interference engine

is the wr450 engine an interference engine?

Edited by psmcn

Yes. There are actually indentations in the piston for the valves

Virtually all modern four stroke dirt bike engines are interference engines.

 

All interference means is that one or more valves drop into piston air space.

So, you can touch a valve from piston contact if you cam chain slips or breaks, and usually destroy the top end parts.

also know as 'safe' engines, those that the valves cannot touch the piston (im the event of timing chage breakage / slippage etc)

 

too get the performance out of a 4 stroke, that modern bikes have, its not possible to make them 'safe' and still get the valve lift required and compression ratio

That's why the rotary valve heads looked so promising. About 10-15 years ago some guy was developeing these heads to use on existing engines (small block V8s) and he was getting incredible HP numbers....twice that of poppet valve motors. Don't know what happend to the guy or his idea.

That's why the rotary valve heads looked so promising. About 10-15 years ago some guy was developeing these heads to use on existing engines (small block V8s) and he was getting incredible HP numbers....twice that of poppet valve motors. Don't know what happend to the guy or his idea.

The auto industry either bought him out or had him disposed of. Things like that aren't good for the auto industry, money is too important.

Wouldn't surprise me as it's happened several times before. The laundry detergent companies bought the patent on an ultrasonic clothes washer to put it on the shelf.

Thanks, That is what I thought.

The auto industry either bought him out or had him disposed of. Things like that aren't good for the auto industry, money is too important.

This is cool stuff! When can i get one for my yamaha????

This is cool stuff! When can i get one for my yamaha????

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