Need to gps mine but I'm sure I'm getting around 55mph on a stock motor and Raggae tires running 15/37sprockets with a TB pipe, 20m carb and a rev box.

Hoping for a few more mph when I do the race cam.

My 94

Speedo showed 50+mph and I'm sure the bigger tires are messing it up. Gota make a vid with my gps on her lol.

 

Just 4 fun: I'd be interested in the GPS number. I've hit 46.1 on GPS and I'd love to get another 10 mph out of it! So this is with the TB head and pipe. I have to replace my carb. It's trash and was going to purchase a Chinese stock replacement. What 20 mm carb do you have? I also need an exhaust. Mine has a hole in it. What is a rev box? If you had it to do over again, would you do it? Would you have installed the cam originally? And the big question....can you just ride it, or are you having to constantly tune or tinker with it? Thanks. Probably should have just sent you a PM.

 

Get a complete 125cc (or more) lifan motor swap and you will be happy.

 

Larrynsr: Is that a direct bolt on? I have a three spd semi auto that I want to retain. Do they make that configuration? What could I expect as far as a top speed? and can these regularly sustain 55mph for 20 minutes without blowing apart? Thanks.

 

Keep the Honda motor. Make it a 108. Tb stroker crank and 88 race head kit. Will pull like mad and fly. 17T/ 32T. Done deal.

 

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What he said!

This is my plan when I blow up my stock motor along with a 4 speed trans with an HD clutch and if you want speed now then the 88 will do it but the stroker 108 is WAY better.

No TB head on my bike just stock and still waiting on my cam. I have TB 20mm carb and the rev box is from TB also, they call it the "Red Box" it basically advances the spark timing slightly and eliminates the rev limiter.

As far as can I ride it without tinkering . . . . . I have put 800 miles on her in 2 months and the only issue aside from constantly needing to fill my tiny tank way too often is I snapped one of the exhaust studs off and had to have a machinist remove it for me.Best $40 I ever spent.

Bottom line is the 91-94 ct70's are a CRF70 motor with a lighting coil, neutral switch and slightly different gears in the trans.

That said, do a race cam and rev box with the plug out of the pipe and it will look stock and go good or you could add the carb and pipe like I did too.

The Chinese motor swap is easy since these bikes are 12v and motors are $300-700 which make them cheaper than building up the stock motor but the honda will run better and stronger in the long run.

 

What he said ^.

 

Chinese motors are pretty much bolt and go. I believe it's a better bang for the buck. Yeah you can buy stroker cranks and big bore kits....but guess where are those made in?.....yes China.

 

I have run both motors a 124 and a modified 70 motor in my atc70. The stock motor, if the cases and tranny are good that's the way to go. If the cases leak oil and the tranny skips out of gear then the lifan motor is your best bet.
The low hp 124 lifan motor is about the same as a takagawa 88 kit with a head. The tb kit pulls hard but the 20mm carb is less then disirable.
The 108 stroked motor is a blast to ride and the motor looks stock aside from the giant exhaust and extra large carb.

 

If you want something that is scary try the 155zs with the crf style head. I am pulling 55mph on balloon tires.

 

Based on what people are saying, I couldn't go wrong either way. I'm sure I would likely be happy with the Lifan 125 or 140. It sounds easy and I don't fool with my stocker. Are these available in 3 and 4 speed auto with the 125 and 140cc? This is for a plated around town street rider.

 

Are these available in 3 and 4 speed auto with the 125 and 140cc? This is for a plated around town street rider.

I believe this is the largest cc motor with an auto clutch.
tmas

BLack Lifan 125 SEMI Engine - Engines - Lifan 50-150 Engines - TRC-1795 - TBolt USA, LLC

 

Thanks tmas. So, it comes without a carb, CDI is not included, and they suggest a pipe. What carb would go best? Is the ignition something I can use from mine or do I need new? And is the big bore type pipe appropriate?