After 10 - 15 minutes of riding loses all the power

[vybrano]

Thinking about it with clear head again... .

- White smoke could be just a WD40 I used (there is no coolant to make a white smoke).
- Screw not reacting could be just and auto enricher (which I didn't connected and according to Google it means it is in open state) dumping a fuel, making it too rich for a screw to react?

Which means there would be only leaking exhaust seal ($1) and that "10 minut losing power", which could already be solved with new carb or by new CDI, which I already have. Which would mean there would be only that $1 seal left.

I have to look at it again.

---------- Post added at 08:18 AM ---------- Previous post was at 08:11 AM ----------

Oh. You send a new reply meanwhile. I will go through it and use it tomorrow. Thank you.

Just a quick reply - I wasn't able to tell if it's leaking the oil or the fuel. It definitelly wasn't water. But consistency, color, smell - all of that was between oil and gas. I just coulnd't tell no matter what I did.

 

[Karttekk]

I realize there's no coolant, just explaining what different exhaust colors represent.

---------- Post added at 10:54 AM ---------- Previous post was at 10:50 AM ----------

If you're talking about the auto choke, it has to work or your engine will keep running rich and possibly flood. The auto choke "plunger" is pulled back for cold starts then slowly extends into the enrichment port to block excess fuel as the engine warms up. You really need to get a handle on how things work and how to diagnose, otherwise you'll be spinning your wheels for who knows how long.

 

[itsid]

you can still collect water in an air cooled engine
(usually it would no longer run at all... but hey.. maybe a weird 'on the edge' situation)
Watter can get into the tank and or into the air filter..
and thus via the carb into the cylinder.

it can also get into the exhaust
(drowned in mud/water for a bit.. rain.. backsplash.. you name it)
thus white smoke can still be water in an air cooled engine..
maybe just the exhaust, likely not coolant, but the idea is still valid

It's better to have every possibility ruled out even if it's less likely than others.

'sid

 

[vybrano]

Diaphragm on old carb is OK, but looks bad and I wouldn't be surprised if it didn't seal at the sides.

Smoke is consistent no matter how long it runs. Gets darker when I open full throttle.

I just changed the oil. The old oil was consistency of a water. I don't mean there was a water in it - but it was so heavily contaminated with fuel. When I opened oil screw it just poured out of it like a water. It wasn't viscosious like oil should be at all. I didn't try to run it yet.

 

[vybrano]

Is it supposed to be this dirty?

Head.

 

[itsid]

unfortunately well used heads do look like that more often than not, yes...
it needs a good clean though, it'd be a shame to put it back not having it cleaned first

watered down oil is 'good news' in a weird way..
it explains some of your symptoms.
the smoke (although it should not have been white IMHO.. nevermind)
and the wet exhaust port are more than likely a result of that.

The main cause aside the overflowing carb (which you already replaced)
will be a failed piston ring (or fully worn cylinder wall)
But since it looks like you are on the way ordering that 17 dollar cylinderkit anyways..
all that should be solved in one shot no matter what or what combination thereof,
carb has been replaced already and once the head is clean that engine should be back in business with an all new business end .
You might want to see if the crankshaft bearings are still good while you have access
just to prevent a future failure
(wiggle the cam shaft left to right to see if the crank wiggles along)

But the problem you had should be gone once everything is back in place

'sid

 

[vybrano]

unfortunately well used heads do look like that more often than not, yes...
it needs a good clean though, it'd be a shame to put it back not having it cleaned first

watered down oil is 'good news' in a weird way..
it explains some of your symptoms.
the smoke (although it should not have been white IMHO.. nevermind)
and the wet exhaust port are more than likely a result of that.

The main cause aside the overflowing carb (which you already replaced)
will be a failed piston ring (or fully worn cylinder wall)
But since it looks like you are on the way ordering that 17 dollar cylinderkit anyways..
all that should be solved in one shot no matter what or what combination thereof,
carb has been replaced already and once the head is clean that engine should be back in business with an all new business end .
You might want to see if the crankshaft bearings are still good while you have access
just to prevent a future failure
(wiggle the cam shaft left to right to see if the crank wiggles along)

But the problem you had should be gone once everything is back in place

'sid

Oh, wow! What a good news!

Crankshaft bearings looks OK. No play in them.

I'm going to order that kit then.

