Bottom end modifications

Tanka

New Member
Joined
Nov 18, 2020
Messages
15
Ive been messing with the bottom end of my 48cc engine lately since and I've done the current mods so far; Stuffing crankcase, balanced the crank, and replaced the bearings. I believe I added 60mls of JB weld to the cases (2 tubes) and when I checked how much I balanced the crank today now that I have a proper set up, it is 48%, before I randomly drilled a 1/2 hole 15mm deep between the two other holes through the side of the crank (I wasn't too worried about f-ing up because I have a spare crank and it works better then stock)

I hear a lot about "trenching" with other 2 strokes but never have with motorized bikes. I figure since I'm in the crankcase again I'll balance the crank to a factor of 56% and do some extra port matching, and maybe some trenching if it's doable with these bikes

Also, because I'm too lazy to make another post, does anyone know of an aftermarket 50cc cylinder head or cylinders from moped at are compatible with these engines?
 


Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
3,854
Ive been messing with the bottom end of my 48cc engine lately since and I've done the current mods so far; Stuffing crankcase, balanced the crank, and replaced the bearings. I believe I added 60mls of JB weld to the cases (2 tubes) and when I checked how much I balanced the crank today now that I have a proper set up, it is 48%, before I randomly drilled a 1/2 hole 15mm deep between the two other holes through the side of the crank (I wasn't too worried about f-ing up because I have a spare crank and it works better then stock)

I hear a lot about "trenching" with other 2 strokes but never have with motorized bikes. I figure since I'm in the crankcase again I'll balance the crank to a factor of 56% and do some extra port matching, and maybe some trenching if it's doable with these bikes

Also, because I'm too lazy to make another post, does anyone know of an aftermarket 50cc cylinder head or cylinders from moped at are compatible with these engines?
Look up Minarelli vertical cylinders and or use the search here and look at minarelli hybrid, tbh there are a lot more options for the 66/69 base than the 48 but there are still plenty and lots of cast iron offerings.
 
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