loopy and V7 sport starburst drive box

[jacksonracingcomau]

I had a butchers at my 67 V700 rear drive box today, loads missing off bike but only 4700 miles on clock.
I believe it, gears splines bearings like off the factory floor, think it's never been removed, through bolts not studs, smells and looks like 1967 Agip 80/90, clean as a whistle.
Kindly rescued from a shed in USA, $2500

Question for those who know, Charlie ?
Housing has no provision for later feed and drain for pinion bearings but lovely catchment area for oil.
Did these ever fail at pinion bearings ?
Or chuck all the oil up swingingarm ?

To mod or not to mod, that is the question, will prob go on my Tonti just to confuse experts (yes I know about flange width,I've run deep sump loopy/850T one for 30 years, best for longevity for sure, starburst for looks)

Thanks
MH

[Antietam Classic Cycle]

Did these ever fail at pinion bearings ?
Or chuck all the oil up swingingarm ?

Pinion bearing failure isn't an issue. Same rear drive on my '69 Ambassador has 107k miles on the original bearings.

As long as shocks of the proper length are used (vs. too short), "oil up the swing(ing)arm" isn't an issue either.

[jacksonracingcomau]

Pinion bearing failure isn't an issue. Same rear drive on my '69 Ambassador has 107k miles on the original bearings.

As long as shocks of the proper length are used (vs. too short), "oil up the swing(ing)arm" isn't an issue either.

Thanks, second part is sort of obvious, oil will drain down when parked but because factory changed the bearing housing (flange) to have feed and drain,. Even with long shocks I use, over rough terrain 2-up it may have been that oil could not drain quick enough on the run.



Pinion gear in shrouded case looks to be very clever, first time I've studied the old case, I'd always thought they went to deep sump because of failure, maybe it was more that foundry that was making them stopped for another reason and newer one far cheaper to cast. Ditto for next gen disc type. Fourth gen on Cali 1100 etc very slightly different again, beefier around pinion bearings.

Fixing problems that didn't exist, or just worn out dies ?

Anyone with premature gear or bearing failure on starburst ?

feed and drain holes on late (disc) flange and on deep sump flange but not on 67 on right

[jacksonracingcomau]

so as not to detract from Pete's broken carc thread, I've quoted Charlie back in this one
I did modify case for oil holes & fit later flange above, seemed mad not to, factory went to bigger bearings and oil galleries for a reason
but oil level is definitely quoted all over the place

No issue with cracking that I'm aware of. I'm sure someone somewhere has managed to bust one open, though.

The factory recommended oil volume for the "starburst" rear drive was always 180 cc (160 cc gear oil, 20 cc moly) and never changed. The volume went up to 360 cc for the "deep sump" rear drive that followed and dropped back to 250 cc for the rear drive common to Tontis from the Convert on.

I've found 3 different levels on Gregs site
from his guide
180cc
In the 67 V700 riders handbook

QUllntity required: about. 0.300 liters (5/8 pint )
Oil recommendation: Shell Spirax 90 E. P.
.3 litres is 300cc[/b

From V750 riders handbook (Ambo)
Same

 Realr wheel drive 0.300 liters
(5/8 pints)

then a few pages in

Quantity required: lIbout 0.230 liters ( 1/2pint)
Oil recommendlilion: Shell Spirllx 90 E.PLubrication of

That's 230cc

Best one from Chiltern manual
4oz for 700 and 750

Hope no-one believed that one !!!

300cc obviously blew seals, figure of 230 sounds like what they tried next
180cc maybe the figure that's been used since but not in any official book I can find


Not a biggie, I'll run as much as I can without leaking seals, in my experience seals leak overfilled but work again when level correct.
But I'm sure this has confused someone before now.

Gratuitous pic of box ready to run

[Antietam Classic Cycle]

but oil level is definitely quoted all over the place

180cc maybe the figure that's been used since but not in any official book I can find

180 cc is the volume specified in every factory V700/Ambassador manual I have. Like here on page 8:

http://www.thisoldtractor.com/mg_manuals/workshop_manual_700_750.pdf

In any case, that's what I've run for the last 17 years and 70k miles and the gears still look like new with 107k miles on them.

[jacksonracingcomau]

180 cc is the volume specified in every factory V700/Ambassador manual I have. Like here on page 8:

http://www.thisoldtractor.com/mg_manuals/workshop_manual_700_750.pdf

In any case, that's what I've run for the last 17 years and 70k miles and the gears still look like new with 107k miles on them.

I have that but hadn't seen the capacities list, really odd the riders handbooks differ so wildly from each other and from workshop manual.
Not important now but could've been at time, new owners would've had handbook but not the manual.
Handbooks from here

 http://www.thisoldtractor.com/mg_manuals/riders_handbook_700.pdf
http://www.thisoldtractor.com/mg_manuals/riders_handbook_750.pdf

Both scans of originals