Stiff Downshifting

[tricyclerob]

Hi all, I have a 1986 R-65 which seems to be developing a problem with stiff downshifting. It seems to take far too much pressure on the shifter lever to get it to dnshift. Upshifting is fine. If I really"jab" the shifter it will dnshift. It seems stiffer going from a higher gear, 4th or 5th, but once down from the higher gears, 3rd and 2nd seem smoother. It does not seem to matter how careful I try to match engine speed. The bike has about 30,000 miles and I have had it for about 10 thou. It never seemed to downshift "silky smooth", but this is a much noticable change. I have read about diff.years that had a "c-clip" or a clip and a groove for the clip left out by the factory which caused problems. Does anyone know if this applies to the '86 R-65? thanks, rj

[baldwithglasses]

You're gonna need the tranny serviced pretty darned soon.

I had that same difficulty (http://www.bmwmoa.org/forum/showthread.php?t=19159) on my '82 R65 and ended up having the entire gearbox rebuilt with an improved shift kit that- among other things- replaced the crappy little shift return spring.

Blue Moon in Atlanta charged $700 for rebuilding the transmission and replacing the bent shifter forks that I wrung up trying to mash the gears down. YMMV.

[Paul_F]

Your situation sounds exactly what was happening with my shifting last fall on my K100. Took the transmission out in early December, put in a good used one and then had the shaft drive and rear drive re-machined. It now works great on the lift (with the rear tire raised) but I have a three month snowy wait to actual enjoy the improvement. What perfect timing; no riding time lost.

[20774]

If you're facing a rebuild, you might want to at least try adding some special lubricant. Check out the thread:

http://www.bmwmoa.org/forum/showthread.php?t=20677&

It might not hurt, but then again, it might not help. Seems to me it would be worth a try...

[35303]

The least problem would be the need for clutch spline cleaning and lube. Snowbum has an extensive article here:

http://bmwmotorcycletech.info/transmission.htm

[tricyclerob]

I had thought about a spline lube, but was thinking that would affect upshifts as well as downshifts. Does anyone know if lack of spline lube affects downshifts more? The bike upshifts fine, it's the downshifting thats stiff. thanks, rj

[20774]

I would think that if a spline lube is needed, that all shifts will be jerky or the engagement point will be variable. The lube on the input splines is to allow the driven disk to slide easily as the clutch mechanism is actuated.

It seems that in your situation, you can completely disengage the clutch (thus the driven disk is sliding away as required) but the lever is stiff. Seems to me that has nothing to do with a spline lube. If the clutch were still partially engaged after pulling in the hand lever, wouldn't you have gnashing of gears? As I understand it, actuating the clutch separates the drive from the crankshaft, so that the tranny input shaft can be free of load so that the shifter mechanism can slide the various dogs/forks back and forth.

Can you simulate this problem in your driveway? Without the engine running, hold the clutch lever to the handlebar and shift the tranny with your hand. Do you get stiffness in the foot lever as you downshift from the higher gears? You might need to turn the rear wheel some to better simulate what is happening on the road.

Is the shaft of the shifter going into the tranny wallowing around? I believe there's a bushing in there which could be exhibiting this problem when you press down on it rather than lifting with your toe.

[donbmw]

I have had my transmission on my R90 get hard downshifting but I also had the forward output shaft bearing goning out at that time. When I went in to find what I needed to replace I found that the shift lever had and roll pin missing which is a nylon roller that rides in the detents this could make it hard to shift.

Don

[tricyclerob]

Kurt, I think there is a bush there. I'll have to ck. that when I get home. I'm just trying to make sure I'm not missing something prior to pulling the trans. Try the simple things first. thanks, rj

[BuddingGeezer]

I had thought about a spline lube, but was thinking that would affect upshifts as well as downshifts. Does anyone know if lack of spline lube affects downshifts more? The bike upshifts fine, it's the downshifting thats stiff. thanks, rj

The clutch spline lube affects down shifts more.

I have a K100LT that I thought shifted pretty well, but it took more pressure to down shift. I lubed the spline with 50% Honda Moly 60/50% Valvoline moly fortifed grease. I couldn't believe the difference.

Ralph Sims

[20774]

The clutch spline lube affects down shifts more.


Ralph -

I'm willing to learn more about this...can you explain how the spline lube affects the shift lever stiffness? I don't know much about K100LTs, but could there be a difference between the two clutch/tranny setups and/or process to lube the splines?

[BuddingGeezer]

Ralph -

I'm willing to learn more about this...can you explain how the spline lube affects the shift lever stiffness? I don't know much about K100LTs, but could there be a difference between the two clutch/tranny setups and/or process to lube the splines?

