ts1 no compression after new piston

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tavspeed
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Fri Aug 09, 2019 7:58 pm

mates ts1 was running rough and using loads of petrol,so we decided to put new reed petals in,we discovered what looked like a crack in the bridge between the two windows,so we got a new asso piston.
top end was rebuilt with new gaskets and good sealant,came to start and there was hardly any compression on the kickstart
so have put the old petals back in,which looked in perfect condition anyway,still the same
so put the old piston back in,still the same,hardly any compressionmand wont start
would a knackered drive side oil seal or mag flange oil seal cause no compression
did a basic leak down test with a piece of innertube.and the exhaust gasket was passing,so will sort that tomorrow
any ideas anyone,before i take the crank out,cheers

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garry inglis
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Fri Aug 09, 2019 8:51 pm

You should take side casing off and flywheel so you can do proper air leak test block exhaust port off and put air through your carb rubber and spray all around the barrel and cylinder head nuts inlet manifold maghousing and front sprocket area make sure piston at bdc and it should hold 5psi

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rosscla
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Fri Aug 09, 2019 10:08 pm

If the piston is above the ports you should have compression even with a slight leak in the head or plug thread.

Is your clutch and Cush drive OK? Try turn it over by hand from the flywheel.
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."

dragoonpvw
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Thu Aug 15, 2019 5:00 am

rosscla wrote:If the piston is above the ports you should have compression even with a slight leak in the head or plug thread.

Is your clutch and Cush drive OK? Try turn it over by hand from the flywheel.
Test the compression with a compression tester. One that plugs in the spark plugs hole. . Hope you put the right piston in. Make sure the flywheel is spinning when you kick over.

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