Layshaft BALL Bearing Upgrade - "in situ" - Techniques And Tips Help?

Whilst I‘m sure it was meant tongue in cheek, I would caveat the suggestion of the use of ‘violence’.

The metal between the layshaft and mainshaft bearings is very thin and is easily cracked. Case in point: my bike had done 20,000 miles when I stripped the gearbox, the internals were fine and it even had a perfectly intact Portuguese bearing… but still the case was cracked between the bearing housings !

So, as TW has already suggested, please only pull straight n‘ square and minimise the temptation to ‘free it‘ by yanking side to side.

Better still perhaps… remove the gearbox and post it to Greg… !
 
998cc - thanks for the tool info. but please remember that at this point I can't use it because the bearing is stuck in the case and the shaft is stuck in the bearing. IF- I could get the shaft out I could use a blind hole puller as you suggest, but until and unless that happens, a tool that works on the shaft would be better.

Greg - It's beginning to feel like I can't afford NOT to! I'm going to persist on my own a while longer, but if that fails, I will take advantage of your kind offer. I am aware of the Oregon club - but only through YouTube videos. That could change in the future it seems.
 
Hotter . Just before melting aluminum . Smoke it . From the outside , lower primary side rear , where the bearing is home . No smoke = no luck .
 
Torontonian said:
Hotter . Just before melting aluminum . Smoke it . From the outside , lower primary side rear , where the bearing is home . No smoke = no luck .
Click to expand...
Internet says melting point of aluminum is a shocking 660 degrees centigrade . Go to gas .
 
Tornado said:
I used a propane torch for my bearing removal in situ. Took a good 10-15 min of constant moving flame all around both inner and outer gb shell ..... Followed Hemming dvd guidance to heat until water/spittle boils immediately on surface. The bearing came out easily.
Click to expand...

Just wanted to say that " spit " was ( is still ? ) a well known and recognised practice in engineering trades - often in the past I've given the same advice as Hemmings and people can and do look in horror / think this bloke is mad / what a disgusting way of doing things / surely it has to be a stupid way to do the job etc etc ......

Back in the day when I was an apprentice I was taught to use spit as the indicator for temperature, it is remarkably accurate ( and good fun too in a childish sort of way ... spit smells as it bubbles )

The method we would use " on site " in particular was to place a bearing onto a 1/4" steel plate, heat the steel plate from the underneath using an oxy-acetylene torch and so doing transfer the heat into the bearing. Once the bearing was too hot to touch the occasional gob of spit was then used as a thermometer and when it bubbled and fizzed the bearing was at the correct temperature for fitting.
At that time we typically fitted bearings of between 4 and 12 inches diameter.

What you have to remember is that the max recommmended temperature for heating a bearing will be 120*C so bubbling spit gives you 100*C with a bit of leeway / safety built in.

Naturally you'd need to check manufacturers spec for any 2RS sealed bearing.

Natures resources are not to be sneezed at for it it isn't always convenient to have an induction heater or a thermal crayon available for a job or even the scenario of your wife / better half refusing to allow you to put engine and gearbox parts in the domestic oven. ..... Lol !!
 
Grandad said:
Just wanted to say that " spit " was ( is still ? ) a well known and recognised practice in engineering trades - often in the past I've given the same advice as Hemmings and people can and do look in horror / think this bloke is mad / what a disgusting way of doing things / surely it has to be a stupid way to do the job etc etc ......

Back in the day when I was an apprentice I was taught to use spit as the indicator for temperature, it is remarkably accurate ( and good fun too in a childish sort of way ... spit smells as it bubbles )

The method we would use " on site " in particular was to place a bearing onto a 1/4" steel plate, heat the steel plate from the underneath using an oxy-acetylene torch and so doing transfer the heat into the bearing. Once the bearing was too hot to touch the occasional gob of spit was then used as a thermometer and when it bubbled and fizzed the bearing was at the correct temperature for fitting.
At that time we typically fitted bearings of between 4 and 12 inches diameter.

What you have to remember is that the max recommmended temperature for heating a bearing will be 120*C so bubbling spit gives you 100*C with a bit of leeway / safety built in.

Naturally you'd need to check manufacturers spec for any 2RS sealed bearing.

