749 Swinging arm in M750

Having recently purchased an M750 off a forum member I have now completely stripped the bike to its component parts in readiness for a complete rebuild including some modern extras.

One of these updates is to fit a 749 swinging arm and suspension to the bike, now I am not unfamiliar to fitting things that are not meant to fit and my plan is to keep the forum updated for those of you who are interested in this sort of thing.

The to do list so far and a few pictures.

1, Machine casings to accept 749 swinging arm
2, Chain alignment is slightly out and this can be overcome by using the bush/spigot I made in the pictures or fitting the later output shaft which is longer
3, Re locate and adapt the frame suspension mount
4, Replace crank casing needle roller bearings with solid bushes as the bearings will be in the swinging arm.
5, The rear wheel alignment is fine but there are number of spacer/bearing and caliper mounting issues to overcome.

[Albie]

I love a swingarm conversion project.

[utopia]

Cool.

I chuckled at the sprocket mod cos I've just made a similar thing myself (though still using the std retainer plate).
And then I got to thinking ... how far out have you moved the sprocket ?
And, more to the point, will this disrupt wheel alignment, even though chain alignment is sorted ?
The reason I ask is that I've just gone through most of the alignment thing while fitting an ally swingarm.
My method was to set the rear wheel and swingarm spindles parallel (using test bars and measuring, each side) and then juggle the issues of chain alignment and wheel alignment to obtain the best compromise.
A secondary plan is to re-shim the swingarm to one side to improve this compromise at some later stage.
In doing the above, I realised that there is not a great deal of room for manoeuvre, which is why I wonder how far over you're moving the wheel.
......or maybe the 749 hub covers these differences anyway ??

But, cool.
I'm not a single sider fan myself so this is a mod that I will follow with interest.
And so, out of interest, what are your reasons for doing it ?

Sprocket needs to be moved out around 2/3 mm I wont know the final size until the dry build and not many people realise the output shaft has a standard M8 thread machine into it so fitting a descent sprocket retaining bolt is not a problem. I recently fitted a set of 5 spoke ST4 Marchesini wheels to an old 750SS and had chain alignment issues but this was resolved by just turning the front sprocket round. I am not moving the wheel at all as it needs to be central I just need to take some meat off the crank cases off to accommodate the narrower swinging arm.

Should be cool as you say but it's not a single sider, 749 not 748. LOL

I like this idea
Query: will moving the drive sprocket out that far put unintended forces on the drive shaft?

[utopia]

Originally Posted by dunlop0_1

..... but it's not a single sider, 749 not 748. LOL

Exactly.
That's why I'm interested.
I could perhaps have worded it more clearly though.

Well the load will increase somewhat but the guy I originally got the idea from ran an Elefant for over 15k with this mod and had no issues.

[Dirty]

Looking forward to this thread.

Your inbox is full Dunlop

Crankcases machined today and the swinging arm fits beautifully.

Suspension mounting needs a bit of fiddling as the top cross bar if you will needed to be removed and re located higher up the frame also one of the mounting eyes needed to be moved. Slowly coming together though.

Slowly coming together but everything seems to be in place and ready for some welding.

Empty your inbox !
Looks mighty impressive what you have already done.
Sorry to see the old girl go, but needs must....... :- (

Engine painting and reassembly coming together
Bearings, rings checked along with new crank shells and bolts should be sweet.

Looks waaaay better than it did when i had it. Well done. Can't wait to see the finished item !

All the parts back from Triple S powder coating so reassembly can begin.