Modifying my Motor 125cc

[Bighomedog11]

I have a 125cc bike with the stock china motor in there. It is a 125cc Apollo bike. I am thinking about doing some upgrading to the motor but don't know what..

I already have a Carb and air filter.

I am in school for automotive so i can also do more porting work but not sure what to port and is it really worth doing a this kind of Engines..

Just let me know some good modifications to get and were to get them from because i am trying to get this bike ready for the spring.

 

[Rodney68]

What size carby have you got to upgrade and there are few porting ideas here just use the search key at the top of page and type in porting and have a look and see what you think mate

 

[lets ride]

mate its up to you if you think its worth it or not pal me personaly i like doing things different so i wreckon go for it mate get the head ported get a better exhaust , if your still running a stock one looking into tb part see what they have to offer

 

[needapitty]

look into geting a hi comp piston and cam for it aswell

 

[rotn50]

If you really bomb it then a billet clutch housing will be the go, nothing worse than a stock chine clutch housing destroying itself.

 

[Bighomedog11]

I have the Mikuni carb rite now. I am going to check out the pistons on tb. I was trying to find some other stuff i can do.. I was thinking about porting but not sure what.

 

[Rodney68]

Is it a 26mm Mikuni you are going to use to upgrade i just built up a Lifan 125 the older style one for my chopper details in my garage. It has a 26mm Molkt carb on it which is similar to the Mikuni one i put a 17.5 pilot in it and a 95 main jet with the needle second from the bottom with a Uni-Filter. I ported and polished the inlet port and exhaust port and inlet manifold mainly smoothed out any roughness in theses ports like near mirror polished inlet and exhaust ports and around the bottom of the head area in the combustion area. But i didnt get to carried away with the inlet manifold sanded it with 400 girt wet n dry it help with atomizing of the fuel some people say it makes no differance and some say it does but personly i dont think it makes a differance as i mirror polished the inlet manifold on my braaap and it runs a beautiful colour plug. Get a big bore exhaust that makes a differance also and i put a 7mm lift cam and h/duty valve springs in the 125 also. If you are going to go crazy doing this 125 up it might be good to get a billet clutch setup just to be safe. You can PM me if you want more details or check my garage out. Hope this helps you Bighomedog11.

 

[Bighomedog11]

Is it a 26mm Mikuni you are going to use to upgrade i just built up a Lifan 125 the older style one for my chopper details in my garage. It has a 26mm Molkt carb on it which is similar to the Mikuni one i put a 17.5 pilot in it and a 95 main jet with the needle second from the bottom with a Uni-Filter. I ported and polished the inlet port and exhaust port and inlet manifold mainly smoothed out any roughness in theses ports like near mirror polished inlet and exhaust ports and around the bottom of the head area in the combustion area. But i didnt get to carried away with the inlet manifold sanded it with 400 girt wet n dry it help with atomizing of the fuel some people say it makes no differance and some say it does but personly i dont think it makes a differance as i mirror polished the inlet manifold on my braaap and it runs a beautiful colour plug. Get a big bore exhaust that makes a differance also and i put a 7mm lift cam and h/duty valve springs in the 125 also. If you are going to go crazy doing this 125 up it might be good to get a billet clutch setup just to be safe. You can PM me if you want more details or check my garage out. Hope this helps you Bighomedog11.

Yeah I am probably going to use this carb for the build. What did you use to port the Head with? Also when you ported it did you notice a big difference? I am also wondering did you use the stock head and just bought a big bore exhaust and stuff. What is a good big bore exhaust to get?

 

[Rodney68]

Yes it was a stock head and noticed a big differance when putting the bigger carb on it also. I used a die-grinder and differant grinding stones and bits. Your from the US arent you so i would get a big bore exhaust from a good pitbike dealer so you get a well built one.

 

[my67xr]

there are some porting pics in my Orion thread too.
the link is below, in my sig.

i agree with the comments above, cam, carby, exhaust.
only things i would add to the the above is, an outer rotor kit, and a decemt coil, plug lead and irridium spark plug.

craig

 

[Bighomedog11]

I am going to look up some porting videos and guides. I already have a Mikuni carb n air filter and i notice a difference when i put that on..

I am going to search around for a Big Bore exhaust and what is a good cam to get?