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Barrel Skimming.... top or bottom?
Posted: Mon Feb 13, 2012 2:43 pm
by MadAd
Started assembling my race bike engine and and found that the squish is about 1.8mm so I need to get my barrels skimmed to get my squish down to the desired 1.2mm.
Is it better to get the barrels skimmed on the top or the bottom?
Re: Barrel Skimming.... top or bottom?
Posted: Mon Feb 13, 2012 2:47 pm
by Rane850
I had mine skimmed 0,5 from top. I think it is nearly impossible to do it from bottom since cylinder sleeve skirts.
Re: Barrel Skimming.... top or bottom?
Posted: Mon Feb 13, 2012 3:04 pm
by MadAd
Thought the top would be the best option but have heard of people skimming the bottom.
Not sure how though!!
Re: Barrel Skimming.... top or bottom?
Posted: Sat Feb 25, 2012 11:45 pm
by MadAd
Just thought I would update this post.
My barrels have been skimmed now.
My dad did the machining and we went for skimming the bottom as it made setting up on the miller easier and with there being a recess between the gasket face and the where the cylinder skirts hang out there was little danger of hitting the cylinder casting.
Re: Barrel Skimming.... top or bottom?
Posted: Sun Feb 26, 2012 12:25 am
by Killerwhale
MadAd wrote:Just thought I would update this post.
My barrels have been skimmed now.
My dad did the machining and we went for skimming the bottom as it made setting up on the miller easier and with there being a recess between the gasket face and the where the cylinder skirts hang out there was little danger of hitting the cylinder casting.
Peder on this site has the same tuner as me and on his they took a bit on the head and a bit on the cyl...don´t know the exact though...
Re: Barrel Skimming.... top or bottom?
Posted: Mon Mar 05, 2012 4:59 pm
by MadAd
To get the 11.5:1 claimed for the pistons I would need to machine the head as well but I thought running 11.3:1 was close enough for now.
Got some picks showing where the barrels were machined if anyone is interested?
Re: Barrel Skimming.... top or bottom?
Posted: Mon Mar 05, 2012 5:28 pm
by fung
so we dads ARE good for something, other than dad jokes and long stories.
you are a lucky lad to have the old bloke helping out
.
piccies would be very nice, thankyou
cheers
fung
Re: Barrel Skimming.... top or bottom?
Posted: Mon Mar 05, 2012 8:40 pm
by MadAd
Right picks are here!!
Yes Dad's are great there is no way I could do half the things I do without his skills that I'm doing my best to pick up as we do things together.
I just need a bigger workshop to get a lathe and miller in then I would learn faster!!
It is two way though as I am one of his IT consultants.
Ok here are the barrels after the skim.
And here is a close up showing the relief between the barrel mating face and the cylinder wall.
