Author Topic: 1975 G.E.M catalogue  (Read 760 times)

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Offline tony27

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1975 G.E.M catalogue
« on: July 06, 2016, 01:44:06 PM »
« Last Edit: July 06, 2016, 01:50:12 PM by tony27 »

Offline skypig

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Re: 1975 G.E.M catalogue
« Reply #1 on: July 06, 2016, 04:26:09 PM »
Thanks for that.
I love these old aftermarket catalogues.

When I was a kid (and could ride reasonably fast) I would dream of being able to afford any mods.
Now I'm old and slow, I have a few "tricked up" bikes. (While I enjoy racing them, I'm embarrassed and depressed about MY performance.)

I note:
1. The bikes were so undeveloped that aftermarket improvements could mean massive gains.
2. "Adding boost ports, modifying Pistons and intake ports" were considered standard fare, and within the capabilities of most riders.
Many of today's riders struggle to wash a bike, let alone perform machining modifications. (Option 1 let dad wash it. Option 2 stand back and blast it with a pressure washer.)

Offline tony27

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Re: 1975 G.E.M catalogue
« Reply #2 on: July 06, 2016, 05:15:40 PM »
Unfortunately I haven't seen the instruction sheets that came with the kits to see what they recommended as far as holes in the piston.
I got hold of a unopened kit for a 250 & up Maicos for a mates collection which as far as I know is still unopened
The extra ports in my CZ cylinder are really nicely done window shapes & from what I've read were probably done using a jig to position them, CR high performance uses plain round holes in his conversions now which look to be in the same place. He supplied me with a drawing of the holes he puts in pistons
I'm just waiting for the cylinder to come back from having the worn exhaust port machined & a new sleeve for the header fitted then I'll be fitting my kit onto the bike to see what it does, as far as I know the rest of the ports are standard