Change the valve seals?

[WMarshy]

Hi guys,
Im having a mechanic do some carb work and tuning on my bike next week and was debating having him do the valve seals. As is, the bike has about 33,XXX miles and at one point probably sat for a few years with out being started. I burn about a quart of oil in 1,200 miles. On start up it smokes but once it's warm you cant really tell too much under normal riding. One of my riding buddies told me when I engine break to reduce speed my bike smokes and smells rich, not sure if that is from the carbs not being tuned properly or whatever (smoke is black in color). It also lets out about the same color/smell cloud if I snap the throttle under no load on the stand. Black is excess fuel right? I pulled the plugs and 1 was dark and sooty, 1 was black and wet, and the two inside were tan/white maybe even on the lean side. After the tune up I will do a throttle chop but I expect them to be better by then... A quart of oil every 1,200~1,500 miles seems excessive to me. How hard is it to change the valve seals? Does it require any special tools, homw many hours? Im mechanically inclined but trying to weigh everyting out. Rain for the next few days but a job like this for me would take awhile. I wanna be riding not fixing! Advice? Thanks guys.

[trbig]

You're taking this to a mechanic for some minor adjustment to the carbs.. which most people screw up on our bikes even though they are "Mechanics" and you end up doing yourself after blowing a bunch of moneyu... to asking us if you should let him change out the valve seals.. which would mean pulling the exhaust, valve cover, cams, cam chain adjuster, then the head off of the motor.. then the re-install.. hoping he really knows an XS11 well so he can get the crank and cams all lined back up with the adjuster done right, the possibility of a new head gasket.. most would insist you use a new one.. a new valve cover gasket, a new adjuster gasket...

You're talking a ton of money for something when you could buy a really nice carb synching tool for under $100 and do that part yourself... and a very knowledgeable member (Randy) that is a fellow New Yorker that could probably be bribed with food and beer to help when he has the time. (Don't people like when they get volunteered and didn't even raise their stinkin' hand?!?)

Only you can make the decision though. How much is all of this going to cost? How much is a quart of oil every so often?


Tod

[Crazcnuk]

I would try one of the seal softener (swell) type rpoducts first and see if that helps.

I just replaced my vavle seals, because I had the motor apart for other reason, and TR is right, it's an easy job with the head sitting on your work bench, but a big job if you have to take the top end off the motor.

You would need a top end gasket set, valve seals (if not in the kit) a cam chain w/master link.

I didn't get concerned with my oil consumption until I was using a liter every 200kms!

Rule of thumb: If you get a blue cloud when you let the throttle off (usually from high speed), or when you start the bike after sitting, it's valve seals. If you get a blue cloud when you pin the throttle, it's rings.

Black is over rich (too much gas). Too much gas will also cause oil consumption as you are burning the oil off of the cylinder walls, and eventually the walls glaze over and you need to replace the rings and hone the cylinders.

[trbig]

I didn't get concerned with my oil consumption until I was using a liter every 200kms!

Holy Cropdusters, Batman!!



Umm.. that would be roughly a quart every 120 miles.. So tell me. Does it make your fuel last longer when it's burning a tankfull of oil right along with the gas??


Tod

[cywelchjr]

Holy Cropdusters, Batman!!



Umm.. that would be roughly a quart every 120 miles.. So tell me. Does it make your fuel last longer when it's burning a tankfull of oil right along with the gas??

When I first got my bike, it was using oil at about that rate. However, over the first 1500 miles or so it petered off, and now that I'm about to change it, I'm not having any oil usage issues at all.

[trbig]

I'm not having any oil usage issues at all.

You still are.. it's just that with the seeping float valves, the oil is getting replaced with gas at about an equal rate.

OK.. Maybe that was just funny to me.. lol.


Tod

[TopCatGr58]

Hey Marshy,

It's also been stated in other older threads that there really isn't much oil that gets into the engine from the valve seals. IT's mostly the rings, and as mentioned, too rich fuel mix washing the oil off the cylinder walls, etc.!
T.C.

[Crazcnuk]

"Umm.. that would be roughly a quart every 120 miles.. So tell me. Does it make your fuel last longer when it's burning a tankfull of oil right along with the gas??"

Unfortunately, no. But it did get rid of the 4000rpm detonation and it made it hard to pull redline in 4th and impossible in 5th gear.

I was losing some, burning a lot. The PO had put rings in that were too small. They had over .084 end gaps and all the gaps were lined up together.

The oil rings were getting a real workout.

First major run since the top end rebuild was last weekend. I used about 1/2 liter over ~1000kms.

[petejw]

I know with car engines, the valve guide seals can be replaced
with the head on, compressed air via the spark plug hole is used to hold the valves up, only problem with our bikes, the valve spring is recessed in the head and not sure the valve spring can be compressed enough to remove the collets.

[Crazcnuk]

That and the frame is in the way...

[petejw]

Craz, i dont think the frame would interfere or be a problem,
the problem would be compressing the valve springs sufficiently,
with car engines the springs are exposed and a small
spring compressor can easily be used.

[Crazcnuk]

Ok, but I just changed my valve seals, and I can't see any way you would be able to get a compressor on the inner valves while the motor is still in the bike...

With the head off, it was fairly easy. I used a large carpenters clamp and a socket with the side cut out.

[petejw]

I just had a look at the bike,
yeah youre probably right, not much room there,
well it was just a thought.

[WMarshy]

Thanks for the advice guys. I wasnt sure what changing the valve seals entailed. Sounds like a better project for winter time. You make a good point TC, I will start by getting the carbs where they should be and adjust valve clearance then do a compression test. Just food for thought, is it possible to take the head off without removing the engine? Crazcnuk, do you know of any seal softener product that you can put in your oil that will rejuvenate the seals? Thanks again!

[bikerphil]

is it possible to take the head off without removing the engine?

Yes it is. There is plenty of room, but the cams have to come out first, IIRC.