Click... Click... Stuck

[sunrider]

Hey guys, I've done something bad I really hope someone can help me trace down the problem, and I really hope it's not as bad as I think...

It all started with a hole in my air hose (from filter to carb), right before it connects to carb. Discovered it by stalling on the way home. Couldn't restart, so threw it on a truck and got it home. When I discovered the problem, I put a half-dozen layers of duct tape over the hole and tried starting again. Starter worked, but wouldn't turn over, just a fast ehhh ehhh ehh sound. Took the carb out and soaked overnight in case something got in there. Adjusted my valves for the first time since I had everything off already. Next morning put it back together and tried starting. Same effect, almost. The ehh ehh turned into ehh ehhhhhhhhhh ehh ehh ehh ehhhhh, like it wanted to turn over. Got it started with WOT and holding the starter for like 30 seconds (my kickstarter has been buggy, I discovered I have 2 teeth missing on that big kickstart gear next to the variator - not the one that the kickstarter sits on, the other one). Discovered I could only keep it running with throttle, so I turned up idle and A/F mix to get a free hand. Started adjusting idle down, it stalled and wouldn't start for a while. 30 minutes later, got it started again, same procedure, though I did get the idle and A/F mix down and leaner than when I started. Tested petcock, seemed ok. Tried starting again. Pressed the starter button, it immediately screamed at me and threw something (EEEEEEEEEEEE!!! KLANG!!!). Now, pushing starter button goes Click. Trying to manually turn the flywheel or the variator (front) hits a stop with a metallic clang sound right before the flywheel magnet gets to the sensor. Turning backward produces the same result, something is in the way. I've removed the kickstarter and all its gears. One of the teeth does seem to be unaccounted for. Tried examining the gear behind the variator with my camera, didn't see anything back there. Here's some vids I collected, if anyone has an idea where to go next, please tell.

The missing teeth - 1st tooth and in the middle is obvious.


The clanging noise - right before flywheel magnet reaches sensor


Where the flywheel turns to before clanging to a stop



Please can anyone help me identify the problem / what to check next?

PS- I did notice after all this that my bottom engine shroud had melted directly over my exhaust lead pipe.

[bashan]

Hey pal. Let me know what Jay says, I'm curious how this shakes out. I still think a valve dropped into the combustion chamber and that's what's hitting, could be wrong of course I really don't know what the hell I'm talking about, all theory you know. But, it melted the shroud by the exhaust, wouldn't that mean something went haywire there? Hope you don't mind,I'm gonna post your vids in a couple places and see if anybody has an idea. Rich

[Rebel]

First, Welcome to the forum, I don't think I've seen you here before, but my memory is short.

without looking at the videos my suggestion is that you would be best off just pulling the motor out and tearing it down looking for broken pieces.

That hole in the intake, could have leaned out your air fuel mixture and over time caused a valve to burn, or let something into the air that caused undo abrasion. The clank and won't turn any further, could be lots of things and if it were my scooter I would not be happy until It was taken apart and everything looked over and fixed. Another reason for doing that is to clean out the crank case and get all the loose metal shavings that may be present and if left there will circulate with the oil and cause more problems a few miles down the road.

Sorry to hear about your troubles.

[Rebel]

looking at your videos,

yup broken kick start parts, I saw two missing teeth, and maybe the otherside has a crack I'm not sure there.

the spinning of the variator, that click noise is strange to me, I'm not sure what it is

is the fan hitting on the magnet there where it stops?

Before you tear it completely down, take that cooling fan off and the spark plug out and see if you can rotate the crank over with no problems.

From your typed description it sounded like something big time, from your videos, the places it is stopping makes me wonder if that magnetic pick up is too high, perhaps when the other plastic melted it heated up the fan and the magnet moved out a little, it is kind of hard not being there.

hopefully Kliff might show up and offer either a confirmation to pull it apart or say that I'm wrong and all you need to do is something simple.

[sunrider]

Hi Rebel, thanks for the welcome. This is my first time here, Bashan suggested I might ask Kliff or someone here about my problems.
No, it's not the fan hitting the pickup coil, no physical contact there. It sounds like it's coming from inside the engine. No, I couldn't rotate it with the fan cover and sparkplug off. Same thing, can complete almost a whole revolution (If I backed it as far as possible), then it stops with a clang sound.
I looked into the sparkplug hole this evening, and I do see a piece of piston ring or something (thin, black, curved metal) partly in front of the spark plug hole. I can see something (piston head? it's about 1 cm or so front to back as it goes past the spark plug hole) moving forward right before the clangstop.
I know now I am going to have to open it up to get to the bottom of things. I was just hoping as Jay suggested that it might be something much simpler like the bendix gear. But, I've never been that lucky! lol... Ohh well, I bought this thing to learn mechanics, here's my crashcourse!

[shiftless]

Your vids indicate a problem
Your piston is probly hittin something on the compression stroke
broken valve
Tear it down and rebuild the top end
Flush the case too

[kliff]

Oh jeeeeeez, and II ain't even had my coffeee yet, so I'll try to remain politicly correct....LOL

The last 2 videos helped a BUNCH. From looking at the marks on the flywheel, it appears the damage is near TDC. Pretty much leads me to suspect either a broken valve spring/bent valve, amd/or a dropped valve. EEither one is serious enough, but not unrepairable...

From your desription of events, I'd say you fried an exhaustt valve. Way lean, well beyond temp disign limits. When the engine shut down that first time, had that valve been open, it was probably so hot it sagged, cooled, and was doomed from then on, even if only .010"
At those kinda temps, it probabbly also crystalized the friction weld of the valve and stem. When you did finally get it running, the stress over whelmed the damaged valves abilities, and the head separated.

All classic, "why did my valve drop?" scenario.

