Drive side main bearing

51 years,---obviously so overloaded !!, I seem to remember using my genuine Norton sprocket puller on the main bearing to pull it off,Not a common item but well worth finding. Hudsons video may show this.A heated case and something cold in the bearing ,a drop and mine came out.

Problems removing the drive side crank bearing on 1962 88. On splitting the crankcases the inner race and bearing stayed on the crankshaft and the outer race in the drive side crankcase.

Had to take out each roller to remove the brass cage before getting the inner race off. The outer race refuses to budge from hte c/case despite the 'heat and shock' treatment.

This is the first time the engine has been stripped in its 51 year life....so maybe there is an 'oil glue' problem?! (and yes, I should add that it does need replacing)

Any help and polite suggestions would be appreciated. Thanks

Hi, try a ring of weld inside the race, then shock the crankcase half face down on a flat board. If you warm the case up first, it should work. Hope all goes well, all the best, Paul

Previously robert_tuck wrote:

51 years,---obviously so overloaded !!, I seem to remember using my genuine Norton sprocket puller on the main bearing to pull it off,Not a common item but well worth finding. Hudsons video may show this.A heated case and something cold in the bearing ,a drop and mine came out.

No room between crank and roller bearing for a puller to grip. Hudson video which I had checked first just heated c/case. I'll try that yet again but with some ice cubes in the outer riace this time!!. Thanks

Hello as you have said you have tryed the John Hudson way but he heated the cases with a gas blow gun , try a oven Like i do you need to leave it in there of a good half hour on full heat and have a old copping broad or something like one, to drop the cases on too, but you get a better force if you wear welding gloves and keep hole of the cases and carefully bang out the race, keeping the case fat with the race side down , and you need to warm the cases before fitting the new bearing too so the oven is a lot better than a gas blow gun . as you get a even temperature on the cases yours anna j

Anna is right, cases in the oven. To get the inner race off the mainshaft, heat the race with a gas jet then use a wedge shaped drift to move the bearing a little, then a puller. Shafts can be eased down with emery for the replacement.

Of interest possibly.........

In the first engine strip video, John Hudson used a 1939 German petrol fueled blow-torch. If you watch the crankcase heating scene carefully, you willnotice that he puts the torch back on the bench with the pointing flame towards a backing board displaying a calendar and some posters. You can see these instantly begining to curlfrom the heat anda fewseconds later, were well ablaze. That 'burning wall' section was edited out from the final video.

Another chunk, removed in the edit suite, was the seven attempts John made to remove the outer bearing races. In fact, as time began to take its toll,he even resorted,indesperation, to throwing them down hard onto the floor. But first heremoved the locating pins. He mentioned (possibly also in the video) that it was perfectly acceptable to drill holes in the cases, and then to drive out the outer races. Filling the holes with something like Metal Putty.

A third piece of editing removed the part where John is about to dismantle the crankshaft he has just removed from an engine. He put the crankshaft down onto the bench and then turned around to face the camera and speak. The shaft rolled across the bench and dropped onto the back of John's heels. Painful!!!!

In my experience, trying to remove old bearings by heating, hasgenerallyhada verylow success rate. Often I have had to resort to grinding slots and then heavy hammer work. This is where FAG bearings have the edge. ie some convenient shoulders to push or pull against.

What I have done is drilltwo 1/8" holes 180 degrees apart in the crankcase pointingdirectlyat the bearing outer race. Then lots of heat on the cases and then use aparallel pin punch to tap the bearing out. Rather more elegant than throwing the crankcase half on the floor! A smallskoosh of rtv fills the holes effectively until next bearing change.

Hi John

If you have removed the inner race welding is the best method asPaul said earlier.

All you need is a good man on the welder with good eyesight.

You will be amazed at how easy it will come outif done correctly, case should be sprayed with anti spatter first, when the weld cools down the outer race shrinks.

No need for all the heavy handed hammering stuff, it is also a common way to remove tight bearings in engineeringindustry.

Regards

Mark

Of interest possibly.........

In the first engine strip video, John Hudson used a 1939 German petrol fueled blow-torch. If you watch the crankcase heating scene carefully, you willnotice that he puts the torch back on the bench with the pointing flame towards a backing board displaying a calendar and some posters. You can see these instantly begining to curlfrom the heat anda fewseconds later, were well ablaze. That 'burning wall' section was edited out from the final video.