I have read that BMW improved the transmissions on the K bikes, so they shift smoother. They are still a far cry from Japanese bikes IMO. Even improved, both Rs and old Ks use a dry clutch. I tried to find just were I have read that the 1st symptom of dry clutch splines is hard down shift, from 3rd-2n/2nd-1st harder than the higher gears, but I can't find it. Probably on this forumn.

I believe it has something to do with the dragging clutch makes it harder for the faster spinning higher gear to slow and synchronize with the lower gear. Evidently it is easier for the shift dogs to mesh going up through the gears than down.

Paul Glaves and/or Don Eileberger/ and Anton Lariger ( I can't spell it right) can give you a detailed explanation.

As I said, not having ridden a BMW other than the 2 Ks I own, I thought that they shifted pretty good compared to what everyone says about BMW trannys. I figured that even my though bikes were low mileage they are 20 years old and I wanted to tear them apart and see. Spline damage is very costly to repair. Both were dry, but not hurt. I lubed the splines and it was daylight to dark down shifting 3-2/2-1. I just thought mine shifted good.

You may have other issues, but my understanding is a dry clutch spline has same symptoms R or K.

The 50/50 mix of Honda Moly/Moly fortified grease is Paul Glaves recommendation. The Moly 60 paste seemed too dry when I looked at my final drive splines, I had lubed previously.

I probably won't go 300k miles, but is nice to know you can.

Ralph Sims

[tricyclerob]

Well, I finally got to some garage time, and drained the gear oil. Oil is very clean but there was a little "paste" on the drain plug magnet. Not a lot but "some". No metalflake in the oil at all. Just to try the easiest thing first, I think I'll try some syn.gear oil, and a dash of the "Molykote M Gear Guard. What the heck, ya have to win one once in a while. rj

[lostboy]

Changing the oil won't help. You need to pull the gearbox and lube the clutch splines. Stiff downshifting is a classic sign of dry and/or rusty splines.

Dry splines don't affect upshifting as much because upshifting requires less clutch disengagement.

[warredon]

Well, I finally got to some garage time, and drained the gear oil. Oil is very clean but there was a little "paste" on the drain plug magnet. Not a lot but "some". No metalflake in the oil at all. Just to try the easiest thing first, I think I'll try some syn.gear oil, and a dash of the "Molykote M Gear Guard. What the heck, ya have to win one once in a while. rj

Do not mix the Molykote M Gear Guard with synthetic gear lube. From what I understand, that is a no-no! Use it only if you are using the regular dino lube.

[tricyclerob]

Lostboy, You could be right on target. I just read somewhere else that a need for spline lube resulted in stiff dnshifting but upshifting was ok. I just got around to removing the trans tonight. [I also just put the s/c back on my R69, and have been busy readjusting to riding, driving? a hack.] The splines were dry and "reddish" looking. I spun the trans w/a cordless drill and it seems to up and dnshift ok. I'm going to try the slpine lube and synthetic gear oil and see what happens. Maybe I'll get lucky, it has to happen once in a while. I will report back when all is back together. Light a candle. rj

[AntonLargiader]

The spline lube thing is all about clutch drag and how it affects the tranny's willingness to shift. Pulling the tranny to lube them is a pretty routine thing (not frequent, but routine). You also get to inspect the clutch and look for leaks.

However... your '86 tranny probably doesn't have the circlip at the front of the output shaft, so it should be modified. The fine paste you see is probably the slow deterioration of the bearing that the missing circlip would be supporting. Granted, the R65's pavement-wrinkling 45 HP might not push the gear forward with the same oomph that might happen on an R100, but it's still worth looking at.

Some details on my website: http://www.largiader.com/articles/circlip/

[20774]

The spline lube thing is all about clutch drag and how it affects the tranny's willingness to shift.

How is the clutch drag different upshifting versus downshifting? The clutch doesn't know if it's involved in an upshift or downshift. What is the rider doing that makes the difference?? And if the rider is making the difference, why can't the rider "compensate" for the stiffness...?

[AntonLargiader]

You can upshift without disengaging the clutch at all, a LOT easier than you can downshift. That help?

[20774]

You can upshift without disengaging the clutch at all, a LOT easier than you can downshift. That help?

I know that can be done, but isn't that situation more about matching gears speeds inside the tranny? The situation we're talking about is the separation of the clutch and how the driven disk slides or not on the input splines. If it doesn't slide very well (ie, a spline lube is needed) then wouldn't the dragging clutch affect shifting in both directions since the dragging driven disk is causing the input shaft to not turn completely free from the engine? If it doesn't turn completely free, then the gear speeds within the tranny are not going to be correct for shifting. How is this process (of matching gear speeds) affecting upshifts differently than downshifts?

