Piston condition

Just took apart my recently acquired A35 not sure what it is maybe alu? It’s 44mm though. Bike was running like shit tried 2 differnt carbs no difference. No obvious air leaks so figured I’d tear it down and found this. Top ring is kinda smashed in nor springing out and as you can see the carbon on the piston. Opinions? Cylinder looks pretty good no scoring light cross hatch pattern. Thanks in advance

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Re: Piston condition

The stuck ring and tons of blow-by is probably why it wasn't running too good. I'd clean up the piston, sand down any score marks to make sure they dont have high spots and put it back together with new rings. Does the underside of the crown have a burnt spot?

Re: Piston condition

I’d say Hell yes.

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Re: Piston condition

Running real hot. Timing, and jetting.

Re: Piston condition

Overpriced Parts /

Not real bad, easy fix

Too much oil/wrong oil, too rich maybe at idle but lean at top end (typical of a non multi circuit carb)

Spray with pb blaster, brake cleaner or some solvent then using a bent dental type pick underneath rings try to loosen rings then remove rings cleaning groove and piston with soft brass type brush.

Soak rings and be very careful cleaning them because movement more than a few millimeters will make them snap !

Best way to remove rings with no tools or vice (for me anyway) is to hold piston with my knees and using fingers just spread the ring open such a minor amount so it don’t break, literally Touchin/dragging on the Piston and slide up.

Re: Piston condition

What oil were you using?

Re: Piston condition

I used Walmart synthetic. But I just got the bike recently and was already beat down pretty good when I got it.

Re: Piston condition

> Mj Sizemore Wrote:

> -------------------------------------------------------

> I used Walmart synthetic. But I just got the bike recently and was

> already beat down pretty good when I got it.

Something to keep in mind:

Synthetics may lube better but they do burn a little hotter.

Re: Piston condition

Ok I tried cleaning the piston up the top ring was so baked into the groove I ended up snapping it, guess Ill Probably order some new rings and a piston. Can you put a new piston in a used cylinder?

Re: Piston condition

Those rings were thrashed anyway. I would get a new piston anyway just because it's that easy.

Re: Piston condition

> Mj Sizemore Wrote:

> -------------------------------------------------------

Can you put a new piston in a used cylinder?

Yes , if the cylinder is serviceable .

Note that the cylinder should be measured and the new piston has to match for a plated cylinder.

If the cylinder is sleeved and you're going to use the next size up piston , the cylinder would likely require a bore job or you might get away with a hone .(edited)

Re: Piston condition

You can take the broken ring part, file the end flat and then drag it through the groove to clean the carbon out.

,,,

Overpriced Parts /

If rings are cheaper then just buy rings

Re: ,,,

> Ken Roff Wrote:

> -------------------------------------------------------

> If rings are cheaper then just buy rings

Ya dude I would buy rings and sand/clean piston. Then run good oil and Non-ethonal gas.

Re: ,,,

Even though you broke one ring , you could clean the piston and run a single ring in the upper landing .

I know this from personal experience . It's how my FA50 is running currently .

You might notice a very slight difference at take off and maybe a bit longer to reach top speed depending on how worn the single ring is .

Re: ,,,

It cleaned up good. But ordered a alukit from treats think it was less than a hundred bucks with the current sale. Got 2 bikes with A35s so I’ll put the old one on the other bike eventually. Just want to get this thing running. Butchered my clutch Bell trying to beat out the one way bearing and brass sleeve. Got it out but warped the shit outta it. So gotta wait on parts for that now. Sucks.

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