aprilia sr50 wont start

Im not sure really just strip the bike check for faults in the wires/make sure none have been damaged and just look over it closely to see if anything on the bike has broken or worn i had a problem on my nrg once when i turnt it on it just reved round to like 12-13k and it turnt out to be a split inlet manifold which is not something that would come straight to mind for people not to savvy on engines so just have a look over it and if you cannot find a fault take it to a shop to have a look over.

 

there nout but hard work peds haha :/ well i will check it all over again and if i dont find out i will take it and have looked over fully cos it should get fixed without a doubt that way but thanks for the advice

 

someone suggested easy start, and you never answered to if you had tried it ?

 

i havent tryed that one yet but will do

 

easy start help?

 

these are all the things i have done to try to get it to work...

cleaned carb 3x and fuel hosing/fuel tap
heated spark pug/replaced
changed piston and rings and fitted arrow to exhaust
new gasket set
new reeds (malossi carbon fibre)
used easy start
poored fuel down cylinder/easy start
checked for air leaks (none)
checked it was sparking and is great
fuses are still great
new filter (polini sponge)
new HT cap (NGK)

now i have lost it and cant think of anything i really need someone just to give me more things to check for its just becoming a joke now

 

easy start through the air intake of carb, throttle wide open, will ignite with less compression and with a weaker spark than convential fuel. The ignition timing would have to be out by miles not to get anything, not even a backfire, especially cranked over fast on the electric start.

if you can find it in you, can you try once more the method above.

 

i did it again and still nothing but i took it in and they said fuel is getting in and there is great compression so he said he changed the stator/magneto thinking it was that and still nothing but he said the spark is breaking down under load when in the cylinder so i was thinking it could either be cdi, regulator or ht lead so does anyone know the symptoms if they are broken thanks

 

after checking the HT cap and lead, first stop would be to check the coils resistance with multi tester or swap with known good one. The stator? that can be tested for output and resistance before resignation that it is kaput. If it isn't the coil...... I would of thought CDI.

the above assumes all wiring and Earths are okay.

 

the ht cap is brand new but the lead seems old and in one end its seem a bit battered. when i took it on they replaced the stator and the coils behind it with second hand one but when i go to kick it its semi ires up but then just stops so what could be a sign of and the guy at the garage just was basicll saying you have the spark but its now strong enough thats what he meant by breaking down under load

 

the coils of the alternator and the HT coil are two different things............ Have you checked/changed the HT coil.

 

thats the part that has been changed the coils behind the startor plate but the thing that the ht lead goes in hasnt now i think the coli and cdi are built in to one unit

 

yes they often are

 

the garage said you have great compression, all the H.T has been changed and you have a good spark, you are artifically fuelling, the exhaust isn't a dead end and not even a back-fire...................... they changed the stator, so assume they checked ignition timing. What else is there? In my book there isn't.........

compression
fueling
spark
timing

one of those is at fault. One of those areas has been over looked.

When things turn out like this, the best thing to do is to start at the beginning and check over everything, as if it was the first time and assume nothing.

Lets start with compression, describe why you changed the rings? Did you measure piston to bore clearance. Piston ring installed end gap clearance. Was the piston or bore scored.

When installing the rings did you locate the ends between the pins. Did you struggle to get the piston in the cylinder.

 

re-read your posts.

can you answer the questions from the previous post as well as;

was it a new piston.

What I am trying to establish, as well as if you have compression, is if a seizure took place.

If it did, it normally is caused by,

air leak, including crank seals,
lean mixture from wrong carb settings,
lubrication failure or insufficient lubrication,
cooling system failure, be it air or liquid,


and obviously others.
foreign body in system,
plug heat range wrong,
ragging a new or rebuilt engine,
metal fatigue of component.

 

i changed the piston cos the piston itself had two big markings in it and looked ruined so i bought a brand new piston kit the barel was fine nothing wrong at all and the compression has been tested and is at the right amount. then i changed the reeds cos the look battered as well so i bought some carbon fibre reeds changed fuel hoses cleaned out carb/jets/needle/holes etc put a new polini filter in so it was getting air through properly. now to check it was drawing it in i put my hand over the inlet cranked it over and it was sucking well. and i know the fuel is getting in cos all the crank area was flooded with fuel. so i then though it must not be sparking it so i put a brand new ngk spark plug and ht cap not the wire though and still nothing so i took it in they changed the full stator with a second hand one but in way better condition so i thought maybe its an other electrical part thats broke so i now presume its the coil/cdi unit and possibly the ht lead.i didnt measure the gaps or anything cos the garage i gave it to said it was all good plus i dont have the tools

 

oh and no seizure took place cos when the bike lost power when i pulled over it was still ticking over and when i got home span the piston to see if it had seized up but didnt

 

im only asking because you havent mentioned, but you did empty the engine of fuel, and wait till it dried out, as with this much fuel in the engine, it would be flooded and impossible to start...

 

yeah i dryed it all out sucked all the fuel out and everything it must be something so stupid apart from the 2 things i think it is