Natures resources are not to be sneezed at for it it isn't always convenient to have an induction heater or a thermal crayon available for a job or even the scenario of your wife / better half refusing to allow you to put engine and gearbox parts in the domestic oven. ..... Lol !!
Click to expand...
Spit/spittle is fine for knowing the minimum temp of the surface...but you cannot know the actual temp, could be well above 100 C. So best to have the spittle present as you apply heat, stop once boiling begins.
 
Whew! After quite a struggle and some ingenuity, the shaft and bearing are out! Heat alone wasn't quite doing it (as we know) so I figured a method of withdrawing that didn't rely on a simple grip of a slippery shaft might be of some help. I had watched a YouTube video of a guy with the same problem and he resorted to welding a nut to the bearing and slide hammering it out. I'm no welder and it seemed brutal (if effective) but it got me thinking. (Mainly about how to jury rig something along the lines of the tool mentioned by Time Warp in post #70.)

A cheap puller with two thin 6-inch jaws hooked over the gear on the layshaft. A 1"x1"x6" piece of hardwood tucked under the snugged-up under the puller's crossbar between the studs and across the gearcase flats with the old gasket in place. A small crowbar and some cautious prying on the puller and ... success. The layshaft out.

The Portuguese bearing, in perfect shape, was still in the case. I may never know why the thing was so reluctant to move, but with careful use of a small spreader-type blind hole puller (no slide hammer for me) and a little heat on the back of the case via a heat gun, it FINALLY slid (not popped) OUT!

It felt like I'd lost all the other battles but finally won the war. No Violence!

Now - take a few days to clean up and regroup - then move on to whatever challenges installing and reassembling might present.
 
Last edited:
I did the job in the bike. It was my first plan also to use a heat gun but found it worthless. Took forever and not enough heat. I used a propane torch until it "fried spit" and was able to pull out the layshaft with bearing with a gloved hand.
I found I needed to replace other bearings, bushings and the mainshaft while in there. There is always something else. Check mainshaft straightness for example.
Russ
 
batrider said:
I did the job in the bike. It was my first plan also to use a heat gun but found it worthless. Took forever and not enough heat. I used a propane torch until it "fried spit" and was able to pull out the layshaft with bearing with a gloved hand.
I found I needed to replace other bearings, bushings and the mainshaft while in there. There is always something else. Check mainshaft straightness for example.
Russ
Click to expand...
A word of caution about straightening mainshafts: I used to straighten them if the owner didn't want to spring for a new one, with the caution of "no guarantee." The last one of those I did failed (broke) on the owner on the way the West Coast rally (I don't remember which one). He wasn't happy. Neither were we. He did get a new roller layshaft bearing though, which was the point of the whole exercise.
 
I had a new one around from a DomiRacer sale years ago, and I checked it with v-blocks and a dial gauge. Hobot used to say they would twist also so couldn't really be straightened.
 
How does one twist or bend a layshaft in the first place? Would there typically be collateral damage or would other damage actually make the layshaft the victim?

After my holiday "rest" and a rethink leading to a decision to go with a roller bearing after all - I'm starting reassembly.

Inspection of components has gone well. Gears, bushings, bearings are good, kicker pawl good, shift dogs and forks good, etc. I have decided that the PO was definitely in the box before I got in there, mostly because of all the Gasacinched gaskets and the struggle to remove the Portuguese bearing (also in great shape BTW) that prompted this thread in the first place.

After the old bearing came out, I was convinced installing the new one would be a PITA also. Just my luck, right? Well, I shouldn't have been so apprehensive!

The roller race went on the freezer chilled layshaft smoothly and simply with a few light taps from a small rubber hammer. The freezer chilled roller bearing slid in beautifully after 5 minutes of heating the case with a propane torch and bottomed in the blind hole straight and squarely - gently persuaded using an improvised installer made up of a 29mm socket mounted "backwards" on an 8-inch extension. I was elated that it went so smoothly, just like the manual and popular wisdom said it should. I couldn't believe it!

That was yesterday and I was so pleasantly surprised I "quit while I was ahead" for the day.

Today or tomorrow, the gears and forks go back in, then hopefully the inner cover...slow and steady...fingers crossed.
 
Kip said:
How does one twist or bend a layshaft in the first place? Would there typically be collateral damage or would other damage actually make the layshaft the victim?

After my holiday "rest" and a rethink leading to a decision to go with a roller bearing after all - I'm starting reassembly.

Inspection of components has gone well. Gears, bushings, bearings are good, kicker pawl good, shift dogs and forks good, etc. I have decided that the PO was definitely in the box before I got in there, mostly because of all the Gasacinched gaskets and the struggle to remove the Portuguese bearing (also in great shape BTW) that prompted this thread in the first place.

