Any tips for squeezing a little extra power out of a 70? I was thinking removing the baffle, removing the airbox and going with a modded XR50 airbox w/ UNI, and tuning the carb. Any tips for tuning the carb? Will just changing the needle clip help or will it need a rejet? I don't want to go with a big bore motor yet because this thing is pretty fun as it is.

if it's a good running motor then just rock it as is. You won't feel that big of a diff by doing what you said.

also...don't waste the money on an 88cc kit. Just jump right in to a 100cc+ Chinese motor. I bolted in a Lifan 125 semi auto 4spd and it was the best idea ever. Less than $400 invested and it is ridiculously fast!

I pull the baffle and put a K&N filter on it. A Uni would work too but the stock one is basically the same foam pad. Airscrew adjustment is all I do for the slightly increased air flow. I also advance the timing a 'tad' when changing the points. But I don't think I gained much of anything noticable. Clean carb, good compression and valve adjustments do wonders.

Depending on what you ride on, increase the tire pressure. Stiffer ride, but less roll resistance...... And the sand just sucks the power right outta these little stock 70. Just the way it is.

X2 on what Vdubspeed posted.

Thanks. I'll just keep it the way it is until I get bored with it and want more power. How does the Lifan motors compare to an 88? I have a TB 88cc with the race head (new style) on my XR50 and it REALLY woke up that motor.

One thing I did was go one ebay and get the atc 70 cdi kit it is about 100 bucks put really woke up my 70 and no more points and really easy upgrade

Well put it this way.

88 kit +HD clutch+HV oil pump = $500 and you still get a 88

125 semi auto 4up complete with carb =$300


Do the math.

Stu,
But dont you have to mod the frame for a battery? get a battery? wire it all up to work?
I'm just asked as to what I thought I read before.

I think dumpin a bigger engine in it is great, but I like to keep mine a honda still. it's like putting a chevy engine in a ford to me,lol

Depends on the 88 kit, I put the TB Parts 88 w/ race head into my z50, it flat out hauls ass. But it's got big ports and valves, a hi-comp piston and a gnarlier cam. Comes as a complete kit for the ATC 70 motors, carb and filter included.

More cc's doesn't always mean more power. My 88cc is a lot quicker than my buddy's 110cc Chinese pitbike. I am talking about power and reliability, not which is cheaper.

Not on the 125. Just add the pull start conversion and your golden.

Stock 70's had about 2.5hp. A 88cc kit with a good pipe will push about 6hp. A Lifan 125cc has about 9/10 hp depending on what carb and pipe is used. Like GlamisGreengo said, do a pull start conversion and there is no need to worry about a battery or extra wiring.
If you need more oomph than that, do a pullstart Lifan 150cc and enjoy 16hp of sand ripping fun.
You could build up a Honda 125m engine with higher comp piston, big port head and a wild cam. That would be nice and powerful plus reliable but cost 3 times as much as a lifan. Maybe more....There are a few people on here with those Honda 125m engines. Would be good if they could reply with some conversion prices and pros and cons.
Cheers.

Yup, just do the conversion with a TRX cover, a spacer or race cut your fenders and use the kick. I hear ya on the Honda thing as well,but after dropping all that $$$ into a 70 case to upgrade to a 88 and still just not satisfied and after riding a properly geared 120 I was sold.


Yes it pretty much means just that, more cc =more displacement = more power. I have a feeling that the 110 was not properly geared or tuned, to many variables to say why your 88 was quicker.


Good post Mardy,
To build a 125m would cost a fortune and you would still have very heavy motor in your frame.

So anyone have an 88kit laying around cheap? I think I can get away with the 88 as I am under the weight limit of a STOCK atc 70 in which case not many here are.lol

I have a 85 atc 70 with a lifan 125cc motor and a 85 atc 70 with 88cc kit 18mm carb and pit bike exhaust and also i installed the cdi conversion it is fast and has good power but no equal to the lifan 125cc also kids got a lifan 110cc dritbike thats a good motor also got my eye on it for atc 70 sitting in basement in pieces