Topic: F3 triple on K3 frame

[70CB750]

I am planning on using this combo, since I have forks and wheels too, but now I am thinking steering geometry and not so sure anymore.

What do you think?

[jaguar]

Tony Foale wrote a great book on the subject.
Worth a read if you want to set up a bike properly.

Plenty of people swap all manor of inverted forks onto sohc bikes.
I personally have not seen anyone do the math for spring rates and such.
Don't know how much they ride either.

[70CB750]

Thank you.  I will get the book and educate myself a bit.

I figured I could always swap the triple if she behaves badly.

[andrewk]

What do you think the problem will be with the geometry?  Most publications say the the rake is slightly different f to k, but it's all in the triple tree offset- at least that's my understanding.

[70CB750]

The trail will be shorter than K3 had.  I also have to use F swingarm to get in the wheel, we shall see 

[Retro Rocket]

The trail will be shorter than K3 had.  I also have to use F swingarm to get in the wheel, we shall see 

Gday Prokop, its exactly the opposite mate, smaller offset of the F3 clamps {50mm compared to 60mm for the K}  will slightly add more trail, seeings though there is only 10mm difference in the offset the change will be minimal.

[70CB750]

You are right of course, thank you!

[Retro Rocket]

You are right of course, thank you!

Too easy....

[jaguar]

Also I had assumed he was talking about a cbr F3 swap for some reason.

[Roach Carver]

you are talking 77/78 f right? If so I have that exact setup in a 71 cb750. no problems at all.

[Retro Rocket]

RR, what do you mean they don't. I put them on mine. I have it in the garage right now? I rode it... lots. I agree they are different offset in the trees. the swingarm is also an inch longer on the F.

the largest modification was removal of the passenger peg mounts. You need the aluminum ones on the 77/78 f bike. Other than that there was no real issues.

Sorry Roach, I miss read your post, I just deleted my response...   I thought you meant they were the same....

[Roach Carver]

No worries Mick.

[70CB750]

you are talking 77/78 f right? If so I have that exact setup in a 71 cb750. no problems at all.

Yes, 78F.

[jaguar]

What are you going to do about the mismatched wheels?

[70CB750]

Only the frame is K3, swingarm, wheels and fork and engine are F. It fits together, i had it mocked up, but it is waiting on a full head job.

[Roach Carver]

The easiest way to do the back end is to get the 77/78f peg brackets. The right side has the pedal and master. You will have to cut  the passenger peg brackets off the frame but the new brackets will have the passenger brackets. The swingarm bolt is also longer.