Crunch time with my gearbox

[tvrla]

If you're having trouble down-shifting it could be your technique or the transmission input splines need to be lubed. The clutch needs to slide on those splines or it won't disengage properly.

Also, considering the expense and fragility of these transmissions (it's a weak link) it's best to use the brakes to slow down. If you're that much in a hurry (or into racing) this isn't the bike for you. If the brakes aren't doing their job, then that needs looking into.

[bangpaul]

Well, the oil change has done wonders, but you could be right: I think my shifting technique could do with some refining. I am still getting used to the bike.

As for not using the gears for slowing down, I'm pretty surprised to hear you consider that racing, I thought that was just part of riding. I would've thought the transmission was built for it, but I am pretty new to motorbikes. I tend to use the brakes in unison, and apart from some squealing they're fine for what they are.

[Barry]

I use engine braking all the time to slow down but not always by changing down a gear.  I find a motorcycle without some engine braking effect is tiresome to ride. Single cylinders are best and multi's the worst in this respect. Airheads seem to have a useful amount of engine braking.

Changing down smoothly on an airhead is easy enough when you are pressing on and using enough revs to blip the throttle. Not so smooth and easy at low revs when you are trundling along in traffic.

Bottom line is anyone new to an airhead is not going to rate the gearchange as it's best feature but you do get used to it in time.

[montmil]

Beemer brakes are much more economical to replace than transmissions. [smiley=thumbsup.gif]

For me, stirring the Airhead gearbox required I practice but three simple skills:
 Â  1. Practice
 Â  2. Practice
 Â  3. Practice

Develop items 1 thru 3, along with the secondary skills of matching engine rpm to gear speed, pre-loading the shift lever, keeping the transmission splines cleaned and lubed, gear lube clean and at correct level, shifting to 1st gear at no faster than a walking pace, clutch cable adjusted by starting at the lever on the gear box and you'll soon be pleasantly surprised.

Just takes time. Great excuse to go ride.

Monte
 

[Bob_Roller]

To a lesser degree, the type of boot or shoe you have can have an effect on shifting .

I do best with a hard boot with the R65, while the oilhead does the best with a 'soft' shoe/boot .

Practice as mentioned is probably the key element in riding an airhead / 'farm implement' .

[Rob Valdez 79 R65]

And if this bike is new to you, don't be afraid to pull the gearbox and check out those input shaft splines.
Especially after the contaminated gear oil you found.

There is also another test that needs to be done with the gearbox removed.  - Push in/pull out on the input shaft and check for play.  It should not be too tight, but not too loose, either.

R/R of a gearbox is a two-day affair for the first time, at worst.  I think the hardest part is getting the spade terminals of the neutral switch un-plugged/plugged.  
Providing there are no parts that need to be ordered.  Have some good 60% Moly grease on hand before you start.  
And replacement fasteners for the drive-shaft flange connection.  And a rubber-tipped attachment to lube your swing-arm bearings.  And a 27mm socket for the swing-arm lock-nuts.  Some sockets will work as they come from the store - others will need to have the outer surface removed to fit in the available space.  Any of them should have the taper removed so you get full purchase of the socket/fastener.



The Moly paste goes on the gearbox input shaft splines only - not the mating splines on the clutch plate!
Also put a dab on the tip of the push-rod, after checking it for deformation.
The Moly paste is also used on the large splines on the rear wheel hub of the twin-shock models.
Mono-shock bikes do not have these rear splines.

And don't forget that second gear oil change for your gearbox, to clean out the junk that was in there before.  Every potential purchase should have that gear lube checked for color.  If it is coffee w/creme, walk away or at least beat the price down $500.

[Semper Gumby]

HI Bangpaul,

+1 what Rob said.  The Snowbum has an excellent file to read on this.  READ THIS FILE buried on this website.  http://bmwmotorcycletech.info/

Change the oil in the gearbox/drive shaft/final drive often -- at least once a year.  I change it out twice a year because I use a 85W140 in the summer and 80W90 in the winter.  

