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Getting my cylinder bored out.
Posted: Tue Jun 09, 2009 12:20 am
by Arctic Wolf
Im getting my cylinder bored out .50 on my 50cc motor tomorrow. Im just wondering what my new cc would be?? I read a good article on this a few weeks back but cant seem to find it anymore. Is there anyone out there that could possibly help??
Id go for a big bore kit.... But when I bought the bike it already had one and the guy didnt put the clip in proper. So needless to say there went the piston. You know the saying. Once bitten Twice shy... I wont go with another one for a while. Instead Im going to play with it for a lil bit and see where I end up.
Re: Getting my cylinder bored out.
Posted: Tue Jun 09, 2009 5:34 pm
by Kenny_McCormic
If you are boring it for power there isnt any to be had doing that, you bore em out when they get too worn to use standard size pistons in em. You are only getting a whole matchbook covers worth of bore.
Re: Getting my cylinder bored out.
Posted: Tue Jun 09, 2009 5:50 pm
by Arctic Wolf
Yeah but I know that I saw something on this matter. I know it didnt raise the cc's much but it did raise the cc's non the less. So what would me new cc's be?? 52?? 55?? Its gota be something
Re: Getting my cylinder bored out.
Posted: Tue Jun 09, 2009 11:09 pm
by Kenny_McCormic
I doubt its over 51, any gain in power will be lost throwing the huge piston around on the now too light crank. Balance is everything.
Volume = Pi x R Squared x Stroke
Posted: Tue Jun 09, 2009 11:11 pm
by Wheelman-111
Greetings:
Now don't you wish you'd payed attention in Geometry class?
A 0.5mm bore-out on an SE50 (AF05) nets you 50.5cc.
A 0.5 bore-out on an AF16 (Dio SA50) gives you just a bit more. -50.7cc.
Look up the bore and stroke specs of your model, add the 0.5 mm diameter of the new bore and plug in the numbers.
Re: Getting my cylinder bored out.
Posted: Wed Jun 10, 2009 3:44 am
by Arctic Wolf
Thank You Wheelman. Thats what I was looking for... It was that simple.. Not all the Jargin about performance.
Re: Getting my cylinder bored out.
Posted: Thu Jun 11, 2009 6:42 pm
by Towlieee
I don't know scooters, I do'nt know 2 strokes..
But generally, a 'next size up' bore is .02 over, not .2, not .5, .02!!
It's not about making more power, it's about getting fresh cylinder surface so your rings can seal
On a side note, how much you spending on this bore and piston? Have you looked into big bores? You could go 70cc+ for as cheap as $130++
Re: Getting my cylinder bored out.
Posted: Thu Jun 11, 2009 9:13 pm
by Kenny_McCormic
.5mm is just short of .020"
Re: Getting my cylinder bored out.
Posted: Fri Jun 12, 2009 12:10 am
by Towlieee
Kenny_McCormic wrote:.5mm is just short of .020"
ahhhh I'm a retard, I was thinking they were saying .5"
that's what I get for opening my mouth instead of reading more

Re: Getting my cylinder bored out.
Posted: Thu Jun 18, 2009 10:27 pm
by Lunytune
I don't know what kind of prices you are looking at for bore, new piston and rings, but I tried that route and was quoted "around" $200. The HondaCharlie delayed a month, so I cancelled him out, and bought a kit on eBay for $165 plus shipping. My local Honda man was talking in terms of "one over" and "two over", meaning one millimeter and two millimeter. He didn't talk inches. My overbore kit was 6 over (equivalent to 243 caliber bullet), putting it up to about 72cc displacement. I'm not sure about a 1/2 millimeter, or even if there is a piston and ring that size. That's not much more than honing. For the cost involved, I'd go with the overbore kit.
Re: Getting my cylinder bored out.
Posted: Thu Jun 18, 2009 11:55 pm
by maddog
its .060 or one over, yes i bought several polini 72cc kits yrs. ago for $90 no they are not for sale, yes my moderator days are comming

Re: Getting my cylinder bored out.
Posted: Fri Jun 19, 2009 1:55 am
by Kenny_McCormic
maddog wrote:its .060 or one over, yes i bought several polini 72cc kits yrs. ago for $90 no they are not for sale, yes my moderator days are comming

1 millimeter = 0.0393700787 inches, nowhere near .060, no your mod days are not coming XD
Re: Getting my cylinder bored out.
Posted: Fri Jun 19, 2009 7:48 am
by Lunytune
Kenny_McCormic wrote:maddog wrote:its .060 or one over, yes i bought several polini 72cc kits yrs. ago for $90 no they are not for sale, yes my moderator days are comming

1 millimeter = 0.0393700787 inches, nowhere near .060, no your mod days are not coming XD
You mean understanding metrics is all that's required to be a mod? Then sign me up. I thought what was required was knowing the firing order on all Sprees and Elites. I've been tinkering with metrics in old military rifles so long I've got 'em mesmerized. That's how I knew the Polini kit was just under 1/4" overbore.

Been crunching the numbers, but just last night bid on a set of metric calipers so I won't have to anymore. My brain doesn't function like it used to.