Another chunk, removed in the edit suite, was the seven attempts John made to remove the outer bearing races. In fact, as time began to take its toll,he even resorted,indesperation, to throwing them down hard onto the floor. But first heremoved the locating pins. He mentioned (possibly also in the video) that it was perfectly acceptable to drill holes in the cases, and then to drive out the outer races. Filling the holes with something like Metal Putty.

A third piece of editing removed the part where John is about to dismantle the crankshaft he has just removed from an engine. He put the crankshaft down onto the bench and then turned around to face the camera and speak. The shaft rolled across the bench and dropped onto the back of John's heels. Painful!!!!

In my experience, trying to remove old bearings by heating, hasgenerallyhada verylow success rate. Often I have had to resort to grinding slots and then heavy hammer work. This is where FAG bearings have the edge. ie some convenient shoulders to push or pull against.

For once Phil I have too disagree with you on heating the cases will not work, I shall Make this very clear for every one. On no account Should You Drill the Crankcase to remove a bearing outer track. you should all way heat the crankcases in a Very Hot oven , And Do NOT try Heating them By a Blow Lamp This Will not work. and You end up burning your self or something around you. a Very Dangerous Practices. and NOT one I recommend On Heath and safety grounds, The Oven is the right way but you must be properly booted and suited and have the right gloves for the job hand and all your work area clear to move quickly around think safety first in all these operation Yours Anna J Dixon

Why should you not drill the crankcases? I first found this mod on a pair of used crankcases I bought. Works a treat. So I have perpetrated this sacriledge on other drive side crankcases if the bearing has been a bit reluctant to shift.

It takes a lot of heat to get crankcases properly warm - an oven is best. A piddly little gas blowtorch just isn't up to it. It the outer race has been put in with Loctite for whatever reason, it needs to get really hot to degrade the adhesive qualities and release the race.

Hi Gordon

It simply sets up additional stress areas that for an old set of castings you do not want, when there are better options for removing the bearing shell that do not stress the area around the bearing boss.

Ie pressing, pulling, hammering through the holes that can deform the bearing boss bore, shrinking the bearing prevents this.

Best Regards

Mark

Hi Mark, Two 1/8" holes in a main bearing boss aren't really going to stress the crankcase. Norton were quite fond of drilling holes in the crankcase to attach the alternator and primary chaincase after all. All I can say is that it works superbly for me and that it beats welding things to the race or throwing the crankcase half on the floor. Ouch!

Cheers,

Gordon.

Luckily for me the PO had already drilled a pair of holes so no anguished decision-making. I'd worry more about grinding in case I nicked the inner edges and created a possible crack start point.

I wonder at what temperature the allow heat treatment (if it has any) might be affected? The books suggest something (200C is it?) for removing valve guides from the head. Difficult to estimate without digital temperature gauge (v. cheap in Maplin).

I have had very good luck just heating the cases, only occasionally had to rap the case onto a piece of soft wood ( no danger of damaging the case). Usually the races literally drop right out once the aluminum reaches around 200c. I use a mapp gas plumbers torch, but have also used an oven ,and have also used a propane grill. The excellent NOC club video on Norton Twin engine rebuilding also shows using a plumbers torch, and the scientific method Mick Hemmings uses to determine the right temp. works great for me: when the case is hot enough to bubble your spit, its the right temp. !!! If it works for Mick, its good enough for me. Nowadays you can get the digital thermometers very cheap at the discount stores though.

Previously john_baker2 wrote:

Problems removing the drive side crank bearing on 1962 88. On splitting the crankcases the inner race and bearing stayed on the crankshaft and the outer race in the drive side crankcase.

Had to take out each roller to remove the brass cage before getting the inner race off. The outer race refuses to budge from hte c/case despite the 'heat and shock' treatment.

This is the first time the engine has been stripped in its 51 year life....so maybe there is an 'oil glue' problem?! (and yes, I should add that it does need replacing)

Any help and polite suggestions would be appreciated. Thanks

Hi John,

Today is the first time I've looked at the new w/site so only just come across your post,no doubt you've overcome your problem by now. I have always found that the best method for the job you refer to is that used by Mick Hemmings. My Father showed me this method in the early 1950s when I started motor cycling and it's always worked for me, but you do need a plumbers gas torch.

