MOPED ARMY

Space the cylinder up then either shave down the top of the cylinder or have the head machined on a lathe to sink it into the cylinder 3mm.

Either that or shave down the piston crown as long as the ring fully seats. If I recall the k-star transfers fully open even though the exhaust doesn't. A milled flat k-star head, a head gasket and 1 thin base gasket dial me in at ~1.6mm for squish.

the amount of time the piston spends at bdc is minimal, so "not clearing" is less of an issue then it appears.

more about time/area then fully opening.

small side issue is it will block some of the pipe hit, again, minimal.

These kits and many others nowadays are like this

Stupid huh

We're stupid for not complaining and still buying these kits ,

Junk cdis, junk pipes that fall apart, stuffed cranks that the stuffing comes out and much more aftermarket "racing" parts. That is how they get away from warranting this junk saying "for race only no guarantee"

If you put a shelf at the exhause when the super heated charge exits the combustion chamber it creates eddy currents which will eat away at the periphery of the piston and can also scorch the ring and draw the temper from the ring.

Also the shelf will disrupt the reversion wave and not allow overstuffing the combustion chamber.

You are contradicting yourself mentioning time the piston spends at BDC and time/area, the piston spends more time at BDC and TDC then any other point in its travel. Do the math.

Glenn Kuehn Wrote:

-------------------------------------------------------

IAN!!!

1. Try a different piston? Or

2. Use a thicker base gasket to make the crown flush with the bottom of the exhaust port, then measure your deck height and head gasket thickness. Send all that info and the head to Graham Motzing and he'll fix you right up :)

Ps let's ride! (edited)

RM, you are correct, time, yes, area, no.

draw a bell curve representing time/area

draw a horizontal line clipping the top off, representing the piston stopping before the bottom of the port.

most of the area, vertical is still there, but horizontal, time, it's a fraction.

my choice of wording was poor.

"the amount of time the piston spends at bdc is minimal"

should have read:

"the amount of area the piston blocks at bdc is a fraction of total time/area"

i experienced a similar problem on my grande but modified it like graham M. did