I have seen several threads on this topic, but no one seems to tell whether there issues were resolved, and I have tried every suggestion I have seen. So, now I turn to the experts.


It flat wont start, not even with starting fluid. I have gone through the carb a couple times and have fresh fuel in it. I have, what looks to be strong, spark by grounding the plug against the block. I have tried a new cdi, new plug, new battery, and new ignition coil. I have adjusted the valves. Compression feels so so with my finger over the hole, but with my compression gauge it is showing 50lbs. It is an automotive style gauge with about a 15" hose on it. I have been told before that because these engines have such a short stroke an auto tester may not be accurate, but I don't know if that is true. I did test it with wot throttle as well. The trigger coil tested at 122ohms.


Any other suggestions? The compression is suspect, but like I stated I don't know if my tester will produce accurate results.

 

50 lbs is not enough. I had 60 in my ATC and it wouldn't start. Looks like your doing a top end rebuild.

 

Minimum of 95 psig for compression

 

What about the fact that I used a tester with a long tube on an engine with a short stroke? Or does that matter, ie 50lbs is 50 lbs no matter what tester I use

 

Correct, not much pressure drop, 50 psig is 50 psig, (pounds per square inch gauged).

 

I have 2 testers, a short stubby insert 2" long & the other has a 17" tube, both register the same when I use them

 

It would only make a difference if the one way valve was at the gauge end of the pipe. The valve is usually at the plug end. It may take a couple of extra turns of the engine if you have a long pipe though.

 

In case anyone wonders, I did find the problem. Had to pull the engine and found that the wrist pin keeper came out or was never there to begin with came out and the wrist pin beat the crap out of the piston and cylinder. Gotta love these Chinese engines...

 

The only good thing is that those top end kits are fairly inexpensive. I've seen them around $100 for everything and all you got to do is assemble it.

 

Like this one off ebay for $85 shipped. If you do order this, verify this is for your 125 first.

http://www.ebay.com/itm/54mm-Big-bore-kit-change-110cc-to-125cc-Dirt-Pit-Bike-ATV-Go-Kart-Kazuma-Taotao-/281571262570?hash=item418ef4806a&vxp=mtr