Topic: CB750K4 what did I get myself into?

[BenelliSEI]

Nice work. It will look great with a fresh disc and new tire!

[denward17]

I like it....Is the rim paint or powder coat?

[Kaze]

Just saw the "before" pics. That looks exactly like a project I'd go for. You've really dug in deep. Must be having the time of your life!

[BrockCB750]

Haha! Time of my life? Hmm... I wouldn't call it that. It was a massive relief getting the thing apart with only one broken off fastener. That was exciting.

Work has been a little crazy and some travel but I finally got around to painting the rear hub, new bearings and new rubber dampener things (can't remember what they are called at the moment).

I think its time to lace the spokes.

Paint is a little wet from wiping off some stuff on it. When I get the spokes laced on it I will take another picture of it all cleaned up.

[SOHC4 Cafe Racer Fan]

Those cush drives look like NOS (not the easiest thing to come by).

[BrockCB750]

They are not NOS I believe. "Rear Wheel Damper Rubber Set"
https://www.vintagecb750.com/products/3/suspension-wheel/132/rims-spokes-wheel-seals-tire-valve-stems

[MauiK3]

https://www.yamiya750.com/index.php?main_page=index&cPath=246_251_184_90

Yamiya says they have Honda Cush drive parts

[PeWe]

I thought the separate parts were the older.
Those that are connected with a tang the later.

I have a Honda labeled  plastic bag with the separate, small and big rubber parts.
Ordered from Germany some years ago.

They costed much more than the other I think is later.

Fitness very tight, I gave up pressing in the sprocket carrier despite lube, replaced with the other model.
My K6 need new since the rubber has cracked. I'll try my older set again at next wheel off.

[BenelliSEI]

They are not NOS I believe. "Rear Wheel Damper Rubber Set"
https://www.vintagecb750.com/products/3/suspension-wheel/132/rims-spokes-wheel-seals-tire-valve-stems

Brock…… I’m curious; how snug were these when you went to slide the drive side back in place?  Thanks, I need a set on my K4 and have never tried those. Fairly recent addition to their offerings.

[BrockCB750]

Haven't gotten that far yet. Will report back when I do.

[BenelliSEI]

Please do!

[CycleRanger]

They are not NOS I believe. "Rear Wheel Damper Rubber Set"
https://www.vintagecb750.com/products/3/suspension-wheel/132/rims-spokes-wheel-seals-tire-valve-stems

Brock…… I’m curious; how snug were these when you went to slide the drive side back in place?  Thanks, I need a set on my K4 and have never tried those. Fairly recent addition to their offerings.

Good to see that they are repopping these now.
~12 years ago when I replaced the ones on my K5 all there were was Honda parts and they were getting scarce.
It did take a little effort to squeeze the drive side back in but it wasn't too bad. A bit of soapy water helps to facilitate things.

[BrockCB750]

Been away from this thread for a bit but got a lot done.

Dropped the engine off at a local vintage motorcycle shop to clean the engine up and cerakote it.

Mike Rieck is doing my head work:





I laced the wheels and had a shop true and mount the tires:



Some bushing and bearing stuff:





Some painting/bluing:

[BrockCB750]

I am getting into loosely fit stuff together so I can mock up seat, tank, oil tank, etc. F

Started with the rear swingarm:


I bought some cheap shocks to get everything mounted up. Supposidly they are OEM direct replacement.

Wanted to mount the rear shocks but ran into an issue I need help with. First of all, its a huge pain getting new shocks and bushings on. Once I got the first one on I realized something was off.

I am guessing there was something here before (grab handle? turn signal? idk?) or some other crap that was mounted to shock mount or my cheap shocks are out of spec... either way I have a large gap. Its not something a single washer can fix that I have handy. In the picture those are the original nut and washer. I tossed my old beat shocks in the trash awhile ago so I can't compare them to what I am using now.

I strongly suspect this is not normal and the rubber and shock shouldn't have that much of gap/play.



Here is another thread with exactly the same issue:
http://forums.sohc4.net/index.php?topic=147409.0

Second to last post in thread mentioned about talks about putting a washer or spacer.

1) Is it acceptable solution to throw an extra thick washer/spacer between the frame?
2) I am guessing if I had just gotten the IKON direct replacements I wouldn't be having this problem? Something like these: https://www.common-motor.com/ikon-rear-shocks-honda-cb750
3) Any other advice for dealing with this problem would be appreciated.

Thanks!

[BrockCB750]

Well answered my own question. Got what I paid for or I ordered the wrong thing.

I did some quick measuring. The first black sharpie line is the upper eyelet width of the cheap shocks.

The IKON line is what IKON says their upper eyelet width is. (1.02 ")

You can see the difference exactly makes up the gap that I have.

Whoops. Need to figure out what to do next. Pretty sure I know the answer.

[BenelliSEI]

Was your bike fitted with a grab rail? Would it fill that gap?

[BenelliSEI]

When you do the final assembly, remember to fit the operating shaft for the rear brake before the swing arm. It’s a pig if you do it later……

[BrockCB750]

Thanks for the advice. This has very much been a learning process.

I sent an email to Ikon Sunday to get measurements on the top eyelet on the part I wanted just to be 100% sure. Someone in Australia got back to me within the hour and they connected me to a US Sales person who double checked it was correct and made sure to get my order out as fast as possible. Their customer service is unheard of these days.

Shocks show up today and it looks like I will actually have some time to pull more of it together. I got my seat and seat hoop. Going to be able to mock everything up for the most part probably by this weekend? Well...everything has taken about 3x as long as I expected so who knows?

Ordered a bunch of carb parts from South Sound Honda and those come in tomorrow? Might be able to throw together the carbs this weekend as well. They have been sitting after I pulled them out of the ultrasound since early on in the project. Hopefully I remember how to put them back together!

[BrockCB750]

Fits perfect.

[Floshenbarnical]

What are those rubber damper things? I didn't see any in my Comstars when I pulled the bearings. Do the Comstars get them?

[BenelliSEI]

VERY NICE!

[newday777]

I'm still running a set of the old Konis on my K5 and when they die I'll replace them with the Ikons.

[BrockCB750]

What are those rubber damper things? I didn't see any in my Comstars when I pulled the bearings. Do the Comstars get them?

I looked up a parts diagram of the comstar rear wheel and it doesn't look like you have the rubber rear wheel dampers. But not certain since I haven't had that style of wheel before.

I was wrong! They do!

[newday777]

What are those rubber damper things? I didn't see any in my Comstars when I pulled the bearings. Do the Comstars get them?

I looked up a parts diagram of the comstar rear wheel and it doesn't look like you have the rubber rear wheel dampers. But not certain since I haven't had that style of wheel before.

The comstars do have the rubber dampness. #6 (on a 78 CB750 F diagram)

[Floshenbarnical]

What are those rubber damper things? I didn't see any in my Comstars when I pulled the bearings. Do the Comstars get them?

I looked up a parts diagram of the comstar rear wheel and it doesn't look like you have the rubber rear wheel dampers. But not certain since I haven't had that style of wheel before.

The comstars do have the rubber dampness. #6 (on a 78 CB750 F diagram)

Oh, great! Another thing to do Looks like they're in the hub? Now how do I get the cap off for that hub!