Splitting CB750 case - GLUED TOGETHER !@!


New Member
Anyone have any idea how to split a casing that has been glued together ?

Looks to me to be glued using Liquid Nails (A builders contact Cement ...)

gentle tapping isnt working, but I'm worried to add heat (Bernz'o-matic on hand)

Ideas ?


Over 10,000 Posts
Its Honda or Yama-bond. Most cases have that. Use a thin screwdriver or chisel to split the cases and they'll pop apart.


Staff member
Heat might help a bit to soften things up, but it's 40 year old sealant so it might take some time and persuasion.


Active Member
have you turned it upside down, blocked it for support and tapped the case studs (with a nut covering the end to protect the threads) while gently lifting the bottom half of the case (now facing up)? On the stubborn ones, it might be helpful to have someone else take the weight off of the top case while tapping the ends of the studs. Rotate tapping each stud similar to the pattern of tightening the head nuts. It will go...


Over 10,000 Posts
VonYinzer said:
....... Use a thin screwdriver or chisel to split the cases and they'll pop apart.

What Mr Von Yinzer is saying is that if there is a lug on the back or front of the cases that's designed to be levered, then go ahead. He is not suggesting beating a steel wedge between the cases and causing all manner of permanent damage.

Heat really helps to break the seal. Gray sealer is 3 bond, red or brown is aftermarket goop and a warning sign of problems ahead.

Rubber mallets are good but sometimes it's necessary to use a wood block and large hammer but be careful. Things break easily in there.


New Member
Thanks guys, will give it a go - wasnt allowed to play today - its Father's day here and the kids kept me out of the garage :)



Beer and Grease
Look for a leverage point on the cases. On the SOHC 750 you can flip the cases up side down and use the out put (drive) shaft as the leverage point with a large screw driver. Before you start to pry on the cases triple check that you have all covers off and all bolts removed... The bond should break free pretty easily.


I make things.
honda put small ledges on cases, where a small ledge of one side hangs over the other side, if you use a plastic hammer on the ledges, the cases will pop apart like someone made them for it... someone did


New Member
And its split . . .

A nice tap with the rubber mallet, and it just popped off ...

Good news, the main bearings are fine - almost no wear - certainly no scoring on the journal - ahhh, happy now :)

Huge thanks guys


Coast to Coast
TAKE OUT ALL THE BOLTS AND NUTS!!! you can leave several bolts(larger the better) evenly spaced around the engine and tap on them for some help along with the other suggestions............big thing with this kind of job is knowing when to stop, sometimes there is a fine line between taking it apart and ruining it. joe

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