XS650 engine rattle - help needed please

[surfer]

Thanks Psyguy for the help.

I'm thinking the top of the piston is a only a nick and will be ok to continue running it.

How do I hone the cylinders though?

[Motu]

The cause of the inlet valves hitting the piston will be a worn cam chain.Pull the barrels for a closer inspection.....really worn bigends will cause the piston to hit valves,but they have to be really really bad to do that.....mind you the chain has to be really worn to cause the valves to hit too.I'd replace the pistons,but a ring job is a quick fix.Use a glaze busting bottle brush hone - take it to your local garage.Honda Accord rings will fit,use Hastings rings if possible.

[psyguy]

How do I hone the cylinders though?

you can buy the tool at repco - it goes onto your electrical drill. not expensive
or let the reconditioning shop do it. not expensive either

[surfer]

Bugger is all I can say.

After a lot of umming and ahhing, and scratching of the head, what could it be that is causing the valves to smack the pistons. I got a useful tip and that was to hold onto the con rod at TDC and tap the top of it with a mallet. If it moves then it is the big end. Previously I had been tugging on it to see if it moved and I guess I either did not eat enough ricies that day or it was jammed solid in there. Anyway it moved about 2mm.

So it is engine pull down time . In the mean time I am polishing the tops of the pistons and the the top of the cylinder head to remove carbon. As well as lapping the valves. When I have done this I will get to tugging the rest of the engine apart to get at the crankshaft.

I've also had the frame, rear mudgaurd, and electrics box powder coated black. Got the exhaust pipes painted black. Had the battery box chromed (man that was not cheap). Done some hand painting on a few smaller connecting items and started on the rear wheel, all in black of course. Just leaves the tank and the front and rear wheel to finish . Mighjt leave this until after the engine comes back together and I've managed to get a ride in on it.

Some advice meantime please:

I have not yet taken the engine side covers off. Looking at the engine it looks as though I need to do this for the bottom part of the engine to come apart. When I take the engine side covers off do I need to pull out all the gears, clutch and everything else or can these be left in place to get at the crankshaft?

Is there a recommended easy way of doing this, other than get someone else to do it?

Cheers

[FilthyLuka]

you will need to take off the clutch assembly and flywheel and such... use a hammer... See if you can hunt down the manual for that bike, it will make it way easier.

[Motu]

You haven't pulled the barrels yet? You need to get the barrels off to check the bigends - that hammer trick is practically useless.There are no bolts holding the barrels down,if the head is off the barrels will just lift off too,although it's an engine out job in a standard frame.

The XS650 has a rock solid bottom end,it takes some serious neglect to ruin one.The cases are horizontally split,the top case lifts off leaving everything in place - you can turn it upside down and pull the bottom off too and leave the top end undisturbed.Don't rush into a full strip down until you know exactly what it is you need to replace.

[surfer]

The cases are horizontally split,the top case lifts off leaving everything in place - you can turn it upside down and pull the bottom off too and leave the top end undisturbed.Don't rush into a full strip down until you know exactly what it is you need to replace.

Do you mean that I can seperate the crancase without turning it upside down, or should I turn the crankcase upside down and then split it?

The engine is out of the frame. I have pulled the barrells off, and taken the piston off the con rod on the side that was making all the noise. The small end was fine, no wear. There is a definite 2mm of movement in the con rod at TDC so I am suspecting a worn big end. I can also see a lot of metal shavings in the bottom of the crankcase.

[Pussy]

Sorry, Surfer, but it will really be best to completely disassemble the whole thing and give it a good clean out

[surfer]

Cheers for the tips and advice Motu, Pussy, Psyguy and filthyluka.

So if I am reading this correctly, in order to get at the crankshaft I have to take off everything behind the crankcase covers. After this the top part of the crankcase should be able to lift off the bottom part. Revealing the crankshaft hooray

Or is there another way of doing this without having to remove everything behind the crankcase covers?

So far have polished up the tops of the pistons and cleaned off the carbon. Lapped the valves, and polished the carbon off the inside of the head. Will wait to get new piston rings before honing the barrells. Valves stems are straight and valves ok.

[Ixion]

Nope you need to gut out both sides. Primary drive off, clutch etc, alternator and so on . There will be plates and gawd knows what behind all that stuff which are screwed to both top and bottom cases. Sometimes you can leave this or that still connected but which this or what that is a matter of knowledge of the individual engine.

Pretty much the same with a vertical split though, even the old Briddish unit twins y' had to pull everything off.

[rudolph]

My1982 XS650 special got a bit of a death rattle so I sold the fucker

[surfer]

My1982 XS650 special got a bit of a death rattle so I sold the fucker

Hopefully it wasn't me that bought it! Nice bike in your profile.

[psyguy]

Or is there another way of doing this without having to remove everything behind the crankcase covers?

this is prety much what you're looking at getting as the end product....

i think you'll find it fun though, eventually that is

[surfer]

Woo hoo have a new crank fitted .

I took my engine over to Andrew at Motorcycle Graveyard for a new crankshaft. He decided that he would show me how to fit it so pulled the engine apart and reassembled it with the new crank. I am a lucky bastard as there is no way in hell I would have found the hidden bolts on the crankcases or been able to reassemble the engine. The old crankshaft was absolutely rooted and had left the engine full of metal, everything has been cleaned out now.

So onward with the top end rebuild.

[psyguy]

cool