Also milky oil is a sign of water in your oil.  This is bad.  Milky oil in the tranny is a sign that water is gettting into the drive shaft and the drive shaft is overfilled.  It only needs anout 100 to 120cc of oil.  Any more (the book says 150cc) and once you get to 65 mph or faster the oil slings through a vent hole between the tranny and the drive shaft into the tranny.

For Milky oil in the drive shaft, Change out the rubber drive boot and the rubber bell on the bottom of the speedo cable and seal the top of the rubber speedo bell with RTV and a tye wrap or heat shrink tubing from Radio Shack.

Good luck.

[montmil]

... I use a 85W140 in the summer...

Bill, Can you detect a noticeable improvement is transmission ops during hot weather while running the 85W140?

Hotlanta and North Texas often share similar temps. Just wondering about warm-up temps for the gear box. Smooth shifts from the git go? I may try your blend.

Monte

[Semper Gumby]

... I use a 85W140 in the summer...

Bill, Can you detect a noticeable improvement is transmission ops during hot weather while running the 85W140?

Hotlanta and North Texas often share similar temps. Just wondering about warm-up temps for the gear box. Smooth shifts from the git go? I may try your blend.

Monte

YES!  For me it make difference and is worth the effort.

I'm afraid Atlanta doesn't hold a candle to North Texas for hot weather this year.  How many days over 100 have you had?  Makes me wilt just thinking about it.  I would still ride of course....

[montmil]

Believe the weather wizards said today, Thursday, was the 36th day in a row over 100°. A toasty 106° today but hotter forecast for tomorrow with continued 100+ days all next week.

My rides are not much more than an hour just after sun up. Low 90s by the time I get back. One of our intrepid local news hounds provided a photo of his digital thermometer laid on a street just three blocks from my house... 145°F. I worry about the bike's tires!

Monte

[Semper Gumby]

When it get that hot out on the highway, the heat radiates through the souls of my Tourmaster Rain boots and, no sh|t, burns the bottom of my feet.  Doesn't seem to matter if I'm going 55 or 70.

I haven't figured out what to do about that one...I just suffer though it.  

[bangpaul]

Milky oil in the tranny is a sign that water is gettting into the drive shaft and the drive shaft is overfilled.  It only needs anout 100 to 120cc of oil.  Any more (the book says 150cc) and once you get to 65 mph or faster the oil slings through a vent hole between the tranny and the drive shaft into the tranny.

This makes sense to me. It was noticeably worse after a weekend of lots of riding, often in the wet, and usually over 100kph. I suppose I better change the drive shaft oil too. Replacing the boot was always inevitable, I was just hoping to put it off for a while.

[Rob Valdez 79 R65]

I suppose I better change the drive shaft oil too.

Have you looked in your final drive, yet?

Engine, gearbox, drive-shaft and final drive should have been changed as soon as you got it home.

As well as checking tire pressure - do that often and BTW, the pressure figures on the sticker under the seat or in the handbook are obsolete.  
Do you use PSI in Australia?  If so, consider 36 PSI as a starting point.
As a general rule of thumb, check your tire pressure cold, then ride for 30 minutes or so to get them good and warmed up, and check the pressure again.  It should be within 10% of your cold pressure.
If it is over 10%, increase your cold pressure because the tires are flexing too much.
If it is less than 10%, decrease the cold pressure because they are not flexing enough.
At least, that is how it used to be.

You should also plan on renewing your brake fluid sometime soon, as well as fork oil.
Re: forks - there are tiny little 10mm drain screws on the back of the fork legs.  Use new "crush" washers and DON'T over tighten them!  They will strip the threads on the aluminum legs easily.

In fact, there are MANY steel-to-alloy mates on these bikes.  They prefer a soft touch.

[Semper Gumby]

In fact, there are MANY steel-to-alloy mates on these bikes.  They prefer a soft touch.

...and a torque wrench!!!!  8-)

[Rob Valdez 79 R65]

In fact, there are MANY steel-to-alloy mates on these bikes.  They prefer a soft touch.

...and a torque wrench!!!!  8-)

Which is how SueCanada stripped out those very threads.