XS650 engine rattle - help needed please

[surfer]

My xs650 has developed an engine rattle sound. It seems to be coming from the top of the engine. Blowed if I know what it is. Can anyone help please?

It isn't a cam chain as I have just had a new one put in. The cam chain is adjusted properly and this has been doubled checked. The old one was really worn and knackered. Compression in both cyclinders is ok. The bike has no trouble in acclerating or reaching its top speed.

The only things that I can come up with that it might be are piston slap which is unlikely as the rattle sound does not appear to be consistent, and or worn cam bearings. The cam shaft itself appears fine.

What do you reckon? And should I be really really worried?

[Macktheknife]

As I recall it they often had a rattle even when new, if your compression is ok then it is unlikely to be piston slap, possibly cam bearings but what kind of rattle?
Did the rattle start just after the new chain was put in? possibly a different adjuster used that is causing the noise.
Worry? give it a while and see if it settles, then decide.

[surfer]

As I recall it they often had a rattle even when new, if your compression is ok then it is unlikely to be piston slap, possibly cam bearings but what kind of rattle?
Did the rattle start just after the new chain was put in? possibly a different adjuster used that is causing the noise.
Worry? give it a while and see if it settles, then decide.

Cheers for the reply; will see if the noise settles down.

[Pussy]

You could remove the rocker cover ( easy to do with the motor still in the frame, just remove the top mount) and make sure the cam is dead central. It is possible that the cam may be slightly to one side. I saw this happen many years ago, with a consequence of uneven wear on the chain guides

[Motu]

Not likely cam bearings on an XS650,they have substantial double ball bearings each end.Pull the tensioner out and have a good look at it,they have a sprocket which runs un the chain,this could be worn or out of aligment,also check the chain guides......which you can't unless you pull it apart again.Check the advance retard mechanism for play,and also the shaft - this too runs in neelde rollers each end,they get dry and sticky.Rest assured that no noise in an XS650 is cause for concern,they are way over engineered and can be destroyed only by immersion in the crater of Mt Doom.

[NighthawkNZ]

most likely one of the chain tennsioners needs a tweek... but as stated these were pretty rattlely even when new...

[Pussy]

Not likely cam bearings on an XS650,they have substantial double ball bearings each end.Pull the tensioner out and have a good look at it,they have a sprocket which runs un the chain,this could be worn or out of aligment,also check the chain guides......which you can't unless you pull it apart again.Check the advance retard mechanism for play,and also the shaft - this too runs in neelde rollers each end,they get dry and sticky.Rest assured that no noise in an XS650 is cause for concern,they are way over engineered and can be destroyed only by immersion in the crater of Mt Doom.

The 447 series engines ( about '74 onwards) didn't have a sprocket on the cam chain tensioner, it's just a rubber covered alloy guide, neither was the advance rod supported by needle rollers, just plain bushes. The early 256 series engines had what you described

[Motu]

Yeah,15 years with an XS1 is where I'm coming from.....

[Pussy]

Hey Surfer, try to work out what model engine you have. There were several different camshafts fitted to the 650s over the years, and several different valve clearance settings too. The 650 donk can sound a bit rattly with incorrect valve clearances. I've had three 650s over the years( many years ago) , TX650, TX650A, and XS650D. Great bikes, would love to get one at some stage again, for old times sake

[surfer]

Hey people cheers for the feedback.

The bike is a 1982 special, if that helps. Not sure of the model number.

I was told the valve settings are set at 3 and 6. But at some stage I should reset them to 2 and 4.

[surfer]

Hey people cheers for the feedback.

The bike is a 1982 special, if that helps. Not sure of the model number.

I was told the valve settings are set at 3 and 6. But at some stage I should reset them to 2 and 4.

I'll add a bit more to the above; I think it is a 1981 SH heritage special. it was registerd in 1982.

Would the inlet valves make nosie if they were set to .003 rather than .0026 in? If so will this damage anything if I enjoy the rattle sound?

