Hi All,
I have a TT2 with a 650 allazura engine. I want to up engine capacity to 750.
I've bought a set of 750 barrells but i don't want to bore my 650 cases to accept the 750 cylinders.
I was thinking of buying a 750 engine out of a 90s 750 monster or SS. Are these bottom ends fairly similar to the Pantah engines. Will use my 650 heads.

Biggest difference is that the swingarm pin is only 20mm, and that part of the case is notably wider than on a pantah. So then you are solving a swingarm installation problem, and the compatible swingarms are too wide for your footpeg brackets. Plus the bosses for the engine-to-frame bolts are wider - but those could be trimmed. MikeV

Nice bike.

Thanks for that info

Looking at your first photo, when you came on board, i see your footpegs could be moved outboard. So that hurdle could be cleared. You would still need another swingarm and, then, probably a longer shock.

The 1990s lower end is fine, beefy compared to the 650 Pantahs, and they are all wet clutches, but you may end up with a full rebuild on that unless you get lucky. Can you find a 1988 or so 750 Sport engine?; that would be a step above the Pantah and be a bolt-in.

Also, your stock Pantah heads have 95mm wide combustion chambers, and your new 750 cylinders are probably 100mm across at the top.

Really, if you could fine a cooperative machinist (my problem here) with a horizontal mill, boring the case is the easiest.

MikeV

Hi Mike,
I was wondering about the heads. Can they be modified to fit the 750 cylinders. I do have access to a good machinist. I just wanted to try and keep the 650 cases unmodified as i have 3 good 650 cylinders. I'll see if i can get an earlier 750 engine but as you know this stuff is hard to find. Regards Ben.

Hello Ben,

I used a 1995 750 SS engine
Used the SS front head and a 650 Ally rear head welded and machined to match the front SS heads combustion chamber.
Don’t recall any issues with the Ally head fitting on the 750 cylinder.
I used two front 900 ie cams.
Also used the SS swingarm.
I had no problems fitting this into the Verlicci frame or foot peg mounts clearing the swing arm. Verlicci frame was from Old Racing Spares, so a replica.

Graeme

I have the SS rear head and the front Ally head if you need me to measure anything for you.

Graeme