Chainsaw Repair

hello
thats my first message on this forum
im 33 years old french canadian and looking for help here
my English are not very good but i do my best!
im on the way to rebuilt  2 old saws my dad give me last month
one is a r420 and the other is a p70
in the past my dad was doing competition whit these saws
i have a old racing crankshaft and i need a new crankcase gasket to put it on
but, i dont have the part number for the crankcase gasket and if i can put my hands on a new complete gasket set its would be great!!
anybody known the crankcase gasket number here, or a place to order it??
i see on the    http://store.chainsawr.com/ some gasket but i need the good number to place a order!
any information are welcome!
thanks
Rancho

thanks for your information
i think i will cut the gasket myself like you
regards
Rancho

thank you !

He's how I've done it:  clean case half surfaces with acetone then lightly spray the mating surface of one case half with 3M spray adhesive. Next, spray a sheet of gasket paper with the 3M adhesive and let it air dry for 3-4 minutes, lay the gasket paper with the sticky side up on a flat table and set the case half on top of the gasket sheet.  They should be bonded together now. Next get an x-acto knife and carefully cut out the voids.

++1
Doing it this way the Exacto knife cuts against the edge of the casting and makes cutting a gasket very easy. The gasket will look Factory made when done.