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4 Speed Transmission Overhaul R60/2

pinbill
Posts: 39
Joined: Mon Aug 09, 2021 10:13 pm

4 Speed Transmission Overhaul R60/2

Post by pinbill »

Hey Everyone,

Here are some pictures of the trans. It has 33k miles on it and the original owner knew his way around motorcycles. Since the trans needed new seals and the back cover is off, I am going through it. Lots of great experience on this forum. I might need some help so I am posting up my progress. I have all the tools: depth gauge, parallels, shims, bearings, seals ect... Here is the plan so far.

The initial inspection looked great. There was very little sludge in the bottom of the case. The kickstart gear looks good. No bluing on the gear sliders and the holes for the dogs look real good. The shift fork bolts came out without a problem. Going to pick up new updated ones today. The shift forks are a little twisted but don't show signs of wear on the contacts. I plan to bend them back to square and use eccentric bushings. I don't plan on taking the shift mechanism off, but I would like to set the under and over shift gaps. The current gap is about 1.3mm on both. The Barrington book recommends 2mm.

The neutral light was working fine. I would like to check it but I don't have the jig to measure the angle while the cover is off. Does anyone have an idea for a DIY jig or access to a real one?
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Micha
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Re: 4 Speed Transmission Overhaul R60/2

Post by Micha »

The tools for these motorcycles were manufactured at the time by MATRA.
In the workshop manual book of my model (R51/3) there is a list of tools at the end accompanied by a technical drawing for each tool, MATRA p/n, etc.
You should check if you can get such a book, I got mine on line and I made quite a few tools myself.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

Seek
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Re: 4 Speed Transmission Overhaul R60/2

Post by Seek »

Have a look at the shockabsorber on the inputshaft, they can wear pretty badly.

For the neutral switch you can install just the switch mechanism but none of the shafts. Put the rearlid on the box and now you can have a look through the hole of the inputshaft. When you select neutral the nub on the selector wheel pushes against the neutral switch blade. That blade should move aside about 2-3 mm.

pinbill
Posts: 39
Joined: Mon Aug 09, 2021 10:13 pm

Re: 4 Speed Transmission Overhaul R60/2

Post by pinbill »

Thanks for the info on the neutral light switch. I will check it with the cover on.

The trans seals are so old and dry that they have been hard to remove. I may take the shift mechanism out to take the shift shaft seal out from the inside. It might end up being easier. Also, I don't want to mar the case taking the old one out.

Here is a question. I found a discrepancy with the over/under shift bolt adjustment. Cycle works calls for .5 to 1mm gap and Barrington calls for 2mm. I am not sure which I am going to choose yet. Any thoughts?

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Re: 4 Speed Transmission Overhaul R60/2

Post by Seek »

According to the Workshopmanual it should be "about" 2mm. It doesn't need to be super precise.

pinbill
Posts: 39
Joined: Mon Aug 09, 2021 10:13 pm

Re: 4 Speed Transmission Overhaul R60/2

Post by pinbill »

Hey Guys,

The transmission is coming along. I got gears installed, the shift forks adjusted, and the bearing gaps measured. Here are my findings. The Output and Intermediate Shafts seem reasonable but the Input Shaft seems like a big gap. I didn't leave out any washers or anything when I changed the bearings. I also checked my math a bunch of times. When it came apart the trans had one .4 mm shim on the output shaft.

Output Shaft:
Total Gap is .027"- .004"= .023" / .58mm To Shim

Intermediate Shaft:
Total Gap .017"-.004"= .013" / .33mm To Shim

Input Shaft: (The curved washer is .03")
Total Gap .119"- .034 = .085" / 2.16mm To Shim

Does the Input Shaft shim amount seem excessive?

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jwonder
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Re: 4 Speed Transmission Overhaul R60/2

Post by jwonder »

Yes, .085 seems too much. I had the same type of measurement when I forgot the washer that goes between the kickstart gear and the bearing marked part #18 on this diagram https://www.bmwclassicmotorcycles.com/ ... put-shaft/. Also note they have them in different thicknesses.

I would check that first.
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

pinbill
Posts: 39
Joined: Mon Aug 09, 2021 10:13 pm

Re: 4 Speed Transmission Overhaul R60/2

Post by pinbill »

Thanks for getting back to me. I am not in a hurry to finish this. We just got 5" of snow here.

I included the curved washer #18 in the equation. It is .75mm or .03".

Total Gap (bearing height- cover recess): .119"
Washer #18: .75mm / .03"
Bearing end gap: .004"

.119"- .034 = .085" 0r 2.1mm of shims.

The bearing heights on the Input and Intermediate shafts were almost identical. Here are all my measurements just in case:

Input Intermediate Output
Cover Recess " .607 .504 .577
Bearing Height " .488 .487 .55
Gap " .119 .017 .027
Minus .004" .085 (.03 washer) .013/.33mm .023/.58mm


Does Vech still take phone calls?
Last edited by pinbill on Wed Jan 18, 2023 8:44 pm, edited 1 time in total.

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jwonder
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Re: 4 Speed Transmission Overhaul R60/2

Post by jwonder »

Vech still takes calls, call him!!

662 312 2838 cell 9 am to 4pm CST PLEASE!
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

pinbill
Posts: 39
Joined: Mon Aug 09, 2021 10:13 pm

Re: 4 Speed Transmission Overhaul R60/2

Post by pinbill »

Vech: Whats the cheapest part of a BMW motorcycle? -The Rider-

What a nice conversation. Lots of good info and a few laughs.

The shimming on the Input shaft isn't as important as the Output and Intermediate Shaft. It is important to leave fitted washer #17 1/4 inch down on the shaft when installing the cover. When the cover is installed, #18 will push #17 into the correct position. The kick start spring and fitted washer will keep everything in the correct spots. If #17 is pushed all the way down the curved washer #18 will rattle around.

The picture shows the color of the input shaft where the #17 washer was located. In the picture the washer is too far down and would cause #18 to wobble around. If I measure the bright colored part of the shaft I bet it would be about 2.1mm. I may put a .5mm shim in the top cover with the bearing for kicks.

It is also important to have a snug fit on the forward bearing in the case. A tight fit is what keeps the input shaft in place. If the forward bearing is loose it can ride up and contact the forward most gear face on the intermediate shaft.

After listening to his experience with eccentric fork bushings, I am going to bench test the trans before I put it in. The wooden engine stand I made fits the trans perfect. I rigged up a drill adapter for the input shaft using the old clutch. The idea is to shift it while putting some resistance on the output shaft.

Another tip was to use a jewelers screwdriver to work the input shaft seal over the lip of the input shaft seal surface. Tapping the seal in and working the lip a little at a time. If you pound the seal straight in, the seal lip can curl under and pop the inner spring. Then you have oil all over the clutch. The other way to start the seal was to manufacture a guide by milling down the inside of an old clutch to the size of the seal surface.
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