CB400F Gearbox

[Mr-Gear]

Afternoon Gents,

I'm in the middle of doing a full rebuild on my bike and I've made it to the transmission.

Observe the image attached. where do I go from here? Found a replacement from CSML for +£150 but I'm hoping I wouldn't have to buy new ones. These seem to be the only 2 gears affected

Does anyone have any information on the grade/material these gears are made from? I assume case hardened?

I've only taken the pump off at the moment, so I'm going to expect some damage there given the wear I'm seeing here

Thanks, Ryan.

[Orcade-Ian]

Certainly looks like it's eaten something that disagreed with it, they look like quite large lumps missing, so may have been trapped by the screen in the sump and didn't make it to the pump.  You will strip that anyway, presumably.  What were the crank and shells like?  I don't know what hardening process Honda would have used but it would be a good quality steel to start with, then probably induction hardened around the teeth and dogs which would go deeper than case and still leave a tough core. We're you thinking of having some made by asking that question?  They would charge a lot more than cmsnl or Silvers though for one offs.
There are plenty of sources for good secondhand clusters and even individual gears.  There is a chap who specialises in 400/4 stuff on the net, if I can find his web address I'll pass it on.  They may be the same as 350/4 which was only a 5 speed and lots of those broken Stateside.
Hope you get sorted,
Regards,
Ian

Just found Steve, he's at www.400fourbits.co.uk

[Clem2112]

I would get a complete used gearbox.
It should be a lot cheaper too !

Running new and old gears together may cause noise, premature tooth wear or both imho.

[Mr-Gear]

Gents,

- I was planning a repair weld on the gears with a suitable filler but I'm think the hardness could be matched without post weld heat treatment.

- I emailed the site linked from Ian for a price on a whole unit.

I've been photo documenting the whole rebuild and throwing it into a word document which i'll upload at the end if anyone's interested

Thanks, Ryan.

[AshimotoK0]

Try this guy ... he sold me a caliper body once ...good price in excellent condition after I had bought another pile of Sh*te off eBay and got my money back

http://www.400fourbits.co.uk/

Ash

[mike the bike]

I've got some second hand ones if you want.   You can have them for just the postage.

[Mr-Gear]

Evening!

PM Sent Mike-the-Bike.

So I've seen this a couple of times around the internet from various sources about the top gear in particular, Is this a common thing? if anybody knows

Thanks, Ryan