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CDNTX650
XS650 Guru
not unless they can do my head work with that price. Budget is tight.
OakBehringer
XS650 Guru
You can always just lap the valves yourself for about $8. If you're not getting an elaborate cut, this will be just about as good.
CDNTX650
XS650 Guru
never done it before. maybe have to give it a whirl. I'll clean the Combustion chambers first and see what everything looks like.
Test your valves for leaks before disassembling them. The exhausts are the usual culprits because they're subjected to more heat and take more of a beating. You may find the intakes leaking as well, though. Usually a hand lapping is all it takes to fix them up.
OakBehringer
XS650 Guru
Do y'all feel that the old "gasoline test" is accurate enough to ascertain if valves are leaking?
plane_ben
XS650 Junkie
I've got the same senerio after I put my top end back together. I don't recall using any sealant on the head gasket.
After about two runs of no more than five minutes each, my right cylinder started puffing white/bluish smoke. Got progressively worse when I did a few short rides up and down my street. It got to the point of spitting oil out the header.
I lapped the valves, checked valve guide play, used new valve seals, and honed the cylinders using the old rings, as they were in spec.
I guess what I'm leading up to is... Do you think it's the head gasket? I did run the torque wrench over all the 10mm cylinder studs at 25ft. lbs. They moved slightly, but that is all. I've got the engine out right now because I finished the mock-up and I'm painting the frame. Wouldn't be to much trouble tearing down the top end again.
Didn't mean to highjack this post, but didn't see the need to start another on the same subject matter.
After about two runs of no more than five minutes each, my right cylinder started puffing white/bluish smoke. Got progressively worse when I did a few short rides up and down my street. It got to the point of spitting oil out the header. I lapped the valves, checked valve guide play, used new valve seals, and honed the cylinders using the old rings, as they were in spec.
I guess what I'm leading up to is... Do you think it's the head gasket? I did run the torque wrench over all the 10mm cylinder studs at 25ft. lbs. They moved slightly, but that is all. I've got the engine out right now because I finished the mock-up and I'm painting the frame. Wouldn't be to much trouble tearing down the top end again.
Didn't mean to highjack this post, but didn't see the need to start another on the same subject matter.
It could be the head gasket I guess but they usually seal at least for a while with no sealer. The factory used none. You might try increasing the torque on the 8 large acorn nuts. Most of us use 30 to 35. The original Yamaha spec of 25 or 26 wasn't really enough.
Usually you only hone the cylinders if installing new rings. If you re-use the old ones, it's not required. Maybe they need to re-seat now but that amount of oil coming out does seem extreme for just unseated rings. Did you space the end gaps 120° apart and install the rings with the numbers facing up? I guess it's possible the exhaust guide seal may have popped off.
I don't know what to tell you really. If the use of more torque doesn't fix it then you'd need to pull the motor out again. You might be better off just looking into it now. With the short time it's been together, you can probably get away with re-using the head gasket. Just clean it up good and add the rings of sealer to it. You're familiar with where to put them?
Usually you only hone the cylinders if installing new rings. If you re-use the old ones, it's not required. Maybe they need to re-seat now but that amount of oil coming out does seem extreme for just unseated rings. Did you space the end gaps 120° apart and install the rings with the numbers facing up? I guess it's possible the exhaust guide seal may have popped off.
I don't know what to tell you really. If the use of more torque doesn't fix it then you'd need to pull the motor out again. You might be better off just looking into it now. With the short time it's been together, you can probably get away with re-using the head gasket. Just clean it up good and add the rings of sealer to it. You're familiar with where to put them?
plane_ben
XS650 Junkie
Hey 5twins, thanks for the reply. I didn't know that about not honing with used rings. But I think I'm going to pull it down and look. At least I won't have to pull the engine out twice.
