Hiya everyone, When I push my buggy along the ground it doesn't go smooth theres something holding it back it goes easy holds back goes easy etc...
The brake is defenatly off.

Just a guess, but something is probably warped or out of round. The first step is to isolate each differential to find which one is doing it. Pick the front up, hold both tires from rotating and roll it on the backs, still do it??, then its not the front. Do the same thing with the back, still do it?? then its not the back and may be the center (try to isolate the front and rear from being the problem if at all possible first). In all likelyhood, it is just a screw that holds the ring gear onto the differential carrier, but finding the diff that is the culprit is going to be the interesting part. Heck, its probably time for new diff fluid anyway, so pull all three of them apart and have a look.

It's something to do with the engine I took it off and it moves good without it.

Will the clutch bell spin freely, or is it stuck??

it'll spin about half a turn then stick

You need to take your clutch bell off, you have a spring or a shoe jammed against the bell I'd bet.

When was the last time you replaced your clutch bell bearings?

Take engine off. spin clutch bell, it should spin freely. It sounds like your alignment is off, between spur and clutch bell. (that is if your bell spins freely.)

When the engine is out and it doesn't spin freely, you either have a bad bearing or a spring hung up or your clutch bell spacing is off.

Although I do think its a jammin clutch too, Does your Flywheel intefere with the rear brake disk?