Umarex Umarex Notos return spring.

[purplepom]

Hi all,

Quick question, any body have any experience with modifying the return spring on the umarex Notos poppet valve? Im trying to maximize volume of air (extended barrel) to push some slugs hard.

Any suggestions on a good replacement spring?

If I have to take material off the spring how much should I go? I would prefer not to have to do this of course. I like to preserve all my stock parts.

 

[Dr. Kralenstein]

Find one that fits that is softer tension. Or run without one. Just have to make sure you cock the gun when filling from empty and don't tilt the gun down or the poppet will fall out.

They usually find their home if you tip them barrel up though!

 

[Firewalker]

I cannot recommend removing the spring but replacing it is a possibility.

In my testing, changing the preload spring made no discernable difference in pellet speed but it sure did open up my ES from 6 to 20!

2000 psi vs a #1 spring?

I would not expect any noticeable change.

Porting air passages, TP and barrel port?

Yes! Along with a longer barrel, you will make better speeds.

 

[purplepom]

I cannot recommend removing the spring but replacing it is a possibility.

In my testing, changing the preload spring made no discernable difference in pellet speed but it sure did open up my ES from 6 to 20!

2000 psi vs a #1 spring?

I would not expect any noticeable change.

Porting air passages, TP and barrel port?

Yes! Along with a longer barrel, you will make better speeds.

View attachment 517420

I'm actually getting the porting done now. Btw is that a 700 mm barrel on your Notos? If so I can you DM me where I can get one?

 

[Firewalker]

I'm actually getting the porting done now. Btw is that a 700 mm barrel on your Notos? If so I can you DM me where I can get one?

Yes, it is a 700mm FX liner kit, PM me for details.