hi folks , after seeing a smilar post about movement in the bevel box ...i guess back wheel can be rotated quite a few degrees before taking up in either direction . i started to worry some, when the first responce was "there should be no movement"

wilkir suggested ...check the splines (makes sence)

hmm ..... so i pulled it all apart a few minutes ago and my splines are great .

but ..i see 2 problems
1>.there is a lot of lateral movement of the pinion wheel ...ie: it moves about 1/8th (2 mm ) in and out along the axis of the driveshaft
2> there is lots of backlash when turning the drive shaft with the gearbox in gear ....certainly worth a hard thinking about

thankfully i dont see leaking seals at the final drive to indicate that the output shaft bearings are had it ....and when attempting to rotate the pinion the lack of free play and nice mesh feel indicates a good fit of the crown to pinion, although there is some final gear noise when riding on the road (clutch pulled in)

yes there is a metalic slime around the speedo sensor ,,,and yes there were slivers of metal in the magnetic oil drain at the first change of oils after taking posession

so im thinking new bearing on the pinion and some shims to take up the movement (as the locking bolt was still tight as ), or is this bearing a conical one and prone to some movement anyhow .?

but the gearbox has got me foxed for the moment ...i havent read up on the backlash specs ...but im interested if any of our friends have experienced this before .?

First things first - there should definitley be no axial movement possible for the bevel drive pinion shaft. This gear arrangement is known as a spiral bevel, they are among the highest precision gear sets in the engineering world. Pinion bearings may be ok, but the shims or adjustment nut may have backed off ?? That said, setting them up correctly in respect to both backlash and correct tooth contact pattern to ensure silent operation is a very precise exercise and to the untrained punter it will normally be impossible to get right.
As for the backlash through the gearbox, this will amount to a visible movement (backlash)at the wheel, as we are talking about gears on spline shafts, diving dogs etc, as well as the clutch on a spline and the 2 splines for the drive shaft, so yes, there will be considerable backlash. Maybe we should all do a standard test, like - all place the bike on the centre stand, select first gear, push the rear tyre in 1 direction and make a mark on the circumference against a referenc pointer of piece of timber, then push the tyre around in the opposite direction till resistance is felt and mark off agaist the pointer. Interesting to know the range of measurements.

I'll have a go: using your technique mine has 42mm of movement between 'stops'. I re-checked this morning after noting that everyone else's measurement was considerably more freeplay than mine. I'd not measured accurately and drew a line on the garage floor, then another and used a straight-edge to verify it. The result has been edited from 22mm. Still, not bad in comparo.

Hell !!!, just checked mine (used a tape measure resting on the floor and locked extended), I've got 63 mm, and I know my splines are all good, so the backlash must all be in the gearbox.
Also need to remember that if the engine output shaft has loose rivets there can be a considerable amount (of backlash) there, though in early stages it can be felt a higher resistance till they get real loose.

hhmmm sort of what i thought dennis thanks for that .

ive just checked the haynes manual and found it to be a roller bearing ...and with a adjustment nut on the outer section to clamp it home ....there maybe hope yet ----just have to find the tightening tool .....or build one

i just did your measurement too dennis ,,,mine was 52mm

really hard to guess what that value is to be expected ,so many variables involved with older bikes i guess ...but after seeing twb's result ...maybe we have an optimal value to guage from

trust twb to have a "tight one " heheheh

^5s you guys

Mine has 70mm.

charlie99 wrote:hi folks , after seeing a smilar post about movement in the bevel box ...i guess back wheel can be rotated quite a few degrees before taking up in either direction . i started to worry some, when the first responce was "there should be no movement"

wilkir suggested ...check the splines (makes sence)

hmm ..... so i pulled it all apart a few minutes ago and my splines are great .

but ..i see 2 problems
1>.there is a lot of lateral movement of the pinion wheel ...ie: it moves about 1/8th (2 mm ) in and out along the axis of the driveshaft
2> there is lots of backlash when turning the drive shaft with the gearbox in gear ....certainly worth a hard thinking about

thankfully i dont see leaking seals at the final drive to indicate that the output shaft bearings are had it ....and when attempting to rotate the pinion the lack of free play and nice mesh feel indicates a good fit of the crown to pinion, although there is some final gear noise when riding on the road (clutch pulled in)

yes there is a metalic slime around the speedo sensor ,,,and yes there were slivers of metal in the magnetic oil drain at the first change of oils after taking posession

so im thinking new bearing on the pinion and some shims to take up the movement (as the locking bolt was still tight as ), or is this bearing a conical one and prone to some movement anyhow .?

but the gearbox has got me foxed for the moment ...i havent read up on the backlash specs ...but im interested if any of our friends have experienced this before .?

