corsa won't start

[Gearhart]

if you put gas directly into the cylinder through the spark plug hole and it still wont start its a ignition issue. Either the timing is off or the spark is so weak that when put under compression in a cylinder its not sparking.

[tazland001]

You have lost 40 in compression. If I saw a reading like that and the bike wouldn't start I would remove and inspect the top end. Sometimes when they are at the bottom of the compression range they just will not start or it is next to impossible to start. Try to do a wet compression check and see if the compression goes up. If it goes up to as it should then drops back down its time to pull the top end. You have a vertical cylinder so a wet test will work.

[tazland001]

I wanted to add if there is damage on the cylinder a quick hone and new piston should do the trick if the damage is light. Just use a feeler gauge to check for gap just to be safe. Don't want any slap. The thing is you have to find out why you lost compression or it will or could happen again. The corsa is a good kit so you have to find the problem that caused you to lose compression.

[Meatball]

Possibly a timing issue. Even though the plug shows a spark when hanging out of the motor doesn't mean its operating properly.

Stuck reeds will also cause it not to start. You've proven the fuel is flowing to the carb but is it making it into the cylinder? After trying to start it a few times, is the spark plug wet with fuel?

How old is your fuel? Has it been sitting awhile? Sometimes old fuel collects moisture and can cause starting issues.

Also, did you premix to the correct ratio? I screwed up the math one time and mixed so much oil it wouldn't start. Had to drain it and start over.

[bfowler]

Thank you for all of the information and tips/suggestions, I really appreciate it and all of you. I have work all day today but I'm off tomorrow so tomorrow I will do everything that was suggested.

Currently premixing at 32:1. Going to empty the gas tank and put some fresh gas in there to make sure the gas is nice and clean and it has the correct ratio of gas to oil. Going to add about 2 oz of premix to the cylinder through the spark plug and try to start her up. As per Taz's suggestion, ill also do a dry and wet compression test. Was doing some research and it seems that if the compression rises after a wet compression test then it is the result of bad piston rings. If compression rises I will inspect the top end. I will most likely inspect the top end since as Taz said, there must be a reason the compression dropped so low. Hoping it doesn't have anything to do with the timing since I'm pretty new to scooters and I have no idea how to fix/inspect that. We will find out more tomorrow, thanks again!

[Wheelman-111]

Greetings:

I had a Nikasil 49mm/78cc that measured 115PSI after assembly. Despite a mild pipe and rookie skills, that scooter went over 55MPH. My check of my first Corsa showed mid-120s for compression. That scooter went over 71MPH. I don't think compression is the issue. Corsas make power with RPM and pipe, the "Thuds" aren't all that powerful, but they keep coming, fast.

I've started chainsaws and weed-eaters on 3 year-old gasoline. I don't think fuel is the problem, either.

I would check the reed block for a crack or a chunk of foam wedging one open. That's happened to me when a 9 year-old stock air filter got crumbly and pieces got sucked off.

[Gearhart]

I agree with the compression stat. My corsa's have always been in the 120's according to my compression tester. I don't know how accurate it is but mine seem to run great.

[Meloshameless]

Sounds like the bore walls are all scored up. Id try a fresh plug. If still no fire. Pull the top end and check the bore.

[tazland001]

That is a good question. Did you install a new plug? Thats first thing you need to do is a get a new plug. It is not uncommon for a plug to foul. That would be an easy fix

[Meloshameless]

My first corsa blew from scoring. Ate some carbon build up from exaust port. That stuff is like sand. The 2nd one i thought was also blew so i bought x2 new corsas and turns out it was just the plug. Lol. But it acted the same so i didnt bother checking. Doesnt hurt to have an extra one laying around i guess..

[Rip_City_Spree]

can sell one to me melo!

[Meloshameless]

I thought u liked ur malossi cast? Itching for a corsa again? Lol...

[Rip_City_Spree]

cast is great if you want to go slow and have the same bore forever. and yes I need more power. that c16 rep would pair great with a corsa and then Id be able to keep up with you guys.

[Meloshameless]

But u keep up just fine, when im at 1/8 throttle...

[Rip_City_Spree]

All I hear is braaap braaap braaap braaap to my left.