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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: gmawby on December 10, 2015, 06:07:51 PM
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Hi everyone,
I've been "lurking" for a while now and this is my first post.
My K75 had been sat for years in a garage for years when I bought it and over the last 4 months I've done lots of maintenance tasks including removing the gear box and lubricating the splines. I used a product called Castrol Optimol which was sold to me by my local BMW dealer/workshop. Two months on it is almost impossible to shift down from 4 to 3 even with a pre-load. However if I blip the throttle it changes down easily.
I plan to strip it down again and examine the splines as I'm wondering if the lubricant is not up to the job. If anyone has comments or opinions please let me know.
Glenn,
Sydney, Australia.
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I use Honda Moly 60(no longer available) on all splines, and my bricks(three of them) downshift like riceburners.
Can't speak to the Castrol product. Have you double checked your clutch adjustment?
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Optimol has worked well for me(BIG difference after spline lube for me),if splines are already damaged that may not be the case.
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I have been using Castrol Opitimol for the paste 16 years,but now if you read the posts Guard Dog Moly paste seems to be the new recommendation. Having only done the spline lube 4 months ago, I would be looking at something other than the splines. As Gryphon suggested I would look at the adjustment before going on to anything else.
Regards Martin
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Gryphon Honda moly 60 has been superseded by Honda M77 Assembly paste I don't know whether it is identical.But you can obtain it under that number.
Regards Martin
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The research that I did suggested Optimol would be more than up to the job. Staburags was (is) the lubricant recommended by BMW, I believe. I spoke to the parts guy at a BMW dealership in my area and he said their mechanics used Belray Assembly Lube! They hadn't heard of Staburags. I spoke with a Castrol rep and he could only provide me with an industrial-sized quantity of Optimol. I went with Guard Dog Moly. These folks are a small operation out of Texas, very reasonable and very pleasant to deal with. I would make your inquiries there first. A little goes a long way!
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Actually, you stating that flipping the throttle helps sounds more like a synchro problem..
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If you cleaned your input and friction disc splines thoroughly with a pick and solvent, applied lubricant sparingly but thoroughly to dry splines with a brush, aligned your clutch parts properly when coupling the transmission to the engine and adjusted your clutch free play correctly according to procedure and spec, then your shifting should be smooth. Stripping down the thing to check your work is probably your best move.
I used Staburag NBU 30 PTM for input spline and clutch rod lube because I believed I couldn't go wrong using a product with that many capital letters combined with numbers arrayed in such pleasing symmetry. The bike shifts pretty good.
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I started blipping my throttle for smooth shifting for a couple thousand miles before I lubed the assembly. Shifts nicely afterwards. If it's a synchro problem, it's ok with me if it hides out for a while.
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Hello ,
thank you for the advice.
Regarding clutch adjustment I followed the procedure and I think it is OK. However I started the bike on the centre stand today and noticed that the back wheel rotates slowly when in neutral. If I pull the clutch lever it stops. Is that due to the oil viscosity or is the clutch not properly adjusted? Do all K bikes creep?
On the subject of oils, I originally had 80/90 W and when it became difficult to change I tried a full synthetic 80/140 but I don't notice any difference. I'll probably change back to the original specifications.
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However I started the bike on the centre stand today and noticed that the back wheel rotates slowly when in neutral. If I pull the clutch lever it stops. Is that due to the oil viscosity or is the clutch not properly adjusted? Do all K bikes creep?
Both my 1100's do it when the oil is cold on 1st startup, so yes I would say that it is due to the oil viscosity.
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Regarding clutch adjustment I followed the procedure and I think it is OK.
Your clutch is properly adjusted if you have the correct free play allowance at the handlebar lever, the correct cable length at the clutch lever and a bolt adjustment that makes contact without pressure.
Shifting in either direction between all other gears except 4 to 3 is smooth?
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I checked the clutch cable length and free play and they are correct. I went for ride to test and observed that: going up through the gears is fine, finding neutral is easy from 1 -N and 2-N , 4 -3 occasionally shifts but I usually have to blip the throttle, 3-2 usually shifts but sometimes needs help, 2-1 is the same as everyone else's bike. If I stop at lights in 3rd it won't change up or down and the LCD indication goes blank. When it gets in this state it will change if I slip the clutch.
Others have posted that (http://bmwsporttouring.com/faq/transmission_issues.htm and this tread http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=268144 ) that quick shifts are important. I do tend slow down in 4th as I approach lights then change down and engine brake. I'll try changing sooner at higher revs. My Honda did not mind changing at any speed, but this is a very different bike. Curious that it seems to be getting worse, but maybe it is not the bike but me that is getting worse, self fulfilling my belief that something is wrong.
Time to go for a ride.
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You're on the right track. Shifts need done assertively instead of with a light touch. Performed like that, shifting should be smooth throughout the range.
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Is your gear shift lever solid? Or is there up-down play in it?
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Hi,
yes the gear shift is solid as far as I can tell.
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Go forth, shift and downshift with vigor, Glenn, then please report back.
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Hello,
I've been forth and shifted with vigour and I'm not happy. I rechecked the clutch adjustment and it is as per the manual so I'll take it apart and check my work.
Happy new year to you all.
Glenn.
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Still the 4→3 and 3→2 downshift stubbornness, eh?
Thanks for the feedback, Glenn, and happy new year to you, too. Please let us know what you come across when you take it down.
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Yes,
down shift stubbornness :(
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greetings...
i find it easier to downshift when taching above 7 thousand rpms... generally in the 7 thousand to 8.5 thousand sweet spot...
j o
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Jonny,
you are pulling my leg or I am riding this bike wrong! When I'm at the legal limit on the freeway (110 km/h in NSW Australia) it is nowhere near 7 thousand on the tacho.