 

[itsid]

I'm fairly confidend it is indeed good news, yes..
BUT I used "should" for very good reason..
We can only be 100% sure once you tried, maybe I missed something along the way,
maybe you haven't even spotted another problem lurking behind the bushes or
maybe some devine entity just wants to swipe that ATV off this planets surface *shrugs*

We'll know soon I hope.
But yeah I have a good feeling about the new cylinder kit solving all known issues yet unsolved.
(the CDI is still on my list.. but it's still on the way to you IIRC;
soo we got fresh fuel/mix, fresh ignition and fresh compression... I can't see why we should not have a happy engine with that)

'sid

 

[vybrano]

I'm not a the point of putting it all together yet, but anyway... .

Timing of camshaft and flywheel: I know correct position of both of them to each other. But it takes 2 turns of flywheel to turn cam shaft once. It doesn't matter if it's "first" or "second" turn? Am I overthinking this?

 

[itsid]

it's crankshaft you are concerned about not the flywheel really..
yes I know the flywheel is generally keyed to the crankshaft,
but it's still rather important just in case the flywheel has a marking,
is not keyed and by accident (or intentionally) not lined up that marking could be off!

No, it doesn't matter if first or second TDC..
not on a waste spark engine that is (one that sparks on every rotation)

(I think the gy6 IS a waste sparking engine IIRC)

'sid

 

[Karttekk]

The camshaft does turn once to the crankshaft twice but if you're wondering how to set valve clearance, once the cooling fan is attached to the flywheel turn it clockwise until the hole on the the cam gear is at top dead center and the timing mark is as illustrated. I usually turn the flywheel a couple of times to make sure both valves are closed so there's no tension on the rocker arms. I set them at .005. (This is with the valve cover off obviously.)

 

[vybrano]

I took tons of photos before/while taking the engine apart. Including position of cam/fly. Your photo is exactly the same as mine was. So no problem with setting timing right (I hope).

Unfortunately I don't have that tools for setting a space under rocker arms (these metal sheet pieces of different thickness). So I can't adjust that... .

 

[JTSpeedDemon]

You mean a feeler guage.
Go get one! They're literally like $5 on Amazon! With free shipping!
Setting valve lash correctly can greatly extend your engine life and keep you from pulling your arm off.

 

[vybrano]

You mean a feeler guage.
Go get one! They're literally like $5 on Amazon! With free shipping!
Setting valve lash correctly can greatly extend your engine life and keep you from pulling your arm off.

Yeah, feeler gauge is $5. And cylinder pressure gauge is $5. And variator removal holder is $5. And... And... And... you have $500 in your shopping cart.

Let's first see how my first engine rebuild goes. I'm still waiting for 5 packages to be delivered before I even start. Cylinder kit, exhaust crush gaskets, carburetor manifold... .

 

[JTSpeedDemon]

^^

 

[Karttekk]

Yeah, feeler gauge is $5. And cylinder pressure gauge is $5. And variator removal holder is $5. And... And... And... you have $500 in your shopping cart.

Let's first see how my first engine rebuild goes. I'm still waiting for 5 packages to be delivered before I even start. Cylinder kit, exhaust crush gaskets, carburetor manifold... .

The experience and know-how you're getting is well worth it. That $500.00 will be long gone while what you'll learn will stick with you forever as will any tools you'll buy. Just imagine how you'll feel when the engine fires up and runs well. You'll feel like Rocky Balboa.

 

[itsid]

tools are great.. good tools that is..
and being able to use them is even better

BUT I understand that one's tool budget is quickly drained at times..
but that's what amazon's wishlists are for.. add all you can,
and check back on it if you think one of those 5 buck items can be yours now.
women usually bring flowers when they come over for a chat and a celebrative beverage of choice..
guys bring bottles occasionally.. how about they bring a five dollar tool instead of a 7 dollar wine?

'sid

 

[vybrano]

What are these? They are made of hard rubbery material and have thin metal rings around the end. Can't match it to anything on my old engine.

 

[itsid]

Is that them?


Those are valve oil seals..

and the description on the website that pic was taken from says:

Valve oil seal for GY6 50cc/125cc/150cc engines. If you are seeing white smoke from the exhaust pipe chances are you have a broken valve oil seal.

they sit on the upper part of the valve stem if I'm seeing this correctly, above the guide and covered by the spring pack
(hard to tell from the exploded view I got.. but these I think)


'sid

 

[vybrano]

Thank you!

Already found a Youtube video which requires only a hammer to take it apart.