[Alive]

You have an XS so you have probably already heard of Motorcycle Graveyard in Waiuku.

If not, give Andrew a call on 021 1068693... He specialises in XS's and knows a whole lot about them

:scooter:

[surfer]

Thanks for the reply, been there and done that. He wasn't sure what it might be, hence my post.

[Pussy]

I presume it is the electronic ignition model, with the oil level sight glass?

[surfer]

I presume it is the electronic ignition model, with the oil level sight glass?

It has the oil level sight glass but is a points system. (At some stage I plan to pop an electronic system in but need to save moolah first.)

I did have problems with getting an accurate wiring diagram for the bike as the wiring seemed to be an amalgamation of what was on the SH and late XS650E models (Clymer manual). I managed to make up a new loom which works just fine using the two diagrams.

I am slightly confused still as to the model; the engine number begins 5AP. Any ideas?

[Pussy]

Hey Surfer, I just did some searching on the web (googled), and found some good info to refresh my memory. Try 650wiki.org, found the valve clearances as: inlet, 0.06mm(0.0024"), and exhaust, 0.15mm(0.006"). Hope this helps

[surfer]

Hey Surfer, I just did some searching on the web (googled), and found some good info to refresh my memory. Try 650wiki.org, found the valve clearances as: inlet, 0.06mm(0.0024"), and exhaust, 0.15mm(0.006"). Hope this helps

Cheers for this, it is 1981 SH model. Never looked at this particular site before.

[surfer]

The slight rattle sound coming from the cylinders has got worse and is now a chig ching ching ching sound. Like hitting a hammer against a fire extinguisher. Really lound, more than the exhaust note which is a loud exhaust. I reckon I only did 300km to go from rattle to ching ching. This was after a new cam chain went in.

I have checked the cam chain tension and made sure it is set to the manual specs.

I have reset the valve clearances as these were shut tight at TDC on right hand side piston which is the noisy one and too big on the inlet other side. The exhaust left side was ok. The clearances on the right hand side seem to have been set ok but before TDC.

Compression test is way down at 110 one side and 60 the noisy side. Engine ratio is 8:1 so I reckon it should be 15 to 20 times this, up around 140/150 which it was before the ching ching ching arrived.

I have dumped the oil and found no plastic so I don't think it is the front cam chain guard disintegrating. Also I found metal shavings and flakes of metal stuck on the oil magnetic drain plugs, about almost half a level teaspoonful (for the cooks out there)...not good sign I'm thinking.

Started it again and still got the ching ching ching sound.

I am suspecting the oil has been contaminated by petrol leaking through the carbs. The oil feels a bit thin. I reckon I have shagged the pistons.

I reckon engine tear down time, any thoughts?

[tri boy]

Compression at 110/60. Noises.
Pull it down. Check top end, but also pay close inspection to rods and big end clearance. Good luck.:mellow:

[Paul in NZ]

If it runs a filter you 'might' be OK but frankly - I'd pull it right down NOW before it spits out a rod or something expensive (well MORE expensive)

[surfer]

Cheers for the replies tri boy and Paul in NZ. Will be doing just that.

[Pussy]

Pull down time, I'm afraid, Surfer. The crank, as no doubt you know, is a built up one, can be repaired a bit more easily than a plain crank, although best for your arse pocket if it doesn't have to be. The oil filters on XS650 motors will only filter out stone sized objects. Check the bottom strainer in the sump, it will be knackered. Top end overhaul isn't too bad to do on the 650. Sing out if I can be of any assistance

[surfer]

Pull down time, I'm afraid, Surfer. The crank, as no doubt you know, is a built up one, can be repaired a bit more easily than a plain crank, although best for your arse pocket if it doesn't have to be. The oil filters on XS650 motors will only filter out stone sized objects. Check the bottom strainer in the sump, it will be knackered. Top end overhaul isn't too bad to do on the 650. Sing out if I can be of any assistance

Cheers for this dude, will do.

