[Bullet Mad!]

Hi all.can anyone tell me if it's OK to put just gear oil in gear box of 91 500 bullet or will it leak out terribly? If not OK what should be used?
I just acquired the bike so don't know what is in there whether there is grease or not. Is the only way to check by removing outer & inner side cases.?
Thanks.

[c1skout]

#00 grease was the original fill, I believe. 

[AzCal Retred]

There in an oil fluid level check plug on the side of the gearcase and a filler plug on top. Gear oil is the desired lubricant. I run cheapo Sta-Lube 85W140 with zero issues. Thinner oils seem to result in "notchier" action in my experience, YMMV.

Conversion consists of (as per Snidal) filling the gearbox with engine oil to the check plug then running a couple hundred miles, drain & repeat a couple times. The transmission gears churning, plus heat & vibration emulsify the old grease. After a couple treatments refill with gear oil & move on. The only leakage issues I've had were from the clutch pushrod cap. One machine had a cracked cap and another a bad cap gasket. These machines ARE NOT JAPANESE, so a few drips is to be expected. Back in the day they were as oil tight as anyone else. Keeps the dust down, right? Another use for cat litter. I think the amalgam (oil & grease mixture) filled gearbox was to salve the Japanese oriented Euro & US buyers conscience as grease/amalgam leaks slower than oil. By 1990 when imported Bullets became available in Europe & the USA buyers were conditioned to not see any leakage. Not really possible on this 1935-ish design.

The primary side likes ATF, any multigrade 15W50 or 20W50 engine oil works fine. These are low RPM, low BHP sloggers, not Offenhausers. Any modern multigrade engine oil is way better than the 1940 era straight weight oils. I run Walmart sourced 15W50 Mobil1 ($25/5 quart jug) in everything. I don't own any Space Shuttles. The good news about 3 different oils is that you generally know right away who the big offender is...

[Raymond]

Good - I read the Electronic ignition thread first and replied to that. Seems my reply fits with the general consensus.

Now, must go and have a play, filing the piston ring end gaps.

[ddavidv]

Answered in the ignition thread.

[Tarnand]

This video should answer the oil/grease question once and for all.

https://youtu.be/PaD3wfwu9Gs

[SteveThackery]

This video should answer the oil/grease question once and for all.

https://youtu.be/PaD3wfwu9Gs

Interesting. So it seems the use of grease in the gearbox was a decision by the Indian factory, not a carry-over from the British Royal Enfield.

[Yinzer]

Bilgemaster recommended Quicksilver Marine Lubricant SAE 90 GL-4
I've been using that so far.

No problems.

[AzCal Retred]

Hard to sell bikes to modern fastidious customers if they have icky oil lightly oozing from the cases on the showroom floor. None of my bikes leak, they just exude class...