Topic: Fork Upgrade Options

[01Thomas]

Jaguar, you need to visit Axel's Satanic Mechanic site at http://www.satanicmechanic.org/   
You'll find a lot more info on CB750 SOHC frame kits by specialists there.

[jaguar]

I have been there.
Sad that it is no longer active.
Wanted to add mine to the list.

[MidnightLamp]

Most of the simple "no loss" upgrade is in brakes, and a little in weight of parts. You'll find damping "upgrades" to be very tricky with modern forks as they're often not even closely valved or sprung to what you want and start to cost a lot to change. As for the whole front ends, the problem is that you end up with all kinds of geometry problems unless you're more interested in the current "Coffee Racer" trend instead of actual performance.

Tips:
- Most things from the mid to low 80's are running higher offset triples and similar fork lengths (due to similar rake angles on the double cradle frames)
- Most modern front ends run ~0.5"-1.5" offset triples with very steep frame rake. Also makes the forks shorter (which drops the bike), will generally not be compatible without a lot of work.
- If you can get a set of opposed piston calipers, I find that the feel and the maintenance make them worthwhile.
- 37mm tubes are plenty stiff for SOHC4 weight, and a set of gold valve emulators or something similar plus a well set up front end (progressive springs, good oil, good seals) will get you to something reasonably well handling.
- Pick a front end, pick brakes, then size up master cylinder, and if you want compatibility, run the same model clutch control and adapt the cables. Ends are easy to change.
 - If you can find something that takes an alloy stem and alloy lower clamp, you'll save a nice bit of weight, and be in good shape.

The ideal, simple, bolt on solution is to just go with a set of 900F (or other conventional forks with similar rotor spacing, offset, and length to stock)  forks and use the 2 pot brakes up front or adapt something like fishhead brakes does. Then pick a decent modern master and clutch setup to go with it.

[MidnightLamp]

Double post, sorry.

[scottly]

You will need triples with at least 50mm of offset, or the fork tubes will bash the front corners of the Seeley tank at full lock. I had a Kawi 550 front end on my bike for a while, but due to the 30mm offset, I had to limit the steering to the point where it had the turning radius of a school bus.

[turboguzzi]

You will need triples with at least 50mm of offset, or the fork tubes will bash the front corners of the Seeley tank at full lock. I had a Kawi 550 front end on my bike for a while, but due to the 30mm offset, I had to limit the steering to the point where it had the turning radius of a school bus.

scotly, you just needed to grab a post 84' 550 fork with the non offset axle...
gpz750, 37mm forks are quite good too, both triple clamps being forged alu. All kawi GPZ forks have teflon bushings top and bottom and are not too popular on ebay (yet), maybe because fo the ugly antidive valves (can be removed) .
Jaguar, you'll need simple bearing adapters to make them work. Does the seeley frame have the same bearing kit as stock honda?

[jaguar]

Still looking at the different options.

Unsure about what bearing the frame uses.
The PO did install new races in the frame, They look about the same size as stock, I can measure them and see though.  Problem is that I don't really have the set up to machine anything, even relatively simple spacers or cups.

[scottly]

TG, the '82 550 front end was free. I will say that the damping and overall action, with Progressive brand springs was much better than either the K1 forks my bike came with or the K7 forks currently fitted.
The lower steering bearing is same as stock, but the upper outer race is 2.00" OD. The inner race, at least on mine, is marked as a 1.00" bore, but has been opened up to fit the Honda stem.