well.. she died :(

[tony.mon]

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.

Yes the engine is usually rebuildable, If the cam/head journals are damaged they aren;t recoverable, but I have some spare heads should you need them, also spare std size pistons.
It's the bore wear which will determine what needs doing- if it needs a rebore plus new bearings throughout it comes to more money than a 2nd hand engine.
It's only when you take the opportunity to fit high comp pistons etc that this is worthwhile.

[MGoBlue]

Pull the oil pan off and have a look.

[Wicky]

It's wombles...

[youtube][/youtube]

[roasty_duck]

took head covers off today, turn the engine by hand it seems fairly smooth, untll rear ex and front inlet are being opened together then its a struggle to turn.. after that it turns smooth untill its back to rear ex and front inlet.

manual ccts havent moved, chain tension the same, and it doesnt appear to have skipped any teeth on timing.

boroscope down spark plug holes, rear was all black front was black with 2 nasty half moon clear patches.

ripped both heads off managed to snap 1 exhaust stud on the front and this is how it looks.

Rear


Front


from the exhaust valves on the front it does look as if they have touched at some point recently, i dont have a valve remover so i cant get them out to check.

now this leaves me with a problem..
do i change the valves and hope it was just that?
or do i buy a new engine and try that.

currently my only form of transport, i could rebuild the heads as squiffy has a spare bike and offered parts, but this is a day job (im not great with big engines) if i do this to find its not solved it then i have to drop the engine anyway.

could this really be the cause of the clattering sound i was getting followed by massive power loss and squeaking from the engine, starter motor doesnt seem to start the engine as its too stiff to turn it over/was when i tried after it cut out on me.

could 2 slightly bent exhaust valves cause all of this? they seem to seal up, i put the head upside down blocked plug hole and filled with petrol it didnt appear to lose any.

[VTRDark]

Wow that front has some carbon build up. Is that front cylinder all coked up around the top of the cylinder wall. Looks like it has detonated or pre ignited through overheating along with ring damage as you possibly have some blow back past the rings there. There's also an indentation on the front piston bottom left quadrant. I wonder if that was caused from a small pressure spike. What are the Spark plugs telling you. Even if you do rebuild the top end you may end up with no compression so don't go wasting time and money without being sure.

I'm sorry to hear this is your only form of transport, that's sh1t and I know how that feels.

Replacing an engine in one of these is real simple as long as you don't run into any grief with any of the engine mounts especially the front. You could get the old engine out and new one in, in a day at a push or two days comfortably. It's whether you can find a good engine at the right price. You basically remove the rear end and then remove the front end which leaves you with and engine and frame sitting on bricks or whatever support you have under the sump. Then remove the frame by lifting it off the engine leaving you with an engine sitting on bricks. I use an Abba stand mounted off the rear engine mounts, remove swingarm etc. Seesaw the bike to lift the front and place a bit of timber at an angle propped up under the front exhaust outlet, remove forks, remove timber and carefully lower the bike off the stand onto some house bricks. The trick is to loosen any really tight nuts and bolts before the bike gets unstable especially the forks.

[popkat]

If your valves are bent you'll have no compression on that cylinder, with no compression the motor will spin over easier and faster than normal.

Stand the head with suspect bent valves on end so the port you want is facing up, pour some paraffin into the port and see if it comes out of the valves in the combustion chamber, if nothing comes out straight away leave it a few hours and have another look, if still nothing then your valves are probably not bent..



.

[roasty_duck]

the piston on front has 2 marks from valves and 2 marks either side of valves which tie up with stationary parts on the underside of the head which to me says the pistons gone higher than it should have not the valves coming down as piston went up.

can the pistons be removed without splitting the engine?

im not overly confident doing an engine change on this tbh, i did one on my fzs 600 and that was an absolute nightmare.

[MGoBlue]

With the oil pan off, you can remove the con rod bolts and push the piston out of the cyl.

[AMCQ46]

if you think the piston went to high, are you saying the big ends are now worn and that is the cause?

[MGoBlue]

Which he should easily be able to tell with the pan off and the rod ends right there for the exam.

There was a guy over on the US site that had the big end bearings go out and if I recall correctly, he didn't have any piston/valve make out sessions.

[roasty_duck]

With the oil pan off, you can remove the con rod bolts and push the piston out of the cyl.

this is what i wanted to hear

[StormingHonda]

Do this one piston at a time, and don't mix up the parts, they are machined to fit.

[MGoBlue]

http://www.vtr1000.org/phpBB3/viewtopic ... 6&start=60 Interesting read if you have some time.

[roasty_duck]

the vtr is 1 big roller bearing on the crank so surely both pistons would have made contact?

[tony.mon]

No- the thickness of the shells is lots less than the clearance between piston and valves.
Even with big end shell wear to the point where there's no shell left the piston still wouldn't hit the valves.

Timing out would let valves kiss pistons- before removing the heads, did you check that valve timing was till accurate, with crank in the correct tdc?