2-stroke piston window, rear boost port.

[Lozza]

Yep when synthetics stop working and break down film strength castor starts working. I only know of 1 engine where a specially developed full synthetic oil is specified over a castor/synthetic blend. With the engine probably worth 60,000Euros and fighting for a world title not many were prepared to experiment. From memory the Elf oil was $65 a litre.

[2T]

I did a bit of homework & thought regarding piston window's, thought I'd give it a try.  Reports state an increase in 1 to 2 horsepower on a 500, plus a cooler running piston crown from escaping hot gases from under the crown.

Not worried about any more power but thought anything that may give cooler running is worth a try plus even a slight reduction in piston weight wouldn't be a bad thing?

To tell you the truth, I wouldn't notice any increase in power, I'm not getting what I've got to the ground now!  It does seem a touch cooler in the combustion chamber; plug is a little darker.  And my imagination is feeling there is less vibration (I'm a wanker lol).

Any thoughts?

Hi John,

Obviously, a lot of water has flowed under the bridge since you started this thread. I am wondering if you would now recommend adding windows in a 500cc piston to help lower piston/combustion chamber temps and are there any downsides?

Also, do you still have those pics?

Cheers,
Rob

[John Orchard]

Hi John,

Obviously, a lot of water has flowed under the bridge since you started this thread. I am wondering if you would now recommend adding windows in a 500cc piston to help lower piston/combustion chamber temps and are there any downsides?

Also, do you still have those pics?

Cheers,
Rob

[/quote]

G'day Rob, I never ran the CR on the dyno, so I can't talk on HP, I also did not run any temp strips on the engine, nor use a temp gun on it, I can tell you that my CR did not ping, it was very high compression, enough to split the plastic cup in my artificial knee. CR500RE's were infamous for pinging, if I ever have a bike that has a rear boost port, I'd put a window in the piston, if it doesn't have one.

I'll see if I can find some pics, send me an email; [email protected]