[Rhino]

As Tri boy has said, pull it down now. They are quite simple to work on. I agree with Motu's comments that they are "overengineered" It takes a fair amount of damage for them to actually grind to a halt.

Your mention of metal filings on the sump plug is worrying. Pay close attention to rings, main bearings, big ends, small ends and cam bearings.

As Pussy has said, the crank can be repaired, but hopefully that isn't necessary.

[Kickaha]

Have you rechecked the cam timing? could be a piston to valve clearance issuse

[surfer]

Hello there,

Finally got to pulling the engine apart and got as far as the pistons. I reckon the loud knocking sound coming from the engine was caused by the valves hitting the top of the piston. Attached is a picture of part of the top of the right hand piston. Left hand side piston is fine.

There is no scuffing on the inside of the cylinder. Although there is a groove at about two thirds of the way down that looks like it was carved in there. It runs half way around the cylinder. I think it is lower than where the piston goes.

There is no upward movement from the pistons. That is there is no slack, I can't move them up or down without turning the crank round. So I don't think a big end or small end bearing has gone.

My questions are...

1. Is the groove in the cylinder anything to worry about?

2. Should I take the pistons out and check connecting rod tolerances anyway? And if I do this is it worth sticking new piston rings in?

3. Can I still use this piston or do I need to get another one? As you can see from the picture there is a shiny metal indentation where the valve has bashed it.

4. What should I clean the piston with to get rid of carbon build up and does this really make a difference to the engine?

5. What would cause the valve to bash the top of the piston? Timing out/valve clearance wrong? Bent valve?

Cheers for your help:niceone:

[xwhatsit]

Can't really tell wtf that picture is to be honest, but if the piston just has a little dent in the top of it... I've been using a piston in my CB with a pair of dents from exhaust valves for ~10,000kms now.

As for pulling the barrel off and checking the bottom end condition, that's not really that much more work, even for a complete n00b like me (and only one gasket). Getting the piston and rings back in wasn't too bad, but might be a pain in the tit with two cylinders.

[Warr]

Are you convinced that the valve/s are hitting the piston?
Can be measures by putting plasterceen ?? if you can still get it.
Make a ball of the stuff up and stick it to the valve / or the piston and assemble and turn it over a couple of times. Cant remember what I was recommended when I was doing it in a 351 Clevedon, but something like 1mm clearance from memory.

[surfer]

Can't really tell wtf that picture is to be honest, but if the piston just has a little dent in the top of it... I've been using a piston in my CB with a pair of dents from exhaust valves for ~10,000kms now.

As for pulling the barrel off and checking the bottom end condition, that's not really that much more work, even for a complete n00b like me (and only one gasket). Getting the piston and rings back in wasn't too bad, but might be a pain in the tit with two cylinders.

Hope this clarifies what the picture shows.

The picture is a close up of the piston. What you are looking at is the top of the piston inside the cylinder. The darker patch is the indent where the valve goes (normal) and the shiny white bit (not normal) is where the valve has been hitting the top of the piston. There is a smaller dent on the other side of the same piston where the other valve has been bashing at the top of the piston as well.

I will pull the piston out and inspect the bottom end. Cheers.


Are you convinced that the valve/s are hitting the piston?
Can be measures by putting plasterceen ?? if you can still get it.
Make a ball of the stuff up and stick it to the valve / or the piston and assemble and turn it over a couple of times. Cant remember what I was recommended when I was doing it in a 351 Clevedon, but something like 1mm clearance from memory.

Yep, pretty sure the piston is hitting the valves. But not sure why.

[psyguy]

hi there surfer
by no means an expert, i'll speak from what i learnt from others while rebuilding my gs


1. Is the groove in the cylinder anything to worry about?

looks only a scrape to me (no real damage) and should polish up ok
the worry is to find out what caused it...


