2006 RS125 Is This Barrel Foobar'd? Updated Again

[thomp1983]

Hi hoped there would never be a day when id have to touch an aprilia rs125 but a young lad at the end of the street strolled up when i was working on a car and asked if id mind looking at his bike, the sun was shining and we all had to start somewhere. he rolls up with a 2006 rs125 clearly been dropped on both sides and looking sorry for itself and said one day it rode fine the next won't start, check usual suspects, good spark, fuel getting in, compression test 35psi oh dear. engine out and a ring has seized on the piston, i don;t think the barrel looks bad, i measured it at 53.97 so a stock size 54mm barrel but it has some light marks, with a light dressing do you think it would be reuseable with a new piston or will it need replating?

https://i46.photobucket.com/albums/f109/thomp1983/2012-08-20221115.jpg

https://i46.photobucket.com/albums/f109/thomp1983/2012-08-20221132.jpg

https://i46.photobucket.com/albums/f109/thomp1983/2012-08-20221158.jpg

https://i46.photobucket.com/albums/f109/thomp1983/2012-08-20221223.jpg

https://i46.photobucket.com/albums/f109/thomp1983/2012-08-20221230.jpg

cheers
chris

[Matt-]

With aprilia 2 stroke 125's you have to be careful at this point, because you don't want to spend Any uneeded time or effort or money on it but you don't want to replace everything and it fails.

Sorry for the lack of grammar and punctuation :/ I'm on my phone !

But aprilia are very dependent on top end rebuilds, they seem to wear everything so much quickly than a standard 2 stroke bike, they say 6000 miles from new you will need a top end rebuild, so basically it's properly due a top end rebuild, that's of course if it hasn't had 1 in the past, chances are its going to be knakcnered, slight scoring and slightly
Worn, even I'f you do put it back together it may only have 1000 miles left on it, bare in mind when you put a new pair of rings on their that will also have some wear on the bore!

If it was a NSR,TZR or something I would have said go for it and chance it but not with aprilia ! Get the barrel sent off its about £100 to get it replated. While Your Down on the engine it may be worth doing some bottom end checks and checking the tolorencss
No point
Doing top end if bottom is fucked !

Hope
This
Helps !
____________________
RIP jack (wheelie king), you will never be forgotten.
Current Bike's - Road Legal TZR 125 Pitbike, Aprilia SR50R 2010

[cb1rocket]

You could get away with honing / cleaning it up and a new piston and rings. I have, but not on a highly tuned bike!

Otherwise the best course of action would be a replate unfortunately.

Someone correct me here but I don't think you can bore out a nikasil barrel.

[Matt-]

You will need to get it re plated as i said above, machine shop's and eBay ( Trusted Seller's ) do it for £100 obviously you have to post it to them and they will replate it and send it back to you

not worth trying to do anything with do it properly and you will be fine, but make sure you check the crank play etc... as you will waste your money if you need a bottom end rebuild

Hope this helps

Matt
____________________
RIP jack (wheelie king), you will never be forgotten.
Current Bike's - Road Legal TZR 125 Pitbike, Aprilia SR50R 2010

[thomp1983]

it would hardly be a waste of money if the bottom end did need a rebuild, it would still need the top end sorting. the bike so say ran fine before hand and there's no unusual play in the conrod so no reason to assume the bottom end is broke, even if it did turn out to have an issue once reassembled it took me 90 minutes last night to take the engine out having never touched an rs so to remove it again wouldn't be an issue, it's a young lads bike and budget is an issue so it will likely get the parts required for the top end and go from there

chris

[Matt-]

Well that's fine if you have tested it

Get a good quality Mitaka piston kit off eBay, for an extra £10 you can buy small end bearing which is worth it, as it's easy to fit and doesn't brake the bank. also if the gasket is fucked buy a new one or go and make one out of a cornflake box method

Matt
____________________
RIP jack (wheelie king), you will never be forgotten.
Current Bike's - Road Legal TZR 125 Pitbike, Aprilia SR50R 2010

[Kickstart]

Hi

From the pictures looks more like remains of piston smeared on the barrel rather than damage to the barrel itself. As such it might clean up.

The plating on the barrels is very tough, far tougher than a steel liner. Down side is that if anything catastrophic goes wrong if will get through that plating and then make a mess of the barrel rapidly, and they can't be cheaply rebored.

All the best

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

[cb1rocket]

[thomp1983]

after a bit of digging around and speaking to a few people ive managed to get him a complete mitaka barrel and piston for £50 that's still nice and shiny inside with only one tiny mark, i may hone the stock aprilia barrel at some point or tell him to keep it and get it sorted out when he can afford it for when it needs doing again in the future

cheers for the help,
chris

[Matt-]

[thomp1983]

well the lads had his bike back on the road for a week done about 150 miles taking it gently then came and knocked on the door this afternoon, the bike is making a knocking and vibrating noise at idle and he says you'll be riding steadily along then it will massively vibrate/shake then smooth out again repeatedly. had a quick look, he's failed to put any gearbox oil in it since we rebuilt it so it's done 150 miles with no lubrication in the gearbox.

what's the likely damage caused? the noise sounds similar to the clutch rattle i get in my zxr, ive put some oil in it for him now but the noise hasn't gone away, is it likely to be something in the gearbox failed or something in the bottom end? ive recorded a video of the engine running any help would be appreciated (click the picture to make it play)

https://i46.photobucket.com/albums/f109/thomp1983/th_Rs125.jpg

chris

[andy_uk]

Could be a few things...
Clutch plates, gears & their bearings, balance shaft & its bearings.
You won't really know until you take the side casing off (which can be done with the engine in place).
____________________
Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[thomp1983]

havn't laughed at him yet, ill wait and see how much this mistake costs hims and secondly we've all made stupid mistakes when young and he's not the first person i know to think there's no other fluids to check apart from the 2 stroke oil on a 2 stroke bike.

i did tell him to expect to possibly need a new bottom end so to start looking for engines that are for sale with a shot top end, i won't have chance to take any of it apart until next weekend got to much of my own stuff to fix first so he'll just have to beg/borrow lifts to work for the week

chris

[andy_uk]

The crank and bottom end bearings should be okay. Just the stuff at the gearbox side of the engine will have suffered.
____________________
Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[thomp1983]

that's not really gonna be much of a consolation for him. can the gearbox be fully stripped down with the engine in the frame or is it an engine out and split job in which case the crank bearings and bits may aswell be done anyway

chris

[thomp1983]

removed the engine last night and set about taking it apart this morning. the balance shaft gears are ruined and one of the bearings for the gear shafts is seizing up. also one of his main crank bearings is starting to get notchy. adding up the bearing and seals at pjme comes to £81 and £30 for the balance shaft gears. i need to note down all the bearing numbers and see if a local bearing place can supply them cheaper but i suppose a rebuild was inevitable at some point in the future with one of the crank bearings starting to fail. just need to suffer the pain of cleaning up all the casings and parts for reassembly now

chris

[.....]

I hope he is going to buy you a very nice bottle of something for all your help. Hopefully, he'll have learnt his lesson this time.

[Kickstart]