K75 Downshifting Issue '93

[Recker1]

Hi guys - quick question:

I recently purchased a '93 K75 with 30K miles. The bike runs like a dream but has an issue downshifting. When going down from 5-4-3-2, you have to bump the throttle to increase the rpm's a bit to get the bike to downshift. It will go very smoothly if you increase the rpm's just a bit while downshifting, but if you don't increase the rpm's before downshifting, it simply won't go. Upshifting is perfect though. It's really not difficult to do, I just want to make sure this is normal, and if not, find out what I need to do.

Any ideas?

Thank in advance!

P.S. This doesn't seem to happen at low speeds.

 

[ted]

When was the last time it had a complete spline lube?

 

[acejones]

When was the last time it had a complete spline lube?

Also check the clutch adjustment

 

[yankeeone]

yup, sounds like dry input shaft on the trans.

 

[GREGFUESS]

When was the last time it had a complete spline lube?

Ted, this is an excellent question, and got me to wondering about my own K75, that runs well but has a similar issue. Doesn't happen enough to concern me, but maybe it should. Mine is a 1995 K75 with ABS, and has 47k miles on it, the last 3~4k since I bought it at Thanksgiving.

The service records that exist (not more than the last few years, just Word document not even in hard copy). What happens without a spline lube?

 

[ted]

It becomes harder and harder to downshift. The real problem is what isn't apparent until failure - the degrading and ultimate failure of the splines themselves from wear and corrosion. While some will happily tell you they have gone 60,000 miles without a spline lube with no problems, most agree they should be completely serviced with a good moly lube, either a 50/50 mix of HondaMoly 60 paste and Wurth 3000 or Guard Dog's GD525, every 30k miles or four or so years. The more die hard will recommend doing the rear splines every other oil change - a simple process that with practice will take about 45 minutes. Paul Glaves did an excellent piece on splines and spline lubes in the April 2010 BMW ON page 36, you might try giving that a good read.

The full spline lube is not difficult but it is time consuming - basically the rear splines on the final drive at one end of the drive shaft (which seemingly are the most subject to wear), the intermediate at the other end, and the clutch splines. The extensive break down to do it right (ie not the "paintbrush method") also gives you a chance to easily check things like the swingarm boot and alternator bushings that you should check, and replace if needed, every 30k miles anyway.

Gambling on not doing the service can lead to long tows and expensive repairs - a used rear drive with good splines will run $300 to $500, the drive shaft another $250 or so.

There are literally dozens of detailed write ups here, on the IBMWR site and elsewhere walking through this service step by step, even a few videos on YouTube. If you have a garage, a sawhorse and some basic skills turning a wrench you should consider it. Just be prepared to go slow and label your parts as you remove them, and remember, this isn't a job that can be done in a Saturday afternoon - though I bet folks who have done it a few times like PaulG, LeeF and DonE could have it wrapped up by dinner

 

[Recker1]

That was my fear - the splines. Do you think this is the rear spline, clutch, or possibly all? In any case, thanks for the information. Looks like I may be getting dirty a bit faster than I was hoping for!

 

[PGlaves]

The clutch splines need to be cleaned and lubricated.

 

[98lee]

It will go very smoothly if you increase the rpm's just a bit while downshifting,

You SHOULD be doing that anyway. But cleaning and lubing the clutch splines will make it all better.

 

[GREGFUESS]

The full spline lube is not difficult but it is time consuming - basically the rear splines on the final drive at one end of the drive shaft (which seemingly are the most subject to wear), the intermediate at the other end, and the clutch splines. The extensive break down to do it right (ie not the "paintbrush method") also gives you a chance to easily check things like the swingarm boot and alternator bushings that you should check, and replace if needed, every 30k miles anyway.

After reviewing Paul's article and the IBMWR article by Brian Lally and another one by Dan Patzer, I recognize that this is not something I should attempt without considerable support, such as a video or something that has detailed instructions. Does anyone know of such a resource?

Any thoughts on what a mechanic should charge for performing this service? What questions should be asked to ensure that they are competent to perform the task?

 

[Recker1]

After reviewing Paul's article and the IBMWR article by Brian Lally and another one by Dan Patzer, I recognize that this is not something I should attempt without considerable support, such as a video or something that has detailed instructions. Does anyone know of such a resource?

Any thoughts on what a mechanic should charge for performing this service? What questions should be asked to ensure that they are competent to perform the task?

Greg - I'm hoping to get the EXACT same information myself!

 

[edwarddieck]

It's not that difficult. And it will be many years before you have to do it again you will probably forget how you did it the first time.
I used a saw horse to hold up the bike. Have a friend handy for reassembly. I worked hours trying to get the tranny back in place. Called a friend and it took less than 5 minutes.

