Can anybody help me out? You'd save me ripping out my hair! :D

[fmlyhm9191]

For a while now, my scooter (Kymco Cobra Racer 50cc) has been acting up. When I first got it, it started first time everytime. Now, it makes a god awful sound when I try to start it up. It used to eventually get going but now it won't. Someone said that the flywheel may be knackered. I'm not mechanically minded so I don't know any of this jargon. I've recorded a video of the sound it makes with the hope that somebody more technically minded can assist me!



I've searched for a flywheel all over but cannot find one for my bike - if it is this, where do I get them from?

Thank you!

[sidthesloth]

I don't hear any unusal noises myself, just the starter motor turning the engine over. Your problem sounds to me to be that it will not start, have you checked for spark at the spark plug?

[JustWantToRide]

Sidestand is up, kill switch is set properly, brake is on? 

Is your spark plug oil fouled?

The flywheel is a part of the crank (what the piston and rods connect to).  It is generally just a lump of metal used as weight to balance out the weight of the piston and rod.  Not much that you could do to mess it up.

[axy]

For a while now, my scooter (Kymco Cobra Racer 50cc) has been acting up. When I first got it, it started first time everytime. Now, it makes a god awful sound when I try to start it up. It used to eventually get going but now it won't. Someone said that the flywheel may be knackered.

People definitely pull out those diagnoses out of their butt. Whoever said that cannot distinguish flywheel from flamingo.

No strange noise there, other than the scoot not firing up (which is not a noise).

I had Cobra 10 years ago. First, I see open air filter there. 2 stroke scoots are sensitive to air intake, some of them will not even idle without air filter and most cannot increase revs at all with stock carb and removed air filter. Put back on regular filter, unless you have big bore kit, re-jetted carb and sports exhaust can.

Check/replace plug, check spark plug cable, check auto choke and finally, check intake port (4 stroke engines do not have then, 2 stroke engines do) - sometimes they get broken.

[thebatman]

Yeah, no "odd noises" there... Sounds like no fire?
Keep us posted on this. It sounds like axy and others have you on the right track

[fmlyhm9191]

Thanks for all your replies guys!

I can remember the guy I bought it from telling me he'd re-jetted it. He also put on a sports-exhaust somewhat sloppily. It leaks at the back. I was going to replace everything back with stock anyway, as he gave me everything he had taken off.

For the price I paid for it I knew I was going to have to do bits at it. But like I say it used to run like a charm. Started first time. But because I can't legally ride it as of yet, all I've been able to do is start it up, give it some throttle and fix it up. My intention was to have it all working for when I can ride it, so I don't have to do anything else at it - aside from the usual things.  

I'll keep everyone updated on here though.

[sidthesloth]

From what I heard on the video, there are no unusual noises. I would be looking at the cdi first as they can be a problem on these small Kymco 2-stroke scoots. Also, chaeck that you are getting fuel to the cylinder.

[JustWantToRide]

With a K&N pod filter and a leaking exhaust - be careful not to run it hot and burn it up.  Fix the exhaust leak before you do anything else.  Then pull the plug and give us a picture of it's tip.  If it's been running hot then it may be fouled  with white deposits - which means you'll have to replace the plug (I own a plug bead blaster and clean up oil fouled plugs - but hot fouled plugs I just toss).



If the plug doesn't look like it was running hot then clean up and dry it off - then put it back in cap and hold it against a good ground source (unpainted frame bolt, bare engine metal...).  Carnk the starter and see if you're getting a spark.  If you are - then turn it back off and with the plug still out and no throttle - kick the engine through 20 or 30 times to clear out what is in the cylinder.  Then put the plug back in and try it again.


2 strokes can foul plugs easily - especially when you aren't riding it or aren't riding it hard enough.  I doubt you can run it hard enough on the stand to keep if from oil fouling, and I bet that's all it is.  Find some smooth dirt trails that you can ride it on or a big empty parking lot.  Walk it there and ride it - or wait until you can ride it on the road.  Running it on the stand isn't going to do you or it any good.

[RegMilk]

The sequence of no engine turn over then the long turn over with no ignition is similar to my experience with a 2006 People 150 with 9000 km:

1) often after over night, engine will not turn over with starter NOR with the kick starter (even with all my weight on kick starter)

2) eventually after jogging E-starter and K-starter engine will turn over BUT needs 1/3 throttle kept open to come to life

Local shop replaced battery and cleaned carb but didn't fix problem and shop is out of ideas to fix.  Claim ethenal is problem though I've been running the gas additive they recommend (now Mystery Oil).

Any idea?  What once was a great, easy ride is now a tiresome, rustrating experience.

December 26, 2011 - GOT IT SOLVED.  THE FUEL TANK CHECK VALVE WAS LEAKING GAS INTO THE ENGINE; THUS, HARD START (FLOODED) AND LOCKED KICK STARTER (CYLINDER LOCK).  THIS WAS, FINALLY, AN EASY AND CHEAP FIX ($53 FOR NEW VALVE).

[HabHazard]

That's a nice scoot man, hope you get it running, I love mine, better than any woman I've had yet. hehe Check for spark and gas first. I'd also put the stock air box back on it if you have it, I tried an after market breather on mine and the stock box works much better. These cobra's are very particular, but when they're running good, they run great. Also, don't pull one of my stunts, make sure your putting good 2 stroke oil in the tank, I used some junk from walmart and it caused me nothing but trouble. Best of luck getting it running man, and if you decide you want to sell it and your anywhere near Indiana, let me know...