Ok. So I picked up a Suzuki LT80 for our twin daughters BDay coming up in April.
I have already posted in the tech forum but I thought it couldn't hurt to post in kids quads too.

When first got it about 2 weeks ago. It had no fire. So found that CDI/Coil unit is very expensive. So we robbed a CDI Box and a coil off a wrecked Chinese quad. Got fire now. So checked compression 30psi. Replaced jug, piston, and rings. Rings are right, arrow on the piston to the exhaust (back of bike), torqued down. eBay kit BTW. Ok still only 30 Psi. The fact it didn't change tells me something else is wrong. I would question the piston/cylinder if it had at least jumped to 60psi or anything else. She puffs smoke, coughs, and pops. Definitely getting fuel to cylinder.

I need compression. Tell me why a crank seal would cause me to lose compression?I've read and had another member point me in this direction and even seen that LT80 Jack also said this would cause a no start condition. Ive built and rebuilt engines of all types shapes and sizes. Compression is the key to this problem. Pulling the engine tomarow and going through new from top to bottom. I just need help understanding? And maybe some points in the right direction.

 

A seal will cause trouble starting/etc. but don't effect compression.
I'd pull the head and take a look see but understanding that compression is made when the piston goes above the exhaust port to TDC, seals and anything else shouldn't effect comp.
How fast is the starter spinning it?
The first spin over the comp gauge should jump to 30.
Stupid question, but seeins the gauge stayed at 30, could the gauge be bad? Check it in another motor?

 

Basic two stroke operation. Has to have a good top end compression along with the lower crank case ability to compress the fuel/air oil mixture and shoot up the transfer ports for ignition. If crank seals are leaking,it can't do this properly.

 

It spins fast. It's odd. I thought about the gauge but it's new. But from harbor freight so heck can be 100%. I can return it and get another from somewhere. It read 100psi on my bayou 250. Yea I figured about the ports in the cylinder. Do you think I could try a light honing and try agin reinstalling cylinder. That was going to be my next step. I used synthetic when reassemble. Man she smokes like crazy but won't run to save me. I tried the oil trick to. Built an extra 6-8 psi. Pulling hair out at this point. Oh timing is right and marks lined up. Keyway is fine.

 

It's like the gauge builds up. After two or three spins.

 

Is the pipe plugged?????
After watching OPT's video, yes I can see how a seal can effect the comp reading but I feel that most leaking seals don't leak enough to make a comp reading go as far off as this particular (or most all) circiumstance.

 

Ya, it should have to spin some to build the comp.
I take it when testing comp you are: holding throttle wide open and spinning till the gauge peaks...
I usually can watch it hit 30-60 then up as it's spinning.

 

Disconnected pipe and same result.

 

Well I think your going to take the cyl/piston off and measure.
For all the work you've done so far, that isn't too hard.

 

10/4. I'll get back to you guys as soon as I get a micrometer. Thanks for all your help.