Decompression Valve Problem

Hi, you guys might have already read my problem in another post but now I'm specifically tackling one end of my problem. My decompression valve on the cylinder keeps on going up and down when my moped's motor is on. I've been told it should stay in place and that's why my moped sounds like a harley or like firecrackers are going off. Can anyone help me fix this decompression valve problem? I really need to fix this problem soon for my Father. Thanks in advance.

Re: Decompression Valve Problem

There should be a wire on the valve going to the lever on the handlebar. There should also be a spring on the valve holding it closed unless you pull the lever. Check to see that everything is there.

Re: Decompression Valve Problem

Just checking, I can only see the spring if I take off the cylinder head and look inside right? The spring can't be seen from the outside, only if I take the head off and look inside of it? Also, I heard that decompression valves aren't necessary so couldn't I just sodder it shut? Thanks.

Re: Decompression Valve Problem

Getting rid of the valve can make it harder to start. That's what it's there for.

If you plug it, pull the stem in the middle up- that's how it closes.

The spring on the sachs is external, and the cable that goes to the starting clutch should go thru it.

Re: Decompression Valve Problem

Alright thanks man. I just realized something though. I've never had a spring on it ever since I've gotten my moped. The loud harley sound I hear from the cylinder head stops when I close the valve or when I plug up a hole in the underside of the cylinder head. Is that hole supposed to be there? Thanks. And if anyone has a diagram of a decompression valve, please let me know. Thanks.

Re: Decompression Valve Problem

Hey guys, thanks so much! I actually realized my decompression valve was more screwed up then I said (it was quite bent up) , so I knew it would be hard to put a spring on. I ended up taking some key chain wire and shaping it to what I needed. It now works just like it's supposed to. The valve stays closed unless the lever is pressed. So no more harley noise!! Thanks, haha, and also my moped runs a little faster now. It has a lot less lag when starting from a standstill. I appreciate the help guys, thanks for sharing the knowledge.

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