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Montjuic
Bikes: Fire-blade, Monster 600
Posts: 72
Join Date: Sep 2014
Location: Saham Toney, Norfolk
Mood: Living the dream!!!
So today I carried out a compression test, engine warm, throttle fully open and assuming the valve clearance is correct; the results are as follows:-
Front Cyl - 100-105 psi bouncing dry and 122 psi wet
Rear Cyl - 115 psi dry and 125 psi wet
As the book compression ratio is 10.7:1, assuming atmospheric pressure is 14.7 psi I take it is just a case of multiplying 10.7 by 14.7 equalling 157 psi or there abouts.
If this is correct the front cylinder is losing 57 psi overall made up from:-
157 – 122 = 35 psi from the valves and 122 – 100 = 22 psi from the rings and the rear cylinder is losing 42 psi overall , 157 – 125 = 32 psi from the valves and 125 – 115 = 10 psi from the rings
Or looking at it another way the front cylinder is working at 63% and the rear at 73% giving me an overall engine performance of 68%.
Bad news for the engine but at least I can keep eating pies and drinking ale.
What to do now?
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