Any tech. guys in here?

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yeah it pays to check them ive built over 20 engines in the last 12 months and they have all been difrent, soem of the clone motors are shocking
 
the GP290's (cy 36mm topends) are around 17.5:1 compression in stock form. HIGH Compression. probably the highest compression out of the motors we can typically use for our addictions.


you ll find a few of the builders like ESP modifies some heads to accept the 2mm stroker crank and still use only one .020, stock thickness head gaskets. the ESP 27.2 and the ESP 30.5 topends are milled out for a stroker motor and stock cylinder gasket, so no stacking up to .060 in gaskets to get clearance, no oblongating the coil mount holes to drop the coil low enough to get proper clearance ect....

plus on the ESP 30.5's (and the other stroker modded topend he produces) the compression ratio gets dropped from the 17.5:1 to a 14.5:1, and the squish band is lightly modified for a better burn.


after 12 plus gallons, i just had to rebuild my ESP 27.2 yesterday. new ring, new TFE Ceramic crank bearings, new oil seals and gaskets all around. if the rain stops today, its getting installed and ran in, if it doesn't stop raining, its getting installed and ran in tomorrow at Turtles track.
 
some cy 29cc 35mm head kits are suit for the 30 mm cranks with just a 0.20 gaskit

you can get cy sikk 26cc (27.2cc) head kits suited for a 30 mm cranks also.

both of these are factory jobs.

ive never had to elongate coil holes to run 0.60 gaskits on a 30mm cranks as there normaly is enough adjustment to still be able to set the coil corectly using a zen air gap tool for the fly wheel coil adjustment.

but milled heads are the way to go, if you have the extra money its an extra $54 usd just for a milled head with no performqance gain, just an extra 54 bucks so you don't have to stack a couple of gaskits

or using a stack combination of 1 x 0.020 papper gaskit on the bottom, 1 x 0.020 copper gaskit in the middle with 1 x 0.020 papper gaskit on the top, is a good combo that will not leak or weep

or a 29mm crank used with one 0.040 copper head gaskit, with provide the motor with one extra cc an a little more torque and there is no need to stasck gaskits.
 
yea,its always better to keep the ports as low as you can,that will give you more freedom when tuning the cylinder,plus you get better port numbers then you would by stacking gaskets on the base to begin with.
 
yes very true, but the average joe blogs, stacking gaskits is fine and cheaper, and you cant even tell the diffrence from running stacked gaskits or milled heads,

but like i said its the go if you have the extra 54 usd,

but most guys will never be able to tell the difrence
 
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