Scooterotica

hi daz, simple way to think of is a one way valve, its self governing, in other words when the engine crankcase creates a vacumn the valve opens allowing fuel and air mixture in, when a positive crankcase pressure is created the valve closes so ingested mixture cannot escape,its then sent to the transfer ports and then combusted above the piston, allows inlet timing to be much longer duration than that of a normal piston port engine, a more modern inlet system introduced in motorcycles mainly during the 1970s/80s and is standard fitment on most modern 2 strokes these days, helps to reduce fuel spitback out of the carb as well.

Cheers Holty
Read all this thread tonight really interesting great explanations keep it up mate and the others guys

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ive done an all day session in the garage working on my case, heres a few pics, first is the crankcase opened up big engough for the crank webs, next shows the circlip to retain the drive side main bearing, and you can see the trench ive cut to give the big end some clearance, and then a view looking into the inlet, some more shaping here and there, but happy with the progress.

[imgIMG_0631_zpsyom10gfk by stephen holt, on Flickr][/img]


[imgIMG_0645_zpswwuejkwu by stephen holt, on Flickr][/img]

[imgIMG_0646_zpsopw0kskq by stephen holt, on Flickr][/img]

[imgIMG_0941 by stephen holt, on Flickr][/img]

a pic showing the drive side oilseal fitted

before the oilseal was fitted, bearing fitted and circlip

[imgIMG_0932 by stephen holt, on Flickr][/img]

[imgIMG_0942 by stephen holt, on Flickr][/img]

first fitting of the crankshaft

[imgIMG_0943 by stephen holt, on Flickr][/img]

and then magflange and packers in place

[imgIMG_0944 by stephen holt, on Flickr][/img]

piston fitted to rod, just to check clearance at bdc, i neednt have worried there was plenty of clearance.

IMG_0945 by stephen holt, on Flickr

i had o do some repairs to the endplate studs, so i added 2 extra ones while i was at it in an effort to make it stronger
IMG_0933 by stephen holt, on Flickr

hi holty that circlip on the bearing looks great and that reed valve opening looks massive what reed are you useing