Oily smoke? Could it be as simple as a valve seal leak?
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
What have you done to your XS today?
- Thread starter I am Carbon
- Start date
-
- Tags
- maintenance
Yep oily smoke
Do you think the seal could have popped off?
I took a look with a borescope down the bored and all looks good
But on the side that's smoking I can see a small amount of oil in the inlet valve pocket on the piston
Could the oil get there from the rings letting it by?
Or is it more likely from a valve guide seals coming off?
I don't have time at the moment to pull the carbs and check for excess oil on the inlet valve
But on the side that's smoking I can see a small amount of oil in the inlet valve pocket on the piston
Could the oil get there from the rings letting it by?
Or is it more likely from a valve guide seals coming off?
I don't have time at the moment to pull the carbs and check for excess oil on the inlet valve
Inlet valve guide seal leaking is probably the most likely cause. The inlet valve stem seal is subject to quite high negative pressure at tick over or small throttle openings. Causes oil to be pulled down the valve stem into the combustion chamber. It's not 100 per cent guaranteed that's your problem, but it's likely.
I'm away for 10 days from this evening which is frustrating because I'd like to check the seal but it'll have to wait
I popped the valve cover off to take a look but I can't see through the spring if the seal has come away
I could really do without the extra expensive of a rebore and pistons at the moment
There's a thread here about fitting new stem valve seals without removing the head. Well worth a read, there's a YouTube video to go with it. Could be worth thinking about it while you're away. Good luck with it.
I've thought about the Indian rope trick
I may have a go at it but I'm no gynecologist!!!
And it all looks a bit tight and fiddly in there Mind you I really don't feel like pulling the engine out again!!!
The way I see it, there's nothing to lose. I'd try it as per YouTube video and if I couldn't do it like that, the engine is coming out anyway.I've thought about the Indian rope trick
I may have a go at it but I'm no gynecologist!!!
Mind you I really don't feel like pulling the engine out again!!!
My memory was jogged today by fuel leaking from the tank cap when I put the bike on its side stand. I said I'd order a rubber seal next time I placed an order with Fowlers for parts. I forgot. So, rubber seal ordered this morning. £10.21 posted. Not bad for a genuine Yamaha part.
Question is, there's nothing in the shop manual about the fuel cap. So, how do you change the rubber seal? It doesn't look obvious to me?
Question is, there's nothing in the shop manual about the fuel cap. So, how do you change the rubber seal? It doesn't look obvious to me?
I'm wondering if it's be possible for oil to migrate past the rings and pool in the valve pocket of the piston without being burnt off?
But then I suppose the same would be true if oil came down the valve stem
It'd be immediately burnt off?
I doubt there's enough oil in the head when the engine isn't running to reach the height of the valve guide seal and run down onto the piston (if the motor stopped with valve open) that is
I Vaguely remember Jim
Having a text on difference ..Was it smoke from rings when revving / blipping and valve stem seals at other situations startup ?
Most likely valve stem seal.
I would try a compression test
Having a text on difference ..Was it smoke from rings when revving / blipping and valve stem seals at other situations startup ?
Most likely valve stem seal.
I would try a compression test
It only smokes when it gets hot
It smokes when revved and it smokes on deceleration
It's blue smoke and only from the right cylinder
It's done just over 200 miles since I fitted new rings
The bore was in spec so are the pistons and so is the ring gaps
It's not obvious, I agree. I struggled with the same thing and just disassembled everything I could on the cap and finally realized I could "brute force" it by just working the seal over the metal part(s) with a little rubber lube or Armor All. Maybe I cut the old one off, can't remember. But the new one will go on with some persuasion. I think some of the older caps had a better method of assy in this sense, but this is all I could find to do on my '78E cap.
Thanks for that. I am going to take another, closer look shortly on 650D. I can't see a way to dismantle the spring loaded part of the cap that the rubber part fits into. Sounds like I'm going to have to cut the old rubber off like you said, but then it's past the point of no return. Thanks again.
