How does my piston look
- Thread starter heatlbj6
- Start date
I would run a leak test to see if maybe a leake caused it. Do'nt do the top end and not check anything else. It might have been fine for along time but something failed and it cooked ur piston recently.
Well you want to figure out what caused that to happen. Could be jetting, air leak, etc. The piston in the blaster I bought a few months ago looked like that. They had too small of a jet in it and ran it lean which caused all that damage.
Just on the exhaust side? That is the hottest side of the piston.
Only rubbed at the exhaust port, breakdown of the oil film possible.
The picture of the crankcase seems to show a dark oil remnant.
No 2 stroke oil looks like that, looks like the wrong oil was used.
Ah, so that oil would have had to come from the crankcase.
Bad seal? Loose case bolts? Time for a leak test.
Bad seal? Loose case bolts? Time for a leak test.
yes that is what he meant. can be pulled in through the crank seal, crank colar, or an crack/leak between the cases
On a 2 stroke engine, the crankcase and transmission area are segregated even though on a blaster, they share a casting. The crankshaft spins inside of the crankcase while the transmission occupies the back half of the case.
Best is referring to the dark coloration of the oil in the crankcase (looking down into the crankcase with the rod hanging out).
That oil must have been pulled in from somewhere.
Best is referring to the dark coloration of the oil in the crankcase (looking down into the crankcase with the rod hanging out).
That oil must have been pulled in from somewhere.
The suggestion earlier about doing a leakdown test before you rip it apart was to prevent exactly this type of question. Basically, you'll need to get it back together to do a leakdown test to find out if you need to yank it all apart.... Not the best option if you could have avoided it by doing a leakdown test before removing the top end.
No use crying over spilt milk now. Use a strong flashlight and look around the middle of the crankcase area behind the crankshaft to see if you see any holes in there.
If you don't see anything, chances are you don't have blown cases. I would suggest changing the crank seals while you already have it apart to make sure you don't have an issue with the crank seal.
Yes.
The case looks like this on the inside:
The area on the right is the "crankcase" where the crankshaft spins. The part on the left is the transmission part.
On each end of the crankshaft there is a grease seal. One small one sits behind the stator (left side of the engine) and one larger ID one sits behind the primary drive gear assembly (under the clutch cover) with a "collar" inside of it to make the seal. The one under the clutch cover can go back allowing the vaccum inside the engine to "suck" transmission fluid into the crankcase.