Inquiring minds want to know!! ...at least I do!

[lkchris]

Inquiring minds want to know!! ...at least I do!

Until you get the explanation you want, you should just listen to the experience of others, i.e. hard downshifting is successfully addressed by a spline lube. BTDT.

[20774]

Until you get the explanation you want, you should just listen to the experience of others, i.e. hard downshifting is successfully addressed by a spline lube. BTDT.

Well, that helps...or not...! I'm not trying the get the explanation that I want, I'm just looking for a reasonable understanding of what's going on. What I understand are some of the basics of the clutch operation and the transmission and I don't see the connection to hard downshifting.

Guess I'll move on...

[PGlaves]

Well, that helps...or not...! I'm not trying the get the explanation that I want, I'm just looking for a reasonable understanding of what's going on. What I understand are some of the basics of the clutch operation and the transmission and I don't see the connection to hard downshifting.

Guess I'll move on...

I'll try. The clutch is like a slice of balogna between two slices of bread. The bread is attached to the engine which spins the bread - the bologna is attached (via splines) to the transmission. The back piece of bread is fixed - it doesn't move. The front piece of bread is either pushed back hard against the meat and fixed piece of bread, or pulled away from them.

If you pull the one piece of bread away from the meat then the meat needs to slide a little to be away from and not dragging on the stationary piece of bread.

In clutch terms the pressure plate pulls away and releases its presure on the clutch disk, but if the clutch disk is reluctant to slide slightly away from the fixed clutch cover it continues to drag on it. This drag applies torque to the input shaft because the clutch disk (bologna) is connected by splines to that shaft.

If the splines are dry, rusty, or filled with metal grindings mixed with dry grease then the disk doesn't slide slightly and the torque applied to the input shaft makes downshifting difficult.

Why more on the downshift than the upshift. Nature of the beast. I can ride my K75 around all day, upshifting without the clutch without clanking or grinding. The same is not true of downshifting. But I can say with absolute assurance: dry spline = difficult downshift. The converse; difficult downshift = dry spline is sometimes true but there could be other causes internal to the transmission.

I have seen several cases where a transmission was pulled and opened up looking for a problem. No problem found so the transmission was reinstalled and the problem went away: because in the process the splines were cleaned and regreased.

[bikerfish1100]

I'll try. The clutch is like a slice of balogna between two slices of bread. The bread is attached to the engine which spins the bread - the bologna is attached (via splines) to the transmission. The back piece of bread is fixed - it doesn't move. The front piece of bread is either pushed back hard against the meat and fixed piece of bread, or pulled away from them.

If you pull the one piece of bread away from the meat then the meat needs to slide a little to be away from and not dragging on the stationary piece of bread.

In clutch terms the pressure plate pulls away and releases its presure on the clutch disk, but if the clutch disk is reluctant to slide slightly away from the fixed clutch cover it continues to drag on it. This drag applies torque to the input shaft because the clutch disk (bologna) is connected by splines to that shaft.

If the splines are dry, rusty, or filled with metal grindings mixed with dry grease then the disk doesn't slide slightly and the torque applied to the input shaft makes downshifting difficult.

Why more on the downshift than the upshift. Nature of the beast. I can ride my K75 around all day, upshifting without the clutch without clanking or grinding. The same is not true of downshifting. But I can say with absolute assurance: dry spline = difficult downshift. The converse; difficult downshift = dry spline is sometimes true but there could be other causes internal to the transmission.

I have seen several cases where a transmission was pulled and opened up looking for a problem. No problem found so the transmission was reinstalled and the problem went away: because in the process the splines were cleaned and regreased.

so do you put the mustard on the bologna or the bread??

[PGlaves]

so do you put the mustard on the bologna or the bread??

The mustard goes right on the shaft that goes in the little hole in the center of the meat where the meat gets hung up on mustard free (or dried up mustard) splines. A bit of moly in the mustard is a good thing.

In actual practice the spline lube should be applied ONLY to the transmission shaft, after both the shaft and clutch hub are clean and free of grit and/or old grease. It should not be applied directly to the splines in the clutch hub. Here is why: If applied to the shaft any excess will be pushed to the back side of the clutch hub which is not in line with the clutch disk lining. If flung by centrifugal force it does no harm. If applied to the clutch hub directly, any excess will be pushed to the forward edge of the hub, which is directly in line with the disk lining and if flung, can foul the disk clutch with lubricant.

