Krytac CRB busrt fire

[callumbagshaw]

Hi guys,

Bought myself a Krytac CRB last week and it's GREAT!

The only thing is (and I'm not sure I'm complaining because I kinda like it); I took out the fuse, and wired it to deans - since then, semi-auto has decided to become 2 shot burst. Does anyone know why that might happen?

Cheers.

 

[Samurai]

Did you happen to switch to lipo at the same time?

 

[callumbagshaw]

Always used lipo's in it... Just moved from 7.4v tamiya (with fuse) to 11.1v deans (fuse removed)

 

[Samurai]

Oh, then it's the 11.1V.

I read it here somewhere here where just switching from nimh to lipo caused this for a guy.

 

[Giliador]

[SIZE=10pt] CRB in UK have lower rate main spring so manufacturer recommend 7.4v lipo or 9.6v NiMH otherwise it will overspin on Semi and double shoot.[/SIZE]

 

[callumbagshaw]

CRB in UK have lower rate main spring so manufacturer recommend 7.4v lipo or 9.6v NiMH otherwise it will double shoot and even have problem with feeding.

Shit... Well the 11.1v lipo offers a FAR superior fire rate... What steps could I take to ensure I get maximum performance out of the 11.1v?

 

[Giliador]

In uk there is not much you can do, you can get the US high torque motor but on lower tension spring it will still overspin, and if you change spring it stop double shoot but your fps will increase, is there noticeable difference between 7.4 and 11.1v? you might notice feeding issue as well on 11.1v

 

[Baz JJ]

yeah I use 7.4V on mine (20k motor and standard UK spring) and its fine on semi.

 

[callumbagshaw]

In uk there is not much you can do, you can get the US high torque motor but on lower tension spring it will still overspin, and if you change spring it stop double shoot but your fps will increase, is there noticeable difference between 7.4 and 11.1v? you might notice feeding issue as well on 11.1v

The fire rate difference is more than noticeable, it's evident! Further to that, my FPS on .25's was 280, 320 with .2's - my site limit is 365 so there's room there. That said, it shoots fantastic even at 280!

 

[Baz JJ]

Ive bought PTS EPM mags for mine and plan to try with .25s and .28s.

Not too bothered about ROF as I rarely use full auto unless it's in very short bursts of 3 or 4 rounds.

 

[Giliador]

In theory changing spring should stop overspin but might make the gun hot on 20, but don't quote me on it. Try Krytec forum I'm sure Kriss Sierra Tango or Allizad will be able to help

 

[callumbagshaw]

Disregarding rate of fire - even for semi auto (despite it shooting twice with the overspin) the trigger response with the 11.1v lipo is evidently better too...

 

[callumbagshaw]

In theory changing spring should stop overspin but might make the gun hot on 20, but don't quote me on it. Try Krytec forum I'm sure Kriss Sierra Tango or Allizad will be able to help

Thanks mate I'll have a word.

 

[ImTriggerHappy]

The UK ones with the 20k motor are usually ok using m100 or m110 springs with a 11.1v lipo. I am guessing if yours is 20k then your spring is lower than an m100.

If yours has the US 30k motor inside and you use an 11.1v lipo with a lower rated spring you will get overspin and double firing issues.

Check which motor you have and then use the battery and spring combo which works best or change the mosfet for one ab type.

 

[ImTriggerHappy]

CRB in UK have lower rate main spring so manufacturer recommend 7.4v lipo or 9.6v NiMH otherwise it will overspin on Semi and double shoot.

Wrong.If you have a US version with a 30k motor and a spring below 120 you can get overspin when using 11.1v.

The Uk ones with the 20k motor can run an 11.1v with springs as low as m100 and it shouldn't be an issue. Thats why the UK has a slower motor to compensate for the lower rate springs when using 11.1v.

 

[Giliador]

Wrong.

If you have a US version with a 30k motor and a spring below 120 you can get overspin when using 11.1v.

The Uk ones with the 20k motor can run an 11.1v with springs as low as m100 and it shouldn't be an issue. Thats why the UK has a slower motor to compensate for the lower rate springs when using 11.1v.

This is quote from Krytac

Depend on your region. US , CA, South America and most of EU have no issue with 11.1v lipo as long as you keep the discharge rate within 15-20c.

For UK, Italy and Japan, a 7.4v would be recommended due to a weaker spring. A 11.1v will tend to overspin on Semi.

20k is to balance performance, not to make gun compatible with 11.1v

 

[ImTriggerHappy]

But not with the 20k motor they use for the EU now. I have wired up a couple with deans and an 11.1v and they have been fine. If the 11.1v has a high discharge rate that could be an issue.

The 20k is to allow the gun to be used with an 11.1v which is what Krytac was led to believe is the most common used battery by the UK distributor. That came from a Krytac rep that I was talking to.

 

[Sitting Duck]

your options are:

Lower Juice - obviously

Stronger Spring - but risk of too hot for UK sites

AB Mosfet - hmmm as it is built into box not that easy

Shortstroking - this is the reason for shortstroking preventing overun/double cycle & possible Pre Engagement at higher speeds

You in effect plop in say a M110 or M115 placing you over at 360-375ish

But then remove 2 rear teeth off sector+piston to come down 15fps per tooth = back to 350fps

Piston has 3 or 4 metal teeth on it

However the SS method will void any warranty so I would suggest lowering the juice on a M105 spring or some spring that gets you 349.999fps

You could use a different motor that may perform slightly faster/slower but tbh it isn't the motor but higher juice & m100 spring setup

I would like to point out that if a gun is starting to over-run - heck double cycle in you case....

If a gun is firing twice on semi - then that is an early warning sign of possible PE if pushed any more

So do not think the 2 rnd burst is great coz going a bit quicker like on a freshly charged 11.1v @ 12.6v or a higher C or burst rating

Will risk possible PE - you may be another 5rps off PE or just a few off PE - so be warned it is not a great thing to be left ignored

The gun is in effect talking to you - so I suggest you listen to it and perhaps ease up on double firing

Yes Krytac could of SS their US guns a tooth or two - still plenty for a barrel up to say 400mm

I'm guessing you are well into the 20's possible approaching 25rps

try 9.6v - but forget LiFe batteries - they do not offer the grunt as you would expect imho

Trigger is correct - the 20k motor shouldn't over-run on 11.1v unless you got a mofo 11.1v in there

That is why the UK is supposed to get the slower motor than US, though tbh it isn't ultra insane motor

reckon you got a 30k or a mofo lipo or a weak spring - suggest you have a rethink...

Then speak to shop if they got a direct import and possible spring/juice/motor option

 

[ImTriggerHappy]

Could just be the deans and fuse removal has left the pathway very clean. Try adding the fuse back in to create some resistance which you should do running 11.1v anyway. Then put a few bursts of full auto through if its a freshly charged battery to deaden it slightly.

A lot of well set up guns can double fire when you put a fresh battery in, mine does.

 

[Sitting Duck]

Indeed - especially on lower springs, doesn't take much to pre-cock or over-run like you said....

Would advise plopping fuse back in, heck there are some nice fancy blade holders up to 30a

that have a led in them to tell ya if fuse blown..

I might not have a fuse in some of my guns but I'm a stupid risk taker on cheap guns so wtf

£300 gun with a precision box - no fuse is stupid, I still got fuse in my s/hand krytac

Deans will boost 1 to 1.5rps - as shown on youtube then 11.1v fresh off charge - that is quite an increase in power

Ease up a bit - a bit of over-run is fine but consistent double firing is sailing a bit close to the wind - even in my wreck it ralph book