Aprilia rs 125 heads off (page2)

[G19RKE]

hi guys i have been running my bike to and from work for past couple of days and noticed it has not been using much oil from the tank.. it has used a full tank of fuel but the oil has only gone down a small amount. maybe a quarter of the way down from where it was...

i check regularly due to the nature of the bike i meant to adjust it once i got home from work once i realised it wasnt using much but before i got chance it kind of started spluttering on me just down the road from my house as if it was running out of fuel or something then it cut out completely as i slowed to pull onto my driveway.

i have since wound out the adjuster on the oil pump cable to try and get it using more oil but it seems to have stopped my bike working completely.. the lines on my pump are slightly apart so it is set to use slightly more oil as i was running the bike in.

so will this be stopping my bike from starting or will this be due to something else... its turns over fine, and actually almost starts some of the time but just doesnt, and if it does then it dies almost instantly... the battery is good, i even charged it to make sure, iv removed the spark plug and tested and it has a spark but cannot measure strength of sparks but it looks fine! the starter is new and compression isnt an issue as its a fresh top end!

im thinking either the pump has completley failed or i just need to play with settings but wanted to see what other recommend.

cheers

[Boxing]

Hmm, how many miles has it done since it had a topend rebuild? Any race stage upgrades to the engine?

Also oil pump might have packed in. Or isn't adjusted correctly.

If it won't start again, incorrect mixture has probably caused a heat seizure.

Take the exhaust off, look up the port. Shine a torch up there if you have to. See what kind of condition the piston is in, if it's black and covered in oil, then it needs top end rebuild.

Then just a case of getting the engine out and pulling the top end off. Check the condition of the piston when / if you do this. If the piston has smashed, then you'll need to strip the whole engine down to get the smashed piston out.

Post up some pictures if you can. Sadly these Aprillia RS 125's get messed around with a lot, and sold on when they're about to blow up.

Did it rev OK through the gears? Or did it stop revving past a certain RPM range?

[G19RKE]

it has done roughly 700km since rebuild... i ran it under 6k for first couple hundred then upped it to 7k for 200 then 9k for 200 and now its on nearly 800km im only just starting to take it to redline as iv worn it in stages.

the oil warning light did flash just before it started to die and yes it did loose power and wouldnt rev up. i was nearly home at the time and i dropped a gear and pulled on throttle and it seems to keep it going a little but then it dies again so i dropped another gear untill finally i was down to 2nd gear and at my house so i pulled in the clutch lever and it died!

i dont have a problem taking it apart as iv pretty much renewed every bit of this bike now and im enjoying learning ill be annoyed if the oil pump has failed and damaged the engine as its literally only not long got to where i wanted it to be lol actually running beautifully and i was just starting to enjoy the bike with proper power

i doubt the piston is smashed as the spark plug gap is fine and looks fine from spark hole and iv had it on previous bikes where spark plug gets fouled by piston, and compression seems fine and bike turns over fine seemingly..

[G19RKE]

oh and as for upgrades it has standard 28mm carb, arrow end can and is apparently full power but even when i brought it was not seem to me full power. it just about does 80mph in all fairness, it doesnt have the restricted flatspot of the cdi so thats been changed, it has rave under seat, it has power valve, and has twin airbox and rave cable and motor so all of the gear is there as far as i know it just has never seemed right since iv owned it, and the guy i brought it from had just completed the top end rebuild aparently and had used mitaka top end kit including barrel.

[_Iain_]

Honestly, think for a second - when an engine with umpteen moving precision components starts to run badly, sounds wrong or starts refusing to take any lubricant what would be the best cause of action?

Keep it running flat out so that whatevers going bad gets a chance to smash everything else to bits

OR

Immediately switch it off to prevent any further damage

The autolube pump probbably airlocked or failed, you ran it dry of any lubricant oil & it's gone metal to metal till you had zero compression or too much heat and it siezed.

Budget for a new barrel, piston, rings, autolube pump & complete top end gasket set.
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[Boxing]

[Boxing]

P.S the RS 125 will do about 5,000 miles (according to the net) before it needs a new piston. A DT does about 10,000 miles before needing a piston.

If you're using it for getting around daily, I'd suggest getting a 4-stroke. It won't be as quick, but it'd be more reliable, if you don't go for a Chinese bike like a Pulse Adrenaline or the other brand names they're under.

But 4-strokes don't like being raced, so if you can get your 400CC tests nailed, and buy a 400CC. A GSX-R 400 is a nice bike, or a DRZ 400 but the DRZ will blow up quick if you're ragging it around all the time.

[G19RKE]

well i did as you said and removed the exhaust and had a good look... theres no oil or crap in there it all looks pretty clean but it looks as tho the power valve is scraping the piston..

https://i18.photobucket.com/albums/b115/clarkie3985/null_zps09dfff87.jpg

this is what my top end looks like from above, this was aparently replaced just over 6 months ago by previous owner. it doesnt look very new to me but i do live right by the coast and it was stored outside through the winter under a cover so that may have played a part in it..

https://i18.photobucket.com/albums/b115/clarkie3985/null_zps705fdee8.jpg

and i have also put the oil back to standard settings and wound it all the way out i am just waiting on a new oil pump to arrive then ill fit and test..

[Timmeh]

That engine looks conclusively fvcked to me. Running a 2smoke engine with no lube will damage just about everything inside it.

You should really test the compression before you start messing with it or spending loads on new parts.

