Hi
I am taking bearings out of some nos crankcases I have - drive side bearings - despite the awkward retaining clip came out relatively easily
The inner race on the inner most bearing - timing side - came out easily too - leaving the outer race still in the case
There is no obvious lip that I can see that allows you to tap it out - so is it just heat required to get these 2 bearings out
Being a dumbo tonight
Br
Jo’b
email (option): jonnyob1@googlemail.com
On Norton engines, I stick the cases in the oven and then whack them down on a plank of wood. I've never knocked a bearing out.
Timing side roller outer and ball bearing?...There are two holes in the crankcase accessed from inside the timing cover...These line up with the 'back' of the bearing outer...Warm the crankcase and knock them out from the back using a parallel punch and hammer...Ian
email (option): ian@wright52.plus.com
If you are going to replace them then run a continious bead of weld around the bearing then let it cool
The bearing will fall outSame technique works a treat on the steering cups
Heat did the trick & ians pointer to access holes for a drift At the rear saw them out easily enough
I have thoroughly cleansed the casings - removed both cam spindles to remove caked on grease & dirt & refitted these.
Bearings show no evidence of deterioration or discolouration on surfaces - so I have been able to save them for use
Bearings are ready to be fitted along with new crank shims - any pointers for refitting to the crankcases - heat required of course - but is a press recommended for this ?
Or
Any other proven method of drifting these in ?
I have build many Japanese motors at work over the years & Triumph preunits previously - but after all the years of m20 riding - this is my first full motor build - no idea how I avoided it
Br
Jo’b
email (option): jonnyob1@googlemail.com
This is all well described in the BSA M20 instruction manual.
email (option): wdmotorcycles@gmail.com
Leave the bearings in the freezer overnight in plastic bags...Then heat the cases to 100 degrees or so (boiling water temp.)..I use a propane torch for this. Let them get nice and hot so that some 'spit' will sizzle right off them... The cold bearings will then more or less drop in...If you get one slightly out of square the minimum application of a hammer and punch will get them in...On the drive side fit the outer bearing, then drop in the circlip and then fit the inner bearings outer race...The clip can be located correctly when the case has cooled...Ian
email (option): ian@wright52.plus.com
Thanks Ian
That’s what I had in mind more or less - but asked just in case there was an alternative method
Br
Job
email (option): jonnyob1@googlemail.com
Tonight I dropped the bearings into the cases
I was surprised as to how hot they really needed to be for them to drop in - but a good learning experience all the same
Also pressed the fixed gears onto the main & Layshaft - these were also NoS parts and went together with relative ease with the press
Crankcase assembly- crank install with cams, gears, oil pump shafts & next - then to be followed by cylinder & piston when in the frame
If there are any gems of experience- I am open to guidance
Enjoying it at this time
Job
email (option): jonnyob1@googlemail.com
Fit the oil pump drive shaft and oil pump first before you fit the crank...That way you can check that the shaft and pump turn freely while there's still room to turn the shaft by hand...Also fit the crankshaft pinion to the crank to ensure the fit is good before fitting the crank to the cases...You may need to ease the sliver key to get the pinion fully on...DON'T knock it on if it's a tight fit, ease the key until it's a smooth sliding fit by hand but without side play...Patience is the thing with that job..Put the pinion to one side once you've done that...Also make sure you have the long and short crankcase joining studs in their correct respective positions...
It may sound dumb, but when you put the crank into the crank cases don't forget to fit the mag straps to the crankcase joining studs....How do I know that?:laughing::stuck_out_tongue_winking_eye:...
I put the crankcase on a vice with the jaws wide enough open to accept the bearing boss and so that they are sitting on the primary case face, with the drive side bearings facing upwards...Drop the crankshaft bearing spacer on top of the outer bearing and then fit the crank, feeding the mainshaft down through the spacer and bearing..Make sure the conrod is in the correct position not to foul the crankcase as the crank is lowered in...Finally, apply some jointing compound and fit the aforementioned mag straps and the timing side crankcase half, followed by the three joining bolts etc.. Ian
email (option): ian@wright52.plus.com
Thanks Ian
It was a question of mine in fact to figure if the oil pump drive spindle should be fitted & pump operation checked prior to crank install
It all sounds relatively straight forward
Br
Job
email (option): jonnyob1@googlemail.com
With the cases given a final clean & bearings lubed - I cleaned the cams & idler gear of cosmolene - cleaned the outrigger plate & & bolts
I noticed the fitment of the crank oil flinger - that although it has defined edges - cut out section & a straight edge - there was nothing on the crank for this to align or fit securely against to locate it
Is this correct ?
Is it retained due to the placement of the bearing - spacer & pull from the Cush drive ? It just seems a bit odd to me
I just want all right before I seal the bottom end tomorrow
I have built many Japanese motors & boxes in years past - however - sometimes BSA logic beats me
I have been taking photos here too as I have progressed - hopefully I can collate these into some form of quick view guide
Br
Job
email (option): jonnyob1@googlemail.com
The cut out in the oil flinger plate should be placed in alignment with the big end nut...If you then slightly bend the plate inwards either side of the cut out so that the ends contact the big end nut if you turn the plate, it will stop it rotating should the crankshaft shock absorber nut ever come loose...Ian
email (option): ian@wright52.plus.com
Hi Ian
Thanks again
I checked a number of cranks I have here and all are missing the flinger plate - but this evening I found one where the tabs have been bent back on the upper section and are in contact/ close contact to the retaining nut
I’ll crack on with this tomorrow. Then get it back into the frame at last
Br
Job
email (option): jonnyob1@googlemail.com