Kymco 250cc - Can't Start it

[garibaldi]

Nothing inside indicates any impact. Valves are spotless, and I just took the head into a dark room with a flashlight to check for any gaps. The valves are sealed perfectly and completely - no light visible thru them. No bent valves. I pulled the cylinder off too, and tried wiggling the piston/conrod. There is no play there at all - I was worried that the lower-end bearings or crank might be loose or something. And its not a random CLANK like a loose item laying in the crankcase.

Its too harsh of a sound to just grit my teeth and crank it till it fires... lol. I'm at a total loss for what it might be.

[zombie]

Is it poss. you forgot the pin roller bearings?  ( piston pin)

[garibaldi]

I had to go double check the manual real quick, because I know there is no bearings on the piston pin as installed. The parts list verifies this is correct. No bearing. The piston is snug on the pin, the pin is snug in the conrod, the conrod is tight on the crank... nothing is loose, nothing feels worn. I was hoping this would be a simple job, and I could be riding the darn thing right now. This sucks...

[zombie]

Take a look at the starter itself, You may also want to pull the cvt cover to see what is happening while you are cranking! Do you get the sound if you use the kick start?

[garibaldi]

 

It started! I'm so excited! After almost 3 MONTHS, it's finally running! Hooray! Now to see if I can remember how to put all this plastic back on, so I can have a seat to sit on for it's maiden run!

By the way, is there any specific break-in procedure?

Thanks Zombie for your input!! I pulled off the CVT cover, and then I could hear much better what was happening. I focused on the starter, like you mentioned, and sure enough the sound was from that! It's like a back-lash against the starter motor from the compression stroke or something. Once I decided it wasn't an internal problem, I bolted it all up, and cranked it up. Fired up and started within 2-3 cycles. Bam. Running like it's never been apart! This is awesome!

Thanks again for all the input. I was on the verge of selling it as a project (read CHEAP), and be done with it. Ok, on to the plastics puzzle.

 

[zombie]

Oh NO, If the starter does tha it means the entire scooter is no good at all. I'll give ya $20.00 for it if you ship it out!!!  Just kidding man, it.s wonderful you got it going. I tend to rush breakin time, so I think common sense is most important. Keep your rpm's low to mid for the first 45 Min. to an hour. Make sure your carb is tuned right in these lower ranges. Vary your speed, NO power take off's, and take all the plastics back off to check the torque on ALL the nut's/ bolts/ fittings involved. Once you are SURE nothing is going to fall off, cruise it around a little more (30-40 Min.) and start hitting the throttle a LITTLE. Look for smoothness throught the range of the throttle. At this point you will start to look for carb tuning issues. There are LOTS of posts here dealing with this. I would suggest getting the carb as close as you can before any extended full throttle bursts (30 seconds or so). By this time you should have 2 hours +,-, so I would once again tear it down to Re-adjust the valves, check your torque, and go for a little ride. I believe it is VERY important to vary the rpm's so as not to let the new parts wear in at a set point! The piston and rings will settle in quickly, but the valve train will take some time, so I would check the adjustment once again around 20 hours. This is ALL my OPINION! It's what I do. Perhaps some others on the forum have more info, or advice... At any rate it is GREAT to hear you are scoot'in.