Valve Adjustment Problems

[drawkward]

Got the 150 gy6 started yesterday. Wasn't running right, so I told my dad we should do a valve lash adjustment. We did it. We pulled it up to the car to jump start it, and it wouldn't turn over. We tried the valve adjustment again, 3 more times. Pretty damn sure we got it right this time. Can hardly kick the thing over. The compression at TDC is just WAY too great. I put my ear next to the valves with the cover off while turning it to TDC, and could hear a slow air leak. That's where I'm at now. Had a running scooter, did a valve lash adjustment, and now it will barely turn over due to a HUGE increase in compression.

Just FYI, I had it at TDC (I'm absolutely positive) every time I did the adjustment. Was adjusted to .006mm, then .005mm. Right now it's at .005mm and same problem. We are at a standstill right now. He seems a little frustrated with me because the valve job was my idea. I would love to just have it be like it was before, but that's not happening. Gotta figure this one out

[90GTVert]

That's way too tight. You want somewhere around .003" intake / .004" exhaust. Notice, thats inches, not mm. .005-.006mm is only .0002".

I was actually working on a valve adjustment video today. If you can hang on for a few so I can get it processed, you can check that out.

EDIT : (may take a few to process)

[Fox]

The book calls for .05mm which equals .0025inches. I set both valves to .003 inches on all scoots 50-150cc.

Truthfully, anywhere from .002 to .004 is fine. It's better to err on the sloppy side than to be too tight.

That air you heard was probably air pushing past the rings into the crank case.

[Goosey]

That's right. for the 150cc the Arrow manual says .08mm, I set mine at .07mm and it's good.
I also had to adjust the clearance on the pickup to the reluctor on the flywheel when I couldn't get spark after a valve adjustment.

[drawkward]

Ok thanks for the input guys. I did read earlier that people were loosening there's up to get less noise / less wear and tear on the rocket arm, I guess. Right now it's set at .005mm.

We figured out that we were just not used to kicking over 150cc scooters. When we first got the scoot, it was VERY easy to kick over - it didn't seem to have the same compression as it does now. It would start up - but then not run so well. The fuel tank was rusted and had bad gas that I had drained when it first got here, but I doubted that I had gotten all of it at the time. I had my doubts, but for some reason I put it from my mind.

After doing the valve adjustment to .005mm it had a much stronger compression stroke than before - It was almost impossible to turn it over right before TDC without standing on the kick starter, or getting a sort of "running start" with the kick starter. We thought we did something wrong, so we redid it three more times, to come out of it all with same results.

I eventually went to the store to get a gift for my cousins birthday, and when I got back my dad had it running! He had it out in the street hooked up to the car's battery via jump cables. It was still not running right, though. As soon as I rolled up I proceeded to try to change the idle, and it died out - He wasn't very happy. I could tell he had worked hard to get it to start. Took us a long time to figure out what was wrong with it. We finally figured out it was rust still coming from the gas tank that was causing it to run like shit. I was thinking maybe I tightened the clearance for no reason, what if it was fine before? Maybe it just had bad gas and the fuel system needed to be flushed. The valves were NOT the same before, that's for sure. The exhaust is supposed to have a slightly larger clearance than intake, but it was the other way around when we first opened it up - And now it feels like it has much tighter compression (a good thing?) and runs very smooth. It will idle all day long at a consistent RPM (by sound). Couldn't have hurt it very much, right?

We also fixed a few electrical gremlins. Both lights work at the same time. Lower beams, and higher beams - both . Is this typical? We found spliced and taped wires all over the place behind the headlight assembly in the wiring harness, including a live 12v floating with no cover on the internal wire bouncing around. Figured out why it was blowing fuses when we found that..

---

That was the best video I've seen all day on GY6 valve adjustments. I watched a lot of them earlier, btw. Very well done. Great angle, great instructions. No time was wasted. Every word was informing us what to do, and advising us how to do it. Great video man, really.

[Goosey]

.005mm is way too tite, .05mm is more like it , if you are using a guage with inches, .005" might cut it ( but I would trust the guys and go .003inches), same for both valves is fine too.

We also fixed a few electrical gremlins. Both lights work at the same time. Lower beams, and higher beams - both . Is this typical? We found spliced and taped wires all over the place behind the headlight assembly in the wiring harness, including a live 12v floating with no cover on the internal wire bouncing around. Figured out why it was blowing fuses when we found that..

Hah, there was a guy on another forum who thought his lights were broke, and fixed em so they both worked high and low together. Had a few issues after. Wonder if that's what happened there.
Mine both have the single light, with hi/low.

[90GTVert]

What she said, the valves are still too tight at .005mm. Valve clearances tend to tighten over time, and you've got no room to spare. If they tighten up too much your valves hang open and then, on top of what I said in the video which is a really worst case scenario, you could have a valve remain open enough to end up with a burnt valve. The valves need time in their seats to transfer heat away.

Usually you have one side on for low and one side on for high. If wired up properly, it would be nice to have both work high and low if the lighting circuit could handle it. Do yours have 2 low beams on and then 2 high beams, or is it just one low and one high all the time? Or were you saying that both filaments in both bulbs work all the time?

Thanks for the compliments. Glad you liked the vid.

[Fox]

I think maybe he's using a .005 in. gauge and just typing "mm" by mistake.

PS: The looser you set the valves the more noise they'll make drawk.

[2strokd]

Hope ya got the rusty stuff out! My Pops scooter wouldnt run right and kept quitting until he flushed the WHOLE fuel system good.
I set all the GY6,s i work on at .004". If i hear em i know there workin . Plus when they heat up real good the gap closes a tad itself.
Im sure you have it running good by now


Edit: Just watched the video! Thats a real good one Brent :thumb: !
Sounded like a pro :cheers: ! Was that you??? :censored:
Jusss-skiddn buddy, great job ;D

[90GTVert]

:rant: lol

[drawkward]

Sorry for the delay. Got it running real well. The chino-meter reads 65 on a good long stretch. Starts right up, even after sitting all night under the porch. Went through everything and got it all tight. The plastics were all loose and missing screws before.

I mean both BULBS work at the same time when low beam, then both bulbs work the same on high beam.

I plan on removing the tank and fuel lines. I need to flush the tank out really well. I've run about 2 tanks through, and every once in a while it'll sip water or something and bog out for a split second. Plan on replacing the lines with clear hoses anyways.

I'm starting to get really attached to this 150... been driving it the last couple days. Sure is a smoooooth riiiiiide... Really don't wanna have to give it up to my pop later Maybe I'll make him an offer, which I'm sure he will refuse since I've got it running so smoothly

[90GTVert]

As long as the rest of the electrical system is operating OK, I think I'd leave the bulbs like that. They suck stock (1 at a time).