Aprilia rs 125 engine problem

[jinis dust]

hi

was riding home the other day an bike started to have no power at all and was bogging?? then all of a sudden cut out and now wont start.
when i got it home and tried again, the engine sounds like when your turning it over with no spark plug init??

any help much appreciated,
thanks

justin

[Kickstart]

Hi

Take the spark plug out, with the plug held against a bare metal part of the engine and with the HT cap on the plug crank the engine over and look for a spark.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[ClockworkJesu...]

You mean like it lost all compression?
How old is the bike and when was it's last rebuild?

[Nope.]

[jinis dust]

Hi

Yh i have got a spark that was the first thing i tried.
Bikes on a 52 plate obly have it 5 month and dont know wen was the last rebuild. As its now gettin horrid weather i think its gunna have a new piston n rings. So gunna further investigate wen its in bits. Not too sure bout compression as i havent got a tool to measure it.
Thank

Justin

[P.addy]

As a quick test, pop your finger over the spark plug hole and try to start the bike. It should try and force your thumb off pretty hard.

Although... compression isn't everything. I had apparently 128psi and all looked good. Main bearings were slowly dying and was causing the crank to lock solid every now and then

[Kickstart]

Hi

If you have a spark then that is the simplist thing out of the way.

If it is spinning over rapidly on the starter then that suggests low compression. Run a compression check. However for it to go suddenly it suggests a failure rather than just gradual wear. If so then possibly a hole burnt in a piston or possibly it has snapped a ring. If it has snapped a ring then it has probably scored the barrel.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[jinis dust]

Hi

Took the head n barrel of earlyer n took piston off. Wer the piston faces the exhaust port it has sort of melted the rings to the piston...
So think i need a new piston. Will post on weather its ok after.
Thanks

Justin

[jinis dust]

Hi

Took the head n barrel of earlyer n took piston off. Wer the piston faces the exhaust port it has sort of melted the rings to the piston...
So think i need a new piston. Will post on weather its ok after.
Thanks

Justin