49cc dirtbike not going as fast as it used to

[masso]

my 49cc bike doesn't go fast an more in can even go up a little hill what should i do to make it go fast again.

and i also wanted to know if you could fit a 110cc engine on this bike.

 

[zumanity]

check your spark plug......they come with shit china plugs in em...get a bosch or an ngk plug and you should notice the change. failing that pull the exhaust and carby off it and clean all the crap out of them.
the exhaust is packed with fiberglass home insulation and soaks up the oil from the fuel real quick.replace that and the plug and you should notice a difference.

 

[masso]

and could you fit a 75cc engine in them

 

[zumanity]

i dunno mate. can u put a pic up of the bike and we could tell ya.

 

[masso]

its something like this.

 

[$heepy]

its prob not worth it. i would say just save your money and get a 125 later once this bike blows up.

 

[zumanity]

yeah my 5 year old rides one of them.
as i said earlier check/replace the sparky and check the exhaust out.
oh and like sheepy said.....dont waste your time or money on a 75cc donk.
save and get a 125 you wont regret it!!

 

[zumanity]

my boys bike lost power and i bought an NGK spark plug and repacked the exhaust with insulation and its going like new.
be sure to get the ratio of fuel and oil right or you will oil up the plug and get crap performance.

 

[Tyrets]

try running about 40:1 fuel/oil like the others said could be carb or exhaust issues. another one to eliminate is leaks check over you case gasket and crank seals for seapage when they start to go you will lose power till it just stops completely If 2 strokes dont seal they dont run. my daughter has a quad wit the same engine as those bikes and again it had plug problems to but generaly that will just make them stop.