Subscriber, Thanx for your post notifying us to the existence of the 634's. I bought one and am one happy camper. Thanx again. Joe
I bought another 634 to detune and make an indoor plinker. The piston seal had a big rip and it wasn't sealing well. So I grabbed my calipers and coffee can of old piston seals....Long story short: the oem seal from my Gamo Accu was the same size and fit well other than needing the O.D. sanded down a few thou to fit the tube perfectly. So if you need a seal, check out the ones for the Gamo family of rifles that share the same seal with the Accu. I believe the Crosman B19 series are the same seal as well? I'm going to to order a few seals from Crosman and see the next time I have a 634 apart.
Quote from: LAalex on August 19, 2017, 03:43:39 AMThanks. Spare parts availability is my only gripe with Cz. Any idea where to find a spring to fit as well?I'm experimenting with a .113 Vortek spring right now. It fits perfectly on the rear guide that I expanded slightly.Full length at 35 coils gives 10.42 fpe, but is hard to install, (too much preload) and harsh shot cycle.28 coils gives 7.98 fpe, very easy to install, easy to cock, and smooth shot cycle.27.5 coils produces 7.8 fpe, has about half inch of preload, easy to cock, smoooth. This is where I stopped because I am tuning to make an easy-shooting rifle.I don't have data for the range of coils between 35 and 28 because I didn't realize my piston seal was so bad when I was experimenting in that range. The 35 coil data was taken after replacing the piston seal by using another new spring I bought for another project. Based on my results, if I wanted a factory 10 fpe power level and shot cycle I'd order a spring with 32 coils. Or I'd go with the .118" spring.Here's the spring:http://vortekproducts.com/ourstore/airgun%20Springs/Air-Gun-Springs/spring-coil%20spring-airgun%20springI also have a Vortek .118" spring. The I.D. is a few thou smaller than the stock spring and about .010 smaller on the O.D. It fits slightly tighter than stock on the rear guide, but still a loose fit. I didn't try it, but I'll bet it would be a drop in replacement if you called Tom and told him how long your stock spring is and wanted the new one cut to the same length. From eyeballing what I have here it looks like 28 coils would do it. I'd likely order 30 and clip a half of a coil at a time until I got what I wanted.http://vortekproducts.com/ourstore/airgun%20Springs/Air-Gun-Springs?product_id=106
Thanks. Spare parts availability is my only gripe with Cz. Any idea where to find a spring to fit as well?
I found 38 red stock 634s listed for sale at Cromwell's Firearms for $107: http://www.cromwellsfirearms.com/index.php?route=product/product&filter_name=slavia&product_id=88455