Basically, no. You can't go far enough back in a straight line to insert it. Install from the front with the new felt in place...leave the tip sticking out about the same distance as the old transmission was.
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1971 R75/5 Tranny Output Flange
- Thread starter DonTom
- Start date
Basically, no. You can't go far enough back in a straight line to insert it. Install from the front with the new felt in place...leave the tip sticking out about the same distance as the old transmission was.
DonTom
Member
Kinda what I expected anyway, so I will have to pick up the rod before I work on the bike.
This part I am not understanding. I thought I would just put the clutch push-rod in the tranny as far as possible when I install the gearbox.
I will go down to the shop later in the afternoon to get my clutch push rod. Perhaps even the completed tranny, as they should be working on it right now.
Even if ready, I think I will install the gearbox I just bought in SF--just to make sure all is fine. It seems fine by hand.
I already checked the basic functions by hand. It all seems to work. I can see the four gear ratios as well as the neutral operation and kick start, all tested by hand. Neutral rotates the splines for the clutch as the flange for the drive shaft doesn't move when the kick starter is pushed by hand. I guess there's not much else to check if the case is not opened (and I won't even try that again!!) or put on the bike for a test ride--or is there? The only question is what happens during full load. But the woman (she's the shop owner--from Germany) who sold it to me tells me it's ready to install as it came from a running bike. But if that's the case, where is the clutch push rod?
I also wonder why the bolts for the oil filler and drain plug were extremely tight. I did get both loose without using an impact wrench but I was about ready to go to the garage and use it. Instead, I used a long breaker bar and a lot of force to loosen them. But after I got these bolts off, there wasn't a drop of gear oil in the gearbox. I know it is normally drained when the gearbox is removed from the bike, but I question how the bolts got so tight. Did this same shop put them back on with an impact wrench or what? And if so, why? Any tighter, IMO, would have damaged the threads on both. Since they were on so tight, it makes me wonder if they have been on for a very long time. Hopefully the gear oil didn't all leak out or something like that!
-Don- (in rainy SSF, CA)
Don -
The rod is installed from the front with the pointy end point to the front. At the back end of the rod is a long groove cut out...this is where the felt is wrapped around the rod. The felt is needed to keep gear oil from collection and running forward on the rod onto your clutch plate. Put the felt in place, start the aft end of the rod into the center of the input shaft, wiggle to get the felt into the hole while keeping it in the groove. Once the whole felt is inserted, it will stay in place. Then continue to shove the rod towards the read...it will get tight...might even need to "persuade" it a bit. I wouldn't put the rod in so far that the pointy end is flush with the input shaft. In normal operations it will be maybe 6mm proud of the shaft. No real matter...if it's too far in, when you get back to the back of the clutch to install all of the pieces there, they won't fit and will stick out too far. You'll need to "persuade" the rod back the other direction. The danger is that if you get the rod too far to the read, the felt can become exposed...it can then be a biyotch to get it back into the shaft and moved forward. I've heard people tried to install the felt from the rear...frankly I don't see how it can be done. I've heard of dental floss, etc...still seems very difficult.
Those plugs shouldn't be that tight. Steel plugs tightened too tight into the case will deform the aluminum...there will be problems down the road. Be sure and pick up some new crush washers or wavy washers as needed.
The rod is installed from the front with the pointy end point to the front. At the back end of the rod is a long groove cut out...this is where the felt is wrapped around the rod. The felt is needed to keep gear oil from collection and running forward on the rod onto your clutch plate. Put the felt in place, start the aft end of the rod into the center of the input shaft, wiggle to get the felt into the hole while keeping it in the groove. Once the whole felt is inserted, it will stay in place. Then continue to shove the rod towards the read...it will get tight...might even need to "persuade" it a bit. I wouldn't put the rod in so far that the pointy end is flush with the input shaft. In normal operations it will be maybe 6mm proud of the shaft. No real matter...if it's too far in, when you get back to the back of the clutch to install all of the pieces there, they won't fit and will stick out too far. You'll need to "persuade" the rod back the other direction. The danger is that if you get the rod too far to the read, the felt can become exposed...it can then be a biyotch to get it back into the shaft and moved forward. I've heard people tried to install the felt from the rear...frankly I don't see how it can be done. I've heard of dental floss, etc...still seems very difficult.
