Hi RobI have my 1720 setup with a Lane reg set at 90 bar and am getting 725 fps with 10.34s and 790 with 8.44s using a 3.5mm port all the way from valve exhaust, TP and barrel so if you have not opened the valve exhaust and barrel to 3.5mm yet it needs to be done. I am using a JSAR end cap with the dual spring setup but you may be able to just get by with a short heavy spiting since I do not think the JSAR Kit is still available. I get about 45 shots with it set up this way. the big key is no restriction in air flow from valve to pellet and eliminate all hammer bounce so you just sip enough air for each shot. You need a short heavy spring so you can hit the valve stem hard enough but still have some free play between valve stem and hammer when uncocked so the hammer is not rebounding off spring after each shot. I run about .060" to.080" free play between hammer and valve stem when uncocked.Hope this helps.BD
I am not sure but I think the maximus uses a shorter stiffer spring. Its best just to take the stock one out and go compare to some from a hardware store or indusrtial supply house to get several to try for the best tune.The part number for the maximus spring is GBMP-009 from crosman.The tuning is half the fun IMO.BD
Quote from: buldawg76 on June 19, 2021, 06:02:06 PMHi RobI have my 1720 setup with a Lane reg set at 90 bar and am getting 725 fps with 10.34s and 790 with 8.44s using a 3.5mm port all the way from valve exhaust, TP and barrel so if you have not opened the valve exhaust and barrel to 3.5mm yet it needs to be done. I am using a JSAR end cap with the dual spring setup but you may be able to just get by with a short heavy spiting since I do not think the JSAR Kit is still available. I get about 45 shots with it set up this way. the big key is no restriction in air flow from valve to pellet and eliminate all hammer bounce so you just sip enough air for each shot. You need a short heavy spring so you can hit the valve stem hard enough but still have some free play between valve stem and hammer when uncocked so the hammer is not rebounding off spring after each shot. I run about .060" to.080" free play between hammer and valve stem when uncocked.Hope this helps.BDHi BD.Any idea where you have your hammer spring and valve throw set on this setup?Thanks
Quote from: robs5230 on June 20, 2021, 05:31:33 AMQuote from: buldawg76 on June 19, 2021, 06:02:06 PMHi RobI have my 1720 setup with a Lane reg set at 90 bar and am getting 725 fps with 10.34s and 790 with 8.44s using a 3.5mm port all the way from valve exhaust, TP and barrel so if you have not opened the valve exhaust and barrel to 3.5mm yet it needs to be done. I am using a JSAR end cap with the dual spring setup but you may be able to just get by with a short heavy spiting since I do not think the JSAR Kit is still available. I get about 45 shots with it set up this way. the big key is no restriction in air flow from valve to pellet and eliminate all hammer bounce so you just sip enough air for each shot. You need a short heavy spring so you can hit the valve stem hard enough but still have some free play between valve stem and hammer when uncocked so the hammer is not rebounding off spring after each shot. I run about .060" to.080" free play between hammer and valve stem when uncocked.Hope this helps.BDHi BD.Any idea where you have your hammer spring and valve throw set on this setup?ThanksHammer stroke is set fully CCW or maximum throw and hammer spring is about two turns CW in from fully CCW but I am running the JSAR twin spring setup so it will not correlate to your gun with stock or shorter stiff spring. I would set reg at 90 bar, open valve exhaust port, TP and barrel to 3.5mm/.140" and hammer at full stroke then just play with hammer springs and settings of them to get desisted tune.Your plenum size on the huma reg could be different volume than my lane reg so that can make some differences as well with settings.BD
You have already been told that Magnum Air Power has them.
Does your reg set right against the valve face or is there a spacer of about a 1/2" to 3/4" that sirs between the reg and the valve face. Or is the spacer part of the huma reg so that there is some plenum between the valve face and reg body. If no spacer or plenum you likely do not have enough volume of regged air to provide sufficient amount of air to get desired fps.Need at a minimum of 1/2cc per fpe desired. Or if desire 12fpe you need at least 6 cc of plenum but 12cc would be ideal.BD
Since you have the power you want from it now your goal is to use the air more efficiently per shot. You likely don't need a short stiff spring now, you just need to eliminate the hammer bounce which is wasting the air. If you do not have any gap between the hammer and valve stem when uncocked with spring tension fully CCW and hammer stroke fully CCW then you need to cut coils off your current spring until you have between .060 to .080" of gap between hammer and valve stem or put another way you want .060 to .080" of free flight of the hammer before it contacts the valve stem to stop the bounce caused by the hammer rebounding off the valve stem when the valve closes and then having the hammer spring recompressed throwing the hammer back into the valve stem. Its all a balancing act to get your power desired with only one single opening on the valve stem per hammer strike. Measure your hammer spring length, wire diameter and number of coils and go to a hardware store that has a supply of coil springs and find ones of similar dimensions to test with and modify to find one that gives you the desired results.BD
If using the factory hammer ... it has more than enough weight.WANT MORE POWER ..... Raise the regs output pressure
Quote from: buldawg76 on July 26, 2021, 08:56:00 PMSince you have the power you want from it now your goal is to use the air more efficiently per shot. You likely don't need a short stiff spring now, you just need to eliminate the hammer bounce which is wasting the air. If you do not have any gap between the hammer and valve stem when uncocked with spring tension fully CCW and hammer stroke fully CCW then you need to cut coils off your current spring until you have between .060 to .080" of gap between hammer and valve stem or put another way you want .060 to .080" of free flight of the hammer before it contacts the valve stem to stop the bounce caused by the hammer rebounding off the valve stem when the valve closes and then having the hammer spring recompressed throwing the hammer back into the valve stem. Its all a balancing act to get your power desired with only one single opening on the valve stem per hammer strike. Measure your hammer spring length, wire diameter and number of coils and go to a hardware store that has a supply of coil springs and find ones of similar dimensions to test with and modify to find one that gives you the desired results.BDThanks.The factory hammer spring won't be man enough when I cut it, but I do have a slightly stiffer spring (.93mm) wire that I will try to shorten a little. That makes 12ftlb at fully CCW on tension and throw.