NOTE: taking a very little bit of moly paste on a brush and burnishing the inside of the hub with the moly is acceptable but it needs to be brushed off so that there is nothing for the shaft to push forward through the hole.

Stuff they teach in school (or you learn the hard way) but which they fail to mention in most manuals.

[bikerfish1100]

and if one prefers mayo to mustard? what then?

(forgive the slight hijack- just feeling goofy)

[tricyclerob]

Paul, I glad you mentioned the caution about grease on the hub, I had not thought about that grease getting pushed in and "flung aroung". thanks.
Also, when I pulled the trans it did not look like it had ever had any grease, or very minimal. The splines looked dry with a hint of reddish tinge, but not a lot of dust , metal or debris. I looked at the splines w/a magnifying glass and they do not look bad. The saving grace here is that it is a low mileage bike and has not been flogged in any way.
I can understand that a dragging clutch can make dnshifts difficult, but I will be suprised if this cures my issue. I think the c-clip/ bearing problem might be at work here. But, in and out of the trans is not that big a deal and I think it's worth it to try. I guess this is a good "test case".
Thanks to everyone for their input. It's been a big help. I will post the results of the lube. thanks, rj

[tricyclerob]

I managed a little garage time tonight, but I'm not getting much done w/Barrett-Jackson on. All I can say is must be nice to have 50-100 grand in disposable income. Anyway, I was cleaning up the outside of my trans, as I can do that and stare at the auction at the same time.
Does anyone know what the original finish of the outside of the trans['86 R-65] is? Does not appear to be bare alium., more like a flat silver paint. I'm not really thinking about painting because it does not look that bad, and If I did, it would not match the engine. Just curious. rj

[lostboy]

The original "finish" was bare alumnum. If you'd like to bring it back to near original looking, there's another thread going about restoring a crankcases's finish.

Quit watchin' TV and get back to work! :)

[tricyclerob]

I finally had some time, got the trans back in and went for a 1 hr test ride today. [29 degrees- wonder what the wind chill was at 45-50?]
Well, I am happy to report that the spline lube cured my stiff downshifting.
Shifts like butter!!!!
As you may recall, the splines were very dry upon inspection. The bike seemed to upshift fine but was very stiff, to the point of having to "jab" at the lever to shift down.
All is now fine. The only thing other than the lube was a refill with "Amsoil" synthetic gear lube. The oil that came out of the trans looked fine so I really think it was the spline lube. Logical or not, It made all the difference.
I am a happy camper...

[20774]

Rob -

I guess that pretty much answers the question. I'm sure you - and the bike - feel better.

I queried a few other people about why splines needing lubing would show up as stiff downshifting. It's hard to visualize, but the way I understand it is the issue with getting the engine speed to match the tranny speed as you go from one gear to the other. In upshifting, when you pull the hand lever in, the friction of the engine, etc., will tend to slow it down, as well as the clutch disk which may still be in contact with the flywheel due to the inadequate lube. That works out OK with trying to match up with the speed of the spinning gears in the tranny. But when downshifting, you need to keep the engine speed up in order to better match the tranny, but with the dragging clutch disk, it makes it harder to do that. So the shifter seems a little stiff as you're fighting the speed differences in trying to mesh the internal gears.

That's about as much as I understand...I'll have to think about that some more and pay more attention the next time I ride.

[PGlaves]

Rob -

I guess that pretty much answers the question. I'm sure you - and the bike - feel better.

I queried a few other people about why splines needing lubing would show up as stiff downshifting. It's hard to visualize, but the way I understand it is the issue with getting the engine speed to match the tranny speed as you go from one gear to the other. In upshifting, when you pull the hand lever in, the friction of the engine, etc., will tend to slow it down, as well as the clutch disk which may still be in contact with the flywheel due to the inadequate lube. That works out OK with trying to match up with the speed of the spinning gears in the tranny. But when downshifting, you need to keep the engine speed up in order to better match the tranny, but with the dragging clutch disk, it makes it harder to do that. So the shifter seems a little stiff as you're fighting the speed differences in trying to mesh the internal gears.

That's about as much as I understand...I'll have to think about that some more and pay more attention the next time I ride.

In addition to matching speed there is another factor at play: simple friction. When the splines are dry and the clutch disk is dragging on the clutch cover torque (twisting force) continues to be delivered by the engine to the transmission. So there continues to be side pressure on the shift dogs which are engaged in the holes for the gear you are in and trying to shift OUT of. This continued side pressure makes it difficult to disengage those dogs. Now once you have shifted out of that gear, the speed of the shafts in the transmission need to be proper so that it can go IN to the lower gear.

In any event, the proof is in the pudding - or in the lubing. I think he said "shifts like butter".