Is This Worth Doing.................

[RS125_Tecky]

My Aprilia RS 125 is in need of a top engine rebuild after the piston touched the barrel.

The barrel is no off the bike and so is the piston.

Im thinking of taking the rest of the engine out, splitting it and changing the bearings and crank seals. whilst im doing this i was going to send the crank to prox to be looked at and serviced.

This would cost around £170 for the parts and for prox to sort the crank and conrod out, if it needs it.

Im in no rush what so ever to be back out on the bike.

Would you say its worth doing???

Oh yeah the bike is currently on 15,000 khm

Cheers for any help
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2004 ZX6R B1H

[stevo as b4]

15'000km isnt really that much, id expect to get through at least 2 and maybe 3 top ends for every crankshaft assembly and main bearings replacement.
Im in a similar situation now with my kmx200, in that it seems that the 23'000mile bottom end looks ok. But as im going to be having the bore re-plated anyway, and about £140 of tuning work done by Graham File tuning, im not going to take a chance on the bottom end, as if i wrecked a newly plated and modified barrel in a short space of time after the re-build, id not be best pleased really!

[RS125_Tecky]

yeah i see what you mean,

but i forgot to mention in my previous post that my bike was stolen for 11 days in which it would have had its arsed ragged
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2004 ZX6R B1H

[cagiva gezzer]

My cagiva crank went at 23,00km. I so wish i had sorted it when i had the engine out at 19,000km.

If you've got the tools and the skill go for it.
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"because one stroke isnt enough and four strokes waste two"

[Kickstart]

Hi

Do you have the skills and tools to put the crank back into the cases? It does need pullers, as if you just push the cases together over the crank on the RS engine you will leave the main bearings with a sideways load and pretty much ensure that they will need replacing again within 1000 miles. There should be a tiny amount of lateral movement in the crank (basically you put the bearing into one crank case, and then pull the crank into the other crank case).

Top end rebuilds are fairly easy. Has the snapped ring damaged the barrel?

Personally I would just do the top end, unless you have a reason to know that the bearings are on the way out (and main bearings tend to whine when they are on the way out). You are reasonably likely to cause a problem replacing the bearings.

All the best

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

[tater]

Like kickstart said, just do the top end. Check the crank, its easy to know if its alright as there should be a little bit of play side to side when wobbling the con rod, but NO up and down play with the big end bearing when wobbling the con rod up and down.

Just make sure you know the crank is running smooth by rotating it, if its knackered you will 'feel' it.

Also make sure you pure abit of two stroke oil onto the big end, little end etc when assembling so it isn't dry when you start it.