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I bought a used corsa cylinder and head...

Posted: Thu Mar 05, 2009 2:50 pm
by zilerobe
So a guy I am aquatinted with sold me a corsa cylinder and head a couple days ago with gaskets that he had sitting around for $50. It is used but the wall seems smooth and the head is still pretty mint. I ordered the piston and rings etc from daywot and had the cylinder honed yesterday.

I have a 98 elite s with a high speed variator and 9.1:1 gears.

2 things;
What setup do I need to get this thing to run without blowing up?
and...
What setup should I eventually get to get all I can out of it?

Right now all I can afford to do is ...hardly anything. I'm wondering if a stock carb/filter (with re-jetting (tell me what you guys know about possible setups)) and pipe will be harmful to the point of seizing.

This summer when I move back home and can start working again I won't have a problem buying a larger carb and exhaust but I'm trying to get away without it for the time being.

Thanks!

Jetting To Corsa.

Posted: Thu Mar 05, 2009 4:37 pm
by Wheelman-111
Greetings:

I broke in and ran my Polini 65 on the stock carb with jets on the lean side but no obvious ill effects. The Polini came with an 86, I believe. If you didn't get a jet with your kit, you will surely need to do something. You can drill your stock main out to 90-ish and see what the plug says. Leave the airbox on for break-in. Ping me for drill bits if you like.

Posted: Thu Mar 05, 2009 4:37 pm
by burnt_toast
Can get away with upjet and stock pipe for now, keep the stock airbox in this case instead of going to open filter.

To get best performance you'd want:
24-28mm OKO/Keihin
CT manifold + throttle cable
PG Long or similar

All of which set you back on $$

Posted: Thu Mar 05, 2009 5:58 pm
by zilerobe
Alright.
I guess I'll start at a 90 main and see what happens from there. Spring break is this week and I'm obviously too broke to go anywhere so I get to sit home and mess with my elites. Thanks for the input and I'll keep you updated with how it works.

Posted: Fri Mar 06, 2009 5:04 pm
by losthope
id start out with nothing smaller than a 95 main. ive got an 88 main in my elite and its mostly stock

Posted: Fri Mar 06, 2009 7:22 pm
by scooterwerx
a lil rich is much better than a lil lean, especially on a 2 stroke!

Posted: Fri Mar 06, 2009 11:06 pm
by maddog
if you want your corsa to survive, change the gear ratio to 7:3:1 and go to a 24mm or 28mm carb, open the oil pump to full, the stock airbox is fine just punch out the plugged side on the intake located on the cover.

Posted: Sat Mar 07, 2009 11:38 am
by Kenny_McCormic
Carb
Pipe
Gears
Oil pump plug and premix 24:1

Posted: Sat Mar 07, 2009 1:52 pm
by zilerobe
9 to 1 is too low? I want it to be quick and on my daily commute all I have are 35 mph roads tops. Think a higher gear is necessary?

Gearing

Posted: Sat Mar 07, 2009 2:31 pm
by Wheelman-111
Greetings:

Elites with stock gearing can exceed 40 with sufficient power. The fastest way from 0 to 40 is with stock 12:1. Anything lower will increase top end potential, but at the expense of slower acceleration to get there. If you really don't plan on exceeding 35, then spend that gear money elsewhere.

Posted: Sat Mar 07, 2009 3:14 pm
by zilerobe
I'll more than likely keep the 9 to 1 unless my route somehow changes and I need to cruise faster. Right now I have everything ready to go I'm just waiting on the parts which should arrive sometime this week. I drilled out an extra jet I had to .938 mm as a starting point. Ill increase the size in about 3 hundredths increments until its too rich then I'll back it down an increment. If anyone has a setup that they have already dialed in im all ears. Otherwise this is the best method I can think of. One of the exhaust pipes I have has the restriction washer removed and I plan on running the corsa with that. Any other changes to the intake aside from the jets anyone knows of?

Posted: Tue Mar 10, 2009 1:22 am
by zilerobe
I just put it together this afternoon. It ran fine through about half throttle then sputters and 4 strokes. yay for tuning! now I know what my whole day will consist of tomorrow....

Corsa Jetting

Posted: Tue Mar 10, 2009 1:34 am
by Wheelman-111
Greetings:

With the stock Airbox & stock pipe, 93 may already be too rich. Check your plug after a hot ride. Anything darker than Fry's cocoa suggests you're on the rich side of ideal. I still have that Keihin 88 if you want it. My bit set starts at 89 - 91. PM if you need any/all.

Posted: Tue Mar 10, 2009 4:31 pm
by zilerobe
Thanks for the advice and offer Wheelman. My dad has a nice needle-like bit set that starts at .02 inches and goes up by .001 inch increments, perfect for drilling out jets. Ive got a ~88 size jet in there now and it is running very well. With the less-restricted pipe it almost sounds like my rm 125! ha. I've been riding it around the neighborhood with about 80:1 oil ratio in the gas tank which I might continue to run until I finsish the project completely with an oil plug and 32:1 premix.

Smokin'

Posted: Tue Mar 10, 2009 4:36 pm
by Wheelman-111
Greetings:

I'd like to score that bit set myself. Can you ax Dad where he got it?

I've run 50-60:1 in the tank since the 65 Conversion, and left the pump wired to deliver full volume just before full throttle. Seems to work fine so far. (600 miles) I see no need to disable the pump, which partially compensates for low and high-need situations. Keeps the smoke to a minimum at idle too.