Odd clutch / trans behavior

AntonLargiader · Post by **AntonLargiader** » Tue May 26, 2009 10:19 am

Sounds like something broken in the gearbox. I don't mean to be that obvious but the details don't really matter. The gearbox will need to be opened up to replace the output shaft so you will see the cause at that point.

It's probably either a broken shock coupler on the input shaft or broken dogs on the output shaft shift wheel for 5th gear.

Allan.Atherton · Post by **Allan.Atherton** » Tue May 26, 2009 10:48 am

Sounds like... broken dogs on the output shaft shift wheel for 5th gear. 4th gear.

Darryl.Richman · Post by **Darryl.Richman** » Tue May 26, 2009 12:23 pm

If you don't already have a parts book for your bike, you should get one. It's very helpful to make sure that you have all the parts and they are in the right order. It's not perfect, but it's a lot better than nothing. Vech has them.

BTW, I had no idea what a "guibo" was, so I did some googling. It's another word for the rubber disk that we all know as a Hardy disk.

jcasaretti · Post by **jcasaretti** » Tue May 26, 2009 3:19 pm

I have a couple of days off, so i'm going to raise the bike, pull the transmission side covers and work it through it's gears on the bench. I'm sure i'll open it up and see a broken part laying on the bottom. I just was wondering if there was a common problem that would cause gears to drop (like synchros in a car tranny, etc.).

I have a parts and repair book I purchased when I first bought the bike. I had a friend in Cologne, Germany translate some of the more difficult stuff for me, but overall the pictures and blowouts are invaluable.

Darryl, it's funny you should say you had to google "guibo", because I had to google "hardy disk" when I first saw the term used here. I used to repair and rally race E30 BMW's and the flex guibo is a similar part that fits between the transmission and driveshaft in the 3-series cars. I can build and rebuild those engines in my sleep.

This is not only my first BMW bike - it's my first bike period. I wouldn't trade this learning experience, and I won't ever be selling my first bike. I'm sure most of us wish we still had our first car (71 Firebird) so I won't be making that mistake again.

I will post back any interesting findings.

schrader7032 · Post by **schrader7032** » Tue May 26, 2009 5:02 pm

This is not only my first BMW bike - it's my first bike period. I wouldn't trade this learning experience, and I won't ever be selling my first bike. I'm sure most of us wish we still had our first car (71 Firebird) so I won't be making that mistake again.

Ahh...I still have my first car, a '73 Firebird. I had someone ask me how much I wanted for it and I said he couldn't afford it! I will keep it as long as I can drive...and then some!

A thought Delorean was involved with the 2nd generation Firebird, but it appears he used his design magic on the 1st generation cars.

Kurt in S.A.

AntonLargiader · Post by **AntonLargiader** » Wed May 27, 2009 9:53 pm

Sounds like... broken dogs on the output shaft shift wheel for 5th gear. 4th gear.

Oops. Maybe I'm just used to 5th being the helical at the end of the output.

Yes, fourth.

jcasaretti · Post by **jcasaretti** » Sun Jul 26, 2009 2:00 am

Well it's been 2 months since I installed that tempered woodruff key into the keyway I chiseled out, and I've put around 2200 (rainy) miles on it during my semi weekly commute from Staten Island to Newark airport.

Today I finally pulled the covers on the gearbox to see why 4th gear was not engaging. I've been riding third gear at 50-ish MPH, a sure way to inspire road rage here in NYC. After draining some fluid and removing the hand shift cover, I worked the gearbox through all gears without a hitch. I did notice the rod for the hand shift lever jumping back and down slightly as I shifted into fourth gear, so I left the gearbox in fourth as I screwed down the cover.

VOILA! I now have fourth gear, but (of course) I'm missing first. This is a much better situation, as I rarely use 1st anyway and have basically been riding a 2 gear scoot for the past two months.

If anyone is horrified by all this, I apologize. There are no prima donnas in my life, and I don't believe in owning a concourse machine to trailer back and forth to bike shows or to enjoy an occasional ride. This '52 67/2 (with a load of 51/3 parts on it) brings a lot of smiles to faces as I pass by on my way to work, but no smile is bigger than mine...

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:52 pm

Hello all, This is my first post, and I would like to thank you all for your insight over the last two years that has allowed me to care for my 1952 R67/2.

Last winter, I installed a new clutch assy, NOS clutch lever and cable from S.Meyer in Germany and changed all the seals on the tranny and driveshaft. No leaks when I was finished and I was able to finally stop swabbing out the trans shelf before and after a ride. I put about 2500 miles on the bike last summer, then stored it for the winter.

Last month, I pulled her out of the garage, changed the fluids and had her started in three kicks. When I dropped into first gear and released the clutch lever, the bike did not move and I heard a slow squeal-squeal-squeal. Shifting up to third just gave me a faster squeal-squeal-squeal but I felt a bit more grab. I rolled on the throttle for a bit and it became grabbier, but was not really pushing the bike forward.

At this point I assumed I had a saturated friction plate from a leak over the winter and I was screwed. But it was such an awesome day, I just sat on the running bike rolling it up and down the driveway. After about 5 minutes, I had so much grab that I had to hit the front brakes to stop from rolling, and in 5 more minutes i planted the front tire against a wall and rolled on the throttle until the plate grabbed full in third gear and the bike stalled. I kicked her back up and worked through the gears riding up and down the block, thoroughly confused but happy. I did not have 4th gear though.

I put my helmet back on and rode about a mile to the highway on-ramp, but as soon as I rolled on hard up a slight hill to get to highway speed, the rear wheel lost all power with a big clunk, and my rpms raced.

I had to repeat the above scenario on the side of the highway until I had some grab again and limp home.

I have repeated this scene about 5 times, actually riding the bike for two days at a time before I get that damned clunk. Still no 4th gear engagement though. I know what a saturated clutch feels like on this bike because I bought it with a badly worn and saturated clutch. This feels nothing like it.

I pulled the transmission yesterday and examined the plate. It still looks new with very little wear and no fluid - dry as a bone. Ring looks fine and evenly worn. Rod and felt ring show no sign of fluid and the only small leak is on the eye shaped kickstarter spring anchor/cover on the bottom of the case. Teeth under the foot shift and channels under the hand shift cover appear to work through all 4 gears and engage like I remember after my gasket and seal change 2 years ago. I reassembled it all this morning, adjusting the cables carefully allowing the proper recommended play, with the same results : squealing then grabbing after a time.

Has anyone experienced anything like this? Seems like it might be two seperate problems, but I was hoping someone has had a similar experience and can enlighten me.