You raise an interesting point. I had a 250 Honda twin that red lined at 13.5 K and I'd spend my time riding at 8K + rpm. When I got the BMW I "slowed down" in a psychological way , thinking 750cc , loads of torque, smooth and effortless etc. On my daily ride to work (legal speed 60Km/h) I'll do most of that in 4th gear. I probably need to reset my thinking or buy a Royal Enfield :)
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:mbird 60kph is 2nd gear country, maybe third. You'll get used to it. Saves a lot of wear and tear on the toe of your left boot...
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Hi everyone,
The gear box is out and on the bench. I've checked the splines and they still have Optimol paste on them, they look to be in good condition , no broken splines etc. Same for the splines on the clutch and drive shaft/final drive. Checked the clutch alignment with an alignment tool and it fits snug. I've re-read the workshop manual and it says: lubricate the splines AND the end of the push rod. I did NOT lubricate the end of the push rod, in-fact last time I cleaned it before I put it back together. Other observations: there is no oil in the clutch housing so seals are good. The rubber boot on the back of the clutch has split and needs replacing.
I'm in two minds whether to measure/replace the friction plate since it's in bits. Opinions and suggestions most welcome.
Glenn.
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Glenn at 140,000 Ks I had to replace my slightly weeping rear main seal, so I thought I might as well replace the clutch friction plate as well. I had to special order the clutch plate. Once I had it all stripped down I found there was very little wear, but seeing as I could not return it, I replaced it anyway. Standard thickness is 5.05 to 5.55 mm service limit is 4.50 mm as per Haynes Manual.
Regards Martin
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Thanks for the update, Glenn. Seems like you've got the nerve and skill to do what's needed. How many kilometers on the clock?
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Laitch,
there is 135,000 Kms on the clock. Not much really :-)
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If it were my bike, I'd check the friction disc for wear. It's only a little more work. Mine checked out with 5.00mm at 80K km.
You may not need this reference but here it is anyway. Start viewing a 4:28. https://www.youtube.com/watch?v=LcbvZPJa1W0
Anticipating a successful forth-going after reassembly is complete. :riding:
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Hi Laitch,
thank you! I like the hysterical laughter at about 9:50!
I'll probably take it off and have a look.
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Hi,
I took the clutch friction plate out and it measured over 5mm so I put it back together. The bike is back on the road and shifting smoothly. I hope I don't have to do it again for a long while.
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It's recommended to use moly grease on the clutch splines, the pushrod end and the ring upon which the diaphragm rests. All of these need grease to ensure the smoothest clutch engagement/disengagement.
It's probable that the clutch friction plate is still within the service limits if the milage on the bike is low. I helped a friend with a spline lube this past weekend and his was still 5.05mm even after 30 years and 80K kilometers.
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Good work, Glenn!
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Hi,
my shifting problem came back after about 2000 kms so I took it to a dealer. They took the gear box apart and found that the shifter drum(?) and shifter were worn. I've had new bearings and good drum and shifters fitted and it changes great.
Good for another 25 years!
Glenn.
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Glad to see your problem is solved, now go for some long rides, and enjoy the fruits of your labour. :clap:
Regards Martin.
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. . . so I took it to a dealer. . . . and it changes great.
Good for another 25 years!
That was a good decision, Glenn. I hope crowd-sourcing was unnecessary. :hehehe
If it had been my bike I probably would have kept stomping on that shifter trying to make it conform to my idea of reality until I'd ground down the guts of the transmission into garden mineral dust and wound up pushing it into the shop.
Good riding and thanks for the update!
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Too bad the lube didn't do it. The good news is that you got to meet Chris Harris. I could watch this guy for hours. His somewhat rough countenance is a nice balance to the snooty brand of bike he works on, don't you think?? And who can beat that laugh!! Price-less.
Have fun!
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my shifting problem came back after about 2000 kms so I took it to a dealer. They took the gear box apart and found that the shifter drum(?) and shifter were worn. I've had new bearings and good drum and shifters fitted and it changes great. [as of February 22, 2016]
Can I ask if the problem has stayed fixed with that work having been done? I have the exact same syndrome on my K75RT, 59K miles, which I bought last month and have put 600 miles on--and the shifting seems to be getting worse.
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Hi,
I rode the bike for about 100 K and I had a problem shifting UP from 1 to 2 so I took it back. The shop took it apart and fixed it for free ( worn selector that they missed/forget to change). I've done over 1000 km since and it is fine.
glenn.
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What do you think of the idea that this is just the way these K-75's are? Part of this "syndrome" as I called it might be the normal fact that we don't notice everything with crystal clarity and when we do notice something we seize on it in horror, not comparing it to all the similar sets of circumstances. I'll go further out on the limb and say that maybe "these Germans" build transmissions with other ends in view so that if the transmission doesn't go "clunk" when you shift, you're not worthy to ride the bike.
Well, we shall see, if we live long enough.
I bought this bike after a guy creamed me on my F650CS from another member of a BMW club, and that F bike was my first, I rode it for ten years from 1.7K miles to 36K miles, after a few years thirty years ago with an R-69US and then a couple of years with a junker Suzuki, neither of which I took care of. By contrast I did the scheduled maintenance by the book with the F bike, at a dealer. The seller of the K-75 and a couple of other senior members (we're all senior members) are all honorable gentlemen of the road and in fact these other two men superintended at the sale like attendants at a wedding. I suspect that in general they're waiting for me to prove myself worthy of this bike.
All those dancing emoticons sure are annoying.
Thanks for your comment and experience.