1982 cb750K swing arm question

[hedrives]

Would someone be so kind as to send me the measured width between the axle tabs on a stock swing arm? I do not have the part to measure.

Thanks in advance.

[hedrives]

Can some please help me on this? TIA

[Re-run]

What are you wanting to do? Just fit a larger tire?

If so, I have a 78K, it has fairly wide swingarm, probably comparable.
I think it is possible to fit a 160 sized tire in there but there is very little space left, the rear brake arm might need bending to fit. Anything more than that and mods would probably be needed.
My stock tire size is 130.

[hedrives]

I found the measurement on another forum. It is 10.5" ID.

I have a fabricated swing arm that has 'spread' a bit and I was trying to see how far I needed to tweak it.

Thanks for the reply.

[Re-run]

Custom stuff like that is in somewhat short supply here. If you wouldnt mind, maybe you can post some info on it.

[hedrives]

Here is a build progression from a custom forum I'm on:

Started working with Carpy from cb750cafe.com on a Dresda style boxed swingarm for my cb750k project.

Sent him my stock arm and here is what he fabbed






It uses adjusters just like his sohc swingarms, so I didn't take a picture of them.
Then, I got a gas tank from Benjies and a seat pan from RocCity






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Then, Did a test fit of the swingarm today along with putting one of my shocks on.
Basically I am look at alignment and measuring wheel travel so I can finish mockup of my seat area, battery move to rear, etc.
Need to do this before I send the frame to powdercoat.

Here are some pictures:






---
Done some more work on the back end of the bike.

I removed the fender brace and am mocking up an aluminum plate
that will follow the frame top from under the seat and all the way back
before bending upwards to fill the tail section.

The panel will rivet to the frame to strengthen the rear and spread the shock loads.

My electrics will be in there. Plan to add a small scoop with a slot to send air through and vent out the back either side a round taillight.

Probably put brass screen in vents for a steam punk look.

Need to do some glass work on the seat pan area to fill in the areas cut out for fabrication and detail the underside in the back as that will be painted, too.

And, yes, it will clear the tire at full compression. :)









Been working on my hubs getting them ready for painting before re-lacing my wheels with spokes from Buchanan's.

This is the relative grime level I am dealing with here.



This is the result of many hours work.
I also drilled some steampunk style 'cooling' holes in the rear backing plate.
I am being amazed at how crude many of these casting are compared to new technology.
Lots of neat imperfections in the surfaces.



Next up is black epoxy paint and new bearing and seals.
---
Recent work...





Took parts (rims and various brackets) to powdercoat Friday.
Frame to follow this week.
---
Started epoxy painting my hubs while my frame and rims are at powdercoat.
Here are two of the parts.



Got all new bearings, seals, drive bushings, etc. to go in.
PLUS, I get to learn how to lace and true my wheels.
---
Assembled my wheels last night.
First time for me and it was not too bad.

The front was the easiest:


The rear was a mother due to the spokes being as short as they are and the epoxy on my hub creating 'just' enough interference. I worked it out though.


Slow, steady progress.

Again, the iphone camera shifts the red color.
These are Honda red in real life.
---
Been working on the frame this weekend.
Some were warning me the panel would be too close to the tire, so I measured one.more.time.

I made a cardboard radius of the tire diameter, then remeasured the shock and what the mount to mount centers would be a total compression (springs in total bind, on the bump stops and actual shock travel without springs or bump stops).
Next, I fabbed a piece of aluminum angle to bolt in replicating the rear suspension at total bottomed out.
Then, I mounted to rear axle with cardboard tire on it. I measured with the rear axle at each end of the chain adjustment locations and the tire clears by .5"

Remember, this is at TOTAL compression of everything.





After doing this I deel good that the tire will clear my frame panel, so I went about bending and rolling aluminum.
All I have is a small 18" brake and a few metal working hammers, so this is what I came up with.







Next will be to final grind the rear half moon section to fit my fiberglass seat piece. My wheel truing stand is coming in Tuesday, so I can true my wheels and get some Dunlop GT501s mounted & balanced. I have some fork tubes from Franks coming in and I'm putting Racetech springs and valve emulators in them.
---
Final attaching to frame using stainless pop rivets.



Took a few shots of the rear end with body work on it to further illustrate where this is going.

The battery and main electrics will be under the bodywork, of course.
I have a nice black Dime City 2" round tail light that will fit right on the recessed area along with turn signals.



--
Worked most of this weekend truing my wheels, then installing new bearings, drive bushings, and rear brakes on the bike.
Need to get tires and tubes in so I can get closer to rolling this thing.



Also noticed I need to make some bushings to properly space he rear wheel in the swingarm as there is a bit of a gap.

[woodsrider250]

SAAAWWWEEEET!

hedrives wrote

Also noticed I need to make some bushings to properly space he rear wheel in the swingarm as there is a bit of a gap.

Why did you have the custom arm made by chance?  As was asked, for bigger tire, or just cosmetics?  How much was it?

Looking forward to the progress!

[hedrives]

The stock swing arm is ugly.
I wanted the bike to harken to a race bike of the late 70s/early 80s and Dresda style arms were one solution.

So, I contacted Carpy at cb750cafe.com and finally talked him into making one for a DOHC bike. It is stock length, but seems to be about .25" wide at the axle which I will fix with new spacers now that I have the dimension.

I'm using stock size tires.

Thanks for the nice words,
brad

[Re-run]

That is going to be one awesome looking bike when you get it all together!
that swingarm looks killer!
Can't wait to see your finished project. Super nice work.

[hedrives]

Thanks, Re-run.
I'm taking my time and doing it my way.

[woodsrider250]

Yes, the stock swingarm blows....not just asthetically.  So, if you were to have it built again, it would be 1/4" narrower?  Is he going to start fabbing these?

[hedrives]

I can't answer that until I get home and futz with the swingarm.
Carpy gave me a longer center-bored axle and I am waiting on a 20mm x 1.5 castle nut for it.

I think it may all pull up snug.
This is a prototype.

Oh, Carpy has a jig built, so I am sure he'd make more.

[hedrives]

Update on my build:

Put new All Balls Racing bearings in the steering stem.
Wasn't the most fun I've had, but nice to get that checked off the list.



One of the things I am doing is making my own brake torque link.
I started with some 1" x 3/16" aluminum bar stock and hand-tooled the tapered ends.







Next is working on my bar clamps.
I'm removing the fuse block mounts as you can see in the last picture.

[Lucky 1]

Those were NOT imperfections in the casting.

They were designed that way for a reason.

"imperfections" Cheeeesssshhh!!!!!

[shinyribs]

How did i miss this build?!?!Lookin good man!I dig it.Looking forward to seeing more of it

[Daddyman]

Ya! its bad a$$!

[Half-Caf]

shinyribs wrote

How did i miss this build?!?!

Probably because the last time he posted on this forum was June 2010. Although it looks sweet, not sure he's still around...

[shinyribs]

...oh yeah....good eye half calf