Author Topic: Nighthawk wheels on 75 CB750F (Read 17172 times)

DollarBill · « **Reply #25 on:** October 31, 2008, 12:26:44 PM »

I was sitting here wondering about the bearings myself. Are the bearings the only thing that touch the axle? I don't quite have enough experience in trying something like this so I am all ears.

DollarBill · « **Reply #26 on:** October 31, 2008, 12:37:46 PM »

From the looks of these images it looks the collar might come into play along with the bearings. What does the collar do?
#5 is the collar in both images
#16 is the bearings on the front wheel
#14 is the bearings on the rear wheel

FRONT

REAR

eldar · « **Reply #27 on:** October 31, 2008, 02:24:43 PM »

I would guess the collar keeps the bearings spaced out and in place. Since I have not seen a wheel in person, I can only guess. It probably gets bathed in grease and acts like a bushing sorta.

mystic_1 · « **Reply #28 on:** October 31, 2008, 02:48:22 PM »

Quote from: eldar, Master of the K8 Thunder! on October 31, 2008, 02:24:43 PM

I would guess the collar keeps the bearings spaced out and in place.

Correct, it also allows the axle to clamp down on the bearings' inner collars without pushing them together or side-loading them.

mystic_1

TomC · « **Reply #29 on:** October 31, 2008, 02:59:37 PM »

Hi Wheel Swappers
Two comments: Mag wheels that are intended for use with tubeless tires should be marked that they for use with tubeless tires. Someone maybe CycleX??? sells sprockets that are offset 1/4", I think, for use with wide rear tires. This might help with centering the rear tire and keeping proper chain alinement at the same time.
TomC in Ohio

Alan F. · « **Reply #30 on:** October 31, 2008, 05:38:05 PM »

There was someone around here very recently making a CB900 rear comstar fit on a 750, among other things he removed the studs from the sprocket carrier, and turned it in a lathe to remove some thickness, as he didn't need an offset sprocket, but just the opposite. He turned down just the area that the sprocket mounts to, but left the bearing area alone I believe. Reinstalled studs and sprocket and bolted it on. A quick search found no results, anybody remember this one?

Alan F. · « **Reply #31 on:** October 31, 2008, 05:48:31 PM »

Here it is, Topic: StrongPerf 550 project! WHEELS/SWINGARM/CHAIN/SPROCKETS thread with pics http://forums.sohc4.net/index.php?topic=28324.45 he's got a few other threads referenced to, this guy seems to have been where we want to go!

TomC · « **Reply #32 on:** October 31, 2008, 09:00:48 PM »

Hi Alan
One more good way to get things alined.
My interest is in a CB550 that I have that a PO started a conversion to late seventies Yamaha wheels. My current guess is in the front fork tubes with the wheel and brakes were pulled from the Yamaha triple clamps and put in the Honda triple clamps. I guess that the the distance between the fork tubes on the Yamaha is close but not the same as the Honda.
On the rear of a CB550 spacing the front sprocket over a 1/4" would solve the clearance problem with an X-ring chain.
Happy wheel swapping! TomC in Ohio
PS I would say that the stock disk on my CB750F1 is a bit to heavy for what it does.

754 · « **Reply #33 on:** November 01, 2008, 08:56:29 AM »

You can cut the wheels back to bring brake/sprocket in closer.

Unless you have access to a realy big lathe, I prefer to do them on a mill. Clamp down, and clock in the contact points, then mill.. be careful clamping.

Keep in mind you may cause the tire size to be a bit less, by doing this..

DollarBill · « **Reply #34 on:** November 01, 2008, 11:52:26 AM »

Okay, here's the measurements from my CB750F. I used measuring tape and ruler...don't have any calipers but these should be close enough to give us a good idea of what needs to be done to make it work. They aren't too far off from the NH which is a little encouraging.

REAR

FRONT

Alan F. · « **Reply #35 on:** November 01, 2008, 01:59:45 PM »

WOW, now I'm all fired up to mock everything up and find the flaw.... I wonder how far the NH rear wheel center is from the wheel center... it's tough to measure with the chain on there, I've got a spare NH rear wheel downstairs, I should pop the cush rubbers and sprocket carrier into it and measure that. I'll also measure the diameter of the sprocket carrier, so we can figure out just how large of a lathe we'd need to turn down the sprocket carrier....

DollarBill · « **Reply #36 on:** November 01, 2008, 09:11:53 PM »

YEP! When I saw that the distance from swingarm to wheel centerline was identical for front and rear I got a smile on my face. Now, granted I was just using a tape measure with the wheel on so it may not be exact...even if not it's darn close.

It is KILLING me not having the NH wheels here yet.

I saw a photo somewhere on the net this evening of another sohc with some 80s NH wheels and it looked stellar. I'll have to see if I can find it again...

Alan F. · « **Reply #37 on:** November 02, 2008, 05:40:36 PM »

80's nighthawk wheels? I thought they were all shaft drive except the 450. The 550, 650, 700 there wasn't a chain drive among them in the US anyway...right?

I'd be interested in seeing it too though.

DollarBill · « **Reply #38 on:** November 02, 2008, 06:07:04 PM »

In that case I could be mistaken. They looked exactly like the star versions that were on the 450s...I think. Here's the bike in question and a NH wheel off of eBay. Search for "nighthawk wheel" and you will see a few like this. They look pretty dang close don't they? Pretty sweet huh?

