Ok guys, i think I got it. Cam/chain misaligned.

[scootnewb]

So after reassembling the top end (stock parts with new gaskets). There was terrible clatter like noise. I kept trying to adjust the valves but nothing worked. Then I realized the cam was one tooth off with TDC. Today I adjusted the cam so it is correct at TDC. Does this sound right?

Disclaimer:

This is how it runs after setting the cam correctly. It is very similar to how it ran before I messed with the top end. It sucked at cold starts and the starter would fail a bit. It also would not idle. But I am working on that. The valve clearance is at .003 






But it still sounds like a sewing machine.








I bought the scooter pretty cheap, it would idle but any throttle it would die. So i ordered any old 18mm CVK carb from ebay, put it in and it went. It never really idled right but it was enough for me to drive it away. Since then, i replaced the fuel filter vacuum and fuel lines, removed the air box,  put on a high flow air filter and removed the pairing system and the air box. I thought for sure it would be running lean but this looks rich?



Any advice on what this plug indicates? Is it rich or lean? The plug looks darker IRL.  I have some pilot and main jets so I can go up or down. I do not know what jet is currently in the carb. 


Thanks.

[KSR Moto]

i.stack.imgur.com/VTbgW.jpg

Campare to your spark plug

Btw..engine sounds good now

[KSR Moto]

I had an engine that no matter what I do didnt want to idle.. it also had hard starting issues,and no power

It had low compression, piston rings were worn

[scootnewb]

Thanks, I found it still ticks a little.  But the replacement piston for the bbk is arriving early. It arrives today. The Glixal kit that was supposed to be here today is somewhere in RI. XD

Once the piston arrives, I'm going to install the BBK, make sure I got that TDC link on the chain marked and cross my fingers.

Learning to wench is hard. Did you guys have someone IRL to learn from or did you figure it out by reading and trying things?

[scootnewb]

Apr 27, 2018 7:06:42 GMT -5 KSR Moto said:

i.stack.imgur.com/VTbgW.jpg

Campare to your spark plug

Btw..engine sounds good now

Thanks. I looked at those plugs, they all seem much worse than mine and I don't see where mine fits in there. It probably does but I can't figure it out.

Err actually I see now. looking at the bottom of the plug, it fits in the good category. My bad, I've literally been up all night waiting for the sun to come up so I could fix the clatter. 

[GrumpyUnk]

Oh, many posts going on. The valves don't sound too bad. I think the choke relaxed, and the engine idle slowed a lot, making the noise more significant. I think a little loose, but not real bad.
The plug looks good to me, but a better pic showing the side(bent) and center electrodes & insulator would be more informative. What I saw was a slight carbon coating, quite normal. Not 'white' from being too lean, and not looking as if it was coated with powdered charcoal.
Good luck with the BBK kit install. Check the end gap, and slurp a lot of oil on everything as you assemble. After you have it all together, rotate the crankshaft a couple turns(spark plug removed is easier) to let the chain tensioner kick in, and get the cam aligned to its final spot. Then check the valve clearance.
tom

[scootnewb]

Thanks. I will do those things and my bad for all the posts. I went kind of haywire looking for advice in the middle of the night. 

[jackrides]

I found learning to wench to be impossible. Wrenching was only difficult. (sorry bout that) Working with an experienced person is best, but it sure looks like you are on your way climbing up the learning curve. You ask good questions, and have sticktoitivness.

[cagiva4ever]

OP:

be aware notice that these china engines 139qmb tend to BlowBy some motoroil (more than Quality engines), hence it MotorOil will also color the Plug... its not all just from Fuel mix....

also other china made engines tend to do same, especially for example PitBike engine's.

on 139qmb's , its not rare to find a carbon deposit "edge ring" at Cylinder Bore , at TDC location above upper piston ring max travel location. ive seen various Bores having it at 2000km 5000km etc intervals...even as big as like 0,2mm thick carbon buildup ring/edge at Bore TDC.
Not to mention about carbon deposit buildup at Valves and Exh-port...


i have personally about 15 Engines 139qmb, and several used Cylinders etc, and i regulary inspect parts at bike breaker what i find....and buy/get free...


so always keep in mind the "China blowby" if you have any hint/suspicious of summink not matching up, when choosing Motor oil grade,changeing inspecting used motor oil, doing jetting etc, regarding what ever it "BlowBy" has an effect into.

