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Tips For Removing 850 Commando Engine ?


My '74 850 mk2A has leaks I want to fix over the winter,

I have and have read the "850 and 750 Commando Workshop Manual. In section F it deails how to remove the motroe from the frame.

Please share any ideas/tips that will make the operation go well.

I plan to reassemble with JS Motorsport's fiberglass reinforced silicone gaskets,


Can anyone suggest improved seals vs the OEM originals ?

Thank you in advance,

Ron Wellman

Midland, Michigan





one general tip is to consider laying the bike on it’s side, with plenty of dust sheets / cushions etc, and thereby support engine as it is eased out of the protected frame. 

In reply to by jan_nelder


Laying the bike on its side never occurred to me.  Great suggestion, the images in the manual all show the bike upright. Makes good sense so the engine assembly with the rear wheel attached doesn't flop over and break something.


Keep in mind that you will have difficulty rolling the chassis around if needed without the engine in place - Andover among others offer a temporary fixture that fastens to chassis to take the place of the engine to enable bike to be moved around


Easiest to pull the whole engine/gearbox/primary drive as a unit. Remove front isolastic (I think that's in the book), remove the swinging arm and clamp/strap frame down to bench by lower rails so it stays put. Protect frame with rags and much easier with two people.


Seeing as you are going to replace the gaskets, then remove the large items as you go, head, barrel cases, gearbox etc. This can easily be done with one person and, the bike can be kept upright throughout. Don't forget the isolastics when the bike is dismantled like this. 


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