B-shop164 Posted July 3, 2019 Report Share Posted July 3, 2019 Hi, i have 20 cc BB race fuel domes from f.a.s.t in a cheetah cub and i have only 130 psi on each side? I chek with two new gauge and the same result ? Whats the prob ? Domes or leak?? Brand new motor fresh rebuild Quote Link to comment Share on other sites More sharing options...
Keno Posted July 3, 2019 Report Share Posted July 3, 2019 Hi, I have 20 cc BB race fuel domes from F.A.S.T. in a Cheetah Cub. I have only 130 psi on each side. I checked with two new gauges and obtained the same result. What is the probblem? Domes or leak? Brand new motor fresh rebuild. Who built the motor? What did the domes have engraved in the side of them? What is the squish? Is the motor drag ported? What brands of compression testers did you use? How many times did you kick? Did you hold the throttle wide open? Was the motor pressure tested? Right size pistons? Quote Link to comment Share on other sites More sharing options...
B-shop164 Posted July 3, 2019 Author Report Share Posted July 3, 2019 Cilinder kit cheetah cub 68/58 brand new and piston from fast clean ports /domes 20cc/10 /052 and the squish is .050 Brand new gauge and another gauge said 130 psi to ,throtle wide open and 20 kick and over .. the two side is exacly the sames compresion and all seal and all around is brand new ! Quote Link to comment Share on other sites More sharing options...
Keno Posted July 3, 2019 Report Share Posted July 3, 2019 Is the Schrader valve in the tip of the tester? If the Schrader valve isn't in the tip of the tester it will read low, additionally the tip needs to extend the same length as the spark plug. Do you by chance live at a high elevation? Quote Link to comment Share on other sites More sharing options...
Ayesully810 Posted July 3, 2019 Report Share Posted July 3, 2019 (edited) hold throttle wide open, use a good tester not a cheap 20$ dollar tester and kick it hard till the gauge wont move any more. must use same end as stated above. this should give you an accurate reading unless you are living at 7k Edited July 3, 2019 by Ayesully810 Quote Link to comment Share on other sites More sharing options...
B-shop164 Posted July 3, 2019 Author Report Share Posted July 3, 2019 8 hours ago, Keno said: Is the Schrader valve in the tip of the tester? If the Schrader valve isn't in the tip of the tester it will read low, additionally the tip needs to extend the same length as the spark plug. Do you by chance live at a high elevation? Yes i have a good tester and the domes is suposed to have the good elevation Quote Link to comment Share on other sites More sharing options...
B-shop164 Posted July 3, 2019 Author Report Share Posted July 3, 2019 Only 400 feet Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted July 3, 2019 Report Share Posted July 3, 2019 Has it run yet? Sent from my SAMSUNG-SM-G891A using Tapatalk Quote Link to comment Share on other sites More sharing options...
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