Gearbox failure

[Flip]

I was coming back from the brass and the bike went bang.

http://www.youtube.com/watch?v=wVvQq-5edCw&feature=plcp

Didn't know what had broken until I got it home and found a crack in the side of the gear box. I have just lifted the gear box out of the bike and found it is really easy to service the gear box with the top smashed open.



Lost a tooth off the small gear on first that jammed itself back between the gears.

Bugger

[Paul in NZ]

Ouch - expensive....

How did that happen? The oil looks a bit milky. Some moisture get in there and corrode a tooth?

[HenryDorsetCase]

http://bakerdrivetrain.com/

I wondered about that milky look as well.

Presumably you had to push the thing home after taking a swiss army knife to the final drive?

[Murray]

Your speedo doesnt work either!!!

[unstuck]

FUCK, bummer dude.

[Akzle]

I ...found it is really easy to service the gear box with the top smashed open.

i find a socket set to be a much cheaper alternative...


i really REALLY doubt "a tooth would have been corroded"
although milk in your oil is a sure sign of moist getting in.

small gear on first you say, you're probably in for new bearings.
check runout on all shafts. and check all journals (if it has)
(incase you needed to be told)

[98tls]

Buggers right,no doubt you will have it fixed pretty quick.Good Brass other than that?was going to go over but never quite made it..again.

[Flip]

A little water always gets in through the speedo drive hole, all these bikes have milky gear box oil.

the root cause was a classis fatigue failure at the root of one of the first gear small gear teeth. The fourth gear set that do all the miles is perfect condition.

If I had to I could weld this up, but it has had such a large internal loading to do this that it will be very difficult if not impossible to get it straight and tru again. I have almost every other part for this bike other than a spare gear box. I called up my friendly spares man in Hongkong who promptly got a new (yes brand new ex military box) off the shelf and had it rebuilt with new jap bearings and has alredy got it away air freight to me. The cost was only $US500 + $US170 air freight.

It should be back together in a couple of weeks.

The brass was brillant, as per usual, we went up the Waitaki and through the lindus. Which was a long ride at 80kph.

[Laava]

Shame, I was enjoying the vid! Needs Flight of the Valkyries over it tho! Haha!
Hope the repair goes OK.

[HenryDorsetCase]

A little water always gets in through the speedo drive hole, all these bikes have milky gear box oil.

the root cause was a classis fatigue failure at the root of one of the first gear small gear teeth. The fourth gear set that do all the miles is perfect condition.

If I had to I could weld this up, but it has had such a large internal loading to do this that it will be very difficult if not impossible to get it straight and tru again. I have almost every other part for this bike other than a spare gear box. I called up my friendly spares man in Hongkong who promptly got a new (yes brand new ex military box) off the shelf and had it rebuilt with new jap bearings and has alredy got it away air freight to me. The cost was only $US500 + $US170 air freight.

It should be back together in a couple of weeks.

The brass was brillant, as per usual, we went up the Waitaki and through the lindus. Which was a long ride at 80kph.

So thisis not out of your Road King? What bike?

[pete376403]

Ural maybe? Or the Chinese version?

[unstuck]

So thisis not out of your Road King? What bike?

Hmmmm, Im thinking chang-jiang CJ750.

[Flip]

So thisis not out of your Road King? What bike?

I am sure it was you I met in town one lunch time.

[HenryDorsetCase]

Ah, yep that was me. :-)

Back in the good old days when there was a town to meet in

[Paul in NZ]

i find a socket set to be a much cheaper alternative...


i really REALLY doubt "a tooth would have been corroded"
although milk in your oil is a sure sign of moist getting in.

small gear on first you say, you're probably in for new bearings.
check runout on all shafts. and check all journals (if it has)
(incase you needed to be told)

Back in the day - we would see gearboxes sitting in polluted oil and the bits that were dipped lowest would corrode around any imperfect hardening. Once there was a pock mark it would just get worse until...

Looking at the quality of the alloy casting I assumed it was NOT the Road King.