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Removing engine/tranny from 74 R90/6 frame

dmftoy1

New member
Googling and searching and it looks to me like I need to take the tranny off and remove the jugs to make this easier. Since I'm doing pushrod seals who refurbishing everything it's no big deal to pull the jugs but in a perfect world I'd pull them later this winter while working that part of the project.

So what say you? At all viable to pull engine/tranny as single unit with jugs attached or am I just creating one of those "I can't believe how stupid I am stories"?

Thanks in advance for any advice/insight.
 
to make this easier.

Guess it depends on how you define easier ... pulling the engine isn't necessary to replace your push rod seals.

And you don't need to pull the jugs to remove the engine. If you're working alone, removing the transmission would lighten the load, but you don't need to pull the transmission off to get the eng/trans combination out of the frame (although pulling the swing arm would give you a little more maneuvering room).
 

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Well I'm going to have the frame powder coated so that's my primary motive. This is how far I've got it stripped. I can pick whole assembly up by myself but it's about at my limit. Was thinking of straps to rafters to suspend engine/tranny from and then dropping table a bit and maneuvering frame out and hanging off to side. ImageUploadedByTapatalk1347218233.438057.jpg
 
You have gone that far

I would secure the frame a little better, maybe a couple straps both up to those rafters and then down to the bench. pull your tranny, four fasteners after the air box is off and then pull the motor out with the jugs and heads still on. I personally would not pull the motor out with the tranny attached, in fact I would go a step further and block the crank shaft and yank the clutch and flywheel too because your going to want the rear main seal and oil pump O-ring replaced now instead of shortly after your maiden voyage after its all back together.

Its lighter this way and you cam protect the pistons and head assembly just in case you have one of those four hands would have been better than two deals happen. You also have fewer small parts to keep track of while the frame is redone.
 
So you'd replace rear main seal even with only 19k on motor? I'm all about doing it "right"
 
I've heard people install an engine/tranny into a frame on its side. With the engine firmly supported, it's easy to maneuver the frame over the engine and slip in the engine mount bolts. Then upright and finish.

It might be possible to reverse that and separate the frame from the engine while on its side. :dunno
 
Attached pic old fart with bad back lifts anything!
 

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That's pretty cool - are those just 2x4's making up that tripod? How are they attached at top?

Pulling tranny was really good suggestion and what I ended up doing was resting oil pan on wood blocks to pull engine mount bolts, carefully slide frame forward to clear nose of engine and then tilt it away from me, I was then able to lean into frame window and lift engine up/out. If I had to do it over again I'd have called the neighbor as two people would've made it a lot easier. :). (definitely a lot older than my mind thinks I am!!)


I wonder now if I need a new rear main seal, definitely some seepage from something at bottom of tranny where it bolts to engine.

Time to read the cylmers I guess.


Thanks for all the advice guys.

Have a good one,
Dave
 
I wonder now if I need a new rear main seal, definitely some seepage from something at bottom of tranny where it bolts to engine.

Since you're this far in, I would replace the rear main seal and the oil pump O-ring. Search the forum for these as there has been plenty of threads/discussion on the matter.
 
Since you're this far in, I would replace the rear main seal and the oil pump O-ring. Search the forum for these as there has been plenty of threads/discussion on the matter.
+1 :thumb And the tranny input shaft seal.

You said: "definitely some seepage from something at bottom of tranny where it bolts to engine."

The three primary sources of oil in the clutch area of an airhead:

Engine rear main seal -- drains down the rear crankcase wall.

Oil pump cover (directly under the crank, also hidden by the flywheel) -- drains down the rear crankcase wall, just doesn't have as far to go to reach the bottom.

Transmission input shaft seal -- drains down the front of the transmission.

Your description suggests an input seal leak, but I'd like to suggest carefully checking the seepage path/source. One clue: gear oil smells like sulphur; engine oil doesn't.
 
