Topic: 1978 750f dual front disc setup

[johans]

I am currently at the end of a 76 750f build and i recently purchased a 78 750f with the stock dual disc setup . Are there any weak links on this setup or things i should look out for/ or any upgrades.  Also, why does everyone opt for the GSXR setup ( my son is doing that on the 78K we just finished ). How many years was this setup used ?    I'm sure the GSXR assembly is better , but it seems that the 78 to 76 swap is a bolt up application. I am also probably going to use the Comstar rims if i have to. Is the rake the same ?  ( i have the 76 in the basement and the 78 in the garage ) . Any thoughts are greatly appreciated !  Thanks in advance.

[seanbarney41]

Yeah, it bolts right up and 78f is the best front end that bolts on to these bikes.  Bolt on better dual piston calipers from a dohc era Honda and a more modern master cylinder and your brakes are sorted.  Or leave the stock single piston and its still worlds better than anything Honda before '77.  Tarrozi (or other) fork brace solves most of the major 35mm noodle woes.  Good springs, and fork oil will get the suspension under control and for total domination Race Tech cartridge emulators will have any blindfolded riders not believing that gear was built in 1978!  (until they crash into a tree lol)   Should be little worry about trail changes.  Just measure overall length and adjust with springs and spacers or just slide forks up in the trees as I am sure the 78 forks are longer than the 76.  That's the problem with any USD sport bike front end swap...they are ALL wayy too short! which, of course, screws your trail up.  And it takes a ton of work and/or $$$ to fix that.

[johans]

Thanks for your fast informative reply !

[scottly]

Just measure overall length and adjust with springs and spacers or just slide forks up in the trees as I am sure the 78 forks are longer than the 76.

The overall length, measured from the top of the fork tubes to the center-line of the axle, is very close to the same on K1, K7, and F2/F3 forks. The fork lowers on K7/K8 F2/F3s are longer than earlier bikes, but the overall length is the same.

[seanbarney41]

Just measure overall length and adjust with springs and spacers or just slide forks up in the trees as I am sure the 78 forks are longer than the 76.

The overall length, measured from the top of the fork tubes to the center-line of the axle, is very close to the same on K1, K7, and F2/F3 forks. The fork lowers on K7/K8 F2/F3s are longer than earlier bikes, but the overall length is the same.

good info...I wouldn't have guessed that for the F2/3's

[scottly]

The K7/K8 F2/F3 forks have 10mm less offset than the earlier K bikes, but I'm not sure about the F0/F1? In any case, slipping the late F tubes up into the early F triple will preserve the original geometry. If the Comstar is retained, it's a bolt-in upgrade.