Topic: engine rebuild question

[KirkBurner]

I am rebuilding a cb750 k-3 engine.

The crank shaft was turning ok.
I put the head on, and suddenly everything was stuck.

Removed the head and it was turning freely again, anyone got any tips?

[Jerry Rxman Griffin aka MuthaF'er]

So the pistons move in the cylinders freely? Spark plugs removed so no compression? Cam installed? Rockers all loose? Is it stuck with the cam installed? If so check that your cam isn't out 180 degrees perhaps and a valve hitting a piston. Cam chain binding?

Not really enough info.

I'm putting mine together as we speak but realized I didn't order a slotted sprocket so I came in to do that and saw your post.

[01Thomas]

I've had this happen with a Kawa GPz1100 engine I was rebuilding. In that instance the engine had been resleeved to take a big-bore kit - and two of the sleeves were long enough to contact the crankshafts' counterweights when the head was torqued down.

Is your camchain not bunching up somewhere/somehow when you put the head down?

[KirkBurner]

I check the ring gaps before installing.

I didnt have the the rockers installed, so no cam.. had a loose camchain

no compression as I pulled all the sparkplugs.

I just found this really wierd, so I thought Id ask around if someone else had experienced this.

[CB750F2]

Do you have the correct head gasket for the size bore that you have? The pistons maybe fouling on the gasket fire ring when you tighten the head. As Jerry mentioned - not enough information. Pat