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#805
Maybe they use a complete set of Ceramic Ball Bearings in the Transmission to Facilitate High RPM?
Any thoughts?
The Shop
What.
Think of it this way. If you could somehow put a ESR 325 cylinder on a YZ125. Might run and idle, but the 125 bottom end displacement is designed to flow enough for a 125cc. A 325 would choke it off massively.
Lesser extreme, on a YZ250. The bottom end is still only designed to flow enough for 250cc worth of airflow. 325cc would need extensive modification.
As for ceramic bearings. You wouldn't use them in a RT180 to make it fast. That's something you do when you already have a fast engine, lots of money (factory teams) and you're trying to get every little iota of internal friction out of engine for that last .25%
MXA Ceramic Bearing Article comment:
As far as motocross use goes, some factory and privateer teams do use ceramic ball bearings. As a rule they use them in places where the light, ultra-smooth and perfectly round balls make it easier for the bearing to acceleration. The light and smooth balls spin without hesitation and drag. By reducing bearing drag you create horsepower. A ceramic bearing here and there, like on the crank, won’t make much of difference. But, the cumulative effect of ceramic bearings on every turning spindle, axle and shaft in the drive train, as well as in the wheels, can make a noticeable difference. Used in unison they could reduce friction by one to two percent—which may not sound like much, but could equal a half horsepower gain on a 250 four-stroke. That is an easy horsepower gain.
It is however not a cheap horsepower gain because ceramic bearings cost three times more than the most expensive steel bearings. For example a steel crank bearing will cost $20, while a ceramic bearing will run $85. For a factory team the cost of ceramic would spread across four race bikes and eight engines (at least). And since those race bikes are typically torn down every two hours, the cost could run to several thousand dollars in a 29-race season.
Help a brother out!
If the case was indeed too small, you might end up with a scenario where torque is increased, similar to running small runner on an intake and increasing fuel charge speed like a venturi. Because the swept volume will be much more with new piston size. Would be interesting to see what the flow bench and dyno would say on that point. But no doubt a case engineered for stoichiometric combustion for 250ccs will not be large enough for 325.
Bearings are not even related anyway to what the guy was talking about
While maybe the case infact in no shape or form mathematically be tailored to accommodate the crankcase volume needed for a 325cc kit . While maybe ireelvent to the fact , but when someone mentioned crank case volume , you start spewing out some stuff about ceramic bearings yadda yadda. That is also irrelevant to anything to do with crankcase volume .
Try again dude ...
I kept seeing some odd choices regarding things being close to the track. Like I am surprised to see this little gem in this day and age at a pro track.
Pit Row
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