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Oh the horror. Ebay 2001 Aprilia rs 125

Discussion in 'Modifications and Projects' started by Steamfrog, Feb 13, 2011.

  1. Well this weekend I set about taking a look at the 2001 Aprilia rs 125 (17,000 k's) I bought on Ebay (never again) fools rush in and all that stuff. Anyway coolant was draining into the crank case, in fact that much that the oil was basically coolant mostly green.. not good.

    So it's raining and I thought hey might take a look at those seals so I took off the case coolant everywhere poring out of the gearbox and other assorted holes.

    First thing that struck me was this shocker...
    Now I'm no mechanic but f*k me that ain't right... Oil pump drive gear,chewed to the sh*thouse.
    Anyone have an idea what causes this to happen?
    The balance shaft gears are looking close to this as well ordered new parts from the UK.

    After some garage mechanics and multiple trips to super cheap auto to buy tools I took the power valve out - black and oily and covered in carbon, gave it a clean but think I just get a new one.

    So I decided to take off the head...if the rest of the engine is way it is and the engine having done 17,000 km's I don't reckon the piston or rings have ever been done, great more fricken money.

    Off came the head and this is what I found.
    this is after a hard scrub so I could read the numbers, it was black and totally caked in carbon about 2mm thick.

    Because the oil pump doodad was funked check out the side of the piston
    and the other side

    And the cylinder. Does this need replacing? there is wear but I cant feel any dips.

    Also I made a video of the play on the conrod can someone please tell me if this is too much side to side play.
  2. That looks nasty mate.
    I'm just wondering, since there's not dips inside the cylinder, would it be possible to have it polished?
  3. Yeah I reckon I'm lucky it didn't seize on the way home from buying it..
    I just ordered a whole new top end from the UK. That way everything should fit nice.
    This dam bike is costing a fortune.. at least I'm saving a bit with labour.
  4. I would still replace that cylinder sleeve tbh. It's not so much the dips you need to worry about as it is the warping from the heat that would have been generated in those spots. It only takes a slight warp to immediately stuff your new piston as well.
  5. Yeah just got whole new top end including cylinder and prox pistons.
  6. There due for a new piston at 16k im still waitin for mine to get here i went with vertex
    Did you get a new little end bearing
  7. Don't worry too much about sideplay on the rod. It's whether there is detectable vertical movement with the crank stationary that matters.
  8. unlucky mate, my buddy recently got a bike off ebay. it went good for about 10km, then the engine died
  9. :shock: My eyes, my eyes :shock:

    Looks like a mechanical nightmare....
  10. Terrible luck there, think i know the one you bought.
    I was looking at bidding but held back for another bike that i missed out on anyway.

    Keep up the rebuild posts!
    I hope the parts postage from UK is not too extreme.
  11. Okay, first off, I'm no Aprilia expert. But I have rebuilt quite a few 2 strokes in my time. Rebores (my old man had a pretty decent lathe) crank rebuilds/trueing, conrod kits etc etc.
    At a guess, I'd say the oil pump has had a siezure. That would explain why the drive gears are all chewed up. Or some hack/butcher phucked up badly last time they worked on it. Before you put ANYTHING back together, or try to start the bike, get the oil pump checked. Or check it yourself -there will be some way of checking its flow rate. Find out how.

    Next, the only real way of checking the cylinder is to check it for wear by measuring it. I'd suspect you don't have any internal micrometers, or telescopic gauges and external mic's, so head down to an engine reconditioners and get them to check it for you. If it is within tolerance, they should also be able to tell you if a hone will clean the bore up as well. Visit a few bike shops and ask them who does their engine machining. Then go there yourself.

    As for the crank, get a hold of a workshop manual for your bike, or see if your local dealer would be generous enough to photocopy the relevant pages for you. This will tell you the allowable amount of side play between the conrod and crank webs. Should also give you a tolerance in degrees for amount of axial movement of the conrod in relation to the crankshaft.
    Check the little end bearing for ANY signs of pitting (the conrod) or corrugations -for want of a better word. Rotate the crank while holding a bit of load on the conrod and feel for any rumble or lack of smoothness in the big end bearing. If you are suspect of it in any way, strip it and rebuild the crank. If you don't, and the big end fails, there's a pretty high chance it will take out the rest of your nice new top end.
    If you do have to rebuild the crank, buy the parts yourself and find out who does the Jetski engines in your area. They rebuild cranks on a pretty regular basis and usually do a pretty decent job at a reasonable price. A single cylinder crank will be a piece of cake for them. Replace the main bearings, and most important of all, the crank seals. Dodgey crank seals are about the quickest way to kill a 2 stroke.
    Hope this helps, and doesn't depress you any further.
  12. Thanks Roarin, I reckon it's a hack phucker as the balance gears are not lined up right, lookin at crash dummy's pics mine are wrong way and possibly upside down.

    The pump seems to move ok opened bleed screw and it came out freely the oil pump gear has no major damage on the top where it connects to the pump but I will check and recheck tonight. The casing had silicon around it as well as the gasket and the previous owner ( dam him to hell ) said his mate worked on it.

    Maybe I can put it back and run premix in it to check flow.

    There is no pitting on the small end or any play on the big end.

    Lookin at getting a new oil pump.
  13. Freakin' unreliable European 2 strokes, why do you guys bother??? They need a rebuild after they've been delivered from the factory to the dealer. Gallon of petrol and a match, mate, then go buy a 4 stroke bike that will do 100000ks before you even have to LOOK at it.
  14. Unless you buy a full race rep four stroke, then you're up for even more maintenance, & even more moving parts!

    The bottom end on a modern 250/450 MX'er is reputed to last a good 50 hours, it's a bit less than the 16K you'd get from a 2 stroke 250!
  15. @rc36 yeah when on opens. Already looking at Daytona 675 - or KTM rc8.
  16. @ the naysayers....

    a 4 stroke will never leave that aromatic smell of the good oil behind.

    a 4 stroke will never leave that crisp clean 'on the pipe' 2 stroke song behind

    a 4 stroke can only leave the noise of the 'geese farts' of a mass flock flyover

    a 4 stroke can only leave a puddle of pungent black oil on the ground.

    2 stroke GP bikes 4 ever......f#ck u honda
  17. Love that smell. Love that sound. Love that powerband.
  18. Back to business...

    Is the Aprillia a sleeved cylinder, or is it nikalsil plated ???

    If its a plated cylinder, talk to Ben Reid ( KLS tyre warmers ) as he has good OS contacts to get this type of cylinder repaired and replated....properly...not a lot of Aussie 125gp guys use the local service....
  19. I ordered a whole new top end, new cylinder, gaskets seals, prox piston and rings, this that and the other, the new cylinder is nikalsil plated all from pjme.co.uk.


    Aprilia RS125 MITAKA CYLINDER KIT ( ROTAX 122)

    Now I have a spare, so might look into that.. I am actually just rebuilding to sell it. I have a brand new 2011 model.