2. Should I take the pistons out and check connecting rod tolerances anyway? And if I do this is it worth sticking new piston rings in?

i was told it's always a good practice to hone the cylinders and use new rings when rebuilding an engine - then you're care free in that department for a while... and can exclude that as a cause if faced with performance problems down the line


3. Can I still use this piston or do I need to get another one? As you can see from the picture there is a shiny metal indentation where the valve has bashed it.

as above


4. What should I clean the piston with to get rid of carbon build up and does this really make a difference to the engine?

there's a spray can at repco for that purpose. i assume clean piston tops ensure cleaner fuel burning and less further build up


5. What would cause the valve to bash the top of the piston? Timing out/valve clearance wrong? Bent valve?

valve clearance should't be a problem - the valve shouldn't be able to touch the piston even with clearance "0"
wrong timing could do it, this would be my first guess, but i assume you'd also notice poor performance if that was the case (and you say the performance was ok)
do that simple test as someone suggested above - taking care the timing is 100 correct
bent valve would again influence performance - i guess you can compare the two valves to see if they're different

my best guess is to check your valve guides and valve stems for wear - there should be no valve stem play when the valve is fully open (or in any other position). theoretically, a valve that opens on a wrong angle could touch the piston, i think

good luck

[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 :crybaby:. 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 :niceone:. 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 :niceone:

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

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.:woohoo:

[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? :doh:


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

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

[surfer]

Woo hoo have a new crank fitted :sweatdrop.

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 :woohoo:

[Warr]

Motu suggested it would be rare for a catastrophic like this to occur. Do you have any ideas why??
Dirty oil, too long between oil changes ...


Not likely cam bearings on an XS650,they have substantial double ball bearings each end.Pull the tensioner out and have a good look at it,they have a sprocket which runs un the chain,this could be worn or out of aligment,also check the chain guides......which you can't unless you pull it apart again.Check the advance retard mechanism for play,and also the shaft - this too runs in neelde rollers each end,they get dry and sticky.Rest assured that no noise in an XS650 is cause for concern,they are way over engineered and can be destroyed only by immersion in the crater of Mt Doom.

[surfer]

Motu suggested it would be rare for a catastrophic like this to occur. Do you have any ideas why??
Dirty oil, too long between oil changes ...

Yes, I have an idea but am not certain yet. Basically I think it has something to do with the groove that appears two thirds of the way down the barrel. The groove is at the front of the piston and below the piston rings at their lowest point.

I have no idea how the groove got there, it might have been caused by the piston but it is a funny shape for this as it doesn't match the piston shape. Or it might be a mistake that someone has made at sometime in the past. Failing this my money is on aliens.

It may be that the piston skirt is catching in this groove and this is throwing the piston and connecting rods forward causing damage and wear to the big ends. However, this is theory only. I am off to seek some advice from an engineering shop with the offending barrel.

I will put up a post and let you know.

[Motu]

They have an all roller and ball bottom end - they don't need oil pressure just flow and not much filtering,the XS650 has a couple of mesh filters.Age,really,really,really old oil or none would do it.Friend of mine ran an old XS650 on waste engine oil he poured into a drum....it did finally die,but took some time doing it.

[surfer]

Motu suggested it would be rare for a catastrophic like this to occur. Do you have any ideas why??
Dirty oil, too long between oil changes ...

Yep, dirty engine oil was the culprit. Previous owner couldn't have liked changing oil.


They have an all roller and ball bottom end - they don't need oil pressure just flow and not much filtering,the XS650 has a couple of mesh filters.Age,really,really,really old oil or none would do it.Friend of mine ran an old XS650 on waste engine oil he poured into a drum....it did finally die,but took some time doing it.

Motu yes, you are right. Cheers.

I took the barrel into the local place near me, Engine Specialties. They reckon the groove is a machinists error in setting up for a rebore when the barrel was rebored. They are measuring the pistons and barrels for me though.

The piston and barrel seem to have suffered a lot of wear and has signs of running on dirty oil as there are marks running down the sides of the pistons to indicate this as well. This would also account for the damage to the crankshaft.

Many thanks everyone for your comments, suggestions and help. Much appreciated.

Onward with the top end rebuild now.