Cylinder shot, to go big bore or not?

the496rocket · Post by **the496rocket** » Sun Sep 18, 2005 9:29 pm

I figure my cylinder is worn from the engine running so long without oil, and having 8000 miles, I am thinking of getting a big bore kit, I am looking at the Polini Contesta 70cc kit on ebay, it comes with everything, and it comes with different jets, so would it get enough fuel? If not, what does big bore require? Also where else can I get a bigger cylinder and piston, (preferrebly 70cc or larger) or is it a waste of time and should I get stock. I want to get me aero going faster.

MySpree · Post by **MySpree** » Sun Sep 18, 2005 9:40 pm

whut type of scoot do ya got?

the496rocket · Post by **the496rocket** » Sun Sep 18, 2005 10:01 pm

1986 Honda Aero 50, I posted earlier wondering what the problem is, I figure it is a worn cylinder. With new rings, it didnt seem to have hardly any compression, I could hold my finger over the spark plug hole and crank it, and it was nothing. I am just wondering what big bore kit to get and where to get it, and if it is worth it or will I need new carb, exhaust etc

MySpree · Post by **MySpree** » Sun Sep 18, 2005 10:04 pm

ok now i will say. plz bak me up weete toast and dio or correct me.... YOU CANT PUT A BIG BORE ON A AERO50 ENGINE!!!! ONLY A AERO 80 AND STILL NOT WITHOUT SOME FABBING!

the496rocket · Post by **the496rocket** » Sun Sep 18, 2005 10:19 pm

Then what the heck is this? It says right in the item description that it will fit an 85-87 HONDA AERO NB50

http://cgi.ebay.com/ebaymotors/POLINI-7 ... enameZWDVW

Scam? or Rare?

darat · Post by **darat** » Sun Sep 18, 2005 10:47 pm

well my elite needed new rings and then i went full blown raceing 65cc eng
so i would say to do it.

vette76 · Post by **vette76** » Sun Sep 18, 2005 11:07 pm

no! that is a DIO kit for sale in that auction. hes saying he has a kit available for your scoot. email him and work it out. the kit listed wont come close to fitting your bike.

the496rocket · Post by **the496rocket** » Mon Sep 19, 2005 12:48 am

He says he has multiple kits available, and let him know the make of your bike. He has good feedback, and here is a site where someone restored an aero 50, and they said they bought a 70cc cylinder kit off ebay, and the one I am looking at is 70cc, and it wasnt that long ago. That is why I am wondering if it will fit. I think if it was a scam he would have some negative feedback. Here is the site.

http://www.minidoodle.com/id61.htm

what do you think?

vette76 · Post by **vette76** » Mon Sep 19, 2005 6:11 am

by all means, get it.(if he says it will fit) it will be cheaper then getting the stock stuff if it turns out u need a overbore. the thing is, u might need a bigger carb, and definately a bigger exhaust to get the most out of this kit. but, he would be the one to ask.

good luck man.

Post by **noiseguy** » Mon Sep 19, 2005 9:46 am

The '85-87 Aero has a Polini kit available through that vendor. If it fits it would be the way to go; a stock overbore will run over $100 with stock parts, the Polini kit is about $150, as I recall.

I have a theory that this kit could be made to fit the Spree too with an adapter plate.

You may want to contact your local Vespa/Piaggio dealer as well; these places seem to be able to get Polini kits through their distributers.

darat · Post by **darat** » Mon Sep 19, 2005 9:59 am

if it does work i will get one for my spree.

the496rocket · Post by **the496rocket** » Tue Sep 20, 2005 9:41 am

Ok, I took the engine apart, and it had a stuck ring, I got stuck the SAME WAY it got stick before, the 2 little tabs on the ends of the ring, 1 of them broke off (brand new rings) and got mushed in the piston, and expanded the metal causing the ring to be stuck. This is the same problem as before!
Is this a problem with the cylinder or piston? or is it bottom end? rod, crank? I am going to get the 70cc kit, cause the cylinder is shot now.

Also Should i go through the engine before I put on the new cylinder and piston to inspect and check for sand? or can I used compress air and blow through the engine? Thanks

vette76 · Post by **vette76** » Tue Sep 20, 2005 2:24 pm

sounds like u installed the piston the wrong way and it clipped the exhaust port. the piston is now bent. need new. exhaust port side is labeled "ex" on top of piston.

Post by **noiseguy** » Tue Sep 20, 2005 3:31 pm

Either that or the rings weren't aligned on the locators the right way.

Go big bore, let us know how much faster you go.

the496rocket · Post by **the496rocket** » Tue Sep 20, 2005 5:36 pm

I also bought a speed variator clutch from that guy, that other guy I mentioned on minidoodle installed the 70cc and variator, and he says his will go 45, the aeros will always go about 35-38 stock, and I guess with that combination, you get good results. I am going to tear down the bottom end while i am waiting, i a skeptical that there might be some sand down in there, and with a brand new engine, better safe than sorry right ?

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Cylinder shot, to go big bore or not?

Cylinder shot, to go big bore or not?

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