Those plugs shouldn't be that tight. Steel plugs tightened too tight into the case will deform the aluminum...there will be problems down the road. Be sure and pick up some new crush washers or wavy washers as needed.
fxray
New member
Don,
Didn't all this start because there was a slight weep of gear oil at the rear gasket on your original box? The one you got on eBay looks like it has been leaking at every seal it has. You might be better off putting the original back in and keeping the eBay box as a spare. You could take your time rebuilding it.
Didn't all this start because there was a slight weep of gear oil at the rear gasket on your original box? The one you got on eBay looks like it has been leaking at every seal it has. You might be better off putting the original back in and keeping the eBay box as a spare. You could take your time rebuilding it.
DonTom
Member
I just got back from the shop. They tell me of the countless BMW trannys they have done--mine has been the most trouble of them all. They still do NOT have the flange out after stripping out their new stronger bolts as well. Now, they are talking about cutting the flange out and replacing the destroyed parts. I told them do whatever they can do. It's beginning to look like repairing my old tranny will probably cost more than the used one I just picked up yesterday.
Somehow, I was thinking that thrust rod for the clutch just slipped right out and in. But now I see there's a lot more to it. I never tried to remove or install one before. I picked up my old rod, I see it's in six pieces. I then looked it up in my parts book, which, IMO, is often better than a service manual because of the detailed photos. At first, I thought the felt ring was torn, but now I see it is supposed to have a spit in it.
My parts book shows:
1971 BMW R75/5 rod parts : page 21/3
1. 23.21.1.230.106 (Thrust Rod)
2. 23.21.1.230.440 (Felt Ring)
3. 23.21.1.230.962 (Thrust washer)
4. 23.21.1.230.961 (Ball bearing)
5. 23.21.1.230.107 (Thrust piece)
6. 21.52.1.020.109 (DT RG)
(this last piece shown below doesn't really count here):
7. 21.51.1.230.109 (Dustcover--is usually removed before taking out the tranny).
This parts book shows which way the pieces go in, which is nice.
The parts were quite dirty and I cleaned them off. I see on page 57 of my Haynes manual, it says "Rub hot grease into the felt". Hot grease? That's a new one for me. It that the only thing on this rod that I should grease or put oil on or whatever?
This manual also says "rod must be inserted from the flywheel end."
-Don- SSF, CA
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DonTom
Member
Yes, and now I wish I just let the little leak stay there. I wasn't expecting this much trouble.
Even though I have the tool to remove the flange, I don't think I want to even try again. I think my new rule will be to let somebody else do my trannys after I remove them. However, the shop isn't having any better luck than I did on removing this flange. And unlike me, they have done it countless times--this was my first attempt--figures!
I cleaned up the gear box & now it looks nice and shiny. I too wondered why it looked so funky, but I won't know anything for sure until I install it and put some miles on it. My main objective is to get the bike running well enough to ride it to Reno, my primary residence. Then I will have more room to work on it and such. As long as I can do that 225 mile ride, I will be happy, even if I have to tear the bike apart again when I get it there. Because of the weather, I probably won't ride it to Reno until spring is here.
First, I want to put 100 or so miles on it around here, to make sure it is ready for a longer trip. So there is no real hurry. But I don't want to try to rebuild this one too--and screw it up.
But another option is to let a shop tear it apart and check it out. I don't have any experience with trannys. This all started with a clutch job. I do have the clutch installed, which was my first clutch job ever on anything. But I cannot say it's complete until I put the bike back together. But so far, the clutch job seemed to go fairly smooth until I decided to fix the slight leak in the tranny gasket, which I now wish I never even thought about doing. If it were not for that, the bike would already be in Reno--most likely.
