Author Topic: New crank bearing  (Read 1045 times)

Offline Drew Back

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New crank bearing
« on: 26.01. 2015 22:41 »
Since I have cases appart I thought I would replace crank bearing however the only bearings I can find is the later model roller would this go in without any issues/better replacement vice the ball bearing type??

Offline muskrat

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Re: New crank bearing
« Reply #1 on: 27.01. 2015 02:31 »
G'day Drew.
My book gives the bearing size for the long stroke in imperial as ID 1.12" OD 2.5" width 0.62" ball 67-1240.
The short stroke is metric ID 30mm OD 62mm width 16mm roller 67-670.
The draganfly site https://www.draganfly.co.uk/index.php/bsa/bsa/a710--b3133--c101112--m202133/category/876-pre-unit-a-group    says 67-1240 use 67-670. *dunno*. The 67-1240 is an order in.
IF it (the roller) does fit the crank would need shimming like the short stroke as the long stroke is held in position by the ball bearing.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Online Brian

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Re: New crank bearing
« Reply #2 on: 27.01. 2015 04:54 »
This particular subject has been well covered in the past as roller versus ball.

The "longstroke" motor was fitted with a ball bearing and I would recommend putting a ball bearing back in. In this case I believe the ball bearing to be better than a roller.

Drew if you have to order a bearing make sure it is a know brand, if anyone tries to sell you a bearing that does not have the manufacturers brand on the actual bearing then do not buy it. Unfortunately like a lot of stuff there are some very poor quality bearings on the market.

Offline Drew Back

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Re: New crank bearing
« Reply #3 on: 27.01. 2015 08:37 »
Thank you that is exactly what I thought I will be sticking with the ball..