125cc Honda copy conversion

[dirttrack71]

Well I just completed the conversion on my sons TRX90. I put in a 125cc manual clutch chinese knockoff. I have seen this particular brand on some pit bikes in my area and was impressed with the performance. If I would have went with Lifan I could have swaped the flywheel and all the OE ignition system. But the motor I chose had a different bolt patern for the stator. So I had to do some machine work on the part of the pull start that attaches to the flywheel. I also had to tap holes in the flywheel to attach it to. If you are running stock rear brakes there is no way you can use the kick starter. Anyway I finished it today and have been running it around the yard. I cant believe the power this thing has. Tommorow we are going to the local track to get the kid used to the clutch. He rode it in the yard today and never stalled it once so I dont se it being a problem. My camera is in the shop or I would take pics.

[tcr0148]

what engine did you choose? Because if its a jialing, zongher, GPX there are tones of mods for them! your current set up is making somewhere between 7-8.5 hp. If your looking for more hp take a look at www.tboltusa.com and or www.dratv.com. they have the big valve E22 head that comes with 23mm exhaust and 27mm intake, 26mm carbs, rev boxes etc. You may also consider swapping out the cam for a G1 or G2 but these wear the stock springs out pretty quick, therefore, you want to upgrade to a heavy duty single spring.

[tcr0148]

this is a picture of my 110 lifan swap

[tcr0148]

and another

[Pappy]

be prepared to have major issues with the manual clutch. the added torque will start ripping motor mounts apart.

[dirttrack71]

Did you do something to yours to stop this problem? If so can you post? When you say ripping the mounts apart what exactly do you mean? I was worried about reliability issues.

[Pappy]

Ours took a heck of a beating (tranny) but finally destroyed itself.


The engine mounts kept breaking and i reinforced them, but it then started twisting the mounts at the rear area. On your model, I am not sure what can be done any differently, and it will also be dependant on how hard your rider beats the quad.

[dirttrack71]

Well I can tell you this from looking at your pictures compared to Cody we are casual riders. Man that kid flies. On the bottom there is one bolt coming up from the bottom. There are 4 bolt holes in the motor. I wonder if it would help if I went ahead and added a couple of more bolts.

[tcr0148]

fabricate a frame cradle mount that utilizes all anchor points

[Pappy]

I was just going to suggest along the lines of what tcr0148 just posted, but becareful. there is not much room for add on's and they tend to affect exhausts, carb heigths etc.


We had thought of adding a mount to the front of the engine where the dirtbike mount actually goes.