PISTON AND RING REPLACEMENT

[BAD398]

I JUST GOT ME A 01 426 I WAS WANDERING HOW OFTEN WILL I NEED TO PUT A PISTON AND RING IN IT. WILL IT BE AS OFTEN AS A 2-STROKE OR NOT?

[Glen_T]

I put 2 years on my piston before I replaced it. It could have gone longer, but there were some marks in the side.

GLEN

[PK]

I agree with Glen, I had 2 years on 99 YZ400 and pulled it apart to replace the piston and rings and found everything was still within specs. I figure every 2 years I'll pull it apart and check it, or if I feel it's getting a little tired. Kind of a crap shoot really. You can't do a compression test on them because you need to use the compression release to turn the motor over.

Pat

[Shawn_Mc]

Your thumper wont eat piston like a two stroke even if you ran it without the air cleaner. When you change the oil as much as most of us do, engine "wear" is almost nil. Most of the time there an engine failure, its a bad part from what Ive seen. Recurring topics: counter balancer keyway and clutch innerhubs&baskets. The odd trans lets go, but for the most part, these bikes are pretty tough. 2001 counterbalance gear on your bike is splined so your not going to have that problem. The clutch is a wild card. The piston will out last you probably.

[PumpkinHumper]

I still have the stock piston and rings in my 99 yz400. I have never had the motor apart. I havent even checked the valve clearance yet. I know I REALLY should have checked the valves earlier. This fall the motor is coming apart. I think it will finially be time. But it still runs great!

[DJDMX46]

I'm with you , I have 1999 YZ400 and I have NEVER had the motor opened up. I have raced it for 3 years now 20 races a season ( 2 classes each race ) = 120 motos, and count less holeshots ? All i do is change the filter every week, and the oil once a month. By far this is the most bullet proof bike I have ever owned.

[RIDEPATE]

yup, same here 99yz never been apart, i've got all the parts for a re-ring but really havent seen the need to do it,no smoke,plenty of compression, so no need to bust the cherry.....hehehe