Lightweight reed piston

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mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
So.... I cut my piston all to ****. but, it works, wonderfully I might add. Took off my intake before I took anything else off and noticed that at BDC my piston closes the intake. No need for that, the reeds will do that for me :) So I pulled out my dremel and removed even more crap from the piston. Now I have 2 1/4" holes on each side of each wrist pin hole, one large reed window, and one smaller one closer to the rings. I'll let you know how it runs, in the mean time, have a look:



Weighs 97.3g, about 13g less than stock. they're heavy for a piston, but at this weight my bike is ridiculously smooth riding, smoother than most 70's-80's cars I've rode in. I'm looking to buy a titanium wrist pin (already found one) that'll reduce the weight a further 8.5g. Using the G circlips will reduce your weight an extra 0.1g (rather than the double ended ones), but I imagine using a real circlip will reduce it a bit more. Every little bit counts.

Once I get all that done, I may buy a new Minarelli piston (thinner rings, probably lighter weight and stronger), and if that meets my needs, I'll finally balance.
 

mew905

New Member
Sep 24, 2012
647
9
0
Moose Jaw
smh as usual something goes wrong... got a compression leak now. Put two new, custom gaskets on, thinner than normal. it sounds grunty, like it wants to go, but has troubles starting and troubles going, a definite power loss somewhere. I'll try a different head gasket, and see where that gets me. Only other thing I can think of is the thinner base gasket sets the timing too far off (or perhaps the exhaust port is open at TDC :O ). Other than the extra hole in the piston (which lines up very nicely with the bottom of the intake port at BDC), and widening the exhaust port a bit (using a dull cutter sucks, I have 2mm to remove at each side and this cutter would do it in probably an hour per 2mm), and using the stock head, torqued to 10 ft/lbs with head gasket (I was using the puch hi with permetex gasket previously), nothing else has changed.