ET: Engine (Twin) Primary side main bearings

Cyborg

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VOC Member
Youtube is your friend.

Youtube doesn't have everything. I have successfully set a frozen banana instantly ablaze, by creating plasma at home with nothing more than a microwave and a few closely guarded incantations. No video evidence anywhere., you'll just have to take my word for it.

Bill I can't get much life out of my soldering gun so can't confirm. I vaguely recall that for some mysterious reason it makes a difference which direction you pass the bearing or screwdriver tip through the soldering gun. But to be honest I haven't used this method since my teen years which were in the 60's and 70's if you get my drift.
 

Pushrod Twin

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Timken main bearings are not a new idea. H-D have been fitting them since at least 1936. They are fit and forget. A well known vin racer(name witheld) has used them with 100% satisfaction. When asked he said"Ihave to use them as I run oversized mainshafts". I am yet to be convinced about the clearance as H-D manuals give 3-4 thou nip. Like in a car differential pinion bearings.
Harley Sportsters run 1" mains shaft size. There are Vincents running around NZ with taper race mains, it has just never been turned into a big deal. The Sportster motors have a steel insert in the cases and if I recall correctly, the taper bearing set is a pre-assembled cartridge arrangement?
 

oexing

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VOC Member
For demagnetizing get one of these , you will use them a lot for your measuring equipment or drills etc. .
demagnetizer
Any decent toolroom with a surface grinder has an integrated demagnetizer on this machine I´d say.
For turning hardened parts get you some CBN tool tips, from China at good prices, well these days that can take a while . . .

When I found these narrowed down no lips roller races in Vincent engines I disliked them at once. Didn´t think about taper rollers on cranks but instead, like in most of my engines, I went for cylindrical roller races - in all places in the B-Rapides, except for the ball bearing behind the clutch. As about all fits in the Argentinian relicts were knackered I bushed all after a minimum boring for getting good sizes for light press fit . Bushes were alu again, bored after pressing in for bearing shrink fit of 2 - 3 thou depending on sizes. I could not find lipped imperial size roller bearings, a bit rare I guess. Anybody got a clue about where to find, just for information ??
Anyway, at this stage I decided to go metric for choice of bearing types, lipped or not on outer or inner race, metal cage or glass fibre reinforced cage, last type my choice definitely. The crank was homemade one piece, so 30 mm mains, 20 mm at timing side outer bearing. I aimed for easy fitting so inner races got no lips except both inner bearings with lips at the crank web side.
The taper roller mod requires the outer bearing inner race to be a push fit as you can only mount it after having the crank in the case. But at high load places I prefer a few microns press fit so my design seems more to my likings. Also setting play in a taper roller design is critical, not so easy to tell what happens in an alu case when hot.
So depending on avaliable bearing types I believe it to be a suitable idea to have a standard 1 " crank mains bushed for 30 mm metric bearings. You don´t have to weaken the cases for a repair bush when the 63,5 mm imperial fit is unusable. Instead you´d just bore the case lightly and reduce the fit for 62 mm o.d. , 30 mm main shaft, 20 mm wide, resp. 16 mm wide. You´d get the modern PA 66 cage and more rollers , higher load numbers. Plus the combinations of lips you want to have.
I made a combination of lip (for the shortened inner race of outer bearing drive side) plus steel bush for the triplex sprocket. So any wear from the load of ESA springs goes onto the outer face of the lip, no longer on the inner race directly which is not much on a standard inner race. That should be allright for a long time with my BMW type ESA as I think it will need less spring loads with the progressive lobe shapes, springs here not tasked with preventing end bashing.
The outer circlip was no more usable so both bearings locate on both sides of the inner circlip, a spacer race between inner races acts as the inner for the shaft seal in an alu holder, no scroll type here for definite engine venting via valve caps.
I would hate to drill screws in the surroundings of the main bearings, that weakens the case a lot !! Another reason to bush with alu bushes and a smear of 638 Loctitewhen pressing in . Shrink fit for lipped bearings of course, no Loctite then.

Vic

Two roller inner races plus seal spacer and the bearing lip/sprocket bush combi right :
P1070540.JPG


sprocket bush half mounted :
P1070830.JPG


sprocket thrust face :
P1070832.JPG


drive side :
P1070544.JPG


62x30x20 mm mainbearing bushed , seal between mains :
P1070623.JPG
 

oexing

Well Known and Active Forum User
VOC Member
Yes, exactly, I did not want to drill more holes at the opposite side for adjusting the balance factor. Instead I had an idea to drill holes at same radius into the crank case to be able to pull these loctited plugs out after having road tests some day while the engine is on the bike. But in the end I did not so hope for acceptable smoothness as is.

Vic
P1050247.JPG
 
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