Honda-SOHC

SOHC.co.uk Forums => Project Board => Topic started by: Pauarc on July 21, 2022, 09:20:58 PM

Title: twin disc
Post by: Pauarc on July 21, 2022, 09:20:58 PM

I have now finished my Honda CB750K2 twin disc today

Title: Re: twin disc
Post by: Arch stanton on July 21, 2022, 09:28:08 PM

Well done.
Have you tried it out yet? Have you experienced any issues?
Like squeaks or drag etc?
Sean.

Title: Re: twin disc
Post by: Pauarc on July 22, 2022, 08:11:35 AM

I road bike for about 15miles all seam ok
bit extra movement on break leaver may change master cylinder
did not notice any drag
paul

Title: Re: twin disc
Post by: ST1100 on July 22, 2022, 10:57:37 AM

Quote from: Pauarc on July 22, 2022, 08:11:35 AM

... may change master cylinder

I was about to ask which MC you've installed...
What about the speedo-drive? Any issues?

Title: Re: twin disc
Post by: Pauarc on July 22, 2022, 02:37:11 PM

From ebay speedo drive

Title: Re: twin disc
Post by: Pauarc on July 22, 2022, 02:52:03 PM

How it looks fitted

Title: Re: twin disc
Post by: Arch stanton on July 22, 2022, 04:25:35 PM

I had a few squeaks and things. But has improved with pads bedding in.
I use a GL1000 master cylinder. Works perfectly.

Title: Re: twin disc
Post by: Pauarc on July 22, 2022, 05:57:34 PM

That’s good to know I may have a look at the gl1000

Title: twin disc
Post by: allankelly1 on July 23, 2022, 09:04:43 PM

An interesting point of note is for the Yamaha  RDLC the 250 single disc is fitted with a 1/2” Master cylinder and the 350 twin disc a 5/8 M/C but for better feel and less wooden brakes it’s common practice to swap the 5/8 unit to the 1/2 unit

Yes you get slightly more lever movement due to the reduced swept volume of the master cylinder with the smaller bore but the braking is much less wooden

Incidentally for my RD I am running a 14mm M/C but also have two four pot callipers too and floating discs so much better than the original 1 pot sliding caliper per side acting on a solid disc

(https://uploads.tapatalk-cdn.com/20220723/d0102f5a679e17d2ad8c66b6724ed026.jpg)

And on my CB400F twin disc conversion even though I have a extra caliper I have kept the original M/C and not needed to increase my M/C bore size to allow for the extra caliper

(https://uploads.tapatalk-cdn.com/20220723/fc96547fcf970d649d83ea097b7d1127.jpg)

Best wishes Al




Sent from my iPhone using Tapatalk

Title: Re: twin disc
Post by: sprinta on July 24, 2022, 09:43:49 AM

I would agree with the above post. I still have the original master cylinder on my CB750K2 that I did a twin disc conversion on and it is absolutely fine giving more 'feel' to the brake lever and not the solid wooden feel that you very often get with the larger bore master cylinder.

Title: Re: twin disc
Post by: Bryanj on July 24, 2022, 03:32:30 PM

I twin disced a 500 way back in 76 and could not live with the soggy master that came nearly all the way to the grip, at the time Girling were starting to do japanese cylinders , cosmetic seconds i think, so i fitted an early GL1000 one and it was perfect

Title: Re: twin disc
Post by: philward on July 25, 2022, 06:06:32 PM

I've used a GL1000 on the twin disc setup on my CR750 and it feels fine

Title: Re: twin disc
Post by: Sesman on September 04, 2022, 06:47:16 PM

I’m using a GL1000. It’s mighty fine.

Title: Re: twin disc
Post by: Pauarc on September 08, 2022, 09:40:45 AM

Now I have been using my cb750 and 200miles on I am happy with front brakes much better now

Title: Re: twin disc
Post by: kevski on September 08, 2022, 09:57:27 AM

When I twinned my K3 500 I used a gl1000 master cylinder, never had any problems.

Title: Re: twin disc
Post by: McCabe-Thiele (Ted) on September 08, 2022, 10:43:32 AM

Aside from the different swept volumes for an equal amount of lever movement the resultant lever effort on each master cylinder piston  per square cm will make the brakes feel heavier to apply on a larger piston to give the same pressure at the caliper end. Hence the loss of lever feel on braking with larger bore M/C's.
Imho