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Old 01-29-2015, 06:37 AM
cannonball2's Avatar
cannonball2 cannonball2 is offline
Motorized Bicycle Elite Member
Join Date: Oct 2010
Location: Colonial Coast USA.
Posts: 3,286
Default Re: Curious about the engine, :question:

Rod length is important. Most of the 38mm cranks(excluding the GT5) seem to have 110mm rods. This puts the piston about 1.5mm in the hole. If you had the 114mm rod then it would be about 2.5mm+- out of the jug using no base gasket and less with one, probably about 1mm or so. If your rod is 114mm then you need the high pin piston. Im curious where my piston will be when I assemble my engine. Im betting at the top of the jug. However there is a curious machined ring(to small to be a squish) in the head maybe for piston clearance. This may account for why some engines arrive with multiple head gaskets.
Who knows!

Another thing this engine has the nicest head gasket I have seen. It is precisely cut not to expand into the cylinder. Im betting the piston has some pop up. In fact everything about this engine is 1st rate in manufacture, even the gaskets are excellent. If it has pop up then its gotta have higher compression than a standard 40mm.
Also I have not paid much attention to the angle of the intake ports on the jugs. This one appears to have a deep angle like the port is lower?
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Last edited by cannonball2; 01-29-2015 at 06:51 AM.
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