Pull the spark plug...any damage? Yes/pull head No/ OK, but still don't rule out pulling head
PPull the flywheel, if I'm wrong about the valve, you may have a dis-lodged flywheel magnet. All magnets in place? Yes/pull head NNo/ replace flywheell.


9 out of 10 times, a damaged plug will tell the tale, and you can go ahead and pull 'er down. That elusive other 1 outta 10, with no damage to the plug, could be because, like with you, you were already doing diagnostics, and when it let go, it stopped immediately. Even with cent. clutches, it takes seconds, @ whatever RPM you're running on the road, for the engine to stop....hellacious amounts of damage done in seconds.
Muulti cylinder engines, 4's, 6's, VV-8's, with common intake manifolds will actually suck and blow LARGE metal particles from the intial cylinder, through the intake to every cylinder of the engine, and literraly leave NOTHING undamaged in each cylinder, if at a high RPM when it lets go.....

HHope that helps, but II think I was late, and believe evveryone else had you headed down the road to recovery already.

[Rebel]

Well Kliff it is always nice to have an expert come in and give a proper description of the possibilities and causes. His post made me think possible major issues, but the vids, had me a little thrown, my eyes are going and can't hear very well, comes from years of loud noises and getting old.

[sunrider]

Well, I wish I had the confidence to pull the head off myself, but I kept on having nightmares last night about getting everything put back together, starting her up, then finding a circlip or something on the ground, lol. A HD mechanic friend's friend agreed to look at it for me for $75, ouch, but at least I'll know all the pieces are there! I hope it won't be too much more to put it back together though!

He seems to agree with all of you so far, though, before pulling it off yet. He thinks the piston's hitting a valve, and that my chamber looks kinda gassy, but he didn't elaborate much more than that, just said he'd rather open it up and let me know what IS happening instead of guessing at it. I'm wondering if a 12-pack would convince him to let me learn the reassembly, lol.

As far as your questions... My spark plug was BLACK when I pulled it (I had turned the A/F mix WAY up while trying to keep it started / running). I was trying to pull the flywheel yesterday, but I don't have a flywheel puller. I was going to make one, but I couldn't find a thread with the sizes / thread pitch I would need. Anyone know? It's part of my reason to pay so much to let HD mech fix it, because I would hate to have everything apart and find out I couldn't put it back together because I didn't have a right tool... Like a springcompressor or one of the other tools I can't remember names of from the gy6 manual... lol Time to build that collection!

[Rebel]

You might be a lot better off when it comes down to it to just buy a big bore kit with a head and put that in the scooter, that would give you a totally new top end with all new parts. there is a how to do a big bore install help in our resource section. It really is not as big of a job as it sounds to just change out the parts.

here is a link, to the procedure, it is to a 50cc but they are so close it is fine for the job;

scooterrebels.proboards.com/index.cgi?board=scooterresources&action=display&thread=327

and the kit should be something like this;

cgi.ebay.com/ebaymotors/Big-Bore-kit-61mm-170cc-for-GY6-152QMI-157QMJ-ATV_W0QQitemZ330405773662QQcmdZViewItemQQptZMotors_ATV_Parts_Accessories?hash=item4cedb8015e

[kliff]

The guys at GES, should warranty the entire top end, just don't forget to tell them about the torn ibtake boot too....all part of the failure, all warranty.

[Rocketdog]

"Oh jeeeeeez, and II ain't even had my coffeee yet, so I'll try to remain politically correct....LOL
". Since when? ROFLMAO.

RD

[bashan]

Mar 3, 2010 7:12:00 GMT -5 kliff said:

Pull the spark plug...any damage? Yes/pull head No/ OK, but still don't rule out pulling head
PPull the flywheel, if I'm wrong about the valve, you may have a dis-lodged flywheel magnet. All magnets in place? Yes/pull head NNo/ replace flywheell.
9 out of 10 times, a damaged plug will tell the tale, and you can go ahead and pull 'er down. That elusive other 1 outta 10, with no damage to the plug, could be because, like with you, you were already doing diagnostics.

Sorry to edit your quote kliff but I wanted to make a point. You use the classic, logical, diagnostic approach that I feel should be made towards every problem: scooter, motorcycle, health care, friggin' bathroom sink plugged. Is it this? Yes/No then this: Yes/no then this. It's perfect, why doesn't everybody do this towards scooters? There's one forum that drives me nuts, not that good things don't happen there but it's always fifty different opinions and suggestions thrown at the problem till something MIGHT stick. Why isn't there a logical progression to solving these problems? It drives me up the wall sometimes. I think fixing scooters should be like any other problem solving endeavor, a flow chart mentality. I'm sure new guys are confused as hell and, frankly, I get sick of the condescending attitude of some of the old. I'm ranting, sorry. I'm going to work on a flow chart on my site to try and sort some of this out. Not one of those crazy ass charts like on that Arrow manual, geezus, that thing makes my brain puke. I'll let you know what happens, and I might ask the elusive kliff a few questions along the way if I might. Rich

[Rebel]

Rich

Kliff has the ability to break it down like that in written word, he typed basically in no nonsense language. The old KISS method. Think it out what is the easiest way to diagnose and progress forward, pull the plug, is it beat up, that would have been a instant you got something banging around in the combustion chamber indication.

I don't know if I know what that other forum you were speaking about was but I do know one that has that problem.

[sunrider]

Got the top end off, and discovered everything from the cylinder up needs to be replaced. GES has agreed to replace it all, big relief!

www.flickr.com/photos/37743438@N07/

Broken air intake tube, broken exhaust valve spring, exhaust valve seat pieces embedded in my piston and valve head and scoring up the cylinder. As Jay called it, "A rather glorious explosion". I didn't get an odo pic emailed before 6 on Friday, so I suppose I should hear back Monday what I'm getting.