Aprilia rs 125 - locked rear wheel

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Aprilia rs 125 - locked rear wheel

I have a 2003 aprilia rs 125 exrema.
i was going down the a414 in herts at about 60 whenlost revs then rear wheel locked (scary)
Jnow it wont start - just strater motor makes a funny noise

cut out a few times on 5 mins earlier on the country roads.

any ideas?>

thx

Sorry m8 sounds like shes siezed her engine

HiYep, sounds like it nipped up. Do a compression check (a Gunsons compression tester from Halfords will do the job and is not hideously expensive).All the bestkeith

Yer done blowed it up....

I wouldnt bother doing a compression test seen as its seized and you wouldnt get much of a reading whip the head off if your handy and check what kinda damage you have, Might be worth getting a big bore kit of flea bay if your a bit numb with spanners get it down to the bike shop (make sure you pull your pants down first to save them the job )

You'll also need to look at why it seized before you whizz off up the road again. Sounds like the few times it stopped beforehand was when it was nipping up (i.e. Telling you it wan't happy and suffering partial seizures), and now you've fucked it good and proper by seizing it solid.Were you using the correct (fully synth) oil? Is there any oil left in the oil tank? Are there any splits in the air hose? Ignition timing?It shouldn't have died at only sixty MPH, so something's amiss.

Had just filled it up with Castrol 2 stroke 12 quid odd stuff.Only thing was I was just about to put a new spark plug in too.So how much dosh do ya think were talking about here????????/

Also no good telling me to whip heads off an stuff - cos errrr whats a head? lol

oh and thanks people dor your replies - even if you have confirmed what id been dreading lol

matt020876 wrote

Also no good telling me to whip heads off an stuff - cos errrr whats a head? lol

Cylinder head. You've seized the engine for some reason I'm afraid. Piston stuffed up inside bore. Damage will most likely be new piston, rings, bearings, cylinder replate and maybe some head work. The crank may also have took a piece and there might be bits of metal in the cases...you don't know until you look so you might as well pull the head off or look up the exhuast port with the expansion chamber off.Doesn't sound like it nipped up if the rear locked solid so expect the worst. You also need to know why it happened as there's always a reason. If you don't find out you'll seize it again after you rebuild.Did you notice anything unusual about the performance? Were you doing anything that you don't usually do? Made any adjustments or noticed something amiss?good luck mate, I think the requisite parts for the RS125 are fairly reasonably priced.

On a long downhill you probably had the throttle closed or almost closed so no oil was being fed to the engine via the auto lube system but the engine revs were still quite high.Cure - keep the throttle open or run premix.Oh and always ride with two fingers on the clutch!

ST2 wrote

On a long downhill you probably had the throttle closed or almost closed so no oil was being fed to the engine via the auto lube system but the engine revs were still quite high.Cure - keep the throttle open or run premix.

What a load of utter bollocks. You've got your "facts" the wrong way around for a start. Premixers will seize on a long downhil with the throttle shut. Not pumped bikes. Especially not something new like a 'prilly.

ST2 wrote

Oh and always ride with two fingers on the clutch!

Apart from this bit - that's right.

DGW-Steve wrote

What a load of utter bollocks. You've got your "facts" the wrong way around for a start. Premixers will seize on a long downhil with the throttle shut. Not pumped bikes. Especially not something new like a 'prilly.

What if the oil pump rate is operated by the throttle cable? You're getting 'tickover' supply with the throttle shut but if you're whizzibng downhill with a load of revs up ......

fastfitter wrote

What if the oil pump rate is operated by the throttle cable? You're getting 'tickover' supply with the throttle shut but if you're whizzibng downhill with a load of revs up ......

...and with premix, the throttle's closed so you're getting no fuel and therefore no oil AT ALL.Most (all?) pumped bikes deliver oil at a rate determined by throttle position AND engine revs, so even with the throttle shut the engine whizzing over at a milion RPM will automatically up the delivery rate.Strokers don't like long downhills - fact of life, but the pumped tickover supply should be enough to cope with all but mountain descents, it's not as if there's a lot of load on the engine when you've got the throttle shut.

fastfitter wrote

What if the oil pump rate is operated by the throttle cable? You're getting 'tickover' supply with the throttle shut but if you're whizzibng downhill with a load of revs up ......

