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Old 09-04-2010, 09:18 AM   #1
Brian-M OP
Melting in GA
 
Joined: Jun 2008
Location: Warm Springs, GA
Oddometer: 956
Yet another airhead tranny issue (shifting issue)

So, I blew up the previous tranny (51k miles, bearings went out, '91 R100GS), bought a replacement from a local shop with a 12month/12k mile warranty. That killed my "fun" money and I've only put about 1,000 miles on this new box in the last 3 months, 2 oil changes since then. In that time I knew that this box didn't shift anywhere NEAR as crisply as the prior unit, but I've also had rare and occasional issues where it just didn't want to shift down. The shift lever feels like when you're in first, it goes down with no resistance ~ you can't pre-load the lever. I thought it was just me/rider error at first because it was so non-consistent, now it's doing it between 4th and 3rd, and 2nd and 1st with fair consistency. Obviously, the oil doesn't stay cold for very long, but I never notice it till I'm out at least 10 miles. Doesn't matter if the clutch is in or out. Splines were Thoroughly lubed 1000 miles ago too...

Trying to do my homework, it looks like there's a $2 spring that's prone to breaking that stops all shifting. And that's the catch for me, I can still always shift up from whatever gear. I've read through Snowbums transmission page just now and don't see any other possible mention. Well, I did (like making sure the bolt for the shift shaft is tight and checking clutch adjustment), but those were checked and found good.

I'd love for this to be rider error, or something stupid and simple that I could fix at home, but I'm afraid that I'll be pulling this transmission for the 2nd time since I bought the bike in April. But I'd love the thoughts of the more experienced among us (at least those not out taking advantage of this 3-day holiday weekend).

Brian
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Old 09-04-2010, 10:36 AM   #2
batoutoflahonda
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My G/S is doing the same thing. If I'm riding it 'spiritedly' it's like trying to down shift with out using clutch (4th to 3rd). Almost like the heavier loads are binding it up.I was guessing the splines needed lubed or maybe some thing binding in the clutch.

I'll be watching this to see what you find. I'll post what I find, but don't plan on taking it apart till this winter. I'm going to change the clutch and look at that end. I just had it [trans] gone through last year. The bike has 73k on it.
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Old 09-04-2010, 11:13 AM   #3
schneller
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Oh, THAT kind of airhead tranny issue!

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Old 09-04-2010, 02:06 PM   #4
Brian-M OP
Melting in GA
 
Joined: Jun 2008
Location: Warm Springs, GA
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Doing some more reading (what else do I have to do?), it sounds like a LOT of people experience this with dry clutch splines. This seems odd to me as I watched the mechanic apply great big gooping globs of this sticky lube to the splines on the transmission (aided with heat to get it to flow) and gave me explicit instructions about cleaning the input on the clutch side, which I did.

Still, if this sounds right, I'll spend the day pulling the transmission again and adding More.
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Old 09-04-2010, 05:41 PM   #5
wirewrkr
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Quote:
Originally Posted by Brian-M
Doing some more reading (what else do I have to do?), it sounds like a LOT of people experience this with dry clutch splines. This seems odd to me as I watched the mechanic apply great big gooping globs of this sticky lube to the splines on the transmission (aided with heat to get it to flow) and gave me explicit instructions about cleaning the input on the clutch side, which I did.

Still, if this sounds right, I'll spend the day pulling the transmission again and adding More.

I can't speak about the shifting issues other than the gearbox wasn't done right if the splines are well lubed and the clutch mechanism is actually releasing correctly.
What I will say with confidence is that big globs of spline lube are a major no-no and a sign of a mechanic who doesn't know of what he speaks or does!
Your clutch splines have probably thrown that shit all over the inside of the bell housing by now, not to mention fouling the clutch.
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Old 09-04-2010, 09:28 PM   #6
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Quote:
Originally Posted by wirewrkr

I can't speak about the shifting issues other than the gearbox wasn't done right if the splines are well lubed and the clutch mechanism is actually releasing correctly.
What I will say with confidence is that big globs of spline lube are a major no-no and a sign of a mechanic who doesn't know of what he speaks or does!
Your clutch splines have probably thrown that shit all over the inside of the bell housing by now, not to mention fouling the clutch.
Umm hmm and whats with the "heat to make it flow" and "clean off input on the clutch side"? What side of the input is left with lube on it?

I know the shifter bolt was checked, but it sure sounds like the symptoms.
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Old 09-05-2010, 07:45 AM   #7
Brian-M OP
Melting in GA
 
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Location: Warm Springs, GA
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Builder was Pete Homan of Bavarian Motorcycles West here in Denver. He has a stellar reputation among the Rockies Region of ADV and is recommended as the ONLY BMW mechanic to take your bike to in Denver.

So, the "spline lube" applied was Very gooey/sticky and thick coming out of his tub. When I asked what it was, he said it was a special concoction (He's been a BMW mechanic, both dealer and independent, for several decades). He heated the splines till they were warm to the touch and spread his lube on them. It wasn't Dripping off (doubt that stuff could drip), but there was a good bit on there.

Guess I'll be pulling the transmission again
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Old 09-05-2010, 07:50 PM   #8
bmwrench
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Before you pull the gearbox, have you cleaned and lubed the shift lever pivot and linkage?
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