well.. she died :(

[roasty_duck]

riding wednesday night, rear wheel suddenly locked up, clutched it scared the crap out of me, no idea what happened, restarted engine carried on fine then did it again when leaning hard... more panic!

limped home and it did it again! pulled over to see my oil was mega super low! put a few litres in and limped the final half mile home...

drained oil today no signs of any metal except tiny little flecks which after 4000 miles or so since last change i expect, bike ran fine for a while then started to rattle badly and lost every once of power, would barely hit 50, cut out on me, tried to restart the engine but wouldnt turn over just half a turn from the starter motor and it stopped.

things i noticed during all this:

engine rattle started at 5k+ only then got worse and was all the way through the rev range
engine breaking was a heck of a lot stronger
power was down massively, mopeds would out accelerate me to 50

noise was like a clacking sound


Any ideas?

im guessing ive seized a cylinder, can they cylinders be taken off without engine removal? im guessing the rears easier to do than the front?

[agentpineapple]

probable cct failure, or oil left to get to low, these engines can burn oil on the over run and the rider will not notice as the engine doesn't always smoke at standstill, oils got so low that the engine seized.

[roasty_duck]

forgot to mention it has ades manual ccts

[lloydie]

If the oil was that low chances are you've cooked the engine and lost bearings due to the heat build up .
No the cylinders are part of the block ,only the heads can be removed .

[bigtwinthing]

ask somebody and get a Boroscope done.

[fabiostar]

big end failure due to low oil? id a 450 supermoto done just what your saying and thats what caused it.. . or has a cct backed off a bit and let the timing slip?

[VTRDark]

Oh dear.....lack of lube will soon seize things. Did she overheat at all. Get the cam covers off for a quick visual check then if you can turn it over by hand at the crank, if OK then cam covers back on do compression test as that will give you some idea's at where things are at. You will need a compression tester though. First things first is cam covers off as you may get lucky and have only dropped some valves, but with no oil there is a good chance of bearing damage in which case it's total engine strip down. Probably cheaper and easier to stick another lump in.

[tony.mon]

My vote is on seized cams in one or both heads.
Pop the cam covers off, pull cams, have a look at the bearing surface in the head.
If scored, the bottom end will be as well, so new or replacement engine needed.
If not, keep stripping until you find what's seized.
The extra engine braking is a sign of seizure.
Seizing the mains or big ends is quite unusual on these, but if not the cam bearings then it'll be piston and rings, next most likely is mains and big ends.
But it's not good news...

[roasty_duck]

got any pictures or something to point out where i should be looking?

dropped the new oil today and i had quite a few gold flecks in there...
any ideas whats gold in the engine?

[VTRDark]

I just realised...this is the bike that has been wheelied a lot too. That would not have helped with the oil starvation. If there is a lot of Gold you may have enough to buy a new engine. I'm trying to think what could be Brass/Gold looking inside there. Maybe bits of the clutch friction plates. Either way looking at specs in the oil wont tell you exactly what damage is done and the engine will require stripping. Why not start with easy stuff like the cam covers, clutch cover, generator cover, sump pan. Your bound to find more clues. Clutch cover may prove to be revealing.

[roasty_duck]

had rear cam cover off and both plugs out, can turn the engine by hand via alternator however its not smooth and sounds dry...

can see front and rear piston moving up and down fairly smooth, cant see any damage to them.

rear camchain looks fine, timings fine on it

[VTR Phoenix]

Is it not the main bearings that will give brass/gold flakes

[popkat]

my guess is Big end failure, and a pretty big one at that. main bearing picked up and spat out, con rod on the crank could explain the gold flec in the oil.



.

[bigtwinthing]

are there thrust washers in these engines? They are normally thin bronze half moon shaped bits, they wont be magnetic.

I would boroscope to check bores it will save you lots of work. If that loss buggered the lump has to come out. If liners are ok and you can see the piston crowns and valve gear this will help. I reckon you've had some valves hit pistons though. Sounds like the ends may have got oil starvation.

You probably looking at a new lump.

[roasty_duck]

got a boroscope so will take a look later on.

if it is a case of big end bearing is it viable to buy new bearings and rebuild this engine?

either way the engines being dropped today or at least make a start on removing the engine after checking the bores.