400/4 twin disk

[Bradleybear]

What twin disk setup would fit the 400/4 was thinking the 400n or something

Many thanks bradley

[Norniron]

Yep,i think the 400n is a straight swap,or u could choose the 550 front end which is a bit more work.
With the 400 n  u may have to use the comstar wheels though!

[Bradleybear]

that's good to know why would the wheels need to be the n style is it positioning of the wheel? how much work is need for the 500 any ideas?

Bradley

[Norniron]

if u use the standard 400 wheel i think there may be an issue with fitting an extra disc plus the speedo drive.i assume  u are gonna use the 400n fork legs too.
I swapped the whole front end from a k3 550.

[Bradleybear]

what year was the k3?

[Bryanj]

You would need to use the N wheel due to the number of disc bolts, the K3 was 77/78 but you would need the complete front end plus a cecond disc, caliper braket, caliper, pipework, master cylinder from something like a GL100 and a modified speedo drive. Plus the speedo would be inaccurate with either setup as the 400 has an 18 inch front wheel

[Chris400F]

If you're feeling brave you could do what my brother did.

You get a spare left fork lower, machine away anything that doesn't look like a brake mounting part then get those parts welded to a spare right fork lower. There must have been some jiggery-pokery to get mounting holes etc in the right places but it worked. The fork lowers were then painted black. You then use the same caliper and brackets as on the LHS with the caliper assembled the other way around on the support so the body is on the outside. His bike has alloys fitted, front one possibly off a Yamaha (on his bike parts could be off anything; rear disk caliper (yes, rear disk too) is from an Enfield I believe) but the disk hole spacing must be the same as he has the Honda disks fitted, drilled for good measure. I'm pretty sure he said he could have fitted twin disks to the standard wheel using longer bolts.

Of course you then have to sort out pipework and a larger master cylinder but after what has already been done that is probably the easy bit! This is the only picture of the bike I can find.

[Bryanj]

Or you could do what i did to a 500 before 550's came out and fit anothe disc brake slider to the non disc side and have one caliper in front and one behind, need to "modify" the front mudguard but it worked well enough to squeel the tyre

[Bodd]

I remember someone on another forum mentioning he used the front end of a 400 NC36 with minimal alteration but there aren't many around. Or you could bid for this. 

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[ka-ja]

Hi,
    Easiest is the cb400n forks etc. they fit straight in the 400/4 yokes.   Ken

[Chris400F]

Sounds like an easy route, but what wheel (or hub / rim combination) would you use with those forks?
As I recall the 400N had Comstars. Also want to keep the 18" rim for correct speedo gearing.

[ka-ja]

Hi,
    Started off with 19in comstar, which did not effect the speedo (as confirmed by police car that stopped me-59.2mph but 60mph on my speedo) but I have since converted the comstar to a 18in spoked wheel, which may make the speedo a little fast. If you can get one, there was a 18in comstar fitted to several Honda's with the same forks!---Ken