How Bad is This

[MickDB1]

Hey up GS 100 gearbox Q
On me way down back from Scotland ( Pre 65 Trial ) I had a rumble on me pegs then it stopped for a while then intermittant rumble
On M18 after a good bit of thrashing down A1M I had a allmighty gggrrrrratinnnggggggggggggg pulled clutch in and coasted down hard shoulder I was thinking of all the threads Ive read on here and what it was

Knocked it down to forth gear and it rode home at 60 with more noise
if third was selected awhine and a half emmitted
I quess its half knackered maybe full knackered but I am thinking after dropping oil and seeing not as much steel as I expected gould I just have lost a bearing or two and gears have come out of mesh / slight damage to teeth
Or what do you lot recon has anyone had it happen to them and what was the final diagnosis
I know I should have stopped - but I didn't - does anyone
Mick

 

[Voyager]

It sounds as though a bearing has gone.

I bought a spare gearbox that had suffered some catastrophic bearing failures - the output drive flange had distorted the sleeve that the rubber gaiter fits around and one of the output shaft gears had machined metal off the inside of the gearbox casing.

However its all back together now and works fine

There are a few people on this site who could strip the box for you and give you an honest opinion on its condition.

A full rebuild - all bearings, springs and seals costs around £150 (that's just the parts).

If you need to replace some gear pinions, selector forks and cam plates as well you can probably double that price and more.

Then there is the famous "Circlip Mod" which is probably worth doing as well (if your output shaft doesn't already have a circlip).

Rob Farmer is the Guru bow ) (but he's busy so might point you in my direction ).

Bob.

 

[Rob Farmer]

Rob Farmer is the Guru bow ) (but he's busy so might point you in my direction ).

Nice try Bob but you don't get out of cherry picking the easy ones that easily

I think it's about time you became our resident airhead gearbox man

 

[Voyager]

Anyone would think that I was looking for work.

I have a tractor in bits I'll have you know


Mick - Is this your bike (seen in Kinlochleven, near the start on Friday 1st May) ??

That's my 'Bumble Bee' in the background .

(LOVE that Matchless ).

Happy to take on another gearbox job (at cost) if there's a need

Bob.

 

[MickDB1]

No mate sorry that bike is a guy called George Gorden from Lancs. - good lad great rider - done some rallys here and abroad
I did speak to him at the scotish - he said the bike had a wireing fault a few weeks ago and bike caught fire - then he told me the bloody thing went out !!!!

I think saw your bike I think in Kinlochleven - Mine was the red and white one with the back box on - I saw another newer one on the camp site
Did you see that black r900 special with a XT front end on it George seen the lad who was riding it and said it dint cost a fortune either looked like a bike I could love
Shame we didnt get to meet
Jaber was with me and we are deffinately doing it next year
Had a natter to loads of folk at the Trial
Makes you wish you hadnt sold some of yer old bikes dont it !!!

Thanks for the info
My box has slight damage to the ally surface which the rubber gater clips around - its cracked but only on the shoulder some liquid metal will seal it from dirt ingress
Me "new old" box is coming next week I would like to keep the kickstarter one as a learner / do up /practice on

We aught to have a Airhead meet up at the next Trils next year
I probebly should have posted my/our attendace up there
Wasn't it good though

Mick

 

[Voyager]

Did you see that black r900 special with a XT front end on it George seen the lad who was riding it and said it dint cost a fortune either looked like a bike I could love

We aught to have a Airhead meet up at the next Trils next year
I probebly should have posted my/our attendace up there
Wasn't it good though

Mick

Mick,

You mean this one . . . .

I spoke to the owner, seems he converted it a long time ago. It sounded great


I saw two GSPDs at the Campsite (one red, the other green).

My neighbour was on his '84 80 GSPD, we were staying at The Tailrace Inn (met up with Tim Britton and his wife there - he's a decent sort, I have spoken to him a few times. He now edits Old Bike Mart).

I think I saw your bike, but didn't get a picture.

We could arrange an 'Airhead Meet' next year


Bob.

 

[(RIP) pastyman]

Just getting this thread back on track

After I bought my Bertha, me and the lads had a bit of a thrash down from Kettering to Gloucester when they left me to trundle back to Cornwall. On the A30 mine started to sound just like you described. After a stop to check things out I continued usind fourth gear only to get home. I decided to get the box out and do it myself, ( cant be too hard can it). The output shaft was completely cream crackered. I replaced all the bearings and a visual check showed no other signs of damage. not to take anything from the experts here but taken slowly and carefully its not too bad a job Its been a couple of years now and no further problems and its a very smooth box even with nearly 100K on the clock. Oh and I'm no mechanic.
Give it a go.

 

[Voyager]

After I bought my Bertha, me and the lads had a bit of a thrash down from Kettering to Gloucester when they left me to trundle back to Cornwall. On the A30 mine started to sound just like you described.
I decided to get the box out and do it myself, ( cant be too hard can it). The output shaft was completely cream crackered.

Did you discover why it failed ??

I assume that Bertha is a 100GS and that your Output shaft doesn't have a circlip at the front ??

The usual culprit is the output shaft shifting in the front bearing (probably due to the helical drive from the intermediate gear when giving it some welly) and producing side loading on the bearings.

You're right, they are not difficult to work on but it helps to have a couple of specialist tools and to shim the shafts to as close to 0.05mm as you can get.

Glad to hear its still going strong


Bob.

