MOPED ARMY

An av7 with the dimoby clutch would be the closest to stock. I imagine that is a dimoby on your seized motor....

As far as the variation, as long as it swings it will probably work. Although maybe a bit shaky. You may have to use your original head on the new engine. As for the spring I imagine that you could retrofit a standard Moby 50v spring and hook setup...

Those complete replacement engines are pretty bad quality wise, as is the variator. Pretty expensive too. You could probably buy a good used french made engine here for far less. Those complete engines are indian or Chinese made clones.

Your also gonna need a new intake and carb. As that old gurtner carb will be much harder to setup with the new engine. If you can even save it at all....a 15mm malossi shorty intake and dellorto 15:15 carb would be your best bet. Get some more power too...don't forget to buy a range of jets in the correct sizes. Don't want to seize it from running too lean

Why don't you just rebuild the engine you have? A new cylinder, Piston, crank and seals/bearings would be much cheaper and a pretty easy job.

looks like the bottom of the engine is mounted with a bracket, if you want to use a variator, you have to mount the AV7 bracket+spring mount so the engine can swing about the top engine bolt. this means you also have to mount the top of the engine in a manner that will allow it to rotate, like with a nylon lock-nut without torquing down the nut. otherwise, you need to get fancy with spacers n bushings.

Aww you'll be fine. I just had trouble with the one I bought. Nothing catastrophic though. I remember I wrote down what I did to mine somewhere. I'll see if I can find it and let you know what I did to fix it up. Your engine might very well be just fine ...quality control wasn't the greatest engine to engine.

68 miiight be ok, I'm thinking a little bit lean. Some one else will chime in but I think I was running a 72 on a stock av7? Regardless you will certainly need more than those two jets. I'd say buy the next few sizes up, 70, 72, doubt it would need a 74...what size is your new intake?

Is that engine a points or cdi? I imagine that you'll have to switch everything over to 12v as the new engine isn't going to be 6v....well I doubt it would be anyway.

With the way the engine mounts I would aim to keep it non variated if I was doing this myself. But you can certainly make it work...

Hi Saabsonettguy, thanks for your reply. Excellent idea regarding the RM9 mounting system. I didn't realise that it was so similar to what's in my head! Although I'm thinking of trying to keep the new engine complete with it's own head and make up some sort of conversion bracket to attach it to the frame. Maybe I can incorporate mounting bushings in that as well. Yes, I could just change the clutch but I do like the idea of have the variator if I can get it to work.

Another idea would be a simplified version of a parallelogram mount like this.

Not sure if those dimensions would all work for your application, but it gives you something to start from. (edited)

I think all those in the photos are aluminum. I think a thinner piece of steel would be ok if you had a tube welded on the big end for the rubber bushings to press into.

Thanks Graham, yes it looks rough all right but I have it completely dismantled now and the frame is solid. It's not worth rebuilding for financial reasons for sure but I have it for about 47 years and sill have the log book etc. It's one of those 'reliving my youth' type situations!