Stuck 1974 KH 400 3 cylinder 2 stroke motor

Hey guys, my buddy just dropped of a 1974 kawasaki kh 400 3 cylinder 2 stroke with a little over 12,000 miles on it. The motor is locked up on it, any tips on getting it free?

You can remove one cylinder at the time and see which one that's stuck. Heat that cylinder and spray cooling gas on the piston once the cylinder is warm - this can break it free in many cases.

I use a 50/50 mixture of Acetone and transmission fluid to break bolts loose on lots of stuff. Had stuck brake bleeder screws and basically all the mounting bolts that have anything to do with the brakes on my Ford F-150. squirted some of the mixture on said bolts, let it sit over night, and the next morning they broke loose and turned right out. Im fairly certain this mixture wont hurt aluminum (i think pistons are made of aluminum). try pouring a mix of this into each of the cylinders and let it sit a few days. All else fails, start jumping on the kickstarter (don't do that) hahaha.

Ill give it a try kitten tooth, i have heard the the kh 400's are screamers, i cant wait to take it for a ride !!!!

What no pictures of the Bike?
Probably stuck the center cylinder, not very many cooling fins on the center. Pretty quick bikes in a straight line though. They're pulling a bit of change if in good shape and running.

Ill snap some pics of it today, it is straight out of the 70's with artwork air brushed on the tank, its way cool.

I've used Marvel Mystery oil to free up engines.

I think the triples guys run fatter jets on the center cylinder to help keep it cool.

I have a lot of it laying around, ill pore some in and let it soack. The carbs are locked up too, ill have a look at what jets are in it when i get them torn apart.

Do you think it would be better to pull the head off, or pour it down threw the plug holes?

try the chemicals we listed. I have seen marvel mistery oil free up a 78 KZ750 twin that sat in the woods with a missing plug for a few years. +1. try the mystery oil down a spark plug hole. If that dont work then try the 50/50 mix i posted. if neither work then start tearing the motor apart. I love then 2 stroke KH400s heres a cool video i found of one.

i found one in Sioux city with a Denco S pipe and another that was 100 % stock. 600 for each of them. too bad i passed it up. I didnt have a job

and hopefull the carbs are just full of Pancake syrup i took the ones off of that KZ750 i mentioned and it looked just like they were full of that. Some carb cleaner did the trick

Now i want to find chambers for it. lol. I poured marvel mystery oil down the plug holes, im gonna leave it set for a few days and see what happens. Il post the pics later on.