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Mares Cyrano Evo HF 90 air leakage question

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

pavel.dolgov

Member
Apr 1, 2016
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Hi All,

I'm fairly new to modern pneumatic and your help with the Cyrano HF that I bought recently. This is a brand new, never shot gun. Have not had time to try it in the water but found an air leakage during the checkup. Leakage does not happen all the time and goes away and returns if I move a piston with a spear a little. It does not seem right to me, but I may be wrong and leakage will go away after shooting in the water, therefore I need your help. Is this kind of leakage normal for a new gun? What could be the cause? Barrel, piston, o-ring, oil, something else? Is there an easy fix or I really have to return the gun to the place I bought it from? Thank you.




 
I had same problem with my Cyrano 850. I suppose it was long time sitting aside before I bought it. Probably sealing of the O-ring/skirt on the piston is a problem. O-ring /skirt become deformed, losing its original shape, elasticity. Try to add some more air, increase the pressure to operating pressure... I think it was on low pressure on video? On higher pressure the skirt would seal better.
 
Last edited:
Thank you tromic! Yes, it was on low pressure. Will increase pressure and see if it helps.
tromic, did problem go away on your Cyrano or you had to change o-ring/skirt?
 
Thank you tromic! Yes, it was on low pressure. Will increase pressure and see if it helps.
tromic, did problem go away on your Cyrano or you had to change o-ring/skirt?

I was unsure about the cause of the problem at that time. I was a newbie. First I complained about the problem. Finally I just replaced the O-ring on Cyrano's piston for thicker, 6 x 2 mm and it solved the problem. Original was different, maybe 8 x 1.78? I noticed it was deformed. It was not oval, more similar to triangle?
 
Increased pressure, made some test shooting over the weekend, problem is gone. Tromic, thanks a lot.
 
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