Running 20/50 engine oil in gearbox

[XSrunner]

Hi everyone just a question has anyone run 20/50 engine oil in there gearbox? WHY YOU ASK? i have had the bike 6 weeks now about 7 days ago i changed the gearbox oil ,it was always notchy and when i put the new oil in it got worse.(hard to shift) then i though maybe to heavy an oil yamaha spec.80/90w. i remember back in late 70's,early 80's ford released a car that had a borg warner gearbox single rail it's oil spec was 80/90 from new then people complained about 1st to 2nd and 3rd to 2nd grinding so mechanics started putting 20/50 engine oil or dex3 auto oil and that fixed the problem.I put engine oil in 3 days ago and it has never changed so smooth before. am i just asking for touble later or what?..

[prometheus578]

"Change it back... lest evil befall you."

You only "think" that it's shiftin' easier.
The middle gear has nothing to do mit der shiftin'. It just changes the direction of force applied from sidewards to rearward for the driveshaft. Same as the rear end in your car does. (drive shaft to axle)
Now, the thinner oil may make it easier to move due to less viscous resistance, but that's about it.
Now then.. would you recommend draining the gear oil out of your differential on you car and putting in motor oil?
Nope... me neither
As for car trannies...
Not all tranny's are designed the same. They are designed to use what the good engineers designed for them to use.
My big Chevy Blazer uses gear lube in it's standard tranny. My son's little Chevy Blazer uses good ol' red tranny fluid in his standard gear box.
Has to do with tempertures generated and lubing properties at those tempertures. (Also with bearings and the cut of the gear teeth, molecule shearing, etc)
Like the old Dextron II and type "F" bit for Chevy and Ford transmissions. Different composition for the different designs.

[Crazcnuk]

Many trucking companies, and the U.S. Military, used to (and may still) run 15W-40 in engines, std transmissions, transfer cases and rear differentials in ALL thier vehicles, including trucks, cars, Jeeps, etc.

The only deal with doing that is you have to change ALL of it regularly.

15W-40 was designed to fill as many oil needs as they could manage, to reduce the number of types of oils the U.S. military had to stock...

[trbig]

Not to make you feel foolish, but just to question things. By "Gearbox", you did mean the middle drive that the driveline attaches to, correct? We have had people in the past think that the engine oil and the oil that goes in at your clutch cover were two different things. 80-90 wt oil in THERE may change things a bit.


Tod

[wa407mpp]

You also have to think about whether the oil will sling well enough to use, if it doesn't it won't get where it's needed.

[XSrunner]

HI all thanks for the info i never thought about the sling properies of the oil how high up the gears does 360ml of oil sit??i asume not far. i just can't believe that it is not notchy going trough the gears now.I don't mind changing it every 1000ml quick job to change,