appears. please help as my son things i,m a real t*sser because i wont let him ride his xmas present. but I dont want to do any more damage. thank you for your help.

JONA, February 2005

My py 90 is starting up but its losing power can anyone help

Craig, August 2015

what sort of an answer is that ! fit a mudguard lol.its a cheap chinese bike fit a genuine yamaha t80 townmate piston in it and it will be ok the t80 has the same piston even though its 80cc and not 90cc but your py 90 has a longer stroke.

adam vintage question answerer, February 2010

It might be because the mud and water is coming up on the engine, my advise would be to buy a mudguard for the back of the front tyre it work for me

Joseph Collins, December 2007

Hi Jona

I've had the same problem and let my son continue to ride. I had to get a new engine fitted after 6 weeks as the piston rings broke up and scored the insde of the engine.

The same symptoms started again, but this time I've had a good look around the bike. The air filter to the carburetor is clogged full of mud. I have cleaned that and the bike seems to run fine now.

I must admit though, my advice is to find a local bike shop and get them to check it over for you. I have used one locally and they are very reasonably priced and did a great job

Alistair, April 2005