ICS RIS M4 semi-auto prob. Cut-off lever?

[AirsoftTechGeek]

I have had my ICS M4 203 RIS upgraded with a CA 170% spring, spring guide w bearing and reinforced bushings as well as a shim job. The gun works ok for over 8 month until recently it had some problem with firing in semi-auto.
It appears that the cutoff lever is catching the trigger and preventing it from firing in semi auto. Almost like a timing issue when the gear is open, I fire the rifle in semi and the trigger will get stuck on the cutoff lever which cams up and down as the gears turn.As soon as I switch it to full auto its fine for a while but sometimes it wont work in that fire mode either. I found that pushing the forward assist would get the rifle to work again but sometimes I have to open the upper to reset the timing. Any help will greatly be appreciated.

[mcguyver]

Try a larger capacity battery. Seriously. I have the same gun with similar upgrades and it has a hard time running those upgrades with the PEQ 9.6v 1700mah battery ICS supplies.

You also have to make sure the shiiming is top notch. I've shimmed more guns than I can count and it takes me an hour to do an ICS M4 lower, but 10 min. for a Marui ver.II. You have to shim the anti-reversal latch as well and you may want to recheck the sector gear shimming to ensure it's properly contacting the semi-auto cut-off (or sway bar as ICS calls it). This will render all your other shimming as useless and you'll have to start again.

The reason you have to push the forward assist is because you are sometimes starting the fire cycle with the piston already in the middle of a fire cycle. This is causing your motor to be under a much heavier start-up load than when the piston is fully forward in the cylinder. The ICS battery (if that's the one you're using) is incapable of delivering the inrush current to the motor when you increase the load by using a heavier spring. Changing motors makes no difference either as it's not a motor problem, but rather a current delivery problem. When you press the forward assist, you return the piston to the start of the fire cycle and decrease the intial start up load on your motor.

And as far as timing goes, there is no such thing. The first full auto burst you fire automatically sets the timing correctly. Semi auto uses the sway bar to set it's own timing and this is not adjustable in any way. It's the biggest myth in airsoft.

[AirsoftTechGeek]

Thanks

[spaceghost0]

More in response to the battery comment than anything: Larger battery packs could do it, but I suggest starting with the motor. It's easy to use smalled batteries and a good (TM) motor rather than a crap motor (ICS) with a bigger battery. My ICS runs fine and I didn't believe the motor was as bad as I had read until I swapped it. Entire WORLD of difference. The ICS motor gobbles those 1700s.

[mcguyver]

Mine has the EG 700 in it already. It won't run an SP110 spring on a 1700mah battery, but it'll run a PDI 190% spring shooting 450+ fps in an SPR.

Motors are only as good as the current to run them and brand/model makes zero difference if your battery isn't up to the task.

[CDN_Stalker]

Nutshell, Available current = available food (fuel provided to make work). Starve a soldier, he won't perform well. Provide all that he needs, he will do his job to the limits! Go higher mAh battery, the highest you can fit in your AEG. mAh doesn't just mean the length of time the battery will last, it also has a huge impact on your rate of fire.

[AirsoftTechGeek]

I'll check out different batteries as soon as i can.

[colazel]

i want to change the cutoff lever on a ics m4. Where i can find it and which brand?? I want to know if it's the lever the problem or changing this spring on the lever will solve the problem??

[Kokanee]

it's a "yaw control bar" and there are some for sale here;

http://www.airsoftcanada.com/showthr...ight=ics+lever

[colazel]

correct me if i'm wrong but it seem to be the same thing as a guarder cutt-off lever on ascarmoury

[beach_boy]

Kokanee is right that its the "Yaw Control Bar," I'm not quite sure if the guarder is the same. Anyways, I had to replace mine in my ICS. I got one off of DB19 and I ordered another through Speedy Toys (which I would never do again) but we are talking about ICS and they don't non ICS parts... I am meaning to test to see if a TM one but I haven't gotten to that quite yet.

[colazel]

thank for the info

[Kokanee]

second beach_boy's point about not ordering from speedy toys. Ordered the yaw bar and a safety cover, less than $10 in parts, the brokerage was over $20 from UPS.

[hondatech]

Bump for ideas. I recently upgraded a teammates ICS m4, and it is now suffering a similar problem. I put in a new upper box with a PDI 150% spring, SRC bearing piston head, ICS bearing spring guide, and G&P poly piston. I had the bottom box apart to install ICS copper bushings. Motor is a TM EG700, battery is an 8.4V 3600mAh large. Same as the OP, it'll lock up in either semi or full, most times the foreward assist releasing the anti-reversal latch will get it back in action, somethimes it's a hard lockup that takes opening the receiver to clear. The gears move freely with no excess wobble when the motor is out. I've tried other motors and the stock upper box, same issue, so I suspect I've done something slightly off in the lower box...

[beach_boy]

I had a some what similar problem, the control bar wobbled because the screw wasn't able to tighten the bar onto the body properly. I asked around and Mcguyver advised me to add a shim in between the bar and the screw... seems to be working fine now.