BTW, here is what that e-bay tranny looks like with most of the grease removed:
In the above, the dent to the left of the tranny input shaft, what could that be from?
-Don- SSF, CA
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DonTom
Member
I just now noticed the word "new". I guess I should order this along with all the other parts for a complete tranny rod so the spare too is ready to go. Where is a good place to order this stuff?
I have noticed in the past, it's a lot easier to find new parts for my 71 BMW than for my 84 Yamaha Venture. But is it still possible to get all this 71 BMW stuff new?
-Don- SSF, CA
DonTom
Member
I just now put the rod in with the old felt to see how everything goes together. The felt stayed and it never got all that tight when I pushed the rod all the way back. I assume a new felt will be much tighter.
However, you kinda make it sound like there's something to adjust. I don't see any choice of how far the rod will go in when all the six pieces are in. And even then, the rod can be removed all the way out from the input shaft. And when the rod is pushed in all the way from the "thrust piece" (rear of tranny) the tip from the input shaft goes out more than 6 mm. More like 15/32 or closer to 12mm.
So what am I not understanding here?
Or is it just the fact that it all gets very tight with a new felt and if too pushed in (such as flush with the input shaft), it's more difficult to put the clutch level on to the thrust piece?
As it is with the old pieces, it seems simple and rather obvious as there seems to only be one way it will all go together. Which probably means I am doing something wrong.
-Don- SSF, CA
Hot grease? That might make it slide a bit easier. Generally, you just lather it up with gear oil. The felt will be partially lubed with gear oil during running operation. But it never really gets that soaked, I don't think. The splash lube is what gets to the aft parts of the clutch mechanism...the races, the bearing, etc.
The new ebay stuff looks good...the forward tip doesn't appear to be worn at all which is good. Not sure about the felt, but you might to consider popping for a new one. The other, aft end, parts can be removed out the back of the transmission if in the future you think they need replacing.
The new ebay stuff looks good...the forward tip doesn't appear to be worn at all which is good. Not sure about the felt, but you might to consider popping for a new one. The other, aft end, parts can be removed out the back of the transmission if in the future you think they need replacing.
Don -
Maybe I should try to explain what I'm thinking by using extremes in positioning of the rod. If the rod sticks too far forward, you will have difficulty moving things around during installation of the tranny (a bit) and there would be no backend of the rod for the thrust piece to slide onto. If the rod were stuffed deep inside the input shaft, then too much of the aft end of the rod sticks out the back and the seal around the thrust piece wouldn't be inside the case and thus there could be leaks.
All that said, once the transmission is in and lightly bolted up, things should align themselves. The way you will be able to tell is if you install the thrust piece, no part of the seal should be showing. In fact the thrust piece shoulder should be flush with the transmission case opening. If you don't have that upon installation something is wrong.
My R25/2 presented a problem to me. The clutch rod is a bit different in that the forward tip is actually a square and fits into a square hole in the pressure plate. I noticed right away that the thrust piece wasn't anywhere near flush...that meant that I had not put the square rod into the square hole. That was a "fun" fix.
BTW...when installing the transmission, be sure and put a small dab of tacky grease on the end of the rod. It will have to spin against the moving pressure plate and the grease extends the life of the tip.
DonTom
Member
I just ordered a couple of new feltrings. But I won't be able to glue the bike back together until I get back to SSF, which might not be for a month or so.
I wonder if the shop will have my other tranny done by then . . .
I think I now understand what you mean about the position of the rod. It's only for when I put the tranny back on the bike--that was the part I wasn't clear on.
-Don- Reno, NV
if it was put on with red loctite, it will release but it needs to get to around 500F, which is smokin' hot. that will cook the seal, which is fine, you're replacing that anyway. the proper tapered shaft installation is both male and female mating surfaces completely cleaned with no-residue solvent and bone dry. sometimes a drip of gear oil will enter the taper area and cause slippage and hence a possible red loctite 'fix'.
as an aside, in addition to the BMW flange removal tool, a simple harmonic balancer puller works well using 2 grade 10.9 bolts (i think they were 8mm x 1.00mm). loosen the nut but keep it on as mentioned, add tension, pop the center bolt with a hammer.
