another engine fitment question

[paco13]

I have a 1980 750 16valve engine.
I also have a '78 750 8v frame, and a '78 550 8v frame.
will this engine bolt into 1 or both of these frame's without much modification?
Thanx

[wazz]

This is a question for Earl, if I recall he did this very swap on vwbeatle's 750......Earl ?

[paco13]

Thanks for the reply.
I turned up nothing with my first attempt with search feature, but searching post's by Earl gave me the info I was looking for.

[earlfor]

I did an 81 16 valve 750 engine into a 79 8 valve 750 frame.

Physically, the 81 engine will fit. There are some problems and it is not remotely a transfer and bolt up job. The 8 valve uses 28 mm VM carbs and the 16 valve uses 32 mm CV carbs. You will not be able to use the original 79 (VM) airbox because of the bigger diameter CV's. There is not room side to side to ream out the airbox to accept the CV's either. The 81 airbox will not fit inside the 79 frame without cutting the rear of it off and fiberglassing/fabricating a new rear half. Pods are probably the best choice for ease of installation and the least work. Rear brake pedal and shift linkages line up pretty well, although I had to cut the right footpeg and weld it back together at an offset to get clearance for the brake pedal/arm.
Throttle linkage lines up perfectly. The rear lower engine mount engine casting is too wide to fit inside the 79 frame. You will need to take a die grinder and cut aprox 3/8" off each side of the lower rear engine mount casting. The upper rear engine mounts will have to be made from steel plate as neither the 79 or the 81 mounts will be long or tall enough. The front upper engine mount will line up as will the lower front mounts. The 16 valve engine has a pair of lower center mounts (one on each side) There are no provisions on the 78/79 frame for those mounts, so those will need to be fabricated and nut plates welded to the lower frame tubes for attaching the mounts and bolting up the engine. The will have to be removable as the engine cannot be installed if they are not.

Its been awhile, so this is as I remember. You pretty much have to align the engine and make your own engine mounts.

If I had it do do over again, I would not. Its too much work for no noticable gain in performance. You also lose the kickstarter if that matters to you.

Earl

I have a 1980 750 16valve engine.
I also have a '78 750 8v frame, and a '78 550 8v frame.
will this engine bolt into 1 or both of these frame's without much modification?
Thanx