GP150 cylinder - Mick Abbey Tuned - Back to the old school !

[tony]

starstream bore 57 stroke 48

vega bore 46.4 stroke 44

Cheers Nick. I take it then the diameter of the webs is the same. If this is the case why hasnt anyone looked into spark eroding or machining a new hole for the big end on the other side if the starstream crank webs are so rare? Or is this just being silly and impossible? Or has anyone made a new crank for these motors?
Is there enough metal on casing to fit larger webs? Is the spline fitting the same as a gp?
So many questions...

[sean brady scooters]

are you thinking along the lines of 54mm stroke/54mm bore tony........?

[tony]

The magic number?! I'm just curious. I have a possible project. We'll see. Not my money.
It seems so far that there are obsticles re the tune. Not a fan of this single chain at all. That sounds dodgy to me. Also this rare crank business. Thats not good. However I like the square stud spacing..(the prob with lammy and pranges). So this is a plus. I reckon they will vibrate like hell without a balanced crank mind you due to the vertical position of the cylinder if we go mad on the tune. Any one know the web diameter? I bet its similar to a smallframe crank?

[jonny snatchsniffer]

cant you use an eccentric pin ? and a reedvalve smallie barrel, might not give you much over 120cc but the stud spacing might be close

[sean brady scooters]

web diameter 80mm/crankcase.....82mm.......i think tony.........
small frame vespas are approx 87mm are they not.......(inlet side)...........

[tony]

Yes mate.... I wonder...
Anyway enough of this jibber jabber... i've a bike to rebuild!

[dapper]

Getting back to the original thread, any news on putting Mick's tuned cylinder in an engine and testing? I am eagerly awaiting test info on this (like a kid waiting for Xmas)

[grimspeed]

so its 2010 now and i have no finger nails left.
have we tested the 150 cylinder that this thread was started for?

[drunkmunkey6969]

yes...ages ago, it was covered in another thread, you'll have to search for it.....anyone got a link?

[scooterslag]

I know its a old thread now but has anyone fitted this tune to their scooter? and if so what's the performance like on the road? reliability (especially using a original spec piston) and fuel economy?