Notos Notos FPS setup confusion?

[Quiet Veteran]

Well I've run out of free Google searches and as I'm new to this need to ask the experts. Purchased a Notos for myself and my 7 year old son loved it so much got him one as well. His is shooting strings depending on pellet type/weight in the low to mid 700s with no adjustment. Mine on the other hand with polishing the trigger screw and adjusting the hammer spring multiple times from full in to flush is only getting low to mid 500 fps but very consistent with about a 1-4 fps spread depending on brand pellet and weight (seems to like any type of pellet put in it) Do I have a bad or improperly adjusted plenum, maybe weak hammer spring ? What am I missing? PCP is new to me so pardon my ignorance.

 

[PasadenaMike]

Sounds like an RMA to me. Don’t say anything about working on it. I’ve owned 2 and they were in the 7-800 fps range

 

[Peyton]

Well I've run out of free Google searches and as I'm new to this need to ask the experts. Purchased a Notos for myself and my 7 year old son loved it so much got him one as well. His is shooting strings depending on pellet type/weight in the low to mid 700s with no adjustment. Mine on the other hand with polishing the trigger screw and adjusting the hammer spring multiple times from full in to flush is only getting low to mid 500 fps but very consistent with about a 1-4 fps spread depending on brand pellet and weight (seems to like any type of pellet put in it) Do I have a bad or improperly adjusted plenum, maybe weak hammer spring ? What am I missing? PCP is new to me so pardon my ignorance.

I would guess regulator pressure.

 

[Quiet Veteran]

Well to add. Just swapped out the Air cylinder with my son's and that's not it so ....

 

[MountainSportAirguns]

Sounds like TP isn't aligned or bad breech oring,

 

[FL22]

I also vote RMA.
Return My Airgun .

 

[Quiet Veteran]

Thanks for all the help Guys .Sadly a RMA is not possible due to a slight "trigger issue" and having to tap and install new trigger stage screw. Note to self aluminum does not like steel when improperly tightened

 

[FL22]

Thanks for all the help Guys .Sadly a RMA is not possible due to a slight "trigger issue" and having to tap and install new trigger stage screw. Note to self aluminum does not like steel when improperly tightened

Well, you might be able to find one that is used perhaps on the cheap from another forum that has a classified section and swap parts. Send yours in as an RMA and then have one for spare parts.

 

[hameditor]

Maybe I can add to the mix...

It seems that the regulator is known good. So we can rule that out.

As you have another gun, I would try swapping the hammer spring next. Hey, you never know! If that makes no difference, then at least it's ruled-out also.

That then would leave a few possibilities:
1. A restriction in the valve or transfer port area, as has already been mentioned. (This has to be the favorite).
2. A "dragging" hammer that's rubbing in the tube and slowing its impact. Unlikely but possible.
3. Missing O ring in the rear of the barrel (the bolt passes through this when in battery). But I'm assuming this is unlikely as you would find a blow of air from the area when the gun is fired.
4. Tight valve stem (where the poppet valve passes through the valve body). Unlikely, but I have seen this in the past.

Sorry I can't be more definitive, but maybe there's some more possibilities to explore.

Good luck!!!

 

[Quiet Veteran]

Maybe I can add to the mix...

It seems that the regulator is known good. So we can rule that out.

As you have another gun, I would try swapping the hammer spring next. Hey, you never know! If that makes no difference, then at least it's ruled-out also.

That then would leave a few possibilities:
1. A restriction in the valve or transfer port area, as has already been mentioned. (This has to be the favorite).
2. A "dragging" hammer that's rubbing in the tube and slowing its impact. Unlikely but possible.
3. Missing O ring in the rear of the barrel (the bolt passes through this when in battery). But I'm assuming this is unlikely as you would find a blow of air from the area when the gun is fired.
4. Tight valve stem (where the poppet valve passes through the valve body). Unlikely, but I have seen this in the past.

Sorry I can't be more definitive, but maybe there's some more possibilities to explore.

Good luck!!!

Well that also makes complete sense. And sadly should have probably thought of a simple spring swap when I swapped the air chamber . Occam's Razor usually makes sense. Thanks again ALL.

 

[Quiet Veteran]

Sounds like TP isn't aligned or bad breech oring,

Following your advice I visually checked the o'ring and held my face next to the breech and fired a few rounds. No puff of air. And thanks for the help and info.

 

[PasadenaMike]

Did you run a chronograph test before you started drilling and polishing?

 

[Quiet Veteran]

Did you run a chronograph test before you started drilling and polishing?

No didn't own one until after I bought my son his. Wanted to try and have them matched as much as possible. And it was not heavy polishing only used 1500 and 2000 grit.

 

[Quiet Veteran]

Did you run a chronograph test before you started drilling and polishing?

And only drilling was retapping trigger for the 2nd stage screw that I stripped.

 

[PasadenaMike]

I know polishing and drilling won’t affect anything but it’s too bad you weren’t able to chronograph it before doing the work at least you could’ve exchanged it.

 

[Quiet Veteran]

I know polishing and drilling won’t affect anything but it’s too bad you weren’t able to chronograph it before doing the work at least you could’ve exchanged it.

Yep , but being a retired cop have confiscated a few guns that have parts polished with less then desirable results ... Or desireable depending on which end of the gun you are on.

 

[Quiet Veteran]

Well think I may have found my problem. My son's first then mine. This doesn't appear to be a standard dowel pin. As one hole is slightly larger then other and can't find a parts diagram. Can someone help me out on what goes here.

 

[Firewalker]

That's the valve retention pin. You two have different generations of the Notos.

The solid pin with splines on the other end is a Gen l, ll & lll design. The gen llll has an M3 grub in front of a loose retaining pin.

My guess is that the valve has shifted.

You can send the gun to me for repair if you wish.

Dave
Firewalker Airsmithing