DollarBill · « **Reply #39 on:** November 02, 2008, 06:08:32 PM »

Now looking at where the points come together on the outer rim there is a distinct difference.

754 · « **Reply #40 on:** November 02, 2008, 07:35:57 PM »

The shaftdrive portion unbolts and you can make a sprocket adaptor to bolt on..

KB02 · « **Reply #41 on:** November 03, 2008, 04:37:17 AM »

Quote from: Alan F. on November 02, 2008, 05:40:36 PM

80's nighthawk wheels? I thought they were all shaft drive except the 450. The 550, 650, 700 there wasn't a chain drive among them in the US anyway...right?

I'd be interested in seeing it too though.

The 82-83 750 nighthawks were chain drive.

Alan F. · « **Reply #42 on:** November 03, 2008, 04:30:26 PM »

Thanks 754! I've heard that could be done, but nobody could tell me about it until now, could you provide any more info about the adaptor? Would it include some kind of cush drive, or just solidly mount a sprocket to the wheel? Wouldn't that risk cracking the wheel?

754 · « **Reply #43 on:** November 03, 2008, 10:29:39 PM »

If you can crack the wheel you are doing good! Machine an aluminum piece to fit where the shaft spline went, make it wide enough to go out to where sprocket would sit..

Alan F. · « **Reply #44 on:** November 06, 2008, 06:30:12 AM »

The NH front wheel only supports one disk, you'd have to find an ST1100 wheel to run two and keep the 18" wheel or get a CBR wheel and drop to a 17" wheel

DollarBill · « **Reply #45 on:** November 06, 2008, 06:34:55 AM »

Alan, have you had a chance to mock anything up yet? The guy I was getting my wheels from sold them out from under me....big bummer. There is a front and rear on eBay right now with "buy it now" prices that are a little higher than I want to pay...especially when you add in shipping.

Alan F. · « **Reply #46 on:** November 06, 2008, 05:57:21 PM »

No, I haven't had a chance yet. Probably will be a little while before I can get to it too. But I'll try to get that measurement of sprocket offset asap. It occurred to me today that if I want to use the K3's axle I'll have to replace the bearings which is no biggie, but the brake backing plate will also need a larger diameter bushing to fit the larger axle. Might be easy enough to do but it hadn't come to mind until today. I'd like to use the K3 axle, chain adjusters and swingarm if I can, the NH axle is longer because of the boxed swingarm and would probably need to have it's threads cut further down the length of the axle to mount in the K3 swingarm, as well as needing some stepped collars at the chain adjusters to make the skinny axle fit.... much simpler to go with the K3 axle I think.

It may be cost effective to find a nighthawk with a bad engine, and keep the parts you want, while you eBay the rest of the parts. I found a very tempting one on craigslist for $500 it needed only a front wheel, but had been parked in a heated garage "since the accident" the bike had 7000 miles on it. Parting out the rest of a bike like that can cover quite a bit of the cost of a project.

Alan F. · « **Reply #47 on:** November 08, 2008, 06:01:02 PM »

Quote

Alan, have you had a chance to mock anything up yet?

Yeah, I did it tonight. My bike is disassembled, so I grabbed the swingarm and chain adjusters from my K3, and the axle and assembled wheel (sprocket carrier and brake carrier installed, no tire mounted) I took some measurements and it seems like it can be done. I've planned on using the NH axle and to distribute it's extra length toward some lift spools left and right of the swingarm. This way the hard part is making the correct stepped spacers, and possibly milling the sprocket carrier for chain alignment.

Wheel centered, we have 4.9" to the inside of the swingarm on either side.

From the wheel center, to the mounting surface of the sprocket carrier is 3.7"

DollarBill measured 3.5" with a ruler or tape measure, so we've certainly got some room to mill down the sprocket carrier.

I've figured dimensions on some stepped spacers to adapt the NH axle to the K3 swingarm and chain adjusters.

I should go through the same procedure and take the same measurements with my original spoked wheel for comparison, that'll give me the sprocket offset dimension I'll need to achieve with the NH wheel to make this a bolt on.

Alan F. · « **Reply #48 on:** November 09, 2008, 10:08:55 AM »

Quote

I should go through the same procedure and take the same measurements with my original spoked wheel for comparison, that'll give me the sprocket offset dimension I'll need to achieve with the NH wheel to make this a bolt on.

This morning I bolted my K3's spoked wheel back up to the swingarm and took some measurements.

The sprocket offset from wheel center is 3.380"

From the inside of the swingarm (not measured from the chain adjuster) I measured 1.425" to the face of the sprocket carrier. (This will be a good reference point when I have all of my spacers made up and my sprocket carrier milled down and I bolt it all to the swingarm for the first time.)

So I simply have to remove the studs from the sprocket carrier, and turn or mill .320" from it's thickness where the sprocket mounts, reinstall the studs, and find a 530 sprocket that will mount...

What do you think?

DollarBill · « **Reply #49 on:** November 09, 2008, 05:03:10 PM »

Very cool Alan! It looks like you are making progress. I on the other hand have been knee deep in sheetrock, paint, and wood laminate flooring the last couple of weekends. Any other spare time is spent trying to figure out the electrical problems with my bike. I should be able to dive back in here pretty quickly.

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Author Topic: Nighthawk wheels on 75 CB750F (Read 17172 times)

eldar