Go Bottomlow compression
 | vw_lover
Join Date: Jul 2009 Posts: 5 tennessee 
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2009-07-08 163904
hello,i have something to add to my last post,if i losen the valves i have 175psi,if i set them correctly i only have 50 psi,what causes this? thanks for your help
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| gatoraider
Join Date: Nov 2008 Posts: 544 Maryland 
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2009-07-09 163906
Your valves have to be set at .005 at TDC of the compression stroke. The only thing that can be wrong, if you loosen them up and you get 175 PSI, is you aren't adjusting them at TDC of the compression stroke. Did you check the valves for dimples where the rockers contact them ? The exhaust valves are usually the worst. This can give you a false lash reading. I assume you lapped the valves and deglazed the cylinder before you put it back together. ....
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| vw_lover
Join Date: Jul 2009 Posts: 5 tennessee
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2009-07-09 163912
Hello! Thanks for the reply. Can you tell me how to make sure that I am getting the top dead center of the compression stroke? Thanks again. ....
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| gatoraider
Join Date: Nov 2008 Posts: 544 Maryland
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2009-07-09 163925
I like to use a long 1/4" drive ratchet extension. Take the spark plug out and put the extension in the hole and let it rest on top of the piston. Rotate the crank until the extension comes out of the cylinder as far as it will come. The way you tell if it is the compression stroke is check for push rod movement when the extension is near the top of the stroke. There will be no push rod movement for approx. 1/8 turn of the crank on either side of TDC on the compression stroke. If you are not on the compression stroke there will be push rod movement going thru TDC as you turn the crank. Simple as that. Make sure the piston is at it's highest point when you set valve lash, .005 ( cold )in your case. ....
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| vw_lover
Join Date: Jul 2009 Posts: 5 tennessee
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2009-07-09 163926
thanks for your help i got it running,but it will not run without the choke on,it revs up and runs desent at halve choke,i removed and cleaned the carb but the main meetering jet,is stuck and will not come out,i suppose the carb is junk and needs replaced,i also checked to see if the carb mounting gaskets were leaking and they are not so i think its a carb issue now,any help or answers on this would be helpful thanks ....
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| gatoraider
Join Date: Nov 2008 Posts: 544 Maryland
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2009-07-10 163941
That main jet meters all the gas from idle to wide open, so it has to be open and completely open. ....
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| hawk1955
Join Date: Jan 2010 Posts: 2 ny
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2010-01-16 168092
I tore my engine apart after checking the carb several times. I went back to the carb after reassembling the engine and found the bushing on the shaft for the butterfly worn. I had a machinist make a new one, he made some extras. I no longer have to run half choke, but have some other issues to correct. ....
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