mboye wrote:It is suprisingly easy to remove the transmission from these bikes. I have some photos of the failed and new transmission if any one is intersted.
Surely yes !
Can you make a thread in How To section with your experience ? I think would be fantastic, thanks
Here goes then,
Whilst not and exhaustive description and without many assy photos I hope this helps
1: Get a manual/ CD as it will help and I consider essential. They are cheap.
2: remove fairing lower and side panels
3: support bike to remove rear wheel. I just use a trolley jack on the rhs of the bike on the frame near the foot peg. This is not an issue as there is not much weight on the rear end and most of the residual weight is taken up by the side stand. Make sure your jack is in better condition as mine as mine slowly lowered overnight and almost tipped the bike on the ground
4: remove wheel (I could do this without removing the muffler)
5: as per manual remove electrical connection plate and push aside water over flow bottle
6: disconnect the arm that goes to the rear drive unit and support the hub. (There is a detailed thread on here about how to do this, which I think is listed under changing rear drive oil)
7. Disconnect lower suspension bolt such that the swing arm can be pushed upward such that the drive shaft is almost horizontal.
8. Remove drive shaft
9. Remove all bolts on the clutch side cover and push cover to one side
10. You now need to hole the clutch basket whilst you undo the central nut. This is torqued to 200Nm and my pneumatic rattle gun would not remove. I had and old Yamaha clutch basket tool (basically like a big pair of vice grips) and put in between two holes in the star spring plate on the end of the clutch. Be careful as to what you use as you do not want to damage this spring plate but being spring steel it is quite hard.
11. Remove clutch basket and all spacers. You may find it hard to remove the basket as there is a tensioning gear on the back of the clutch basket so you have to rotate the basket anti clockwise whilst trying to pull clutch off shaft. You could do what I did and remove the gearbox from the other side prior to removing the basket but BEWARE. I did this and there is a spacer behind the oil pump drive gear. This dropped into the bottom of the engine at the base of #1 cylinder. Luckily I was using my brain when I put it back together as it did not look right and I had to fish around with a wire and found the spacer which was not in eyesight. This would have destroyed the engine.
12. Remove the gear linkage
13. Pushing the electrical and breather hoses away you can get to the top bolts of the gearbox. Remove them and work around the gearbox removing all 8 bolts.
14. One bolt is directly behind the rubber boot connecting the swingarm to the gearbox, so push that to one side. I did not have long torque bits but used my standard L shaped torque wrenches with a closed ended spanner.
15. At this point the transmission should easily slide out. Be careful not to catch any wires.
16. Changing selector forks (if required) requires removing plastic cover from side of the gearbox and removing one bolt, the others are taken out from the gear cluster side and the base plate rotated as it keys into the selector fork shafts.
Get a big oil pan as the bike will dump a lot of oil if you have not drained the oil first.
Putting this back together:
You are meant to use new gaskets on gearbox and clutch cover along with new al bolts on the clutch cover. I did this when I first pulled my gearbox out to realise the gears were rounded and the selector was damaged. I put this back together with a new selector fork hoping it would fix the issue but all it did was destroy another selector fork (even after less than 10 gear jump outs), Because the bike had probably only done 200km from last build I did not change these.
1: clean all surfaces
2. If you have not already done so remove the front driveshaft boot on the end of the swingarm as it will make it difficult to get the transmission in.
3. Inserting the gearbox is hard for 2 reasons. a) All the cables and hoses get in the way and B) the gasket slips of its dowels.
4. I used a piece of welding wire to move hoses and cables out of the way
5. Insert gearbox making sure that you have not pinched any cables. Get a torch and check all around.
6. when the gearbox is half in reach over and make sure the oil pump drive gear AND the spacer behind it are pushed on the shaft. If you push the gearbox all the way home you will not be able to get these on. I discovered this the hard way by bolting up the gearbox first.
7. Just prior to getting the transmission all the way in make sure the gasket is aligned. The first time I did this I used a few of the bolts to do this but after I had difficulties assembling the gearbox and pulled it outward again I lost a bolt. After much searching I found it, it had dropped into the swingarm, again out of sight and would have potentially wrecked the bike.
8. Put in all 8 bolts
9. Put on sleeve that clutch basket sits onto shaft, and slip on clutch basket.
10. To get the clutch basket on again rotate the clutch anti clockwise. This is fiddly. In the manual you are meant to use a special tool to try to align the mating gears. I had limited success with this as I did not have the right tool. If the gears are slightly out you will not be able to assemble. Be persistent and keep trying to rotate anti clockwise (there is enough engine compression to stop rotation). I also used a tap with the wooden end of a hammer.
11. make sure oil pump drive gear is aligned with the back of the clutch basket. You can do this by rotating the basket backward and forward whilst pushing in. You will know it is in the correct position because the main gear on the clutch basket is flush with the main crankshaft gear. If you were stupid like me and lost the spacer behind the gear in the engine you will notice the clutch sites too far in. The gears MUST be flush.
12. Undo crank sensor at front of engine at insert a cheap soft screwdriver and torque clutch nut up to 200Nm. I was very reluctant to do this the first time I removed the gearbox and tried using my clutch basket tool but trying to resist 200nm by yourself whilst also tightening is almost impossible. I was surprised how little force was actually applied to the screwdriver. As I was doing this by myself I had to slip a bit of wood under the screwdriver to ensure it was engaged with the gear. You could of course use the special bmw tool....
13. Put on new clutch side cover gasket and put in new bolts.
14. Push back in rubber boot at front of swing arm, use a bit of grease to aid in assembly. but do not push front flange all the way on to gearbox for reasons I will explain.
15. Put on gear lever, diagnostic plug or whatever it is for, water overflow.
16. When I first pulled out my gearbox I did not remove the lower suspension bolt and had huge issues getting the driveshaft back in
17. To help aid in driveshaft assembly (although this may not have been necessary with swingarm almost horizontal) take a piece of welding wire and thread it down the swingarm from the gearbox end. See photos
18. Bend the wire and insert into end of driveshaft. Grease driveshaft spline then slide driveshaft inside swingarm carefully pulling on the wire. This ensures that the drive shaft also remain relatively horizontal and slides straight in.
19. Wiggle driveshaft whilst moving up and down the swingarm and it should align with the gearbox.
20. Push rubber boot onto gearbox.
21. Assemble rear drive (as per other posts) although there is nothing tricky here.
22. Put in suspension bolt.
23. Put on wheel, muffler and fairings.
It sounds a lot when you write it but it is not that hard.
Below are picture of the old gearbox with slightly rounded corners on the gear, the new gearbox with under cut "dogs" and slots, destroyed shift forks, and some assembly pics.
pic 1, damaged selctor forks. By the end I had 3 of these, pic 2 old gearbox, if you look carefully you will see a slight radius at the top of each slot in the gear (this causes gears to spin out of place), pic 3, this shows how the locking plate keys into the selector fork axle, pic 4 old gearbox from the end (this is 4th/5th gear so is ok), pic 5/6 sshowing wire used to assemble driveshaft, pic 7 shows keeping driveshaft horizontal for driveshaft assembly and you can just see trolley jack on other side of bike to hold it up, pic 8/9 shows where some of the bolts are that hold in the gearbox, pic 10 another pic of ruined selector fork, pic 11 this picture clearly shows how the pegs of the gear have been rounded off, pic 12 two gearboxes, pic 13 new gearbox with under cut pegs
Feel free to send me a message if you want more info.