DRIVE SPLINE WEAR

[Andrewsteward]

I have just changed out my rear tyre and to me it looks like my drive spline is fairly worn.
It measures 1.2mm across the top of the spline.
What is the process in changing out? Am guessing a pres fit on the crown wheel? :-/
Also what further essential parts to order. Am feeling a can o worms coming on!!

[Tony Smith]

I've seen a lot worse - yours are not in need of immediate replacement, but I would obtain a quantity of the correct lubricant and start using it - the correct lubricant, applied every time the wheel comes off, will greatly slow the wear process.
 
Were I you, I would be deciding which method of spline repair I was going to use and start purchasing components and putting money aside for that day.
 
At the risk of being a little redundant, my preferred method is to buy a new set of splines from Motobins (Part No.55551 GBP85.00) and a new spline cup for the wheel (Part No.59454 CBP86.00). I would not buy the rivets from them as I have no way to set the rivets, I would be buying shoulder bolts from Aircraft Spruce & Specialty (refer Snowbum's usual insomnia curing treatise on the topic). There is no point is replacing the splines without also replacing the spline cup, if you do not you will experience rapid wear.

[montmil]

You still have some "flat tops" on the splines. After proper cleaning of both the drive and driven splines, I suggest the easily obtained Honda Moly-60 be utilized as a lubricant. A light coating on all surfaces is sufficient. Use too much grease and the excess will be squeezed out and contaminate brake shoes n' drums. Same procedure needed for the clutch splines. Both areas can be pricey for repairs.

[Bob_Roller]

I don't know if this available in your corner of the world, but I've seen shops repair the splines .
A bead of metal is welded to the existing splines and then machined down .

[Tony Smith]

I don't know if this available in your corner of the world, but I've seen shops repair the splines .
A bead of metal is welded to the existing splines and then machined down .

Bob, in principle I am in favour of the weld repair method, with caveats. Firstly you need a special type of welding rod, the "gold" standard is one developed by Caterpillar for the express purpose of building up drive splines. then you need someone who can weld to a very high standard and lastly you need a machinist to machine the welded splines back to original dimensions.

Unless you own the machine tools required, or can weld yourself, or are lucky enough to live within the catchment area of a shop that is set up to do spline repair on a regular basis, sadly replacement is the economic option as paying a per hour rate for the welding and machining rapidly overtakes the cost of outright replacement. And yes I am aware that few shops are prepared to press out the old drive cylinder and that most will cut the old splines off and weld the new ones on - but this is a far more straight forward operation than individually welding up all the splines using a special rod.  

[montmil]

I don't know if this available in your corner of the world, but I've seen shops repair the splines .
A bead of metal is welded to the existing splines and then machined down .

After first grinding away the weld bead and pressing the spline gear out of the crown gear. As you might imagine, any freshly welded on and machine splines must match up correctly with the splines on the rear wheel.

A few months ago, I assisted a friend in getting a new spline drive installed in his R100/7 crown gear. Same as above: grind away the weld, press old out and new in, then weld. The rear wheel had been replaced just prior to the bike being sold to my buddy. Those splines were as new.

This is the worn out spline gear from the final drive case. Splines were nothing more than "pointy nubs". For comparison, note the remaining splines where the wheel's splines were not engaged.



New spine gear pressed in and welded by Bud Provin's shop. $470.00USD not inc freight both ways.



Airhead David handled the removal of every speck of old gasket material from multiple surfaces. "Nope. Not clean enough. Keep after it." New drive splines and crown gear await.

[Bob_Roller]

I don't know if this available in your corner of the world, but I've seen shops repair the splines .
A bead of metal is welded to the existing splines and then machined down .

Bob, in principle I am in favour of the weld repair method, with caveats. Firstly you need a special type of welding rod, the "gold" standard is one developed by Caterpillar for the express purpose of building up drive splines. then you need someone who can weld to a very high standard and lastly you need a machinist to machine the welded splines back to original dimensions.

Unless you own the machine tools required, or can weld yourself, or are lucky enough to live within the catchment area of a shop that is set up to do spline repair on a regular basis, sadly replacement is the economic option as paying a per hour rate for the welding and machining rapidly overtakes the cost of outright replacement. And yes I am aware that few shops are prepared to press out the old drive cylinder and that most will cut the old splines off and weld the new ones on - but this is a far more straight forward operation than individually welding up all the splines using a special rod.  

There is a shop in the northwest part of the US, Oregon, that does this repair using the specified rod that Catepillar uses, last time I looked, it was around $200US .

[Tony Smith]

There is a shop in the northwest part of the US, Oregon, that does this repair using the specified rod that Catepillar uses, last time I looked, it was around $200US .

I would be very interested in their details and I am amazed if they do the job for that price as I would have thought there was an hour or so of precision welding followed by at least the same amount of time setting up a mill / slotter / shaper and machining the splines. If they can do a quality repair for $200US it would be serious worth my while to send some worn final drives to them form Australlia.

[Ed Miller]

http://www.hansensmc.com/repair-your-bmw-ducati-or-triumph-with-certified-technicians--service

I don't know their prices.  They're about a 4 hour ride down I5 from me.  

Edit:  but it seems like almost everything I've had to have done with mine is about a thousand bucks.  

[Luca]

It's also possible to score some good parts of used equipment if you're patient.

I was given an LS rear wheel by a guy who went over a curb with his (new at the time) LS.  The rim is banged up badly and practically useless... but its got a near virgin set of splines on it that I'm keeping as spares.

[Andrewsteward]

Hey guys, thanks for the input. I will source some grease and squeeze some life out of it.
Thanks Tony for the part numbers and advice.
Thanks Montmill for those pics. legend.
I have a few clunks going on, so I thought this would be a start. I will keep riding it kindly and start sourcing. Am guessing I also have some worn Transmission parts in there too.
Thanks again all, you have been very kind once again with your wisdom and knowledge

[montmil]

Clunks in an Airhead gearbox? OMG!  

Shifting gears on an Airhead is a learned experience. If we are all honest, I believe each of us has "busted a shift" on occasion. With practice and understanding, it's really not a big ol' box o' rocks.

A few things to keep in mind:
 Â   That big, relatively heavy flywheel and clutch assembly is way different from your average Rice bike.
 Â   The gap from 1st gear to 2nd gear is much like driving from Brownsville to Amarillo TX... a long way.
 Â   Matching engine revs to road speed in the selected gear is much of an art form. Practice matching revs.
 Â   Pre-loading the shift lever and holding the lever up after shifting is helpful -especially that 1st to 2nd shift.
 Â   Be positive with every shift. A lazy foot will always find that false neutral.
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[Andrewsteward]

Thanks for that, great advice. Its actually when Im taking off though that I get a clunk and its just after I start moving.