That indicates to me what is termed in the engineering game as "shagged and in need of repair". You can't tighten the retaining nut as that just makes a worse mesh with the crown as it moves the pinion futher away and most likely puts more strain on an already damaged bearing.
You say slivers of metal on the magnetic bung and I say in need of attention. I would not use it till it is rectified as serious damage will result if it has not already happened.

The gear box will have heaps of movement as the engage dogs usually have 12 to 15 degrees of movement before taking up in the opposite direction.
Also there will always be a couple of degrees movement in the sprung shock absorber in side the box. There can be quite a bit of movement from input to output shaft without needing to be concerned. But that bevel needs attention.

I just measured the backlash at the back wheel and get 50mm.

K Freak wrote:
That indicates to me what is termed in the engineering game as "shagged and in need of repair". You can't tighten the retaining nut as that just makes a worse mesh with the crown as it moves the pinion futher away and most likely puts more strain on an already damaged bearing.

If I recall correctly, The bearing #5 has 2 rows of balls and the lateral play is set by modifying the thickness of the spacer #6. If the retaining nut #3 is slacked , you will get the lateral play. This nut is hard to tight. You can safely slack it off to pull the shaft assembly and check the bearing. You will have to warm up the casing of the final drive to break the loctite seal on the thread. BMW uses Loctite 577. As noted earlier, you should not change the thickness of the spacer unless you know what you are doing. Check chapter 11 of the Clymer manual.

Here is the tool I made to remove the nut. This is a 2.5" diameter pipe with thick wall.

Yeah I stand corrected I had the picture of the Z1300 Kawasaki drive in my mind but it still needs repair if the axial movement is 2mm. The ball race is worn out
As soon as power is applied the gears wont align correctly and rapid degeneretion is the only path.

Crazy Frog wrote:I just measured the backlash at the back wheel and get 50mm.

read my mind bert ....i had considered the nut on the pinion ,,,,,but as said it will just drag it away from the crown wheel
i didnt get time to test the looseness of the bearing locking ring , as that seems to be the only adjustment for moveing the assembly closer to the crown ...i checked the parts sites and found many listings of the different spacer shims ...so assesed i was on the right line of thinking .

the the bearing i think is 65.5mm outside diameter so i was thinking a 60mm (id) bit of pipe would fitt in there ....and presto you made what i had thought of ...(can't borrow it, could i ?....grin )

ill let you know what happens when i get back to it next weekend ...but i have a seriously fun ride planned on wednesday with twb and clubc

yes i know its on its last legs and it is a risk (thanks for the heads up k freak ).....but judging by the maintenance schedule of the last owner its been like that for many years.. and after changing the oil on this discovery i found no new slivers of metal.

i was thinking that all that lateral movement wouldnt be happening with the drive shaft in place and weight on the rear end ,,,well not all of it anyhow ...i figure that the splines would be putting some presure back on the pinion holding it in a little ,....but by removing the (lets call it preload) the assembly from load and free to move ..i think im seeing the full movement axially , but thankfully zero movement in any other direction .

not being an agressive rider i recon i can baby it till next weekend at least .



hmm 50 mm bert

lets see thats a 42,50,52,66,70 (thanks ulrich )
im guessing the average will work out to be in the 50 mm area
maybe next weekend i can amend my measurement ( i hope it isnt bigger ...lol )
thanks for the replys guys .......

hey k freak are you up for the measurement as well ?....its pretty simple ...im not judging, im just getting a feel for what should be right

Just measured the critter and 62mm OD (you could go to 63.5 which is 2 1/2 in) and 55mm max ID with 4x6mm wide tangs evenly spaced and that should get the thing out.

Are you still going to meet at the pie shop at Yatla on Wednesday I was wondering if I could join you. I won't be offended if you say no.

K Freak wrote:Just measured the critter and 62mm OD (you could go to 63.5 which is 2 1/2 in) and 55mm max ID with 4x6mm wide tangs evenly spaced and that should get the thing out.

