Engine Trouble Engine problem, knock - wont turn over...[ bad block ]



So me and a friend bought the exact same bikes and the exact same motor kits, and installed them side by side. One works great the other is having some problems.

This bad one took more time start and took more time to find idle. It had this nasty engine knocking at low rpms but then went away with throttle. It would run but boggy and very chunky. Then it get hot after 10-20 minutes of ridding and dies. When trying to start it after this the engine won't turn over even with the clutch adjusted correctly. The clutch just slips and never turns over the piston. But the knock and poor engine performance is more concerning, which probably created the clutch problem.

The knock or chunky engine movement seems to happen more when ridding now besides idle poorness.

Any pointer, or advise would be great. I am stumped. The other bike works great and we have done nothing different.

Pull the exhaust pipe and inspect the piston...it might have seized.
You gotta warranty? I hope.
What should I look for? I figure the obvious...

One thing i forgot to mention, it seems that after the bikes sits for 10 hours and then is started again it will start and the whole problems happens all over.
It does sound like it is trying to seize.

Look for scuffing on the piston or silver aluminum dust in the exhaust port.
Use a strong light and look at the side of the piston carefully. Pay particular attention to the area around the piston rings.

Take macro pics if you can and post them.

Some of these motors do eat wrist pin bushings too and that might be in the mix.
The Chinese factories aren't known for quality. I have seen engines that were poorly assembled at the factory with missing parts. You should pull the head and cylinder and take a look at the piston. It could be something as simple as the piston installed in the wrong direction which caused a ring to break or it could be more serious.
Hi, ya,
Thats a shame to hear,
But its good that you had the other bike there to rate yours against,
But Yeah, a warranty is the go- Even if its only 30 days ,
(like some here in Oz),
that may be in your favor??
Just try at the very least in any case>>..

Good Luck.
Regards djase10
rcJunkie is correct. these companies that manufacture these really lack in quality control :censored: ...one motor off the line can be a screamer, and the next one right behind it goes woof! woof!
use the warranty...quickly, too
The verdect is in! "seized"

take a look at this:




The last two pictures don't really show the damage, but it is there.
The warntee might be a little harder for me as my supplier doesn't really do it.

Maybe I will buy the replacement one from Dax, or if anyone can hook me up with a deal for just a new erngine I would appreiceate it. (I can mail the bad one back if a supplier can get me new one)