R75 Downshifting Problem

[Matt-R75]

I recently purchased a 73 R75/5 toaster. Occasionally when down shifting from 4th to 3rd or 3rd to 2nd, I go into what I call a false neutral-in other words bike does not go into lower gear and a slight chatter can sometimes be heard. I changed all fluids this weekend and adjusted clutch cable but false neutrals still sometimes happen. I saw somewhere that the input spline on the tranny may need cleaning and lubing.
Has anyone else had similar issues and was a spline lube the solution?

Thanks!
Matt

[Major Softie]

Start shopping for a back-up tranny NOW.

That does not sound like it's related to spline lubing to me, sounds more likely to be missing or damaged dogs on the tranny gears.

[Duane Ausherman]

A spare transmission is always good to have waiting to be needed. If dogs were missing enough to not catch, it would be every time. I suspect that the shifting forks are not adjusted correctly, or are rounded off enough for it to be jumping in and out of gear.

Lubing the splines might be needed, but is most likely unrelated to this issue. For many it is a stock suggestion, but seldom an issue.

[SteveD]

I recently purchased a 73 R75/5 toaster.
Thanks!
Matt

Welcome. If it's your first BM Matt, it might be technique? They do require a certain touch.

[Matt-R75]

Thanks for responses...hopefully a new tranny is not required yet. Not ruling out technique as I am new to the airhead realm. I have had the bike for about 6 months now and the false neutral seems to be getting more frequent rather that less though.

It normally happens when downshifting at around 30-40 mph. Doesn't really jump out of gear...just never really goes into gear....and it does not do it all the time.

[SteveD]

Thanks for responses...hopefully a new tranny is not required yet. Not ruling out technique as I am new to the airhead realm. I have had the bike for about 6 months now and the false neutral seems to be getting more frequent rather that less though.

It normally happens when downshifting at around 30-40 mph. Doesn't really jump out of gear...just never really goes into gear....and it does not do it all the time.

The upshift technique is probably the more idiosyncratic method that I was thinking of..preload gear lever/clutch in/snick into next gear/clutch out... but the downshift will benefit from a decent blip of the throttle at slow speeds. Might be worth a try...you might get lucky?

[Dan in IL]

My ol' R75/6 used to do that. I read that if it gets hard to shift after the bike warms up, try switching to a 90w140 weight oil. I did and it made a big difference on my bike.

[Matt-R75]

It does help a lot giving a "blip" of the throttle just after clutch is released on the downshift. Gears always immediately latch into position as I do this....Thanks!. Any idea why this is required? Is there something worn or possibly out of adjustment or just the nature of the beast? I also switched from Lucas 80 90 to Mobile 1 75w 140 and that seemed to help but not as much as the throttle blip.

Thanks again for responses good to know there are resources of information out there.

[Garnet]

" It does help a lot giving a "blip" of the throttle just after clutch is released on the downshift. Gears always immediately latch into position as I do this..."

I do something similar when I'm downshifting my 4 speeds. It's sorta like double clutching a truck. It's harder to do when the box is cold. Your tranny sounds fairly normal to me, but I've hadn't ridden it. 4 speeds are more reliable and cheaper and easier to find used than a 5 speed. Still doesn't hurt to have a spare.

BTW 75/140 oil is thinner than 80/90.

[barryh]

75W140 is thinner than 80W90 but only below 20 Deg C. After that it's thicker by approx. 40% at typical operating temperatures. Thinner when cold is definitely a good thing and if your box runs very hot then thicker when hot may be a good thing too.