Need some help with a few measurements.

[1969Honda]

Hi Everybody! I'm new to the forum and working on a 1969 Honda CB350 cafe/fighter project. I've got an inverted front end from a '98 R1 installed, shaved and reinforced frame, .75mm over bored engine with an aggressive camshaft (drag/race grind) and I'm working on a new seat pan as we speak.

I've had a wild hair for a while to build/modify a single sided swinger on the rear end. I really like the tube design of the MH900 Ducati, but they seem to be pretty rare. I'm currently looking more towards a ducati 748 type arm due to the availability and the shock mount but I'm also open the the VFR/RVF arms as well.

I've been searching around the forum and a few others (customfighters, dotheton, etc...) places getting all the dimensions that I can find and figuring out what linkages and everything I'm going to have to fabricate to handle the added stress of a monoshock. My problem is fairly simple, I'm not sure if the 243mm dimension for a Duc 748 swing arm pivot is the internal or external dimension.

I'm guessing it is the external, if so I need to know the internal dimension. Also if anyone has the same measurements on VFR/RVF arms with the split pivot point that would be helpful as well. Thanks!



(I know the arm in the pic is upside down, but it had the best angle for what I need )

[The Ring-In]

i don't know if this is a stunt or not.......

but I would not be monoshocking a pressed steel frame

[1969Honda]

It's not a stunt, several others have done it before with conventional swing arms. I've welded all of the seams and then welded .095 strap over top off all of the welds, I've also boxed in all of the open areas and will be reinforcing all of the shock mount areas to handle the load. I've got a few Mechanical Engineering friends helping out and supervising the reinforcements and giving advise on bracing, moments and possible fatigue points. I appreciate your concerns and looking out for my safety however.