G200 to G200B

[thayashi]

I have 2 Scubapro G200's that will be used as safe seconds. They both need to be serviced so I was thinking that at the same time I could convert them to G200B's. I have read here that this can be accomplished with a new s-wing poppet, spring, and balance chamber. I have a G250 service kit that includes the s-wing poppet, but I am wondering if there is any source for the spring and balance chamber. If I can get the parts, does this seem like a worthwhile modification for a recreational diver's safe second?
Thanks!

 

[Kupu]

I would only consider upgrading the G200 to balanced if using as primary second stage, but not for alternate second stage, especially if that means spending money on parts.
It could arguably be worth converting both if using an unbalanced first stage.
If you do the conversion and need a couple springs and chambers, I have a few extras.

 

[Couv]

It could arguably be worth converting both if using an unbalanced first stage.

What he said.

 

[halocline]

The spring and the balance chamber are both readily available at any SP dealer, assuming you can find one that will sell them to you. Should be less than $5 for each part. I think it's well worth converting them; they'll hold a tune quite a bit better over time, there will be less wear on the seat in storage, and they'll probably breathe a little smoother. IMO the G200B is an under-rated regulator that's a great performer just like it's cousin the G250.

 

[Couv]

For parts see @Bryan@vintagedoublehose.com or [USER=84549]@buddhasummer[/USER]

 

[buddhasummer]

The spring and the balance chamber are both readily available at any SP dealer, assuming you can find one that will sell them to you. Should be less than $5 for each part. I think it's well worth converting them; they'll hold a tune quite a bit better over time, there will be less wear on the seat in storage, and they'll probably breathe a little smoother. IMO the G200B is an under-rated regulator that's a great performer just like it's cousin the G250.

New stock OEM long crown X type balance chambers less than, new stock OEM springs more than. SP prices have been steadily increasing. Current model parts pricing is getting silly, discontinued model parts pricing sillier.

To the OP, feel free to message me if you have no joy locally/easily, I can get the parts for you.

 

[thayashi]

I was able to source service kits with x-wing poppets and Kupu was able to provide me with springs and balance chambers. One of the G200's purge diaphragms had what appears to be a small but permanent "wrinkle" in it. It seems to work fine, but I have not tested it in the water. Is this something I should replace?
I also noted that the orifice o-ring provided in the Scubapro kit seem a bit smaller than the one I recently used on a G250 service. The annotated diagram I have notes a
010 or .920 o-ring. Is the Scubapro a metric o-ring at .920 and will using a 010 o-ring create any problems? I am assuming all is fine and that the converted stages will be similar in performance to my "stock" G200B or primary G250's. Lastly, as these G200's will be used as safe seconds does slightly "detuning" the regulator by turning in the orifice a bit once flow stops recommended? Thank-you to all the DIY and Scubapro gurus out there for your help!

 

[Kupu]

Do a vacuum test, if the second stage is airtight then most likely the diaphragm wrinkle is not going to be an issue. A shallow easy test dive or two for final check of fresh rebuilds is a good last step. I use D70 -010 oring on the orifice.

Yes for adjusting orifice to detune a bit since used as alternate second stage. That was my primary reason for thinking the upgrade to balanced was not needed since potential benefits would be lost by detuning.

 

[Rusty Shackleford]

I only de-tuned mine to a 1.2. It still breathes great. Between that and the VIVA turned down while not in use is enough to prevent a free-flow. I am glad I upgraded mine.

 

[halocline]

Is the Scubapro a metric o-ring at .920 and will using a 010 o-ring create any problems?

For the orifice, generally a 902 (I don't think that's metric, just a different sizing system from the 010) fits pretty well. It's a little skinnier profile than the 010 but about the same interior diameter. I keep a few of each around and use whatever fits best.