 

[MickDB1]

Love it

love it

This site has to be the best ever
Allmost to a man all as helpfull as can be - If your unlucky enough not to know - You can ask and someone will help = If your unsure - confidance will be given - everyone has dropped the odd bollock - thats one of the three ways to learn The others being - to pay to learn - or to ask, then listen
no one does the last untill they have done one or both the others
I try to help as much as I can - to help repay the generosity of the lads and lasses on here
Pastyman thats just what I needed - I am off to me shed -

I have had an offer of help as well - I will oviously take it and will learn from it for sure

I know I need a flange holder to fix to the output to undo the retaining nut -I will make one of them today before the race starts

Thanks again - I aught to may that my ste name in stead of Mickdb1

 

[Flipfly]

Mick, pastyman is my dad. You've seen my spannering skills, I learnt everything I know from him, says it all really

get ya sen in that garage and fiddle away fella, ya know ya love getting ya mitts dirty.

Dak is back on the road fella, knobblies will be fitted next week

 

[shafted]

Mick,

You mean this one . . . .

That is one sweet motorcycle. Lot's of subtle change's. I like it alot.

Safe riding Karl.

 

[Mick13]

Superb work on this scrambler

 

[pooh]

Any pictures of the other side of that or who made the pipes.....Cos thats as near as dammit what mine looks like.....Ho hum beaten to it again

 

[(RIP) pastyman]

Love it

love it

This site has to be the best ever
Allmost to a man all as helpfull as can be - If your unlucky enough not to know - You can ask and someone will help = If your unsure - confidance will be given - everyone has dropped the odd bollock - thats one of the three ways to learn The others being - to pay to learn - or to ask, then listen
no one does the last untill they have done one or both the others
I try to help as much as I can - to help repay the generosity of the lads and lasses on here
Pastyman thats just what I needed - I am off to me shed -

I have had an offer of help as well - I will oviously take it and will learn from it for sure

I know I need a flange holder to fix to the output to undo the retaining nut -I will make one of them today before the race starts

Thanks again - I aught to may that my ste name in stead of Mickdb1

Glad to be of help.. \if youy are going to make a tool to hold the flange , be careful that it does'nt come into contact with the little extentions on the back of the box that hold the lever for the clutch pushrod( have I described that properly).. I managed to break one off. Very expensive to replace the rear of the gearbox but I managed to have it welded.
Ive no idea what caused it to fail, proably old age, Its done just short of 100000 miles and we had been giving it a bit of stick.
Take yer time and have fun, as you say plenty of advice on here

 

[MickDB1]

Made that flange lock spanner = no problems got me nut off easy
the flange puller is another story
Made one sat a ball bearing in the recess on shaft and tried to Jackit off = no chance
Any super tips - I have left it overnight tonight with pen oil around it and some - quite a lot of tension on it - Yes I have given it a tap

more later / as it happens / I will not post pics of me tools as they are cheap and cheerful - but made from stainless so should last
Thanks for all the tips up to now
Mick

 

[Voyager]

the flange puller is another story
Mick

Mick,

I use an enormous Sykes Hydraulic puller with a 0.5" thick adaptor plate.

The picture shows the puller pushing a bearing onto the shaft, but when pulling the flange I put a turned-up spacer between the flange and the adaptor and bolt them together.

I then use a heavy steel rod (part of the Sykes kit) to press on the output staft and screw down the ram.

Sometimes the flange pops off ( ), sometimes it doesn't ( ).

When the adaptor plate starts to bow, I give it a sharp radial tap with a 2.5lb mash hammer - that usually springs the taper and the whole lot leaps into the air

These things are on tight (torqued down to 163 lbs/ft onto a dry taper).

Bob.

 

[MickDB1]

Thanks to you lads
I have a bike again - I replaced the box with a good old un from a guy Rob F knows, its off an earlier bike but works - quite quiet as well
Then
Took back to the shed with vengence and confidence - got me home made puller - crushed a ballbearing into a 12mm setscew while giving it a good smack - popped off the flange
Got the box to bits today and bottom bearing ( the big un nearest to clutch side ) on output shaft has exploded ( dropped to bits ) letting the gears move apart
I have cleaned up the teeth on gears and although they dont look brand new I recon they will run ( with all my experiance in gearbox re-builds = none )
I will get some parts and put it all back I will post some pictures later

Hopefully you may be able to do this - it took quite a long time but next time I recon I could get it down to between 90 mins and 4 days

Thanks a lot fellas - I love me bike but love riding it more than mending it

Roll on Proffs Dooooooooooo

 

[MickDB1]

Hey up
More news - or at least an update
Got most of me bearings but I am concernd about these beveled Gears
5th and its match on the Layshaft
have a look and give me an opinion up to now I've had 1 for and 1 against
I am sure they will work - they match up - but has anyone fitted any that were as bad or worse and what was the result please

Or has anyone got a fifth gear out of a 82 onwards box and / or a layshaft in back of their shed doing nowt and want it shifting - clearing up
thanks for the tips help up to now
Have a butchers at these pics please

 

[Rob Farmer]

I'd give it a go as it is Mick. Now you know how easy the boxes are to take apart you can soon pull it down again if it's noisy or rough.

This was Thunders desert storm layshaft gear, obviously had some debris go through it at some point in the past.

It's so easy to run up hundreds of pounds on gearboxes that it gets to the point that you may as well just buy a new one.

 

[elevensies]

big puller !!!