Engine seized - Aprilia rs250

[nudedaytona]

Hi all,

Had a breakdown on the Southern Motorway on Sunday. It lost power, the temperature shot up, and then completely siezed - the kickstart lever won't budge. It's a 1996 Aprilia RS250 with 12,500 km on it, I've had it since 9,500km

(As an aside - I'd like to say cheers to the cop who called the towtruck and the two cages who stopped to offer help (no bikers stopped) )

Anyway, all I've done so far is stick it up on paddock stands and remove the fairings. I'm keen to open up the engine, but would like a bit of advice before I do so. Can someone please suggest what to do next? Do I need to remove the engine from the frame?

Cheers

[FilthyLuka]

Take off the fuel tanks and all the fairings, if there is good access to all the cylinders then you shouldn't need to take the engine outta the frame. Pop of the cylinder heads, have a wee squiz, see whats up, may just need a decent thwack and a rehone.

If you decide it ain't worth it, PM me, i want the frame

[Squiggles]

It lost power, the temperature shot up

$2 on headgasket failure leading to a cracked piston which then seized, no idea how to check for sure on a two smoker... *waits for ixion to enter the thread*

[Ixion]

Ah, two smokers, yes, they do that. It's why we luvs them .

Seized, reason could be anything. Did the sun go behind a cloud just before?

Head gasket , possible (it's water cooled). Or base gasket. Or carb popped loose. Or sun behind cloud.

Pull the top end of off (pretty easy), ask Mr GiJoe to send round Mr Block and Mr Mallet. And buy a bit of emery paper.

It'll be as good as new.

[EJK]

(As an aside - I'd like to say cheers to the cop who called the towtruck and the two cages who stopped to offer help (no bikers stopped) )

So much for a "biker helps bikers"

I heard two strokes are way more complicated than the 4 stroke bikes.
Compare to a FXR, I must be the fortunate son...

Anyways, good luck with the rebuilt

[FilthyLuka]

ask Mr GiJoe to send round Mr Block and Mr Mallet.

+1, mr block and mr mallet seem to solve most things

@EJ, nah, not complicated, just different... seeing as they don't follow and sort of logic what so ever!

[HDTboy]

Two Smoker and I saw it up on the tow-truck at spag junction. Nice bike, hooray for Conti's.
If you want, you could drop the bike at mine, and I'll take a look inside 0122517356

[nudedaytona]

Thanks for the offer mate, might take you up on that. It's going to be a bit tricky for me to find the time for this as I've got a lot of other things on my plate, but hope to make a start this weekend.

[westie]

Bummer bout the engine probs.
I can help if you need it.

[hurricane_r]

welcome to the sieze club, this is where you become a true 2-stroke rider

do as said above drop the cyclnders and un-seize the cyclnder,

then find why you sized, temperature can rise quickly with insuffient lubrication
im guessing its oil injected so make sure you..

a. had oil in it,
b. check condition of oil pump, seals orings, shaft etc

check condition of spark plugs, so see how the engine was in its last state.

if the cylnder has scuffing (which it will), you can get it cleaned up at

"taylors automotive, in auckland city, then get a new piston and rings, and off you go, jack your oil pump up to the max, to ensure maxximum lubrication

dont pay a mechanic to rebuild it for you as 2-strokes are easy as hell to work on..

good luck!

if you need help with rebuilding your engine pm me,

[quallman1234]

Luckly your in luck it does sound like a top end! hopefully you can give it a smack and rebore as said before.

Piss easy to work on!

[nudedaytona]

OK I've had a look at it. I've removed the cylinder heads from both cylinders (it's a v-twin for those who don't already know). In the bottom right cylinder there was a bit of metallic grunge which I have removed. Not sure about the cylinder, there may a small amount of scuffing. I've included some photos. Apart from that there is very hardly any carbon on piston and on cylinder head.

The top left cylinder looks structually very good, but there is a lot of carbon on the piston and on the cylinder head. I really need to take out the pistons to clean them and the cylinder, but I don't know how to do this - can someone please help? The manual says that I should be able to remove the pistons without taking the engine out, but I've got no idea how to do this.

The good news is that I have been able to turn the engine over using the kickstart lever.

Photos attached. Should I remove engine from bike? If I leave it in, how do I remove pistons? Thanks?

[Ixion]

You may not need to remove the pistons. But you do need to remove the barrels. "bit of metallic grunge which I have removed" is a BadThing, and must be further investigated.

You may find damage to the piston wall or lands. I don't like the look of that piston crown at all.

To remove the barrels remove any nuts/bolts holding them down (not sure if there are any on an RS once the head is off), and carefull pull them off. Be ready to catch and support the piston as the barrel comes off, don't let it bang around.

Check the piston and rings carefully and report back

If you do need to remove the pistons themselvs, it's dead easy.

Each piston runs on a gudgeon pin, a short shaft through the middle of the piston. The gudgeon pin is held in palce by a circlip at each end. Remove circlip (DON'T LET IT FALL IN THE CRANKCASE !!!) and GENTLY press out the gudgeon pin

[nudedaytona]

OK it looks like I will be able to remove the barrels, but they're attached to the exhaust pipes and also attached to what looks like a pulley system for the exhaust shut off valve?

The top barrel is quite difficult to access, might have to remove the carbs and the splitter box, I'm a little worried about being able to put it back together right, especially if I have to undo the throttle wires and the oil pump wires in order to get at the top barrel.

[Ixion]

Yes, you'll need to drop the pipes, and the carbs, and the power valve actuator. And any remaining hoses etc.

It's easy enough to get off and put back, just Meccano stuff, no skills needed. Unbolt, pull off, reverse to put it all back.

Pay enormous attention to gaskets when reassembling, especially cylinder base gaskets. And of course , correct torque on head bolts, and retighten after a couple of heat cycles.