1999 Honda CB750 conversion to VFR750 sssa and car wheel

[seeme]

Hello! 

 

I am currently on a mission to complete the conversion to sssa on my Honda CB750 and I was hoping to get some help from this forum since the sssa is from a 90-93 VFR750. I am having difficulties figuring out how big of a flange I need to make the car wheel fit and to be centred (I heard that a few mm off isn't too bad either). I was hoping maybe someone smarter could tell me where in what order and how to measure certain things so I end up with the right flange measurements. The car wheel I am using is 17x7 with a 42mm offset. I just had the local tyre shop mount 210/50/17 Metzler tyre on it. I have read some old threads where the adapter sizes run through but I don't know if they're relevant to me since the wheel isn't going under a viffer, just a viffer sssa on another Honda bike. I have my bike's rear end all removed (the picture was taken right before I dismantled it but maybe it'll help in some way) and ready for mounting/measuring. I hope that someone smarter can point me in the right direction.

[vfrcapn]

I put a 4.5"(?) wheel on a CB750 with a 150 tire as I recall - long time ago. Even with that I had to get an offset front sprocket to get the chain lined up. I can't imagine there is anyway a 7" wheel is going to mount and line things up?

Edited July 15, 2024 by vfrcapn
Corrected tire size

[Captain 80s]

20 minutes ago, vfrcapn said:

I put a 4.5"(?) wheel on a CB750 with a 160 or 170(?) tire as I recall - long time ago. Even with that I had to get an offset front sprocket to get the chain lined up. I can't imagine there is anyway a 7" wheel is going to mount and line things up?

 

That minor issue aside, the rest of the concept seems all very reasonable.

[tsmitty]

Sounds fun! Give it a try. Here a are couple things I was asking myself while looking at your pics:

 

I'm an old school CB 750/550 head; the 750's back in the day use to have a "dry sump" lubricating system.

Is that still the case with your bike? If so is the oil tank still under the right side cover? 

Will there be room for a single shock and linkage in the area that houses the battery and the oil tank, airbox?

 

Are you going stock air box, v/stacks or K&N's?

 

Is there room for the new swingarm at the pivot point @ the frame or will the frame get modified; just guessing the sssa is much wider than the stock one and probably cant be made narrower because of bearing/seal casting on the sssa? 

 

I have used a dummy engine with an output shaft to help align the engine and sprockets with the rear but that was for a 100mph straight line bike...you have so many more variables.

Good luck keep us posted.

 

[seeme]

1 hour ago, tsmitty said:

Sounds fun! Give it a try. Here a are couple things I was asking myself while looking at your pics:

 

I'm an old school CB 750/550 head; the 750's back in the day use to have a "dry sump" lubricating system.

Is that still the case with your bike? If so is the oil tank still under the right side cover? 

Will there be room for a single shock and linkage in the area that houses the battery and the oil tank, airbox?

 

Are you going stock air box, v/stacks or K&N's?

 

Is there room for the new swingarm at the pivot point @ the frame or will the frame get modified; just guessing the sssa is much wider than the stock one and probably cant be made narrower because of bearing/seal casting on the sssa? 

 

I have used a dummy engine with an output shaft to help align the engine and sprockets with the rear but that was for a 100mph straight line bike...you have so many more variables.

Good luck keep us posted.

 

Thanks for the reply, the oil reservoir is on the right side, and I plan to mount the battery somewhere else (probably make a box or something for it under the seat). I plan to use the stock airbox but if it will get in the way of the shock mount then I'll just install pods or v/stacks as I have already had that planned in the past. The frame doesn't need any modifications because the sssa is quite much narrower than the stock arm, so I'm gonna need to have some bushings made. I'm thinking that I will mount the sssa to the leftmost side of the frame at the pivot point and then somehow measure out the right thickness for the adapter so it clears the swingarm, and chain and still be as center as possible.

[seeme]

15 hours ago, vfrcapn said:

I put a 4.5"(?) wheel on a CB750 with a 150 tire as I recall - long time ago. Even with that I had to get an offset front sprocket to get the chain lined up. I can't imagine there is anyway a 7" wheel is going to mount and line things up?

Well I have already spent too much money on the parts so I'm gonna have to atleast try to make it work lol

[Presson]

Interesting project. Can I just ask one question: Why?

[Captain 80s]

3 hours ago, seeme said:

Well I have already spent too much money on the parts so I'm gonna have to atleast try to make it work lol

 

Dictionary

Definitions from Oxford Languages · Learn more

 

sunk-cost fallacy

noun

noun: sunk-cost fallacy

1. the phenomenon whereby a person is reluctant to abandon a strategy or course of action because they have invested heavily in it, even when it is clear that abandonment would be more beneficial.

   "the sunk-cost fallacy creeps into a lot of major financial decisions"

    

 

 

 

[vfrcapn]

3 hours ago, seeme said:

Well I have already spent too much money on the parts so I'm gonna have to atleast try to make it work lol

Might try digging around here: http://forums.sohc4.net/index.php

[seeme]

A little update on the build. Did a lot of eyeballing with my father and found out that the spacer should be 38mm thick to get about 5mm clearance between the tyre and swingarm. So I signed up for the Fusion 360 free trial and got to work without prior 3D modelling experience. I decided to 3D print my design before having it CNC'd to ensure that all the holes, etc., line up exactly. I will update this thread as I go along. If anyone has some kind of tips feel free to reply.

[rc24dk]

Does the wheel center in the frame? The hub may be stamped with an hub offset. Common here would be the letters ET followed by the offset in mm. Probably different in US. I would start with centrering the wheel in the frame and then see if sprockets need offset. For tips and experience I would also check the sidecar society (if such exists 🙂 )

Edit: oh well, you can of course center the wheel afterwards by adapting the bushings between frame and swing arm.

[JZH]

Honda SSSA wheels all seem to have the same offset.  Different widths, hub and drive arrangements, but for example, an NR750 wheel aligns perfectly on my RC30-swing armed '90 VFR750FL.

 

 

 

FYI, last time I installed, Fusion 360 was free to use non-commercially "in perpetuity".  There was some confusion about that a while back, but the free version is still free, and is not limited in time.  I can't remember what you have to do after the "free trial" expires, but I did it.  YouTube will reveal all.  

 

Ciao,

 

JZH