After the old bearing came out, I was convinced installing the new one would be a PITA also. Just my luck, right? Well, I shouldn't have been so apprehensive!

The roller race went on the freezer chilled layshaft smoothly and simply with a few light taps from a small rubber hammer. The freezer chilled roller bearing slid in beautifully after 5 minutes of heating the case with a propane torch and bottomed in the blind hole straight and squarely - gently persuaded using an improvised installer made up of a 29mm socket mounted "backwards" on an 8-inch extension. I was elated that it went so smoothly, just like the manual and popular wisdom said it should. I couldn't believe it!

That was yesterday and I was so pleasantly surprised I "quit while I was ahead" for the day.

Today or tomorrow, the gears and forks go back in, then hopefully the inner cover...slow and steady...fingers crossed.
Click to expand...
"A 30 horsepower transmission behind a 60 horsepower engine"
 
We knew you could pull the job off . You won't regret going roller . Best to shim using a rear isolastics shim or 2 at the kicker end . Old Britts article walks you through it . I think the old Hobot post was referring to the main shaft , not the lay . Twist like a candy cane , likely from riders trying wheelie or stoplight bravado stunts way back when . We're more civilized nowadays .
 
Whoops - I lied!

Upon CLOSER inspection, I discovered bad teeth on mainshaft first. Considering the rest of the gears are fine, it left me puzzled, Then, I played "what if" like Sherlock.

I know the PO was in the box some time in the past. (That, or a mediocre mechanic.) I know that layshaft first is like new and the kicker pawl is good also. Why? Elementary. The PO replaced only the layshaft gear (and pawl) without looking at the other.

I also started speculating on lubrication as the original issue. These gearboxes are a bit odd in that they feature stacked shafts. Most motorcycle transmissions use side-by-side gears. It seems to me that previous abuse of a 14t gear, (and its mate) coupled with some inevitable draining of oil film to the bottom of the box, and condensation within the box, leaves plenty of opportunity for pitting and spalling on the upper shaft and gears. Especially on a bike that's fifty years old, with only 12K on it. If the wrong lube is left in it while it sits most of the time, for most of its life = moisture and unprotected steel = rust and pitting = bad gear. BTW- the bike has been garaged throughout my custodianship but did not have a centerstand until I got it, which might have "saved" the other mainshaft gears from damage. I also suspect it lived outdoors for some of its early life, which may have been when this problem began. In theory anyway.

So - in a way, bad bearing aside, it's good I got in there when I did.

Until I have the replacement gear in hand the project is stalled, but I will continue to report any findings and possible reasons for them as I go...if that's ok?
 
Kip said:
Whoops - I lied!

Upon CLOSER inspection, I discovered bad teeth on mainshaft first. Considering the rest of the gears are fine, it left me puzzled, Then, I played "what if" like Sherlock.

I know the PO was in the box some time in the past. (That, or a mediocre mechanic.) I know that layshaft first is like new and the kicker pawl is good also. Why? Elementary. The PO replaced only the layshaft gear (and pawl) without looking at the other.

I also started speculating on lubrication as the original issue. These gearboxes are a bit odd in that they feature stacked shafts. Most motorcycle transmissions use side-by-side gears. It seems to me that previous abuse of a 14t gear, (and its mate) coupled with some inevitable draining of oil film to the bottom of the box, and condensation within the box, leaves plenty of opportunity for pitting and spalling on the upper shaft and gears. Especially on a bike that's fifty years old, with only 12K on it. If the wrong lube is left in it while it sits most of the time, for most of its life = moisture and unprotected steel = rust and pitting = bad gear. BTW- the bike has been garaged throughout my custodianship but did not have a centerstand until I got it, which might have "saved" the other mainshaft gears from damage. I also suspect it lived outdoors for some of its early life, which may have been when this problem began. In theory anyway.

So - in a way, bad bearing aside, it's good I got in there when I did.

Until I have the replacement gear in hand the project is stalled, but I will continue to report any findings and possible reasons for them as I go...if that's ok?
Click to expand...
1704016667706.jpeg



1704016690420.jpeg


"I do NOT want to leave any grenades (pin pulled or otherwise) in the box when this is done. "

That was done in the engineering/accounting office many years ago.
 
Last edited:
You must log in or register to reply here.
Back
Top