With regard to rubbing the shafts down with emery, don't even think about it, the bearings are supposed to be tight for a reason, they can be removed with a bearing puller designed for the job which can be hired for a small sum.

Regard, Ian Hay Thames Valley NOC.

I have had very good luck just heating the cases, only occasionally had to rap the case onto a piece of soft wood ( no danger of damaging the case). Usually the races literally drop right out once the aluminum reaches around 200c. I use a mapp gas plumbers torch, but have also used an oven ,and have also used a propane grill. The excellent NOC club video on Norton Twin engine rebuilding also shows using a plumbers torch, and the scientific method Mick Hemmings uses to determine the right temp. works great for me: when the case is hot enough to bubble your spit, its the right temp. !!! If it works for Mick, its good enough for me. Nowadays you can get the digital thermometers very cheap at the discount stores though.

Yes And thermometers Are Normally all ready fitted to a oven were its a lot safer than trying to follow someone else , who as a disregard for safety NOC DVD or NOT A Blow Lamps Are Very Dangerous In the wrong hand, always think safety before doing any job And Safety is the first thing you learn The Engineers Manual So go try and read it , Yours Anna J

Hi Mark, Two 1/8" holes in a main bearing boss aren't really going to stress the crankcase. Norton were quite fond of drilling holes in the crankcase to attach the alternator and primary chaincase after all. All I can say is that it works superbly for me and that it beats welding things to the race or throwing the crankcase half on the floor. Ouch!

Cheers,

Gordon.

The reason For Not drilling holes in you crankcase to relieve the bearing .as oil seeps into the primary drive side to end up giving you clutch slip and contaminating the clutch rubbers along with premature clutch wear .

Anna, if you re-read my original post, I do say that you must plug the holes with RTV or similar.

In fact, with many poorly sealed and leaky primary chaincases, a bit of oil seepage into them would be no bad thing. Not that I am implying your bike has a leaky chaincase of course.

Would excess oil on the clutch actually increase wear? Discuss.

Gordon.

Anna, if you re-read my original post, I do say that you must plug the holes with RTV or similar.

In fact, with many poorly sealed and leaky primary chaincases, a bit of oil seepage into them would be no bad thing. Not that I am implying your bike has a leaky chaincase of course.

Would excess oil on the clutch actually increase wear? Discuss.

Gordon.

well my bike does not leak from the primary cover, as there is no oil in there any way my primary drive is running in a special chain grease that dose not get into the rubbers in the clutch , or the plates, its this rubber and dirt that gets in the oil thats the coarse of premature wear . you should alway check your machine over on a regular bases , and genially look after your machine . and your machine will look after you. do not neglect your motorcycle. the best way is to keep a book on every thing you have done . and dates and time of service. and parts replaced on it too. this is good house keep hope its helps some of you , happy riding .

On a different thread I mentioned the possible problems of using grease on a primary chain rather than taking the trouble to ensure the chaincase is leak free andholding oil, as the makers intended.

If the bike is used hard with just grease on the chain, the cooling effect of the oil bath is lost and chain heats up and then thegreaseis flung off the chain. The rollers then get hotter through friction and it all starts to go wrong. The chain will get far too hot to touch, upwards of 200 degrees,and the grease turns to ferric oleate. At this point rollers start to fail, filling the chaincase with lots of bits of broken roller, which then get picked up and go between the chain and sprockets. Chains would fail after only 400 miles.

Some of us did a fair bit of research into this as engineering students which convinced us that the oil bath chaincase was invented for a purpose.

George Jackson Churchward did a splendid demonstration in about 1903 on the effects of contaminants in oil. As long as there was plenty of oil, contamination caused very little wear (I paraphrase).

On a different thread I mentioned the possible problems of using grease on a primary chain rather than taking the trouble to ensure the chaincase is leak free andholding oil, as the makers intended.

If the bike is used hard with just grease on the chain, the cooling effect of the oil bath is lost and chain heats up and then thegreaseis flung off the chain. The rollers then get hotter through friction and it all starts to go wrong. The chain will get far too hot to touch, upwards of 200 degrees,and the grease turns to ferric oleate. At this point rollers start to fail, filling the chaincase with lots of bits of broken roller, which then get picked up and go between the chain and sprockets. Chains would fail after only 400 miles.

