TS250 Joy, Then Sadness

[FastDoc]

Maybe it was a failed antique piston from age and corrosion?

[Weldangrind]

That's quite likely a contributor.

[SpudRider]

Wow! 8O

You did an excellent job restoring that bike. I'm sorry to hear the piston fractured. :( As usual, your diagnosis sounds good to me. Please keep us updated with your repairs.

Spud

[Weldangrind]

Thanks Spud. It wasn't meant to be a restoration yet; I merely spent time cleaning and repairing. The more focused restoration will come once the bikes are off the road for the year.

[SpudRider]

You're welcome. Perhaps I used the wrong word; I meant restoration in the general sense of getting the bike running again. I look forward to your reports on the "focused restoration" you plan this winter.

Spud

[Weldangrind]

Son of Weldangrind transferred the battery box over to the TS185, and I installed the orange Polisport front fender. I then had the insurance transferred from the 250 to the 185 and we went for a ride. He couldn't stop grinning; the TS185 easily eats the TW200's lunch.

I love having spare bikes around. Even if they're old junk, they bring many smiles.

[katoranger]

I had more fun on the baja 90 then all the big bikes I had.

[FastDoc]

I understand. My most fun bike is my CB175. :wink:

[katoranger]

Doc, I miss my cb200 even more now. First bike I bought for myself.

[gloud]

The exhaust leak was not your issue. (they ALL leaked back then)
timing or air leak would do it. I melted a piston on the DT175E when the ignition was set to factory marks. After finding another piston I dug up the year priors instruction for manually setting the timing and found the factory marks where Way off. (the timing was advanced by 10 deg's) It was happy till I sold it this spring.

Sometimes you just have to split a case before you run these old 2 smokes. otherwise you blow them up. I would swap the seals. it is a 2-3 hour job at worst. Pistons cost $$ (when you can find them for the older bikes.) time is available.

Glad you and the Lad are having fun.

[Weldangrind]

I found NOS Suzuki pistons for around $30 each. I can live with that.

Thanks for your input. I had another friend on the TS forum share comments similar to yours. He said that he's seen several old TS bikes with holes rusted through the head pipe, and they never leaned out and came apart.

[2LZ]

Doesn't look like heat or lean to me. Looks like excessive piston slap, shattering the skirts from a wore out bore, would be my guess.

[VinceDrake]

Hi Weld! Long time, man!

A couple of late thoughts, regarding your piston explosion:

--A leaky exhaust/air leak/over-lean usually eats the top ring land off the piston, nearest the exhaust port. I am seeing no such damage here.

--Excessive piston slap usually shatters the bottom of the piston, whereas what you have looks more like the bottom of the piston got ripped off.

--Worn out wristpin bearings (Or even seized) cause a "hammering" action at the wrist pin, which at mid-high rpm, could cause what you are seeing there.

--Check your crank bearings!!! I've had it happen to me a couple times, where the ball bearings (main bearings) of the crank broke up, causing large chunks of debris to get caught between the piston and the transfer ports. Rips the piston right off the rod. Leaves no evidence behind, or at least not by the time you get the jug off, and I ruined 3 pistons before I figured it out. Each time, after cleaning out the engine, the crank rolled smooth and silent.

Long story short, I don't think you heat-locked, or oil-seized, you would see a lot more damage that that. I would be have a good close look at the crank bearings before going any further. I mean, the last thing you want is to shove in another piston, and smash it too.

Besides, crank seals are always a good idea.

You 2-stroke loving friend,
--Vince

[FastDoc]

--Check your crank bearings!!! I've had it happen to me a couple times, where the ball bearings (main bearings) of the crank broke up, causing large chunks of debris to get caught between the piston and the transfer ports. Rips the piston right off the rod. Leaves no evidence behind, or at least not by the time you get the jug off, and I ruined 3 pistons before I figured it out. Each time, after cleaning out the engine, the crank rolled smooth and silent.

Smart. That could do it.

[Weldangrind]

Hey Vince! So bizarre; I was thinking about you the other day. Any updates on your quads?

I never thought about the crank bearings; thanks for the idea. I just got the service manual in the mail yesterday, so my first step is to measure the bore and compare it with the cylinder. Perhaps a previous owner slid a standard bore piston into a .25mm overbore. I'll report back as soon as I know.