help: how hard to seat valve stem seals?

[78caferacer]

There seems to be a lot of different opinions on how hard to seat the valve stem seals onto the valve guides. Everything from just pushing them on finger snug to hitting them with a hammer and seating tool as pictured and described in the service manual (although the manual is silent as too how hard). I've now torn down my GS1000E for the second time in as many weeks because it's still burning oil badly until it warms up. I've ordered a second set of new seals and will try again. Others on this site have suggested that finger tight is good enough and that striking them can warp them enough to cause leaks. Any advice will be greatly appreciated. Rick

[Agemax]

dip them in oil first then simply push them on with your finger (or thumb). they may be a bit tight but they will go on. do not hit them with anything as it may distort them

[DimitriT]

OK, I got bit by this a few times.

The top of the guide has a small channel cut into it.
The inner part of the seal has a small ring of rubber
stuck to it.

Rubber ring is supposed to fit in the channel.

Pretty simple eh?

But HOW DO YOU KNOW it's in?

My technique:

1. dab gp grease on the inside of the seal - be generous
2. if you have skinny fingers place the seal over the guide by hand, otherwise use a pair of needle nose pliers
3. the seal will now stay there cause the grease will cause it to stick to the guide
4. apply increasing gentle pressure on the seal until...
5. you feel it pop into place
6. go on to the next seal

step 5 take some practice but you'll get it

the important thing here is that there's no way you can really damage the seal with step 4 but if you go with the tapping with a socket approach, there's definitely the possibility that the seal will get damaged.

How does the seal get damaged? If the seal is pressed down too far and is hammered, the valve guide top lip will punch into the rubber causing it to tear or weaken. It's hard to tell from looking at it if this has happened since the valve will look sealed but after running the motor, the seal will fail.

Sometimes the seal will slip into its channel with so little effort you will swear the seal need to be pushed harder. Resist this evil temptation. It's in there. If you want to prove it to yourself try pushing a valve up through it. The seal will not come off. Think about how hard it is to get the little bastads off to start with. They go on easy but don't come off easy.

[chef1366]

I just oiled mine and they popped on.

[hcritz]

Just as a side note...and not sure on this particular engine...
You can also ruin the seal by compressing the valve spring too far when installing the keepers...the retainer gets smashed into the seal and damages it. Only compress the spring far enough to install the retainers!

[78caferacer]

Great advice!!! Thank you all and wish me luck.

[hampshirehog]

A little trick that aids lining up. Pop the seal on a thin screwdriver and hold the seal up by the handle. Poke the end of the screwdriver in to the valve guide and let the seal run down the shaft of the screwdriver. You can easily centralise it before popping it on and you won't get the seal wedged in between the guide and the head and have to fiddle the blo*dy thing out.