Even back in the 70's, oil pump output was determined by throttle position and RPM to alleviate exactly this problem. I sincerely doubt a modern high BMEP stroker is going to use a pump that only uses throttle position to dispense oil.

Iw as going on a flat but coasting to the turn off..........anyways R.A.C picking up this arvo and tajking to he garage.............£$££$£$£$£$£$£$£$£$

Mr Rooty Tooty wrote

Cylinder head. You've seized the engine for some reason I'm afraid. Piston stuffed up inside bore. Damage will most likely be new piston, rings, bearings, cylinder replate and maybe some head work. The crank may also have took a piece and there might be bits of metal in the cases...you don't know until you look so you might as well pull the head off or look up the exhuast port with the expansion chamber off.Doesn't sound like it nipped up if the rear locked solid so expect the worst. You also need to know why it happened as there's always a reason. If you don't find out you'll seize it again after you rebuild.Did you notice anything unusual about the performance? Were you doing anything that you don't usually do? Made any adjustments or noticed something amiss?good luck mate, I think the requisite parts for the RS125 are fairly reasonably priced.

The engione had bveen cutting out - especially when i went to pull away in 1st.For info the engine had done 6000 KM's so about 3500 milesI have a bad feeling my pocket is going to be very light soon.

matt020876 wrote

The engione had bveen cutting out - especially when i went to pull away in 1st.For info the engine had done 6000 KM's so about 3500 milesI have a bad feeling my pocket is going to be very light soon.

At least they're easy to fix And one less cylinder than my Rs250, so a seizure is 50% off Seriously though, sorry this happened..it's a shitter. 2Ts can be sensitive to changes in set-up but they certainly ain't time bombs like some people suggest. Find the factor that predisposed it to seizure and you'll be golden. There's some very knowledgable sorts on here who would be glad to offer advice i'm sure.NB the Rs250 oil pump is connected directly to the throttle through the splitter box but there is also a piggyback system operating off the powervalve motor. If the powervalves open at 8,000 rpm a seperate cable from the motor pulls the oil pump open as well regardless of throttle position. Don't know if the Rs125 has similar setup but I'd suspect so.Mind you this set up doesn't work if you overtighten a certain screw on the motor Coasting a 2T is usually something to avoid.

Thanks for your advice

DGW-Steve wrote

What a load of utter bollocks. You've got your "facts" the wrong way around for a start. Premixers will seize on a long downhil with the throttle shut. Not pumped bikes. Especially not something new like a 'prilly.Apart from this bit - that's right.

Its really sad when people have to resort to insults to make their point.

ST2 wrote

Its really sad when people have to resort to insults to make their point.

Good grief, you need a thicker skin if you think that was an insult. That doesn't alter the fact that you were talking bollocks. That's not an insult, it's an observation.If the OP had followed your advice, he'd have killed his bike on the first long downhill stretch.

DGW-Steve wrote

it's not as if there's a lot of load on the engine when you've got the throttle shut.

Out of interest, how would a piston know whether it's under load or not? A piston whizzing up and down a bore at 4000 revs is travelling at exactly the same speed if the throttle is open or not, and therefore generating the same friction isn't it? I'd suspect that it may even be running a little cooler with the throttle open as it's getting a fresh charge of air and fuel up it's skirt every time I dunno?

Under load, the compression pressure will higher because the piston is pushing against a bigger load. e.g. consider how much harder an engine would need to work to maintain a constant 4000 rpm on a flat road if you were towing a caravan compared to only having a 5 stone rider on board.The extra pressure generates more heat - same as a bicycle pump gets hotter the harder you pump your tyres up.The friction between the walls and the piston will stay the same-ish, but the extra heat being generated will need to be dealt with by the cooling systemThat's why your cars and bikes get hotter going up hills at constant revs compared to cruising on the flat.

size12 wrote

I wouldnt bother doing a compression test seen as its seized and you wouldnt get much of a reading

