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kickstart oil seals
Posted: Tue Dec 04, 2012 9:44 pm
im rebuilding a 1951 square 4 with a BA box that had grease as a lube. I wish to convert this to oil, or oil and grease, but was wondering about the effectiveness of the felt washers in the outer casing by the kickstart bearing. Will these hold oil in the box or is a modification needed - rubber oil seal?? anyone any ideas, as draganfly motors do not stock anything.
Posted: Tue Dec 04, 2012 10:12 pm
Where are you Mark? Do have any pictures of your bike?
Posted: Tue Dec 04, 2012 10:25 pm
I leave the original felt? and use the grease nipple to fill the bush area with grease regularly. The grease stops the oil leaking. You could probably fit a modern seal. I'm not sure whether you would have to machine the recess a bit. Nev
Posted: Wed Dec 05, 2012 10:16 am
If youre keen on modern seals,you might try a quad o- ring or two to slightly compress in the space,and seal up against the face of the steel bush.A more effective seal is called a Lambda seal,they start at 20mm shaft dia.and up.Neither require machining.I dont think anything is necessary,if you have a good fit between shaft and bush,as the shaft is well above the oil level.Good engineering practice says the lower gear shaft should be submerged in oil only to the centre line.Any higher and the oil will overheat from churning.Regards John.
Posted: Sat Jan 05, 2013 12:35 am
On the BA box of my 1946 Sq4 I had machined a groove near the outside end of the kickstart shaft to take an o-ring. There is plenty of "meat" on the shaft for this and the o-ring keeps the oil or grease in the box. There is no detectable restriction of the kickstart movement. Any good o-ring supplier could advise you as to the recommended size of the groove for that application.