Aprilia RS125 Rebuild HELP

leepick · Scooby Slapper Joined: 24 Jun 2011 Karma :

hi. just put new piston,rings and con rod in the aprilia, the bike is now running but is a bit shaky and not very comfortable. is this because i havent completely warmed it up yet? ive only had it running for 10 minutes or so... need some help please... the 2 stroke hasnt gone thru its pipe into the engine much yet either...

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

It sounds like you have the balancer set wrong. Also, did you just fit the bearings onto the crank then put the crank in the cases? If so you probably have the bearings hugey pre-loaded which will cause early failiure. There is a specific proceedure for fitting the crank which involves heating up the engine cases.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

leepick · Scooby Slapper Joined: 24 Jun 2011 Karma :

i removed the crank, the garage put the new pin and new con rod together and small and big bearings then i fitted it back into the engine... i didnt think there was a big procedure as the mechanic over the road helped me and didnt metion heating the engine cases... what do u recommend?is there anything i can do which doesnt involve taking the engine back out... thanks for the reply by the way...

P.addy · *Formerly known as* P. Joined: 14 Feb 2008 Karma :

leepick · Scooby Slapper Joined: 24 Jun 2011 Karma :

Its a bitch of a job getting the engine back out isnt it.. Laughing

Pete rebuilt my RS, so he knows what hes talking about, but yea teh cases should really be heated... he'll tell you why, but they do make a big deal about it..[/quote]

yeh its a right load of dog muck lol. is there anything u or pete can suggest because i really really really dont want to take the engine back out. ive just posted another link in the forum as i didnt explain much in this one. practically the same tho lol. thanks for the replies. just need the bike running smoothly so i can sell her Wink

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Aprilia RS125

P.addy · *Formerly known as* P. Joined: 14 Feb 2008 Karma :

leepick · Scooby Slapper Joined: 24 Jun 2011 Karma :

what is the balancer? do u mean the balance shaft?..
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Aprilia RS125

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

The reason you have to heat the cases is because the bearing is a VERY tight fit on both the crank and the cases. If you just assemble the engine and use the case bolts to pull the cases together you're putting a tremendous amount of lateral load on the bearing races that they are not designed to take. The ballrace cages will disintegrate and then you'll need new piston, barrell and gaskets when the bits get ingested.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

timsmith · Two Stroke Sniffer Joined: 09 Jun 2011 Karma :

Have the main bearings been replaced? reading your posts it sounds that only the big end and con rod were replaced? Did the "garage" you used to assemble the crank have the correct kit to do this or was it just pressed up on their fly press. The balance shaft and its gear alignment can be checked without removing the engine from memory. you will need to drain the oil and remove the clutch case to see the gears. they should have marks on them that line up on assembly.
To your original question no it won't get better after it has been run in, sorry Sick

Good luck
Tim

leepick · Scooby Slapper Joined: 24 Jun 2011 Karma :

yes the ''garage'' had correct kit. vale onslow in birmingham. it was done proply (i hope)...and all bearings were changed apart from ones in the engine cases. big end and top of the con rod bearings. gudgeon pin etc. can the 'balancer' (balance shaft) be fitted incorrect?. because it seemed to only go in one way. can somebody tell me what exactly needs to be done so i can get to it sometime today..

thanks for all your help
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Aprilia RS125