Are you still going to meet at the pie shop at Yatla on Wednesday I was wondering if I could join you. I won't be offended if you say no.

hey mate ...you would be welcome ,,,,woohooo ....i think club c would be blown out to see more of our friends

in actuall fact i think he is a bit eagar to explore and meet as many as possible ...he has pushed the start time an hour forward (eagar beever )

so for now i think its a 11-00 ish start from yatla ....please join us

OK I shall look forward to meeting you. Mob No is 0427 833 320 just in case of a change of plan.

What ratio is your drive, I have a few here but not sure if I have one for an RS. I think it would be a 12/33.
You would be welcome to one if you need it.

ok cool ...thanks mate ,,,im guessing that has you with several hours travelling to the meet point ..."what a star" !!!!

its an rt kfreak i havent counted the teeth yet ...heheh .....wasnt there a 13-32 or something ...the only reference i have at this time is that the tacho and speedo match in top gear .


btw thats a verry generous offer to help out ...thank you ...i really dont know what they are worth ,,,but i am willing to pay my way

but lets see if there is life in that mesh of gears and stuff ...huh ?

I got it with a heap of stuff that was going to the dump so it owes me nothing and I grabed it because I just couldn't stand to see it on the tip.

Amongst it was a set of three spoke RS wheels and a paralever rear drive which I wouldn't give away and two K100 engines of unknown condition but good for some parts.

omg good find .......you should change your name to "lucky" ....

makes plans to find this magic "tip"

If the wheels are still available I'd consider them. We can talk tomorrow. See you at Yatala.

Mine measures 41mm

cool chris thanks for adding .....

I checked mine today and it is 50mm +- 5 and I know that the gearbox is the only place there would be anything more than a couple of thou play.

good one kfreak thanks for the reply

Two Wheels Better wrote:If the wheels are still available I'd consider them. We can talk tomorrow. See you at Yatala.

In a word NO they are going on my newly acquired K1100LT and the three spokes of that are going on the K75.

thought i had a solution exchange drives ......thanks k freak .
its got a good feel to it .
but i didnt think to look mine is a 16 spline model and the replacement is a 20 ....oh well back to the drawing boards

got some 2.5 inch pipe ...and measured the lip of the drive housing (pinion feed end ) and found the top of the retainer about 12 mm down ....the other unit is about 14mm ...
more to come

Crazy Frog wrote:I just measured the backlash at the back wheel and get 50mm.

K Freak wrote:
That indicates to me what is termed in the engineering game as "shagged and in need of repair".  You can't tighten the retaining nut as that just makes a worse mesh with the crown as it moves the pinion futher away and most likely puts more strain on an already damaged bearing.

If I recall correctly, The bearing #5 has 2 rows of balls and the lateral play is set by modifying the thickness of the spacer #6. If the retaining nut #3 is slacked , you will get the lateral play. This nut is hard to tight. You can safely slack it off to pull the shaft assembly and check the bearing. You will have to warm up the casing of the final drive to break the loctite seal on the thread. BMW uses Loctite 577. As noted earlier, you should not change the thickness of the spacer unless you know what you are doing. Check chapter 11 of the Clymer manual.

Here is the tool I made to remove the nut. This is a 2.5" diameter pipe with thick wall.

Hi all.  I'm just stripping down my K75 conic drive, which has considerable axial play, to see what's up.  I'm just warming it up again to get the double bearing out.

So far it seems a little different from the exploded diag. shown above. The big bearing looks like rollers and there was a ball bearing with a plastic cage and 14 balls which fell out on the floor. It looks a bit like a head stock bearing with individual ball race on either side.  Is there more than one form of this assembly?

Thanks.

[ Hmm, this looks like some kind of hybrid roller + ball bearing, with no identifying marks. The roller has a lip on bevel gear side and the roller part has independent rings either side of the ball cage. I've never seen anything like this before.
 ]

Beamer wrote:So far it seems a little different from the exploded diag. shown above. The big bearing looks like rollers and there was a ball bearing with a plastic cage and 14 balls which fell out on the floor. It looks a bit like a head stock bearing with individual ball race on either side.  Is there more than one form of this assembly?

There could be. My experience tells me diagrams in parts fiches don't change regardless of modifications made to parts in one model. The bearing in the attached photo supercedes a previous version of #5 according to MaxBMW's parts fiche.

That's it . Many thanks.

Does anyone know the spec for axial float.  I'd imagine it's about what you'd expect from any ball bearing of this size. Mine seems rather "floaty".

I daren't try to find the price of replacement. Looks like 250 euro-bucks to me.