Gear Oil

johnny Lagdon · Oct 28, 2019

I have just changed the gearbox oil on my 850 MK3, and after filling and taking for short ride, had a look to check level.
Inside was a lot of foam. I have never seen gear oil foam before, is this normal? I used Silkolene SAE 85,90 medium. "Maintain"
Any thoughts?
cheers

gortnipper · Oct 28, 2019

Sound like either water contamination or overfilling.

Madnorton · Oct 28, 2019

Change it to bog standard EP90 and see the difference, I have also spotted this with alternative 'can be used in place of' gearbox oils.

kommando · Oct 28, 2019

Either Gortnipper has it right or that oil is lacking its anti foaming additives in which case Madnorton is right.

Torontonian · Oct 29, 2019

Change that foaming oil to Redline shockproof. Sticks to gearbox outer springs too and nuts won't rust too. Product endorsement so send me the cheque for that one.

Tornado · Oct 29, 2019

Torontonian said:
Change that foaming oil to Redline shockproof. Sticks to gearbox outer springs too and nuts won't rust too. Product endorsement so send me the cheque for that one.

I'm using this stuff. Despite the name implying otherwise, it is actually green in colour.

MexicoMike · Oct 30, 2019

I've always used the famous "any-old-brand" of gear oil in the weight specified. They all seem to work fine. I tried ATF for a while a year or two ago but the shifts weren't as smooth so I switched back to gear oil. It was Quaker State most recently.

comnoz · Oct 30, 2019

I noticed what TTI said about using shockproof oils in their gearboxes.

I have to think this would apply to the Norton gearbox as well since I ended up with serious wear on the sleeve gear bushing after I ran it for a summer some years ago.

Quote from the TTI manual

"3) Use the recommended oil.
Using the wrong oil can wear out bearings and gears faster than usual, resulting in strange noises and stiff shifting. Eventually the gearbox could seize up resulting in major damage. TTI sequential race gearbox users should make sure they are running Motul Nismo Competition Oil 2189E 75W-140m , or Castrol Axle AP 85W140 or similar spec oil. As outlined in the TTI gearbox owners’ manual DO NOT use shock proof oils as the oil does not flow through the bearings."

black cat · Oct 30, 2019

Torontonian said:
Change that foaming oil to Redline shockproof. Sticks to gearbox outer springs too and nuts won't rust too. Product endorsement so send me the cheque for that one.

Do you use the Heavy, Lightweight or Superlightweight?

ILLF8ED · Oct 30, 2019

Tornado said:
I'm using this stuff. Despite the name implying otherwise, it is actually green in colour.

Interesting. I use Redline synthetic V-Twin transmission with shock-proof. It’s pink.

Torontonian · Oct 30, 2019

illf8ed said:
Interesting. I use Redline synthetic V-Twin transmission with shock-proof. It’s pink.

Yes it's pink not green. Sticks to everything. Coats springs and nuts in outer cover so no rust. Standard box not a TTI. Roller layshaft bearing , new sleeve bush and a few new gears.. so far impressed.

Hortons Norton · Oct 30, 2019

One thing I might worry about is how well it flows through the bushings, if it sticks how well does it flow?

seattle##gs · Oct 30, 2019

I use the lightweight shockproof oil...blue...seems to work. It works very well in the BMW R60/2, really improves shifting. I don't notice any difference in the Norton

alan hodge · Oct 30, 2019

i use redline heavy in all my bikes and the MGB gearbox too ... sticks like dirt to monkey butt

Torontonian · Oct 30, 2019

Hortons Norton said:
One thing I might worry about is how well it flows through the bushings, if it sticks how well does it flow?

No way I know to tell how it flows in the real world of bronze bushings but absorbency and retention of said oil is important. I do know it's not drifting into the primary along the mainshaft like before with the 80-90 Weight.

motorson · Oct 30, 2019

Amsoil Manual Transmission & Transaxle Gear Lube 75W-90

This is what I use in mine. The specs mention protection for brass parts. The synthetic flows well at cold temperatures as well. The price seems to have gone a bit crazy though.

Niagara850 · Oct 30, 2019

I was using Redline Lightweight for about 5 years then my Sleeve Gear bearing let go. Greenish in colour and sticks like baby $h!t to every thing. Don't know if the cause was the lube but using standard CTC 75W-90 after the rebuild. Also have a clutch rod seal in place. Shifts nicely.

comnoz · Oct 30, 2019

Niagara850 said:
I was using Redline Lightweight for about 5 years then my Sleeve Gear bearing let go. Greenish in colour and sticks like baby $h!t to every thing. Don't know if the cause was the lube but using standard CTC 75W-90 after the rebuild. Also have a clutch rod seal in place. Shifts nicely.

I only used Redline Shockproof for a year. I don't remember what weight it was or even if there were different weights at that time. I would guess it was 15 years ago.
It did stop any migration of the oil down the input shaft, but when I found the bushing was loose and pulled it apart I found the outer bushings were dry and the shaft was blue from heat. I went back to ATF and have stayed with it since.

If it's good enough for the manual trans in this, it's good enough for me.

northern750 · Oct 30, 2019

Most normal 75/90 or 80/90 gear oils are GL5 rated which means they can damage yellow metals (bronze bushes). I've heeded this advice and for the last decade used Amsoil Manual Transmission 75/90 which is GL4 rated - smooth shifts, no problems so far.

ILLF8ED · Oct 30, 2019

Redline V-Twin gear oil doesn’t show any GL rating on the container. States recommended for Motorcycles with separate transmission case.

Gear Oil

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