Superblend main bearings.

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htown16

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I'm replacing the ball bearing and regular roller bearing on my 71 bottom end with a set of superblends. I'm assuming that like on the regular roller bearing the lip on the inner race goes against the crank cheek on the drive side. Does it also go against the cheek on the timing side?
 
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I'm replacing the ball bearing and regular roller bearing on my 71 bottom end with a set of superblends. I'm assuming that like on the regular roller bearing the lip on the inner race goes against the crank cheek on the drive side. Does it also go against the cheek on the drive side?
One both sides, the inner race goes on the crank and the lip goes towards the center of the crank.
 
Yup. Wait till the wife leaves for a few days to use the oven and freezer otherwise you risk divorce, open all windows too.
 
I have put the bearings in the freezer and used an aluminum plate heated with a torch to warm the cases. A heat gun will work but takes a while - better not to incur the wrath of the resident female meddling with her cooking apparatus...
 
If you wash the cases well before hand there is very little smell involved. However best to do it
when she is in dire need of something you can do.
...business as usual.
 
I have my own portable electric oven just about big enough for a set of cases! 'er indoors doesn't even know where I keep it!
 
I usually put a crankcase-half over one of the gas jets then spit on it to see if it is hot enough.
 
I've done the oven bit after running the cases through the dishwasher. I'm going to try my gas bbq grille this time.
 
When I have replace my crank case bearing and I have done a few over the last 40 years or so I just put the cases over a gas burner and let the heat rise up inside the cases it only takes a short time for the old bearing to drop out then I flip the cases over while still hot then drop the new bearing in and then let cool down, works perfect every time.
As for the inner bearings I use a puller to pull the old ones off, my puller sits behind the inner bearing and the more you tighten the bolts the more it goes behind the bearing you think its not going to release but when it does it make a hell of a bang and the inner bearing just comes off, to put the new inner bearing on I just put some oil on the crank and use the old inner bearing to tap the new one on, freezing the new ones will help but I have never had any problems putting them on just tapping them with the old inner bearing.
I have always replaced the bearings when I remove the old ones.

Ashley
 
I would think you would want to heat the inner race to expand it before fitting it to the crank. I've heard of people dipping it in a can of hot oil to do that.
 
You don't want to put any heat on the new inner bearings at all, they will tap on using a old inner bearing, I have never had any problems tapping them on and I have done a few Norton motors over the last 40 years.

Ashley
 
Okay, everything went well. Used the bbq grill. When the original bearing dropped out, the new ones went right in. The inner races intalled on the crank with some hammer taps using a socket as a drift.
 
It surprises you how easy it is with just a bit of heat I do mine on the stove over a burner and it only takes a few minutes for them to drop out, the good thing about this site you learn a lot and everyone are very helpfull, now get that bike back together and have some fun but remember do things right think about it before you do something and once together and everything is right you will have a reliable bike.
Good luck with the rebuild and enjoy learning about your bike.

Ashley
 
As far as the inner race of the roller bearings go, you are not heating the bearing until it is BLUE.
All you are doing is heating it for required expansion and it does not take a lot of heat.

The crankshaft journal in this case is machined for a interference fit between it and the bore of the bearing inner race, that tolerance also has some bearing on the interference (ie C0 / C1 / C2 C3)
All you have to do is warm the inner race, it takes very little heat to expand them and they all but slide on, they then cool from that very little heat and go back to normal spec and the interference is obtained with no drama to the journal.
It is the same at removal, warm the inner and when you use the puller it will come off with little fuss.

People do know there are industrial induction bearing heaters for this exact purpose ?.

Please watch this.



Just saying is all because this thread seems to have suggested you should not heat the inner's and they must be bashed on cold which is false (imho)
Someone new finds the thread and they think that is the only way.

I would add, knocking them on can result in bounce when they come up against the crank cheek.
With heat all that is needed is the shaft vertical and a tube type weight used, the inner will then cool hard up.
I also believe hard up the inner applies some support to the journal radius.
 
As far as the inner race of the roller bearings go, you are not heating the bearing until it is BLUE.
All you are doing is heating it for required expansion and it does not take a lot of heat.

The crankshaft journal in this case is machined for a interference fit between it and the bore of the bearing inner race, that tolerance also has some bearing on the interference (ie C0 / C1 / C2 C3)
All you have to do is warm the inner race, it takes very little heat to expand them and they all but slide on, they then cool from that very little heat and go back to normal spec and the interference is obtained with no drama to the journal.
It is the same at removal, warm the inner and when you use the puller it will come off with little fuss.

People do know there are industrial induction bearing heaters for this exact purpose ?.

Please watch this.



Just saying is all because this thread seems to have suggested you should not heat the inner's and they must be bashed on cold which is false (imho)
Someone new finds the thread and they think that is the only way.

I would add, knocking them on can result in bounce when they come up against the crank cheek.
With heat all that is needed is the shaft vertical and a tube type weight used, the inner will then cool hard up.
I also believe hard up the inner applies some support to the journal radius.

Interesting. Induction heater for the inner race. Next time I'll simply warm up the inner with the heat gun a very little bit , not much.
 
Yes a little heat does help but doing them cold also works, I have never bashed them on at all just light taps using the old inner bearings and a bit of lube to make them slide on helps and with the right puller pulling the old ones off without any heat without getting hot or burned hands and fingers, my wife don't like having the smell of old heated up oil in her new oven.

A friend of mine a few years ago his mate was having troubles getting his inner bearings off he was told by someone to heat the inner bearing up using a oxy torch on the bearing them give them a hit with a cold chisel and they just pop off, well it didn't work for him and my mate asked me to give it a go, when I got the crank I could see a lot of blue on the inner bearing as well as the crank, I just shock my head in disbelief, I just put my puller on tighten it up and they popped right off, having the right tools is a big bonus.

Ashley
 
SKF also suggest a "hot dismount" method - I made a solid steel dismount tool to go over the inner bearing with slits and welded wings.

The dismount tool is heated with oxy to quite hot 120degC or more, then dropped over the end of the inner bearing race on the shaft, the wings are clamped up with big vice grips. The inner race expands without heating the crank and the race loosens and comes off quite gently.

I used this remove the inner bearing race on my 961 Commando Balance Shaft.


Superblend main bearings.
 
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