Boygofast 47mm sleeved cylinder info



Frogslayer

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Jan 20, 2019
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Please please do not use self tappers in your low-end on your sweet set up lol. Need to tap and use a real grub or set screw.
 

Spare_Parts

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Nov 29, 2017
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You got lucky with that one imo,those transfers are the preferred ones and known as eyebrowed, they serve a useful purpose in that they create a swirl in the chamber as they first open at the high point and the pressure is at max.The intake could have the top flushed with no adverse affect and depending on induction type you may want to enlarge it yet anyway.The exhaust top of port at 29 is odd 27 or even 26 will be much better and go great with those transfers again deep at 33(high side) that gives 23 degrees blow down duration and retains your torque!
So I just dry fit the jug and with the stock base gasket the piston is 1.1-1.2mm in the hole. I can take it off the top at home but not sure if that is a good idea. Thoughts?
 

gary55

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Nov 27, 2012
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So I just dry fit the jug and with the stock base gasket the piston is 1.1-1.2mm in the hole. I can take it off the top at home but not sure if that is a good idea. Thoughts?
Rather than determining material to be removed by the distance from top of piston to top of jug you should do a squish test for gap betweem top of piston to squish band of head with engine assembled.. Place 1/16" rosin core solder on top of piston assemble and torque. Turn engine over then measure thickness of solder. Shoot for a .8mm thickness of the squished solder with a copper head gasket. Run solder parallel to the wrist pin.
View media item 60815
 
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