Topic: CB550 forks on 750k

[Finley]

Hello, I scored some pretty nice CB550 forks off craigslist last night so I could lower the front end on my CB750k and was wondering if I could use the fork lowers from the 550 on the 750 or do I need to still use the ones from the 750 to mount the brake? Any help is appreciated. Thanks

[scottly]

Hey Finley, what year are your 750 forks? If they are '73 or newer, the caliper "T" bracket should bolt onto the 550 fork lowers, I believe.

[Finley]

Scott, the 750 forks are '72 and I tried last night and the caliper mount is just a little different. I'm now trying to figure out if I can mount my 750 caliper to a 550 mount.

[scottly]

No, a 750 K2 caliper with a "C" type mount will not bolt to a 550 fork leg. I don't think you can replace the "C" mount with the 550 "T" mount, either. It will physically fit, but the caliper won't be located properly over the disc; it will be positioned to the rear slightly, if I recall correctly, and the hole in the arm for the adjuster won't line up with the boss in the fork leg. Sorry.. 

[Finley]

Weak. If I put a CB550 caliper on my 750 would I be losing a sizable amount of brake power? I'm trying to figure out a way to lower the front end on a budget, the bike had fork tubes that were 3" longer than stock. The two forks internally are completely different too. If I put the right groves in the 550 fork tubes for the guides and such from the 750 forks would that work? I was mistakenly led to believe that this would swap over pretty seamlessly. 

[scottly]

To use the 550 caliper, you need to use a 550 disc, which is smaller in diameter than the 750. That would reduce the braking power. (both calipers use 38mm pistons, so that isn't the issue)

[crazypj]

Get a pair of 550 discs and calipers then change master cyl