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Crankcase gasket
Posted: Thu Apr 02, 2015 6:13 pm
by Isettaman
I am told that my 1951 350cc Bullet did not utilise a crankcase gasket, however, I would like to use one if possible.
Would a gasket from a later Indian bullet fit my crankcase?
Crankcase gasket
Posted: Thu Apr 02, 2015 6:34 pm
by John M
The Indian one should fit, but it may affect the crank end-float. Why not use the thinnest smear of silicone sealant or Wellseal?
Crankcase gasket
Posted: Thu Apr 02, 2015 7:42 pm
by Mark M
It's really not necessary, just use a good quality gasket cement, Welseal (as sold by our Hosts) or possibly even better, 3 Bond, previously known as Yamabond, available from Rex Caunt Racing here in the UK. This is the stuff I'm currently using for the main crankcase joint, obviously it's important to get it right!
REgards, Mark
Crankcase gasket
Posted: Thu Apr 02, 2015 10:10 pm
by Isettaman
Thanks for your comments
I have some Welseal and so shall use some. The faces aren't the best I've seen but I'll have a go.
Crankcase gasket
Posted: Thu Apr 02, 2015 10:19 pm
by papasmurf
Isettaman, back in the dim and distant past I rebuilt 250cc Villiers engine using no gaskets at all.
BUT it did take many many hours lapping the mating faces to do so.
Crankcase gasket
Posted: Thu Apr 02, 2015 10:35 pm
by Chris Tindal
I don't think the Indian gasket will fit 1951 cases as they have narrower mouths around the cylinder base. The Indian engines are based on the post 1955 350/500 common crank cases.
Crankcase gasket
Posted: Thu Apr 02, 2015 10:49 pm
by Isettaman
Hmmm.
Not so easy to lap the faces as one side has a lip all round it.
Crankcase gasket
Posted: Thu Apr 02, 2015 11:02 pm
by papasmurf
That only leaves scraping and smoke fitting, then. (That is a rare skill and even more time consuming and one of the reasons a Purdey shotgun is so expensive)
Crankcase gasket
Posted: Fri Apr 03, 2015 5:36 am
by Beezabryan
Our BSA Golden Flash cramkcase has no gasket & in 2006 was assembled with Yamabond.
30,000 plus miles later it is still oiltight.
Crankcase gasket
Posted: Fri Apr 03, 2015 8:23 am
by Mark M
Lapping on a glass plate is perfectly possible, go to your local glass shop with the dimensions including the hole and they will cut it for you. I have just had a piece done to lap some Constellation cases. Get the thickest glass that you can, 6mm is ideal, and get them to bevel the edges so you don't cut yourself. The hole will probably be hand cut although water jet cutting is possible from larger suppliers though more expensive. The piece I had done cost £16, if I had got it hardened for longer life it would be approx £60 according to the man.
REgards, Mark