[scootnewb]

Thanks for the tips. 

[greginisn]

Your cold start idle speed is a lot greater than with my scoot but as soon as the enricher shuts off your motor sounds a lot like mine. Ticking and all. You seem to have everything right now, don't over think it.

Greg

[scootnewb]

Perhaps I am over thinking it 

I am actually losing sleep over this. I haven't slept since Wednesday evening into Thursday morning. 

It is just, I want to learn about this and do it right. It would seem something has definitely changed for the worse as it did not make the ticking sounds before re-doing the top-end. I was kind of enjoying the idea of having a scoot that ran well, really welland make it look like a POS sleeper, and now it seems it is going to look and run like a POS. 

EDIT I am not saying yours runs like a POS (because it also makes the noise). I just have this idea that there is something seriously off causing the clatter on mine and not just valve lash. But yes, i need to sleep. I am redlining and my head is spun. 

Thank you though for chilling me out. I was about to start going on a posting frenzy again. 

[scootnewb]

Yo Greg,

I watched a few yt videos of 49cc scooters qy6s etc etc. They were all ticking.

I can sleep now.

Thanks again.

[cagiva4ever]

Being a CVK diaphram carb, regarding poor idle, always be aware of highly possible weak Vacuum, due intake path AirLeak via intake manifolds leaking "Bakelite seal" and/or O-ring. They are notorious to crack and leak.

even if they look not damaged, its highly possible to be crooked... as a test and an alongside upgrade, use proper suitable heat/solvent resistant gasket "silicon" sealant mildly on the sealing surfaces, on the "bakelite" and the O-ring.

alongside, test and use size #38 idle jet, in a case if your stock is #35.
1st Use sealant with #35 and study results, then change into #38 and study results...

Also, these 139qmb CVK's and engine performance is dependable about the AirBox construction, search posts.. basically CVK needs "backpressure" counter resistance for AirMass, so that Throttle slide diaphram works the best, not just Engine Vacuum suction...

using that "squirrel filter" is worst thing to do for the 139qmb, or any other engine....

AirBoxes have various tasks, like Helmholz resonance, steady pre-filling of AirMass, steady velocity etc. With an "squirrel filter" you easyly get a wildly actingup throttle slide/diaphram, especially if any amount of poor engine vacuum/intake path airleak....

name "squirrel filter" comes from a saying that "even squirrels get through" the shitty filter type like that, not to mention all dirt and water etc grime...


139qmb CVK's are also notoriously dependable about the "china rubber" union tube that is between Carb and AirBox. they tend to harden rock hard like Plastic even in 1~2 years time, and then Leak Air under Clamp...

[scootnewb]

Thanks for the info.

I had a problem with idling and or erratic idle since putting on a new carb and possibly before I bought it. I had to replace the carb in order to ride it home from the seller. One morning it was pretty cold and it wouldn't start or idle well at all. It would always die. I'd have to get it started then jump on it and go.

After riding it for a while it idles ok and yesterday, although the idle was slightly erratic, it stayed running without touching the throttle after a couple of starts. Which is a huge improvement. This is how it was before I removed the airbox, replaced the remaining fuel line,  got an air filter, and a cartridge type fuel filter. 

 

 

maybe it was clicking back then?

Adjusting the fuel mixture screw had little to no effect.

This is that fuel filter.





Do you think it could also be an issue?


I didn't realize the air box was so important. I guess I could put it back.



I have a new intake manifold and spacer. I didn't bother to put it on since the original looked fine. Maybe it is crooked. I have sprayed carb cleaner around the intake and along different lines and there wasn't any effect so I assumed that meant no leaks.



My main focus atm is getting rid of the clatter.

rambling...