aprilia rs 125.HELP

hadden · Trackday Trickster Joined: 01 Nov 2011 Karma :

hi everyone.im new to this site and im after some advice.i was riding my aprilia rs 125 on a dual carriageway last night and it just cut out on me and come to a stop very quickly.iv had the bike for 6 months now and never missed a beat.im not gonna lie i do give it the beans from time to time but not always.now i tried to start it again and you could hear the piston moving up and down but sounded like there was no compression at all. i took the spark plug off and it was as grey as it could get so took the top engine cover off.the piston head looks sound and there is no major scores on the barrel.also the piston was right at the top and i pushed it down with my finger with ease.also there were tiny metal shavings sat on top of the piston.im really hoping its piston rings but as there looks like there is no damage to the barrel im not sure.i would love to take it to a garage but iv skint.so please dont just tel me to take it to a garage.thanks for your time.james

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

Could be rings + piston, top end rebuild time. Shouldn't cost you too much to DIY. Very simple on the RS!

hadden · Trackday Trickster Joined: 01 Nov 2011 Karma :

ok thats good to hear.iv had a good look and it looks like i need the take the whole engine out to get to the head bolts.is it possible without taking it out?thanks

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

What year is it?

Does it look like this one..
https://motoprofi.com/imgs/a/a/e/u/r/aprilia_rs_125_2000_11_lgw.jpg

If so... you just unbolt the tank at the front with an allen key, remove the front seat and it should just lift up.

You can then access the head, piece of cake Thumbs Up

hadden · Trackday Trickster Joined: 01 Nov 2011 Karma :

yeah its the same as that its on a x plate.anyways iv just managed to get the head off and the piston is scored really bad.ill try and add a picture.but im trying to work out how this has been done.is it overheating or oil starvation or is it because every now and then when iv had little money on me iv bought cheap oil??[/img][/url]

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

Christ...

use decent oil, warm it up before riding it properly and get it set up properly with regards to mix in the carb..

Shocked

monty16v · Two Stroke Sniffer Joined: 12 May 2011 Karma :

looking at that piston id say your cylinder is scrap too
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OffTheClockMotorSport

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

hi,
just thought i'd add, there is no need to remove the whole engine to replace the cylinder &/or the piston.
its a bit fiddly (you really need wee hands,lol) but i've done it a few times.
check the cylinder, if its badly scored/gouged, then it will need a re-plate (around £120) or a replacement cylinder. (the mitaka kit is around £250 iirc)
cheers,
GAZ

monty16v · Two Stroke Sniffer Joined: 12 May 2011 Karma :

i have 122 cylinder here £90+ postage
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OffTheClockMotorSport

hadden · Trackday Trickster Joined: 01 Nov 2011 Karma :

cool.aslong i know its been done before ill do it but just looks extreamly awkard.and how can i check the bottom end without taking the engine out?if you can save that for me for a few weeks monty16v then i will have it off you.is it brand spanking or used?

monty16v · Two Stroke Sniffer Joined: 12 May 2011 Karma :

it is used, but came from a running machine i broke for parts. a new one is over £400
cylinder is on ebay at the minute
https://www.ebay.co.uk/itm/220884943842?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649#ht_794wt_932

you cant really check anything in the bottom end without stripping it. Just check for excessive play in conrod
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OffTheClockMotorSport

dobby · Nitrous Nuisance Joined: 09 Mar 2010 Karma :

fully synthetic oil to the spec API-TC** or ++ whatever is on the bottle, agip speed i used to use