250 2c
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  1. #1
    Junior Member Jimmy.T's Avatar
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    250 2c

    Hi
    What should the PSI on 250 2c cylinders be??
    Mine feel good but think i may have a duff gauge .?
    120 psi both cylinders...think it should be more like 140 psi....
    Problems idling and getting hot??
    Last edited by Jimmy.T; 02-06-2019 at 01:19 PM. Reason: updated

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    sounds more like air leaks into the crankcase

  3. #3
    Junior Member Jimmy.T's Avatar
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    Yea its a strange one , no air leaks ignition side or base or carbs , ive ran it up and sprayed around for leaks but nothing really, could be clutch side i guess..I swapped the carbs over and the other cylinder got slightly hotter so could be lack of fuel getting it lean but ive cleaned them out thoroughly and made sure theres a good supply of fuel ,,,pain in the arse!!
    I'm going to strip it down and re do seals and make sure i get the base gasket thickness right too, made my own from 0.20mm paper maybe too thin but i dont know what it should be for right compression??
    Had a long time off due to illness so not done anything in over a year, hopefully i'll crack it soon...
    she'll be right.

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    Senior Member DenH's Avatar
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    Quote Originally Posted by Jimmy.T View Post
    Hi
    What should the PSI on 250 2c cylinders be??
    Mine feel good but think i may have a duff gauge .?
    120 psi both cylinders...think it should be more like 140 psi....
    Problems idling and getting hot??
    . Two strokes have a much lower compression ratio than four strokes,sounds like it's running lean if it gets hot ?
    when i was young i was very indecisive,now im older im not so sure.

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    Junior Member Towerdave's Avatar
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    Quote Originally Posted by Jimmy.T View Post
    Yea its a strange one , no air leaks ignition side or base or carbs , ive ran it up and sprayed around for leaks but nothing really, could be clutch side i guess..I swapped the carbs over and the other cylinder got slightly hotter so could be lack of fuel getting it lean but ive cleaned them out thoroughly and made sure theres a good supply of fuel ,,,pain in the arse!!
    I'm going to strip it down and re do seals and make sure i get the base gasket thickness right too, made my own from 0.20mm paper maybe too thin but i dont know what it should be for right compression??
    Had a long time off due to illness so not done anything in over a year, hopefully i'll crack it soon...
    she'll be right.
    had a similar problem with mine . I did two things: put new gaskets on the barrel side of the carbs and spent ages cleaning the carbs and put new needles and jets in. Result was really nice even idling, smooth running and no temperature issues.

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