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Can anyone help with a top end re build??

Discussion in 'Bling and Appearance' started by syd rs125, Aug 8, 2008.

  1. Ok i have just fixed my broken leg now its time to fix the bike before it breaks.
    It is an aprilia rs125 has 19000 km on the clock and is due for a top end rebuild. I could take it to the shop and get it done but they won't let me in the workshop to watch so i won't learn anything and am pretty keen to learn for myself.
    Is there anyone out there that has extensive knowledge on 2 strokes that is willing to give a hand?? or perhaps maybe have a 2t spanner day so all the smokers can learn to look after their pride and joy???

  2. Take it to a proper mechanic. I reckon the time and effort you save you'll be thankful for. Top end rebuild can only be 3-400 bucks anyway?
  3. dude its easy, just do it.
    just make sure u dont re-use the circlip (I found out the hard way)
  4. I haven't rebuilt it yet myself, but had it so far stripped down that I might has well have. I agree, it's not very hard at all, I will do my self I reckon. And this is the first bike I have worked on, though have had exp with cars. Get yourself a manual tho...maybe put it up as a spanner night. As you say having someone to watch the first time can only help.

    Let us know how you go...
  5. yea cheers i might wait for a spanner day not too confident on doing it without some guidance.
  6. Right on! That's a great attitude, I hope you find somebody willing to have a crack at it with you. Maybe put on a steak dinner and a slab of beer, that usually gets the 2-stroke people interested.
  7. Too true!! We are simple folk ;)
  8. i have rebuild 2 stroke dirtbike motors in the past, it's VERY simple, and i managed to do my first top ender (Honda CR125) with only a workshop manual, normal tools, some oil, and a new piston/ring/gasket kit. Was 16 at the time too!

    the running in period is the shitfull bit!
  9. yah,i rebullt a 3 cylinder 2 stroke, the first bike i ever had, had to google how an engine worked. its really doesnt get any simplerr than a 2 stroke. take it apart replace stuff u have and put it back 2gether.
  10. yea bbq and beer is standard operating procedure.
  11. I might come along watch/lend a hand if theres a beer and bbq ^_^. Took me two weekends to do my mito, but then I didn't have a garage and some parts.

    Anyway, you have to collect all the bits you need first:
    - Gaskets/O-rings (cylinder to case, cylinder to head, thermostat)
    - Piston rings
    - I replaced my piston as well -- piston w/circlips, gudgeon pin, small end bearing. Thought I might as well replace all that while I was that far in.
    - I also pulled out my powervalve and gave it a clean/regrease. I would have replaced the powervalve blade if I had known to order one beforehand. You may need some RTV gasket goo.
    - Circlip pliers, can be used for seating the rings too
    - Feeler gauge to check ring gap

    I would advise you to go reading up rs125 forums and find out as much as you can about rebuilding. See if you can find rebuild photos. Then go order your bits. Get yourself a workshop manual, PDF or hardcopy. I wouldn't try this without it.

    Strictly speaking, you should measure your bore diameter, and select an oversize piston to compensate for wear. But if this is your first rebuild, I doubt you'll need one (or a replating of the bore either). I didn't do the measurements, bore looked pristine. :?

    Doing a rebuild on a naked/dirt bike is a lot easier. :? You don't have to pull off all these fairings and tanks and skin your knuckles reaching around the frame. It may well be easier to drop the engine to do it.


    Edit: At the end of the day, I wouldn't want to do the job again for a while. But then again, if you paid someone, would they take all the care that you did above? They would just bang it all in and bolt it up. That's after it's been sitting in the workshop for a month waiting for parts.

    Tip: Buy your parts from UK sellers through ebay or their website. Shipping takes about a week and it'll probably cost you less than local stealers. Buy good quality parts if not OEM.
  12. one of the fellas from netrider put me onto this site for parts http://www.pjme.co.uk/ seems pretty good and http://www.pjme.co.uk/ seem to have all the information needed.
    now i just have to figure out exactly what parts i need and what tools.
    Im also wondering if i need to replace the crank and bore.
  13. If it's your first rebuild you probably won't need to do either. Doing the crank means splitting the cases which is an engine out job. You'd probably do a gearbox rebuild as well. I'd leave that to 30-35 thousand k's. Give the crank a bit of wiggle around with the conrod, if it all feels nice and tight then don't bother.

    With the cylinder bore, measure it and see if it's in tolerance per workshop manual. If it's not you can fit oversize pistons/rings, get it replated or do a swap for a replated one (or buy new). Dunno who does replating in sydney.

    Yep I bought half my stuff from PJ's, no complaints.

    Edit: Go to youtube, theres heaps of walkthroughs to waste hours watching.