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Post by birdman on Dec 17, 2014 12:18:44 GMT -5
If you have compression, the next step would be to check ignition timing and valve timing since you say u got fuel and spark.
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Post by niz76 on Dec 17, 2014 19:45:56 GMT -5
I don't know if a 4t is the same but on a 2t: 90-100psi minimum to get it to start, 140psi is good, 170-180 is great! But real high compression can start spark knock and/or detonation...
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Troll
Scoot Enthusiast
Fastest 50cc in Upstate SC
Posts: 357
Location: Enoree, SC
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Post by Troll on Dec 17, 2014 22:29:36 GMT -5
If you have compression, the next step would be to check ignition timing and valve timing since you say u got fuel and spark. I did do a valve job on it last week while looking over it and the timing and cam are spot on cause I was thinking maybe I had a valve that tightened up on me but they were loose when I got everything TDC. I went a head and set them to .003, I'm going to put the tester to it first thing in the morning. Got a few honeydews I have around the house tonight.
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nightriderrv
Scoot Enthusiast
Never Give Up- Ride all the time !!!!!
Posts: 177
Location: Western mountains Nebo NC
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Post by nightriderrv on Dec 28, 2014 13:24:06 GMT -5
Did you do a liquid test on the head by pouring gas in to the In & Ex holes to see if they hold the fliud
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Troll
Scoot Enthusiast
Fastest 50cc in Upstate SC
Posts: 357
Location: Enoree, SC
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Post by Troll on Jan 16, 2015 14:48:34 GMT -5
I had a guy tell me to do that, haven't got around to it but I did order a 72cc BBK with head and going to run it
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Troll
Scoot Enthusiast
Fastest 50cc in Upstate SC
Posts: 357
Location: Enoree, SC
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Post by Troll on Jan 26, 2015 12:07:14 GMT -5
Sorry it's been a while, money, weather and family has had me at a stand still. I did a liquid test and sure enough it's the Ex valve that's hung open, gonna clean up both the piston and head and see if I can fix it. I did install a 72 BBK that came with a head, just have to get some oil, plugs and Ex gasket. Also bought a adapter to convert a 150 carb to a 50 but not to sure it'll work so it looks like the stock carbs going back on till I can find a 20mm instead. The old piston and hug still looks good so if I can save that head I'll use them for back up or try to do something with The Block I have that has a bad crank..
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nightriderrv
Scoot Enthusiast
Never Give Up- Ride all the time !!!!!
Posts: 177
Location: Western mountains Nebo NC
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Post by nightriderrv on Jan 27, 2015 18:50:17 GMT -5
It's always good to have a back up set you never know when something could go bad. There are replacement valves on ebay not much $$$ always good to have a set or two on hand when you bend a valve...
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