Does anyone know how to detune an hw90 .25, this is a gas piston, theoben, kinda deal, I need to know how to reduce the pressure in cyl. and also fill it if it gets too low from me messing with it. Any special tools req'd., mine is too powerful and I believe it is the reason it is not as accurate as my HW springers.
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Tuning Hw90 detune
- Thread starter cantankerous
- Start date
Cantankerous Canadian - Yes, there's a valve under the screw head on the back of the receiver. Take it out and the valve is right there. Tap it with a very small hammer - very lightly. Get a small spritz of air out. Put the screw back in and test. It doesn't take much to realize you've gone too far. At that point you'll have to purchase the tools necessary to recharge it from a Weihrauch dealer. Not a difficult proceedure, just fiddly. There's a video on the web about this, I remember one from years ago that listed sources for the valve attachment, fill line, etc. He'd gotten them from special industrial supply houses. I took the easy route and ordered the whole kit from AOA. I've tuned it for a few different pellet weights and to make it more back yard friendly. Pressure up and head to the fields.. .
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It's as easy as can be. As above you use a small punch to let out tiny puffs of air and shoot a couple of groups. Repeat this process until accuracy goes back down or power is too low. Then pump back up to the speed where you got your best results. A chronograph will help you catalog your results.
LOVE the Beeman RX/HW90's
This is the pump you will need.
https://www.bestfittings.co.uk/shop/airgun-charging-equipment/charging-pumps/theoben-weihrauch-hw90-gas-ram-charging-pump-kit/
LOVE the Beeman RX/HW90's
This is the pump you will need.
https://www.bestfittings.co.uk/shop/airgun-charging-equipment/charging-pumps/theoben-weihrauch-hw90-gas-ram-charging-pump-kit/
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Yep. About 3 weeks ago I ordered the Best Fittings HW90 adapter (not including the bike shock pump). I was flabbergasted at how fast the delivery was, About 5 days via airmail. Very pricey, but the adapter is top quality. The adapter has a schrader thread and o-ring at one end and a 1/8" BSPP thread at the other. It screws into the schrader threaded port in the back of the HW90. BSPP is a standard for PCP fittings. My Hill floor pump uses BSPP. I've been looking around for a suitable HW90. If I find one, I'll use the adapter with my Hill pump.
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