-dan
as an aside, in addition to the BMW flange removal tool, a simple harmonic balancer puller works well using 2 grade 10.9 bolts (i think they were 8mm x 1.00mm). loosen the nut but keep it on as mentioned, add tension, pop the center bolt with a hammer.
-dan
nrpetersen
Curmudgeon
PGlaves
#13338
Quote OP from post #4 :
" I just remembered that my tranny has been opened once before by a BMW shop in SF in the early 80's. They installed a double roller bearing in place of the stock one that they say often breaks and leaves people stuck in one gear. They suggested this when the bike was in there for its first clutch job."
A professional job . So far all talk of red Loctite is merely speculation . I am curious tho ..
" I just remembered that my tranny has been opened once before by a BMW shop in SF in the early 80's. They installed a double roller bearing in place of the stock one that they say often breaks and leaves people stuck in one gear. They suggested this when the bike was in there for its first clutch job."
A professional job . So far all talk of red Loctite is merely speculation . I am curious tho ..
DonTom
Member
Here is an update:
I just now called the BMW shop in Mt. View, CA, where I have my R75/5 tranny. So far, they are into my tranny for $111.00. They said after they cut out the output flange to remove it, and looked in the tranny, they say it will cost me around a thousand bucks to fix up from here.
I told them to forget it, I will pick up the tranny and pay them the $111.00 for removing the output flange. I can buy another output flange on e-bay and at this point, I can buy the parts cheaper myself and then decide if I want to rebuild it. Or even have a BMW shop do it after I get the parts. I have seen the flange for sale on E-bay a couple of times.
So I will put on the tranny I bought in SF. Now, I am so glad that I did buy it! I can take my time rebuilding the other one myself. The hard part has already been done for my $111.00.
Maybe somebody here can give me some advice if I should work on this tranny myself, now that they have it open--or will I find I need a lot of special tools. Or what is the best way to handle this. I have never been inside of one of these before and I don't know what to expect on a rebuild.
But other than than little leak I had, it seemed to be fine, so I wonder if I really should do anything other than put it back together. The shop seems to think it needs a complete rebuild, but we didn't go into any detail. For now, I made up my mind that it ain't worth a thousand bucks to rebuild--or is it?
This tranny could still be better condition than the one I am putting in, for all I know. But when I am left stuck, I will worry about it then. I just hope I can get in ride-able enough to ride it from SSF to Reno by spring time.
Any advice on the best way for me to handle all this will be appreciated.
-Don- Reno, NV
I just now called the BMW shop in Mt. View, CA, where I have my R75/5 tranny. So far, they are into my tranny for $111.00. They said after they cut out the output flange to remove it, and looked in the tranny, they say it will cost me around a thousand bucks to fix up from here.
I told them to forget it, I will pick up the tranny and pay them the $111.00 for removing the output flange. I can buy another output flange on e-bay and at this point, I can buy the parts cheaper myself and then decide if I want to rebuild it. Or even have a BMW shop do it after I get the parts. I have seen the flange for sale on E-bay a couple of times.
So I will put on the tranny I bought in SF. Now, I am so glad that I did buy it! I can take my time rebuilding the other one myself. The hard part has already been done for my $111.00.
Maybe somebody here can give me some advice if I should work on this tranny myself, now that they have it open--or will I find I need a lot of special tools. Or what is the best way to handle this. I have never been inside of one of these before and I don't know what to expect on a rebuild.
But other than than little leak I had, it seemed to be fine, so I wonder if I really should do anything other than put it back together. The shop seems to think it needs a complete rebuild, but we didn't go into any detail. For now, I made up my mind that it ain't worth a thousand bucks to rebuild--or is it?
This tranny could still be better condition than the one I am putting in, for all I know. But when I am left stuck, I will worry about it then. I just hope I can get in ride-able enough to ride it from SSF to Reno by spring time.
Any advice on the best way for me to handle all this will be appreciated.
-Don- Reno, NV
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