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Aprilia Rs125 Wont Start

#1 User is offline   cassa-d 

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Posted 17 June 2011 - 10:22 AM

Hi guys
i have a aprilia rs125 and have just bought a engine for it fitted it all up and it wont start
there is spark and fuel (plug is getting wet) but just turns and turns and may give a little pop every now and then

just dont wanna start

any help would be apreciated

also what should the mixture screw be at?

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#2 User is offline   chubbosaurus 

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Posted 17 June 2011 - 11:53 AM

Is the engine brand new? Or has it got a new top end? Use a compression tester on it anyway

Also make sure things like your reed valaves are deffinately in, And that there are no vacuum leaks at all


EDIT: you could also try putting some fuel in the spark plug whole with the piston at tdc

This post has been edited by chubbosaurus: 17 June 2011 - 11:54 AM


#3 User is offline   ajw3008 

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Posted 17 June 2011 - 12:44 PM

sounds like no compression if its popping from exhaust

#4 User is offline   cassa-d 

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Posted 17 June 2011 - 02:55 PM

View Postchubbosaurus, on 17 June 2011 - 11:53 AM, said:

Is the engine brand new? Or has it got a new top end? Use a compression tester on it anyway

Also make sure things like your reed valaves are deffinately in, And that there are no vacuum leaks at all


EDIT: you could also try putting some fuel in the spark plug whole with the piston at tdc


hi mate its a 2nd hand engine i bought that has had a rebuild. i will have to try and find someone with a compression tester

tried putting fuel in spark plug hole still no different never even tried to start just turns over

#5 User is offline   lizard821000 

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Posted 17 June 2011 - 03:00 PM

a 2nd hand engine thats just been rebuilt ay.....:ponder: i see lots of those around. :doh:

#6 User is offline   cassa-d 

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Posted 17 June 2011 - 03:07 PM

Link to engine
http://cgi.ebay.co.u..._fvi%3D1&_rdc=1

#7 User is offline   Jeff 

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Posted 17 June 2011 - 03:15 PM

it was me that rebuilt that engine. the compression was between 155-160psi a the top end. It has new piston, rings, little end, and new gaskets and seals throughout. it was test fired using my bike and worked perfectly on my 28mm carb, stock reeds setup else i wouldnt of sold it on. i know what its like to be screwed over on ebay and wouldnt do that to anyone else.

#8 User is offline   suzukirg125fun 

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Posted 17 June 2011 - 03:47 PM

Didnt jeff sel this engine and buy a new 1? lol

#9 User is offline   lizard821000 

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Posted 17 June 2011 - 03:54 PM

lol, youv been lucky then mate, the lad seems to be on here who sold it.

if the engines as good as said then youv done somin wrong while fitting it, recheck your steps

This post has been edited by lizard821000: 17 June 2011 - 03:55 PM


#10 User is offline   beavis 

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Posted 22 June 2011 - 01:54 PM

same problem ? pls tel me what the normal compression? want be ?

#11 User is offline   Jeff 

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Posted 22 June 2011 - 06:43 PM

good compression is 150+ psi anything above 130 is good, below 130 its time to look at new piston rings

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