Ticking sound after one cylinder got hot

[bubbarowley]

I'm new to this so I hope this is where we post questions.  Front carb started to plug off on my way to class and it started to chug going down the highway, I had a test so i kind of limped it to class.  When I got to class my bottom muffler had changed to the blue/gold color they turn when they get super hot, but just the bottom one.  I put some GB44K in the tank and limped it back the 26 miles to home.  On they way back at higher RPMs the power would snap back.  I cleaned out the carbs the next day and it runs great now!  But it has a ticking sound that comes from the upper end of the rear cylinder now, which it didn't have before.  It's always had the Venox ticking that goes away as the RPMs goes up, but it's different now.  The new ticking isn't too noticeable at idle up as the RPMs goes up it gets louder.  When it got hot enough to change the muffler colors, did I burn an exhaust valve?  Or did I fry my oil and now it's not lubricating like it should?  My wife and I took it out today and it doesn't have any loss of power.  I have never adjusted the valves, do I even need to?  I was planning on changing the oil this week.  Thanks for any advice.

[max oradea]

when was the last time you adjust the valves. and please do a compression test. normally they should not change color, glassing exhaust usually means over heat. loss of power in high rpm is sign of seizure on 4 stroke engine. ticking noise can be from rings...> knocking of engine or piston pin damaged due to over heat and not getting enough oil.
so please check/adjust valve gap if you have not done so recently and after check compression. if everything is ok for the above then it should be a piston pin damage. good luck! and be patient on the gap... its hard to do for a few valve heads because of the tight space.

[bubbarowley]

I've never adjusted the valves.  Is there any write ups on how to do this?  Thanks for the help max oradea!

[max oradea]

yes there should be on the manual. but if not here is a over view of how to do it.
remove gas tank
loosen the radiator and the generator crank screw cover bolt and the sight screw. take off the valve covers and crank the engine with a wrench through the crank hole, and look at the sight hole for T1 and T2 on the compression stroke.
if you have never done it before on any other bike or engine then read the manual.

[bubbarowley]

Ok. I'll do that.  I just called a shop to see how much they'd charge (because almost every bike on craigslist for sale say just had the carbs cleaned and the valves adjusted so I thought it wouldn't be too much to have done) the shop said it'd probably take them 4 hours at $80 an hour which would be $320! I'm totally going to figure this out!  Thanks again max

[max oradea]

Thanks for the confidence. i would say do it yourself, download the manual from a free site or get it from some place. read it through twice then ask what you dont understand on this site and let all of us fill in the blanks for you. in this way everyone will be able to learn from it.
you may download the manual on pride in what you ride website and also be able to view online.
the tool you will need it a filler gauge and some small socket wrench.

[Paperkrain]

Hi

This is a link to the Kymco Venox 250 Service Manual. It's missing the last couple of chapters, but I think what ever you need is here

Kymco Venox 250-250i EN

If you want the last two chapters, Hairy Bob mentioned paying for the full thing* if you can't find a manual online with all the chapters for free

Good luck with your repairs and let us know how you go

-JB

[Paperkrain]

[Paperkrain]

[Paperkrain]

[Paperkrain]

[Paperkrain]

Hope those help

-JB