Plus a possible 4th source...gear oil runs past the felt seal on the aft end of the clutch push rod and runs forward through the middle of the input gear, to be deposited on the clutch disk. Most of the other oil leaks will have a hard time depositing oil on the clutch because the oil tends to drain down due to gravity and then out the small hole at the bottom onto the tranny shelf. But the oil down the pushrod can make its way easily to the disk.
 
+1 :thumb And the tranny input shaft seal.

You said: "definitely some seepage from something at bottom of tranny where it bolts to engine."

The three primary sources of oil in the clutch area of an airhead:

Engine rear main seal -- drains down the rear crankcase wall.

Oil pump cover (directly under the crank, also hidden by the flywheel) -- drains down the rear crankcase wall, just doesn't have as far to go to reach the bottom.

Transmission input shaft seal -- drains down the front of the transmission.

Your description suggests an input seal leak, but I'd like to suggest carefully checking the seepage path/source. One clue: gear oil smells like sulphur; engine oil doesn't.

+1 on all of the above, I just had to take everything apart to replace the clutch and lighten the flywheel and I knocked it all out "while I was in there" My bike has 39k, but it still has a 38 year old seal and the new teflon ones are superior. Even though I didn't have any signs of an oil pump leak or RMS leak, once I pulled the flywheel there was a little bit of weepage at the RMS. I did the tranny input shaft seal and it's kinda a pain, but you can do it if you're careful. that appears to be a newer teflon type as well (or at least my replacement differed from my old one).

Snowbum said something along the lines of drilling 1/32 holes around the input seal and then removing the inner portion, followed by the outer portion. In my case, it was difficult to drill the holes in the first place without slippage and when I did get enough holes in, it was very difficult to extract the seal from the case. I came up with another method- since the old input seal was approximately 1-2 mm proud of the trans. case and I took the smallest flat head screwdriver I could find and took a small hammer and used it on the outer diameter of the seal (and only the seal, DO NOT MAR THE TRANS CASE BY THE SEAL) to lightly collapse the seal inward where it could be easily extracted with needle nose pliers. Was simple to extract after that. The newer type seal seats nearly flush with the trans case so if you already have the newer type my method might not work for you

Something else to consider, I pulled my clutch pushrod and throwout bearing assembly for cleaning and the pushrod felt was completely missing off the rod. When I say pulled it out, I really mean the pushrod just fell out when I tilted the trans because it was lacking that felt seal - don't know when it came off, but I imagine it was consumed by the transmission at some point. I was really lucky that my clutch was shot from wear instead of oil migrating out the pushrod onto the clutch pack. You might also want to consider cleaning the throwout bearing assembly and replacing that felt as well. All this sounds like a lot of work but it's really not once you're already that deep into a disassembly.
 
For the life of me, I couldn't get my tranny input seal out using some of the techniques Snowbum mentioned. I had holes in my seal along with sheet metal screws...I devised a slide hammer to try and pull it out. I gave up and put the tranny in my car and drove to my dealer. He had them out in 15 seconds. He used a hook hammer/wrench of some kind. It has a very sharp point which he could slip into the holes I had drilled. Then he levered them out without damaging the case or input shaft. Best of all, he said "No Charge"! :thumb
 
That's pretty cool - are those just 2x4's

Image shows hoist frame details
 

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Very nice.

Ordered oil pump cover seal and rear main seal today. I'll do some fluid sniffing and then check input shaft seal. (is it a pretty common seal failure?)
 
Looks like an input shaft seal leak to me, don't know how common they leak but Snowbum makes it out to seem like you won't need to replace it until you're ready for a trans rebuilt. FWIW, when I did my rear main + oil pump, my trans input seal wasn't leaking at all, but I changed it as preventative maintenance while I had everything apart, and like I said earlier it seems like BMW updated the design of that seal sometime ago as well. Gear oil wreaks of sulfur and you would definitely be able to tell the difference from motor oil, enough of a whiff will make you feel sick
 
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