Valve stem seals: replacement without pulling the motor

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The credits for this go to @pamcopete for the original idea, Grepper @ XS650 Garage USA. for improving on Pete’s idea, and Farrel @650central for doing a comprehensive write up, I followed Farrels write up to replace the intake valve seals on my XS2. Here is a link to Farrels article.

http://www.650central.com/smoking_due_to_worn_valve_seals.htm

I am not looking to re write the work already done, but to try and supplement their ingenious idea with a comprehensive set of photos. It took me 90 minutes to replace and photograph the first one, I was stopping and messing with lighting and trying to take clear photos. Some aspects of the job are a bit fiddly. Nothing was overly difficult but it does require some patience. The second seal took me 45 minutes. I had been prepared to pull my motor to do this job. So without further ado…….

Part One…..
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Note: the rope in this photo is shoved into an oil return passageway, in case you drop a collet, it won’t wind up in your crankcase.
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Continued in Part Two…..
 
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Some follow up details.
I am trying out this set of Viton valve seals I found on EBay. I’m hoping these work well. They are just a little bit different looking, a double lip where it snaps over the valve guide and about .6mm taller.
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The home made valve compressor tool,
The first one I made , I found a 1/2” black pipe cast iron connector. It was very strong, but I buggered it up and wasn’t happy with the way it came out, so I went back to the hardware store to buy another. They were out of the cast iron connections, so I bought galvanized instead. It came out better but the metal was softer and right at the end of my job it bent on me.
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The reason for doing this job was when my gas tank liner melted and f****ed up my engine, ( :cussing:Marbles Motors )
It built up on my intake valve stems,
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I rebuilt the motor and my carbs, but failed to think about what this might have done to my valve stem seals. :doh:
I reasoned that they were not old and had been working well, but that is not the case.
I recently looked into my intake tract and could literally see oil drips coming off of my valve guides. The back side of my intake valves were oily as well as the crown of my pistons ( as seen through the spark plug holes ).
I pulled my exhaust headers off so I could check the exhaust valves, but they seem fine , so I’m going to leave sleeping dogs lie.
Anyways, I hope my taking a chance on the Viton seals doesn’t bite me in the ass. At least it wasn’t a hard job.
:smoke:
 
Very elegant!

Thank you!

Nice work Bob! Pictures can be invaluable for fussy jobs like this.

Thanks! Yeah I agree. There just wasn’t anything out there when I looked. When I read the written instructions, the job sounded daunting. It took me a long time to get my head around all the steps. But like most jobs, once you get in there and see what’s going on it starts to become clearer.
 
What's up with that piece of rope stuck in next to the valve spring? I 'member using clean soft rope in the plug hole to "catch" the valve head.

That rope is shoved down into an oil return passageway that goes to the sump. It’s there to prevent one of the collets from going down the drain if you wind up fumbling it. Or so I’m told, I’m just following Farrels guide.
 
That rope is shoved down into an oil return passageway that goes to the sump. It’s there to prevent one of the collets from going down the drain if you wind up fumbling it. Or so I’m told, I’m just following Farrels guide.
Been there, done that. Not on an XS though, but on my 97 Ducati ST2. Was replacing the intake side closer shim, when one of the "collets" did exactly that. Went down a drain oilway. And those Ducati "collets" are just two half circles of round spring steel wire, so very small. I had to drain the coolant, remove the timing belt from the vertical cylinder, remove throttle housings, injectors and exhaust system, then pull that head and cylinder, fish out the collet from the crankcase with a magnet. On those Ducati engines, there is a horizontal divider between crank and sump, so it wouldn't come out when draining the oil. After reassembling everything, I did a quick 10 km test ride, and found everything was good. Slapped on the tank bag and hard panniers, put on the leathers and started on our 7000 km tour of Europe. From Tromsoe at 70N to the French riviera, northern Italy, through parts of Austria and Switzerland to Munich Germany. There we "cheated" by taking the overnight Autozug to Hamburg, before continuing north through Germany and Denmark, then ferry across to Norway, and all the way back up north. The beginning of that trip was definitely a leap of faith. The Ducati ran great for the entire 7000 km, except for a blown reg/rect on the Autobahn on our way south. No mechanical issues whatsoever.
 
I remember seeing this method somewhere, probably the source you used, thought it looked a bit daunting so I'm glad to see somebody use the method. Thank you for the notes and especially the pictures!

How did you push valve up through seal? IIRC, the idea is to use a screwdriver or other implement inserted through the plug hole?
 
Thanks guys! It was actually a fun and challenging project, it’s always interesting to try something new.


How did you push valve up through seal? IIRC, the idea is to use a screwdriver or other implement inserted through the plug hole?

I had thought that manipulating that valve through the spark plug hole would be challenging, but it turned out to be super easy. The valve moved easily and at first I thought to use a wooden dowel but it was too bulky, then I was going to use a long skinny screwdriver, but in the end the easiest tool to use was that skinny little punch with the 45 degree angle on it.

What's up with that piece of rope stuck in next to the valve spring? I 'member using clean soft rope in the plug hole to "catch" the valve head.

I had read someone using a piece of rope fed into the cylinder as you described to keep the valve from dropping down , but as long as you keep the piston near TDC, it can’t fall. When you rotate the crank to drop the valve down to facilitate removing the seal, you have to do so very slowly and check where the valve is at frequently, because if you rotate too far, the valve will fall into the cylinder, then you will have to pull the motor. Those warnings are all in the article by Farrel. It’s not hard if you’re careful.

And someone made us a video, of course.

I had intended to do this procedure and I made up the tool. I ended up with the engine out, so I did the top end. It turns out my oil control rings were toast, so the exercise would have been a wasted effort for me.

I was going to mention that video, but it’s so badly made. I watched it, the guy was wearing a GOPRO mounted on his head and his constant movement and turning his head caused the view to whip around so much it was nauseating to watch! :confused: The other thing was , with the camera on top of his head, the view showed the top of the motor and didn’t see into the valve spring area. I did learn a little from watching it though.
 
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