 

[BUDDINGGEEZER]

Other brand motorcycle groups such as STOwners and FJR owners have tec rallies. Someone who knows how to do a certain repair or service agrees to perform the work on their or another's bike and people ride in and camp or motel it and learn how to. Throw in a RTE and general BS session and you got a rally.

Ralph Sims

 

[ted]

Our local club has monthly tech sessions, going back to the mid-90's when a bunch of local folks on the IBMWR list stole the idea from the Pennsylvania club's Shack Packs (we called ours Slack Packs...) The name has been dropped over the years to just tech sessions, but they are quite popular. The problem is time - there is time to do a rear spline lube but not a complete spline lube.

You might try just posting on the regional boards for someone who might help and attack it over a weekend - I know on the K11OG boards this is quite popular (though usually it ends up being a couple people doing all the work and the rest standing around with a cold homebrew "supervising" ;-))

 

[GREGFUESS]

Our local club has monthly tech sessions, going back to the mid-90's when a bunch of local folks on the IBMWR list stole the idea from the Pennsylvania club's Shack Packs (we called ours Slack Packs...) The name has been dropped over the years to just tech sessions, but they are quite popular. The problem is time - there is time to do a rear spline lube but not a complete spline lube.

You might try just posting on the regional boards for someone who might help and attack it over a weekend - I know on the K11OG boards this is quite popular (though usually it ends up being a couple people doing all the work and the rest standing around with a cold homebrew "supervising" ;-))

Thanks Ted, I was thinking about asking on the Houston BMW Club board, but was a little shy about asking. I will go ahead and see what they say, the worst that can happen is no one responds.

 

[PGlaves]

After reviewing Paul's article and the IBMWR article by Brian Lally and another one by Dan Patzer, I recognize that this is not something I should attempt without considerable support, such as a video or something that has detailed instructions. Does anyone know of such a resource?

Any thoughts on what a mechanic should charge for performing this service? What questions should be asked to ensure that they are competent to perform the task?

I would recommend you get or borrow both a Haynes manual and a Clymer manual for the classic K75/100 bikes. Read the portion on removal of the transmission. Those are the detailed instructions for a spline lube, except for the application of the lubricant itself.

Clean the shaft and then use a toothbrush but no solvent to clean the clutch hub splines. Then apply new lubricant TO THE TRANSMISSION SHAFT ONLY. NOT TO THE CLUTCH HUB. This ensures that any excess gets pushed rearward where it does no harm rather than forward where it will sling and foul the clutch surfaces.

 

[GREGFUESS]

Haynes and Clymer?

I have a Clymer, but you say and, not or.

Also, from my inexperienced perspective, these books are guides for people who are experienced and comfortable doing this type of work, and not for the inexperienced who want to learn.

I appreciate your thoughts, and am not attempting to argue, just sharing my perspective. Have asked the local club if they want to host a tech day on this. Hopefully so. Otherwise there is someone distant who seems knowledgeable who has offered to help. Long distance ride verses about $300.

 

[abharding]

QUOTE: Also, from my inexperienced perspective, these books are guides for people who are experienced and comfortable doing this type of work, and not for the inexperienced who want to learn.


I was like you, and apprehensive to get my hands greasy and probably "screw things up". I used to take the bike to the mechanic for the big stuff like spline lubes, but do the minor maintenance such as oil changes myself. But I've found the K Bikes are so well designed and easy to work on, and with the resources of my manuals and helpful forums like this one I actually look forward to working on the bike. Also, not only am I building my wrenching skills but I gain a confidence in how the bike runs and performs, because I know how the work was done. My K100 clutch is starting to act up a bit, after having the mechanic do the splines just last summer, and my first response was "should have done it myself!"

I say go for it.

 

[acejones]

Think I'd pay the $300. Seems better time wise.

 

[GREGFUESS]

Think I'd pay the $300. Seems better time wise.

Ace, timewise you are right, handsdown pay the piper and keep on riding. The difference is that I am now willfully unemployed and want to know more about what I ride. One of the beauties of the K75 is that it is supposed to be easier to work on. I just lack the confidence to start something like this on my own.

I have an R12R and a K12S, but am afraid of messing around with them. Yet the more I mess with the K75, the more I enjoy riding it despite the fact that they are in all respects more advanced, powerful motorcycles.

So, to each their own. I am not disagreeing with you. To the contrary I understand your point and have been in the position where it made more sense to me that any other. But from my perspective today, I want to learn how to do this and more with my scoot.