Unless it was the gearbox he seized. In which case the bill is going to be rather more.The RS125 oil pump is connected to the throttle cable and driven by the engine. Not connected to the power valve solonoid (RS power valve is just a crude fully open / fully closed setup).Repair is not going to be that cheap. Replated barrel will be ~£100. Original piston upwards of £80 (rather less for a pattern one). Replacement pattern barrel kit (includes piston) would be ~£200, original one from Aprilia several times that. Dealers labour is not that cheap.Swapping the top end is a gentle afternoons works once you have done it a few times. Hardest part of the job is getting the springs off that hold the barrel to the exhaust (they seem to harden with age, presume from heat cycles, new ones are FAR easier to fit).All the bestKeith

kickstart68 wrote

Unless it was the gearbox he seized. In which case the bill is going to be rather more.The RS125 oil pump is connected to the throttle cable and driven by the engine. Not connected to the power valve solonoid (RS power valve is just a crude fully open / fully closed setup).Repair is not going to be that cheap. Replated barrel will be ~£100. Original piston upwards of £80 (rather less for a pattern one). Replacement pattern barrel kit (includes piston) would be ~£200, original one from Aprilia several times that. Dealers labour is not that cheap.Swapping the top end is a gentle afternoons works once you have done it a few times. Hardest part of the job is getting the springs off that hold the barrel to the exhaust (they seem to harden with age, presume from heat cycles, new ones are FAR easier to fit).All the bestKeith

True but we could have just said does the rear wheel spin in neutral/can you get neutral. That should eliminate the gearbox and considering its a stroker i would go for the motor first

size12 wrote

True but we could have just said does the rear wheel spin in neutral/can you get neutral. That should eliminate the gearbox and considering its a stroker i would go for the motor first

I was able to put it in neutral and in second as I left it for the garage on a sharp incline this mroning to stop it rolling back.Dropped it off this morning amd waiting for the phonecall to say how many ££££ im going to lose.......... anyways going in the piss tomorrow night.....joys of biking eh. Have only been in the biking world for 5 days........lol

I had a prilla 125 about 5 years ago and it locked up pretty much how yours did m8 It needed a new piston,rings and the barrel had to be welding and re-plated the whole job inc lab and Vat it was £400 as i seem to remember.and i got away with the bottom end.But mine was a strange bore that they hadent seen before (it was an EX italian racebike) yours might be cheaper fingers crossed.

size12 wrote

I had a prilla 125 about 5 years ago and it locked up pretty much how yours did m8 It needed a new piston,rings and the barrel had to be welding and re-plated the whole job inc lab and Vat it was £400 as i seem to remember.and i got away with the bottom end.But mine was a strange bore that they hadent seen before (it was an EX italian racebike) yours might be cheaper fingers crossed.

if its as little as 400 quid ill be pleased! ;-)

DGW-Steve wrote

What a load of utter bollocks. You've got your "facts" the wrong way around for a start. Premixers will seize on a long downhil with the throttle shut. Not pumped bikes. Especially not something new like a 'prilly.

Speaks the man who has evidently never owned a Kaw triple....& those could also sieze up the left pot just by running low on fuel...

How many miles had you done on it? Aparently RS125's need a top end rebuild regularly every 10,000m or so, maybe you dun your top end in?

-mItoman- wrote

How many miles had you done on it? Aparently RS125's need a top end rebuild regularly every 10,000m or so, maybe you dun your top end in?

it had sone 3500 miles

Just heard from garage - worst case scenario unfortunately - new pistons, rings, conrod, crank - pee'd off completely now.

Bad luck mate, the important thing now is to find out exactly why. The garage 'should' check that the oil pump is set up and operating correctly when they rebuild it - make sure they do.Then follow running in procedures and oil tank top up/oil pump checks religiously - and I do mean religiously, like a fundamentalist suicide bomber

fastfitter wrote

Bad luck mate, the important thing now is to find out exactly why. The garage 'should' check that the oil pump is set up and operating correctly when they rebuild it - make sure they do.Then follow running in procedures and oil tank top up/oil pump checks religiously - and I do mean religiously, like a fundamentalist suicide bomber

ANy idea how much this is gonna cost me - they havnt come back to me with a price yet?How would you go about checking yourself that oil is being pumped in correctly?

