On the video you can see the cam chain slack on my gs500. Is this much slack normal?
I have checked the chain and it is within the service manual limits it is under 158mm measured with vernier caliper. Also i have taken the tensioner out and check it function by the manual, and it is working like it should be. It does not back up when i press it, it holds. There is little slack in the tensioner you can see on the second video, but i think this should not scare me?

Hey would you double check that figure?  158mm is like 6 inches.

I believe the tensioner does the work, and that there is no adjustment needed if it is in spec.

Yes it is like 6 inches, but i talk about 20-pitch lenght of the chain. Sorry that i was not specific at the first time

Yes the tensioner works but i am little confused i can not find numbers for normal slack, neither can i find some video or photo about this matter.

Alright, yeah it makes more sense now that the 158mm refers to the chain pitch length.  Looking through the Suzuki service manual I don't see any figures for the slack of the cam chain, just something general that says like "check the chain slack."

Since the tensioner is just a simple plunger on a spring there is no real way to adjust it.  The manual says to replace the tensioner if it the plunger is stuck or the spring is busted.  So by "check the chain slack" I think they mean to observe that the plunger is pressing against the chain guide and providing tension.  If the plunger had gotten stuck upon installation then the chain would be floppy.

It has been a few months since I rebuilt my engine, so I don't remember specifically how much slack there was in my cam chain.

The movement in the tensioner is normal I think.  It isn't a precision part and it doesn't directly contact the cam chain but pushes against the back of one of the chain guides.  For some reason the way you are moving it back and forth makes me giggle a bit.

Goodonya for doing your own engine work.

Don't risk a bad timing chain tensioner!!!
If in any at all doubt, buy and fit a new tensioner, -they're not expensive, and it's a dead easy job, but it could save you destroying a motor.
The first GS I bought had this happen (why I got it very cheap), -the tensioner spring had failed causing the chain to skip sprocket teeth, valves to tangle, bend, hit piston etc. Expensive mech mess!
-Jools

Is it bad?(i guess you saw the video)

Well, I think if we took that approach to engine building in general we would end up throwing away money and good parts.

In the first video it does not look to me like that chain is going to skip a tooth.

Hopefully someone who has experience building several motors can chime in.

On the contrary mate, there are SOME components that are cheap enough, and the consequences of failure dire enough that 'early' replacement is just a no-brainer.

Nikola is asking for someone who has experience to tell him if the tension in his cam chain is correct.  I do not agree with the approach of telling him that if he is worried about a component to replace it.  Some people worry more, or lack experience, or have experience with other types of machines that have more/less slack in chains...

It looks to me like a new tensioner is going to cost $50 before shipping.  To some people that is insignificant, to me I think there should be a reason besides an abundance of caution before making a purchase like that.

Looking at his videos gives me no reason to believe that there is a problem with his chain tension.

To the OP.  The tensioner retracts when you turn the slotted screw in the back.  It should be under a small plastic cover.  If I remember correctly you have to turn that screw and then hold it in place while you screw the tensioner onto the engine.  I can't remember if you just pull the screwdriver out and the plunger extends or if you have to turn the screw counter clockwise to extend the plunger.