Blade/piston interaction is common on old RSes and is caused by excessive wear on the valve's stem and spring.
____________________
GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[Boxing]

That piston looks scored to me. I can place bets on you pulling the head off and seeing the piston head all like this:

https://www.rudigreyling.com/pictures/rotax/combo_2.jpg

https://ebayoffroad.dk-server.co.uk/item2408-0b.jpg

There's some examples of scored pistons.

If you didn't pull the clutch in when it decided to blow its piston, then you probably did bottom end damage. Full rebuild if you have. And you'll never get the piston pieces out if its smashed.

Sadly, these RS's are ragged the hell out of and they blow up a lot. Every 5,000 miles a topend rebuild is needed. Not worth it if you're looking for a commuter. It'd be a waste of money if you do high miles.

[Boxing]

And by the way, them bolts / screws on the top end shouldn't be that bad, even if its kept outside. That would suggest it hasn't had a top end rebuild lately.

Fix it yourself, take the top end off see if the piston is smashed if it isn't, get the bore out take it to a trusted mechanic, get him to rebore it and order you the correct piston and rings. Put back together yourself.

Real easy work, you just need the correct tools and a haynes manual for your bike.

Then run in for 300-500 miles. Within a hundred miles the rings should be bedded in though.

First run would be start up blip the throttle very slightly don't go past 3K, only to start, then leave to tick over until warm and then turn it off, let it cool and repeat the process three times. Then the warm up routine would be to let it tick over and get warm, then you cannot exceed 30MPH or 5K RPMs.

Then it'll be all good and last you a while.

And that noise you heard in your other thread could have possibly been a piston slap.

[Boxing]

Also, when you get the top end off, don't forget to clean the exhaust port, its full of carbon. It'd be slower if you don't clear it out.

And I'm not sure about Aprillia's but I'd imagine they're the same as DT's and the silencers need repacking after so many miles? Worth looking into before you go purchasing the stuff mind you, look for Aprillia forums, they'll know a fair bit about them.

[Boxing]

Also sorry for all these posts, but my DT has done about that many miles and my piston is still in mint condition. That piston looks old and shagged out, the previous owners lied about doing the top end rebuild.

[Boxing]

[P.addy]

The PV should not touch it.

If it does, then its either been assembled by a turd or its broken.

Next time, jam it open. You'll lose some lo down power, but top end will be there waiting.

I doubt it needs skimming, its a nikasil bore, it gets replated rather than bored out.

This is what happens when your lube stops lubing and your main bearings starts seizing/eating themselves.

https://www.youtube.com/watch?v=U6V1UtuyOuw

[G19RKE]

Jam the power valve open? Didn't know I could do that without damaging it

[P.addy]

[Boxing]

Bit pointless opening the PV if the top end is blown?

[G19RKE]

Yea I know that mate but I am thinking ahead. I'm enjoying this bike to give up on it and a rebuild ain't the end of the world I've rebuilt a Honda gx160 4stroke go kart engine before so this should be fine

And I've already ordered Conrad with small and big ends, full gasket kit and all bearings to do my bottom end. Just going to send away top end to pjme.

And then hope my pal can put my crankcases through the parts washer at his work an get them all sweet again:)

[Boxing]

[P.addy]

Take pump off, attach drill to rear, see if it passes oil through and works as expected.

[stevo as b4]

Boxing, I don't know how clued up you are and how much experience you have of all the motorcycles you have talked about in this thread, but Most of your posts to me seem to be full of inaccuracy's and actually wrong in many cases IMO.

I do appreciate your enthusiasm in wanting to help the OP and give advice, but as you said your Aprilia RS125 knowledge is limited, as is mine, and this is somewhat proved by your talk about going to get a re-bore and who you have advised sending the top end to as well.

Maybe I've got all this wrong, but I can't help that think that anyone who doesn't have some direct experience and knowledge of the OP's type of bike should ideally not be replying to his request for help, and possibly giving incorrect or only partly true information?

Where did you get the 5000mile top end re-build interval from BTW? I'm pretty sure it was not from any Aprilia Service literature or dealer maintainence department.

[MarJay]

[evoboy]

Replace plug.

If it still doesnt work, take the head and barrel off.

Report back with pictures.

Chances are its not had a top end rebuild and someone has just stuck new rings on a worn out piston. Seen this done many times.
____________________
Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[MarJay]

Ok here's my assessment.

Lots of people are jumping to conclusions with absolutely NO evidence whatsoever. Whenever you have this sort of issue with a two stroke you should probably use the following procedure.

Is there coolant in the bike? Is the water pump working?

Is there a spark? If yes, proceed, if no investigate. Start with a replacement plug and work backwards.

Does the engine turn over? If yes. Then do a compression check, no, then you'll need to at least take the head off.

Is the compression low? If yes then you need to at very least take the head off to find out why, if no proceed

Is there fuel getting to the cylinder? Does the fuel tap pass fuel through? Will fuel get to the cylinder if the tap is on prime? If the fuel tap works, check the tank breather, check the fuel pipe and then if those are OK, check the carburettor.

You need to investigate bike problems, not just guess at it.

As far as I'm aware RS125's should have a top end rebuild every 10,000 miles. A top end rebuild does not include a new cylinder head so it's hard to judge by looking at the condition of the outside surface of the head. Similarly you can't judge an engine by its cylinder head studs. I'd advise not tearing into the engine until you've proven that you're getting fuel, you've got a spark and you've not got compression.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.