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Porting cases

Posted: Fri Nov 06, 2009 5:14 pm
by dapper
Done a search but can't find it. There was a thread with photos showing the crank mouth ported with extra ally removed to provide better flow up to the transfers, and those thin bits of ally casting removed too. Can someone kindly provide me with a link to it, as I'm thinking of doing the same and the photos would be a great help?
Think it was you Sean or Dan??
Ta very muchly ;)

Re: Porting cases

Posted: Fri Nov 06, 2009 5:21 pm
by sean brady scooters

Re: Porting cases

Posted: Fri Nov 06, 2009 6:10 pm
by dapper
Thanks Sean, but I'm sure the one I'm thinking of had close ups of the inside of the crankmouth showing smoothing out of the tract around the crank webs and those thin casting bits removed. It's just that I've got an engine casing on the bench and when I sit the cylinder on it and looked through from the crankcase, there are all sorts of edges that could be smoothed to aid flow to the transfers. I'm looking do do a similar job to what you did on that 150 engine of your mates.

Re: Porting cases

Posted: Fri Nov 06, 2009 7:40 pm
by Dell Oughta
Hi dapper
there's some pics on my thread 'basket case' I knicked the idea from SB and it appears to have no detrimental effect on the running of the engine (23 bhp 85mph on PSN dyno) ive had 80 out of it on the road, but on my last outing I cracked the pipe....again! So it's not been on the road for a few week, it's not even made it to brid yet (which was one I first started building it over a year ago.

Mike

http://scooterotica.org/tempforum/viewt ... =10&t=1711

Re: Porting cases

Posted: Fri Nov 06, 2009 7:47 pm
by dapper
Thanks Mike. Those were the pics I was after, especially the first one of the inside of the crank ;) :D

Re: Porting cases

Posted: Fri Nov 06, 2009 8:45 pm
by thackers
I was under the impression that when you removed the metal bits that sit round the front of the crank etc you create more space and so loose compression, thats why they used to pad out the crank cheeks, wasn't it

Re: Porting cases

Posted: Fri Nov 06, 2009 9:21 pm
by Knowledge
Careful Thackers, you're in danger of opening-up the high-primary-compression-ratio/low-primary-compression-ratio dabate.

There'll be tears before bedtime.