I'm not even going to guess at a price, someone who's suffered the same will be along to upset you I've no doubt Register on here www.repairmanualclub.com (it's free) and download a manual for your bike if they have one. Then get rid of your copies of Foxy Babes and use it as bedtime reading until you can quote chapter and verse.Bikes are like women - great fun to ride but without regular attention and the occasional firtle they'll let you down and bite you big-time in the wallet area

I'd wager you wont see much change out of a grand... it'll be the labour that's the killer.Sorry kidda.

I can email you the manual if you need it.Using aprilia parts the bill for parts is almost 1k without labour.Order the parts from www.pjme.co.uk

Quote = 1900 ! Bike being scarpped and getting 300 for it.

That's taking the piss I'd ring round for parts prices if I was you. Why does it need a crank? Don't they have rod kits with new bearings and pins like the jap bikes do - split the crank, fit new rod and pin?

No idea - just wanna get rid now - too much hassle - gonna do my DAS instead lol

ZRX61 wrote

Speaks the man who has evidently never owned a Kaw triple....& those could also sieze up the left pot just by running low on fuel...

You're right, I've never had a Kwak triple. The last 2T shite old triple I had was a GT380 (urgh!)However, were the Kwak triple seizures due to lube failure? Or because they ran weak when they were running out of fuel?Bringing this back on topic a bit, has anyone here needed a new crank after a nip up? Or do you think the garage are taking the OP for a ride? FFS, the bike's only got 3500 miles on it, and he's used the proper fully synth oil in it.And now they're offering him 300 quid for it. Hmmm.... suspicious.

Seems ive given some buddies who know a bit about bikes a heart attack - getting all the bits for about 500 quid from the link a few threads back.

Bad luck Matt, I'm no Rs125 expert but I reckon you coud get it done for a lot less than £1900, especially if you do it yourself.Try out the 125 section of www.apriliaforum.com for advice about rebuilding a stroker, sure there must be a step by step guide in net land somewhere...this isn't exactly an uncommon occurence for an Rs125. Rebuilding a single cylinder stroker is as easy as it gets Stan Stephens apparently does a full engine rebuild for £200 plus parts.Good luck!

there's a place i bought a flywheel puller off that did a full bottom job for about £75, i'll try and find the web addy

fastfitter wrote

Why does it need a crank? Don't they have rod kits with new bearings and pins like the jap bikes do - split the crank, fit new rod and pin?

You can split the crank and change the rod.matt020876, get a price from pj engineering, its going to be alot less than £1900.

uktrailrides.co.uk/workshop.htmlhere it is.it's not too much of a job to change the crank tbh, whereabouts are you, someone may be nearby with a workshop and time to guide you through it

im nr ware in herts

jazzy wrote

...it's not too much of a job to change the crank tbh, whereabouts are you, someone may be nearby with a workshop and time to guide you through it

matt020876 wrote

im nr ware in herts

Tomcat wrote

Mate, I'm in Ware. If you wanna search out the bits I'll help you with the rebuild. PM me.

Tomcat wrote

Mate, I'm in Ware. If you wanna search out the bits I'll help you with the rebuild. PM me.

priller.5gbfree.com/Rotax_Engine_Manual_122.pdfengine manual incase you need it.

Mr Rooty Tooty wrote

Bad luck Matt, I'm no Rs125 expert but I reckon you coud get it done for a lot less than £1900, especially if you do it yourself.Try out the 125 section of www.apriliaforum.com for advice about rebuilding a stroker, sure there must be a step by step guide in net land somewhere...this isn't exactly an uncommon occurence for an Rs125. Rebuilding a single cylinder stroker is as easy as it gets Stan Stephens apparently does a full engine rebuild for £200 plus parts.Good luck!

Yep looking at stan stephens really does look a good option - looks like he could do the lot for about 6 or 700 quid.... Weighing it up I have had lots of help from you guys - this is a great forum - many thanks!

Tomcat wrote

Mate, I'm in Ware. If you wanna search out the bits I'll help you with the rebuild. PM me.

What a star :smoke:

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