Some of us did a fair bit of research into this as engineering students which convinced us that the oil bath chaincase was invented for a purpose.

George Jackson Churchward did a splendid demonstration in about 1903 on the effects of contaminants in oil. As long as there was plenty of oil, contamination caused very little wear (I paraphrase).

To get 200c on a chain it would have be doing light speed ,not 4000 rpm were it hardly gets warm,

I'd suggest poking your finger through the inspection hole and try touching a dry chain. You won't want to do it a second time...

Motorcycle chains generally try to transmit more power than any normal industrial chain duty and need all the help they can get. An oil bath is pretty much ideal and that's what Norton provided. Grease just sticks to the surface.

You could of course use 'o-ring' chains and lose 25% of your b.h.p. in bending the thing. The racers don't use them (much to the annoyance of chain manufacturers) because they don't like wasting power.

Also, heavier chains increase inertial loads and are not advisable. I've been offered 'this chain has really good thick side plates - it won't stretch as much so it's much better'. This is untrue for several reasons - a) chains don't stretch - the pins wear, and b) heavy chains = more load on the transmission = more wear, friction, heat...

Previously David Cooper wrote:

You could of course use 'o-ring' chains and lose 25% of your b.h.p. in bending the thing. The racers don't use them (much to the annoyance of chain manufacturers) because they don't like wasting power.

You've probablymissed a decimal point between the 2 and 5 as it's nowhere near 25%. Or does that perpetuate another myth where 72.97% of statistics are made up on the spot. (just like that one).

Getting way off topic now. Of course you are right - it depends how much power you have to start with. Most modern bikes have loads to spare - unlike some of our old things. 5% on an R1 might be 50% on a 16H...

Why get so cross? Do you sell the things? And, if so, how much power do they use? When they are new it's not easy to bend them by hand - they stand up by themselves. An ordinary chain drive only uses a few percent. It would be nice to find some reliable data but everything interesting is buried in commercial interest.

Previously David Cooper wrote:

Getting way off topic now. Of course you are right - it depends how much power you have to start with. Most modern bikes have loads to spare - unlike some of our old things. 5% on an R1 might be 50% on a 16H...

Why get so cross? Do you sell the things? And, if so, how much power do they use? When they are new it's not easy to bend them by hand - they stand up by themselves. An ordinary chain drive only uses a few percent. It would be nice to find some reliable data but everything interesting is buried in commercial interest.

Yes it is a bit off topic, er, why do you assume I'm cross? I don't have any commercial interest in O or X ring chains and I didn'tuse them forracing either but a 25% power lossis bit of an exaggeration.

Previously David Cooper wrote:

Getting way off topic now. Of course you are right - it depends how much power you have to start with. Most modern bikes have loads to spare - unlike some of our old things. 5% on an R1 might be 50% on a 16H...

Why get so cross? Do you sell the things? And, if so, how much power do they use? When they are new it's not easy to bend them by hand - they stand up by themselves. An ordinary chain drive only uses a few percent. It would be nice to find some reliable data but everything interesting is buried in commercial interest.

Yes it is a bit off topic, er, why do you assume I'm cross? I don't have any commercial interest in O or X ring chains and I didn'tuse them forracing either but a 25% power lossis bit of an exaggeration.

I know this is a off topic but how many of you know about Special oils and Special chain grease that work like an oil when it get to temperature and this grease is like a foam and not like grease that you normally get . its special formulated for chains at runs at speed for 8000 rpm .you have many different grease and not all grease is waterproof and then there a rubber grease as well and how many variations of them there are, there are more greases out there than oils, and there all made to do a job just like a oil .

Hi John, glad you got it out in the end. One normally machines a bearing recess with a face for the outer race to sit on, and the rest 0.030" deeper to allow oil clearance for the balls. The corner should have a 0.060 radius. It sounds like someone has hammered a bearing into very cold cases and actually pushed a ring of metal into the corner, so reducing your end float to minus. If you put in Superblends, you will pinch the bearings. I would look at the area under strong magnification before going any further. I have had this happen years ago in a Triumph engine. Best of luck, Paul