Decompression valve

Z.hb71

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6,399
Sooo I need a 8mm/m8 thread diameter (thread pitch doesn't matter) de compression valve that has a thread diameter of around 28mm (can be less, as long as it seals is fine) thread length. Does anyone know (this is more directed at the people who know alot or have alot of lawn equipment) of a decompression valve that could fit these specs?
 

cbaker65

Well-Known Member
Messages
899
Sooo I need a 8mm/m8 thread diameter (thread pitch doesn't matter) de compression valve that has a thread diameter of around 28mm (can be less, as long as it seals is fine) thread length. Does anyone know (this is more directed at the people who know alot or have alot of lawn equipment) of a decompression valve that could fit these specs?
Other than a dirt bike ,I only seen them on big chain saws!
 

TODD

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98
I do not know what thread size those are? I know the ones we used to put into Harley heads were the smallest they had made and they were a 10mm thread on them. Maybe smaller ones are available now?
That was like 5 years ago or so.
 

Seandonato73

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2,255
Just so you guys can see how another cylinder has its decompression valve. Its 10mm x 1.0 pitch. Same valve used from 47 to 120cc in my saws. The cylinder pictured is a 95cc husqvarna. The valve is actually in the cylinder. I back lit the hole so you could see its size and position an 1/8 " drill bit would pass through.
 

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cbaker65

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Messages
899
Damn that's cheap!!! I'll ask about shipping to the US, hopefully not alot!! Cuz I really want that. So much less BS and time!
If you don't get it ,then it is a good idea to install the release on that part ,an not on the cylinder ,in case something
goes wrong ,that part would be cheaper to replace!...
(y)
 

Z.hb71

Well-Known Member
Messages
6,399
alight sooo its gunna be 55usd shipped. what do you think should i get it? the decompression valve itself (this is to installl it on my existing head) is $10, the adapter is $10 aswell, then the machining cost is gunna be 25+. installing it on my head would be cheaper but more work
 

cbaker65

Well-Known Member
Messages
899
alight sooo its gunna be 55usd shipped. what do you think should i get it? the decompression valve itself (this is to installl it on my existing head) is $10, the adapter is $10 aswell, then the machining cost is gunna be 25+. installing it on my head would be cheaper but more work
I would buy it .I noticed that it did fit a 67 to a 71cc ,but if for some reason that it doesn't match up right ,you can
always resell it!
It would save you the headache of having yours done or trying to do yourself!....(y)
 

Z.hb71

Well-Known Member
Messages
6,399
I would buy it .I noticed that it did fit a 67 to a 71cc ,but if for some reason that it doesn't match up right ,you can
always resell it!
It would save you the headache of having yours done or trying to do yourself!....(y)
Alright 👍
 

Z.hb71

Well-Known Member
Messages
6,399
Wait heres a thing, that head is for a domed piston right?? Cuz I have a flat top piston. How's that Gunna work?
 

Z.hb71

Well-Known Member
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6,399
Wait heres a thing, that head is for a domed piston right?? Cuz I have a flat top piston. How's that Gunna work?
Asked the guy with the head to see if his piston was a dome or flat. Hopefully flat, the new 65-71 uses a flat top but this was an older gen one so I don't know. But would a domed head work with a flat piston?? My squsih band is freaking huge on my head, this looks a bit smaller
His Screenshot_20190911-123122.png
MineIMG_20190906_215115.jpg
 

Z.hb71

Well-Known Member
Messages
6,399
It looks like yours ,I think most heads at the top has a round indentation in it!.....:unsure:
Ok so I asked the guy and he says his piston has a very slight dome on it, soooo can I still use this head with my flat piston??
Wish Sean was here, he could probably answer my question!
 
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