This is what mine looks like. The lock/latch comes apart via the two screws, but the spring -loaded part doesn't disassemble as far as I could see. Thus the stretch method...it works, it just doesn't seem right somehow i.e. should be able to be disassembled somehow?
Attachments
Just like your (oh never mind) Warm and lubed they go right on.
And it's a LOT easier than removing the clip on those that have em.
And it's a LOT easier than removing the clip on those that have em.
Last edited:
Well, I just removed my filler cap and it's identical to yours, except mine is a bit rustier. Of course I'll clean it up before reuse. I think that red rust will clean up pretty well.
Removing the old rubber? It literally fell off!
Now, I don't recall this being in such poor condition a few months ago. I think exposure to E10 has definitely accelerated the deterioration of the rubber. Hopefully the new one will not be affected so much by E10 fuel.
Not bad for almost 49 years really.
Very easy to fit the new fuel cap rubber seal. It was much softer and pliable than I expected it to be. Full marks to Fowlers again. Ordered the part late yesterday afternoon, it got here about 9.30am. Excellent service.
I've now rubbed the rusty area with a brass brush and treated it with rust killer. It's now a nice dark grey/blue colour where it was rusty. Happy days again.
I've now rubbed the rusty area with a brass brush and treated it with rust killer. It's now a nice dark grey/blue colour where it was rusty. Happy days again.
gunk
XS650 Addict
Speedo on the xs finally died a slow death. Only thing I could find in mph was an XS400 speedo. Ironically labelled 'For CB750' in paint marker.
Bolted on and works. About 1/4" smaller Dia. and goes to 120 mph rather than 140. No worries about pegging the needle unless I've ridden off a cliff. Bike looks like crap this year. but here's a pic. Just dropped 14,439 miles off the odometer. Amazing improvement in how it's purring along with the mileage rollback !
Bolted on and works. About 1/4" smaller Dia. and goes to 120 mph rather than 140. No worries about pegging the needle unless I've ridden off a cliff. Bike looks like crap this year. but here's a pic. Just dropped 14,439 miles off the odometer. Amazing improvement in how it's purring along with the mileage rollback !
Attachments
G'day everyone, cause I'm an old fart I thought it would be a good idea to ride the xs the long way to the annual xs club meeting last year , just over 3000 miles according to the speedometer.
After around 2,000 miles the xs developed a rattle, but still ran strong so I checked the obvious things and pulled the small oil filter finding nothing alarming.
Once I arrived at the meeting there were twenty or xs owners who suggested what the noise could be and the general consensus was the clutch cushion springs but i had my doubts because I have a rebuilt clutch basket fairly new.
Long story short it made it home ok and when I removed the clutch cover I discovered pieces of the right hand crankshaft bearing, not good.
So a new crankshaft and top end re build later i had her back on the road but with constant backfiring from the right cylinder.
After a lot of hunting I found out that the carby manifold was letting air in through the gasket.
She's running great now but the wife hasn't stopped rubbing it in that her Enfield did the trip without any problems.
We will be leaving in a few weeks to go to the moto gp at Phillip Island but I reckon I will be riding the bmw k1600 this time.
Safe riding gang.
After around 2,000 miles the xs developed a rattle, but still ran strong so I checked the obvious things and pulled the small oil filter finding nothing alarming.
Once I arrived at the meeting there were twenty or xs owners who suggested what the noise could be and the general consensus was the clutch cushion springs but i had my doubts because I have a rebuilt clutch basket fairly new.
Long story short it made it home ok and when I removed the clutch cover I discovered pieces of the right hand crankshaft bearing, not good.
So a new crankshaft and top end re build later i had her back on the road but with constant backfiring from the right cylinder.
After a lot of hunting I found out that the carby manifold was letting air in through the gasket.
She's running great now but the wife hasn't stopped rubbing it in that her Enfield did the trip without any problems.
We will be leaving in a few weeks to go to the moto gp at Phillip Island but I reckon I will be riding the bmw k1600 this time.
Safe riding gang.
