hi I've got a Yamaha aerox 100 2002 and I'm experiencing power problem so much I can even hold the bike back. I've cleaned the exhaust and carburettor and tweaked the fuel to air mixture but It still lacks power, I think the carb might of had it. any ideas much appreciated 

thanks mark

Perhaps an air leak between the carb and the bike, or perhaps the air filter and the carb. Perhaps a crank seal? (These are 2 stroke? right?) When did this start happening? 

It's a process of elimination kid .  First check for visual things like cracks in the manifold rubber / bad airbox seal , new plug , filter etc . Make sure you have the carb back to base settings and then you can make a start .

variomatic, it's got 2 brand new crank seals and a new air filter but I'm not too sure the air box is air tight, I'll try that first. I also turned the fuel to air screw fully in and the bike kept running is that supposed to happen? thanks 

19 hours ago, Mark Halford said:

variomatic, it's got 2 brand new crank seals and a new air filter but I'm not too sure the air box is air tight, I'll try that first. I also turned the fuel to air screw fully in and the bike kept running is that supposed to happen? thanks 

There are specific settings for those screws, usually measured in number of turns, they probably shouldn't just be bottomed out, this is likely a part of the issue. Perhaps the crank seals weren't done correctly. 

ok I had the crank seals done twice and I'm pretty sure there ok. I figured out its one and a quarter turns on fuel to air mix but I'm not sure if my carb is working correctly tbh its the only thing I haven't changed on the bike atm 

also what size carb and jet would you recommend? I'm running everything standard except for a technigas exhaust 

I think I might take it to a specialist 

18 hours ago, Mark Halford said:

 

also what size carb and jet would you recommend? I'm running everything standard except for a technigas exhaust 

needs rejetting, I fitted a new exhaust on an Aprilia SR and got a mains kit from SIP to tune it in

4 hours ago, drewpy said:

needs rejetting, I fitted a new exhaust on an Aprilia SR and got a mains kit from SIP to tune it. ok bud what size jet and carb you recommend? 

ok bud what size jet and carb u recommend? 

4 hours ago, Mark Halford said:

ok bud what size jet and carb u recommend? 

there's no answer, thats why you buy a jet kit and see what happens, its cheaper that way believe me.

Keep the carb, just rejet it

When the air screw is turned fully home the engine should stumble & conk out,  as yours never , = means the pilot jet is too small, ,

what like is the spark plug colour AFTER  a run ?

drewpy. Ok I'll keep the carb, I think I'm running a 76 jet in there atm what size jets you recommend I buy? 

blackhat250. Imnot too sure about the plug I can't get it to run well enough to take it for a run lol is the pilot jet the main jet? thanks

3 hours ago, Mark Halford said:

drewpy. Ok I'll keep the carb, I think I'm running a 76 jet in there atm what size jets you recommend I buy? 

blackhat250. Imnot too sure about the plug I can't get it to run well enough to take it for a run lol is the pilot jet the main jet? thanks

buy a jet kit, only £14 from SIP. individual ones are £4 each with postage

 

for example

http://www.sip-scootershop.com/en/products/jetting+kit+dellorto+7598+_40270200

 

drewpy. ok mate cheers I'll order that kit asap. it will fit aerox yeah? and what is the pilot jet?

26 minutes ago, Mark Halford said:

drewpy. ok mate cheers I'll order that kit asap. it will fit aerox yeah? and what is the pilot jet?

whoa, hold on, that's an example. check what carb you have first

pilots are for low end running, you can adjust those and when you can't adjust it anymore, then try a new pilot.

ok I tried measuring it and got 24mm that sound right? I'm not sure what I'm doing with the pilot though lol 

shall I send u a pic of the carb? 

drewpy. I'm not to sure what I'm measuring on the carb to determine the size any ideas? 

I suggest you get a manual for the bike as they will show schematics. I have no experience of your bike.

you need to strip the carb and determine the thread size and height of the carb so you can gewt the correct mains

ok thanks for your help I'll buy a manual and a set of jets as see how I get on