Rapide ER4 hybrid

[COB]

As with all who have owned a Rapide, I have grown weary of the humongous PIA that the valves are. I recently purchased and began the rebuilding of another Rapide. Rebuilding a leaky Rapide valve has been a hit or miss endeavor for me. The last 2 valves sent me back to a crazy idea that I have been thinking about for a long time. Is it possible to replace the original Rapide valve with a newer double action valve. At this point some may ask Why? The answer is obvious. This is MCB the home of Why Not?
And so began this ridiculous endeavor to upgrade the Splatmaster Rapide. The new"ish" JT ER4 is a double action marker like the Rapide. Because the ER4 is relatively new and cheap, parts should be more available than original Rapdies or GZ 2000s. The ER4 is a functional marker with a long pull double action in a clear plastic shell. The ER4 plastic tends to crack and break when abused. The Rapide has a much more durable plastic shell. So, my plan was to shove the ER4 valve into the Rapide shell.
This is where the real work begins. Fitting the ER4 valve into the Rapide clam shell requires milling the inside of the shell to accommodate the different shape of the ER4 valve. Also, making sure the CO2 piercer aligns with the CO2 channel in the shell. The ER4 trigger and the bolt will not fit into the Rapide shell. Therefore, I needed to use the Rapide trigger and bolt. The Rapide bolt arms are about a heavy 1/16th to 3/32 short. This means that the arms do not relatch to the back of the valve. The 4/40 cap head screws, on the front of the ER4 valve, need to be replaced with smaller round head screws. Additionally, the shell has to be modified to allow the trigger to lean further back, to allow the bolt arms to latch on recocking. Because of the difference in the pierce pin and the valve shape, the CO2 cylinder does not fit as deep in the handle. This will require the modification of the CO2 knob. Fortunate for me, I have a 2 part aluminum CO2 knob that resolved the issue.
End result is a functioning Rapide with a new ER4 valve. There are some minior issues that need to be addressed. The trigger sticks and does not recock. This may require a stronger Trigger/Bolt spring. Additionally, smoothing the interior channels and oiling the bolt arms may help trigger to recock.

[COB]

More Pcs of the Process

[Jonnydread]

ooh I'm interested to see what you come up with! I had an ER4 and it was super fun to break out at the end of the day for shens

[COB]

The latest update for this ridiculously foolish endeavor. Yes, it works, but with a recocking issue. As described above, the arms on the Rapide bolt are just a hair shorter that the ER4 bolt, preventing them from latching on the trigger return.
Both trigger systems are basic cam systems. The ER4 bolt is longer than the Rapide bolt. The ER4 has the slot on the bolt and the posts on the trigger. The Rapide has the post on the bolt and the slot on the trigger.
If you use the ER4 bolt, you need to shorten the front of the bolt and add posts in the slotted collar to work with the Rapide trigger. The ER4 trigger is too tall and would not easily be modified to fit the Rapide frame.
I have tried lubing the arms and sides of the valve to eliminate friction. I have added a block of rubber inside the rear cap to limit the distance for the valve pin can recoil hoping it will cause the arms to catch every time. This is not working consistently. So, for the moment, I will put this aside and stew on the solution.
The marker fires well with the factory barrel. I have also used the freak barrel system on this Rapide. Since I test with total crap paint, I do not see much effect. I do see easier pierce seal and good velocity from the factory ER4 valve. That said, I will resolve the recocking issue and use this magic turd on the field soon.

[COB]

Another update. The ER4 valve is a better version of the Rapide valve. That said, they were both designed by Satan to torture simple minded morons like me. So, I tried a couple of the ideas that I posted earlier. Do not bother trying to modify the ER4 bolt. The draw is too long for the limits of the Rapide frame. The more I adjusted the inside of the frame to fit the valve system to achieve a consistent function, the more issues that arose. The first fit above left the valve unbolted but the pierce in the center of the CO2 slot. In this state the valve moved during function creating trigger and recocking issues. Sliding the valve forward to allow a through bolt to hold the valve, moved the pierce pin off center and caused leaking as the co2 cylinder could not seat properly to seal. Enter to dumb idea of changing the valve to a hard 1/8" line with a macro line connection. Changing the system to constant air. This required complete disassembly of the valve. Remove the pierce pin, drill and tap for 1/8" brass pipe fitting. End result is the same as trying to repair a Rapide valve. Now the valve is leaking both front and rear of the valve. Through a series of repeated efforts, I replaced the rear seal, then the front tip seal. This was a true absolute MF. Valve stop leaking, now it will not fire. And so, I am putting this to the side for a moment. Oh, I forgot to mention that it no longer operates with the valve in the forward location. So, there was no reason for the constant air and full disassembly of the valve internals after all.