Topic: High CR 500-550 pistons anybody?

[crazypj]

Why does a single cylinder piston wear faster than a multi cylinder one?
 The piston acceleration, max piston speed, con-rod/stroke ratio, lubrication and rpm affect how piston wears, not the number of cylinders

[turboguzzi]

Why does a single cylinder piston wear faster than a multi cylinder one?
 The piston acceleration, max piston speed, con-rod/stroke ratio, lubrication and rpm affect how piston wears, not the number of cylinders

he must be talking about the latest crop of 4-str 450 MX'ers, cant remember the exact number but recommended piston check intervals for those are in the region of just a few hundred hours.

TG

[DeppJones]

Yes, I was talking about the latest 4 stroke mx bikes. I know that a friend of mine has to change the piston in his KTM every 30 to 50 hours.
For me that´s very often...

Achim

[crazypj]

In 2006, the check time was as low as every 12 hrs for 250 four-strokes (rev-limiters only cut ignition and couldn't prevent over revving)
 Max is still less than 30 hrs if racing.
 Redline isn't accurate on stock tachometer, Yamaha 17,000 was 'only' 15,500rpm
 Suzuki's I've checked are about 1,000 rpm 'fast' and actual red line (where rev limiter cuts ignition) is 1,000~1,200 rpm lower than indicated on bike rev counter

[dave500]

Yes, I was talking about the latest 4 stroke mx bikes. I know that a friend of mine has to change the piston in his KTM every 30 to 50 hours.
For me that´s very often...

Achim

so,three or four long bush thrash rides and your into the engine?

[trueblue]

Yes, I was talking about the latest 4 stroke mx bikes. I know that a friend of mine has to change the piston in his KTM every 30 to 50 hours.
For me that´s very often...

Achim

so,three or four long bush thrash rides and your into the engine?

Stuff that, I'll stick with my 650

[turboguzzi]

Yes, I was talking about the latest 4 stroke mx bikes. I know that a friend of mine has to change the piston in his KTM every 30 to 50 hours.
For me that´s very often...

Achim

dont underestimate 30 hours or even 12 in racing use @ 10,000 rpm. my 500 race motor require complete teardown every season, new rings every year, rebore every two. and i dont think i even get close to total 12 hours a year. each race meeting is four 20 minutes prectices + 20 minutes race = 1:40 hour X 6 meetings is less than ten hours.

That's what it takes to race a vintage bike...get used to the idea

TG