Airhead Gearboxes

[Voyager]

Padmei,

A word to the wise . . If you are replacing the roller bearing on the Input shaft beware; our favourite suppliers now seem to be selling bearings with nylon cages instead of the more robust bronze ones.

These things can melt when you heat the case to put the shafts back in (DAMHIK ) - Its £90.00 down the swanee if you're not careful.

As Rob says - the cases have to be really hot to get the bearings in and out.

Bob.

 

[Padmei]

Thanks guys. I may need a full on gas set to get sufficient heat.

I have done a bit of a writeup on my build thread about it here

http://advrider.com/forums/showthread.php?t=609828&page=84

I'd welcome any advice re conditions of parts & if you see anything that may need attention. It starts halfway down the page. Please ignore any other modifications you may see

 

[Rob Farmer]

That's a nice write up. It all looks pretty good in there the only thing I can see is the input shaft splines are worn. Probably not enough to warrant replacing the shaft yet but may be worth looking out for a replacement for the future.

Take the oil baffle plate out before you try and pull the shaft out. There's only the one screw in the top of the case but the other end sits on top of the bearing. If you yank the shaft out with it in place you will bend the plate.

 

[Padmei]

Thanks will do- I was wondering about that too.

 

[Voyager]

Its all nice and clean in there .

You should see some of them

Bob.

 

[Padmei]

I've got my box down at the engineers to get the circlip groove cut in & while it's there they may as well replace the bearings for me as I don't have a press & it would only take them 5 mins anyway.

I have a piece of string question.
It seems i will have to buy some shims from motoworks, however I need to have the shim plate set up etc before I know which size to buy. I was wondering if there is a particular sized shim that you learned fellows have found to be more common than not when reshimming. If would save me having to wait between measuring & getting my order shipped from Blighty over the holiday season.

 

[Voyager]

I have a piece of string question.
It seems i will have to buy some shims from motoworks, however I need to have the shim plate set up etc before I know which size to buy. I was wondering if there is a particular sized shim that you learned fellows have found to be more common than not when reshimming. If would save me having to wait between measuring & getting my order shipped from Blighty over the holiday season.

Hmmmmm, Not really.

You will need a mixture of sizes to get the minimum number of shims for each bearing. There are only four sizes to choose from.

Also, measure the stack of shims that you think you require before fitting - you will find that the total is different to the sum of the parts . I keep trying different combinations until I get the correct thickness as measured with a micrometer.

They are not expensive so I just bought 6 (?) of each before I started. I now have four bags of them .

There is more to this than just ordering the correct nominal sizes as they are not consistent (maybe I'm just a bit anal about the accuracy ).

Hopefully someone Down Under will relieve you of any spares when you have finished .

Bob.

 

[Rob Farmer]

The sizing is a real problem. Despite their only being a supposed limited number of sizes I have a large collection of around 15 variations all around the nominal sizes. As Bob says put the stack together and measure again.

Dan at Cycleworks does a variety of unique shim sizes http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_41_45_47&products_id=183

 

[Padmei]

Cheers Guys. I think I'll wait & see.

 

[cookie]

anyone got any good ideas how to get the input shaft bearing bush off without using a factory tool?

none of my pullers seem to want to play ball. guess i'll have to buy a bearing seperator small enough to fit

 

[Voyager]

anyone got any good ideas how to get the input shaft bearing bush off without using a factory tool?

none of my pullers seem to want to play ball. guess i'll have to buy a bearing seperator small enough to fit

I use a bearing splitter and I've turned-up a 'dolly' that fits into the end of the shaft. This allows the threaded end of the splitter to bear on the conical hole in the dolly instead of chewing-up the end of the thread and the shaft.

The outer diameter of the 'dolly' is such that the top hat fitting passes over it.

I have made a few 'special' inserts to prevent damaging the gearbox parts or the tools when separating bearings and so on.

Bob.

 

[cookie]

cheers

i found an M8 cap head that seemed a loose but tolerable substitute for a custom made dolly.

mind you, i've not got a puller to stay put behind the top hat bush yet

 

[Voyager]

cheers, mind you, i've not got a puller to stay put behind the top hat bush yet

I use one of these - it does the job:

http://www.machinemart.co.uk/shop/product/details/cht253-mechanical-bearing-separator-?da=1&TC=SRC-bearing+splitter

I also have an enormous Sykes hydraulic splitter for the serious jobs, I used to use that for drawing the drive flange off until I acquired the pukka puller.

Bob.

 

[DrFarkoff]

I have the Sealey one of those and they are superb for those tight to get at places

I use one of these - it does the job:

http://www.machinemart.co.uk/shop/p...aring-separator-?da=1&TC=SRC-bearing+splitter

I also have an enormous Sykes hydraulic splitter for the serious jobs, I used to use that for drawing the drive flange off until I acquired the pukka puller.

Bob.

 

[Padmei]

As a follow up I had my gearbox circlipped, shimmed & reassembled by some local engineers & mechanic & runs nice now. Thanks for your help Bob & Rob.

 

[Rob Farmer]

cheers

i found an M8 cap head that seemed a loose but tolerable substitute for a custom made dolly.

mind you, i've not got a puller to stay put behind the top hat bush yet

I use a small bearing splitter with the flats facing upwards and a home made dolly for the puller to press on.

 

[cookie]

i bought a cheap bearing splitter off ebay and used an M8 cap head for a dolly and the bush came straight off

 

[Padmei]

Kia Ora my lil English friends.

A few weeks ago I went on a 2500km trip on Schmidt with some other airheads. The bike went flawlessly- didn't miss a beat the whole weekend.
On arrival back home I stopped at the letterbox, got the mail, put it in 1st gear & unbelievably after 5metres there was a weird lurching& whumping sound from the bike.

i went for a cruise on it today & worked out it is only happening in 1st gear. I get the feeling it is slipping in & out of gear.

if you recall this time last year I got the bearings replaced & reassembled. The gears looked ok & I have put bugger all kms on the bike. Any ideas what it could be? I have a spare old box to put on but am I looking at having to open this box up again to get it checked out?

PS it's hot & sunny over here at the mo & lots of bike trips are being planned

 

[DrFarkoff]

Before you do much else drain the oil from the box and see what you get out maybe its nipped a tooth off

 

[Packer]

Drive shaft shock absorber slipping? Broken spring on same?