Tricks for holding down head o-rings?
 

I've got my top end back together and my o-rings don't seem to want to lay down nicely in the grooves. They pop right out as if they are a wee bit small in diameter. These are 10 years old. I got them from Jim when I bought the bike, and unwisely waited a decade to pull the jug. So, maybe they shrank a bit. I dunno...:confused:

I'm thinking of a drop of candle wax here and there to hold them down.:rolleyes:

Edit: 2001 xc300

A light coat of grease and a light stretch running them through your fingers works well. Place in the groove and run your finger around several times until the stay seated. Drop the head on squarely, and rotate it back and forth a few degrees under slight pressure before lining up the holes. A smooth even feel indicates they are in the grooves properly. They should not shrink. What happend to me once is I got the wrong orings for my 250 (for a 200), A mistake by the old distributor. So if you absolutely cannot get them to stay put, just get new ones.

Thanks. All set.

Except now I find that five out of the six screw holes need to be tapped, after Langcourt worked their magic. I sure do wish I checked that while the jug was off the bike.:mad: I'll have to tape off all the orafices, and add another tap to my collection. I'm not liking the idea of tapping chrome out of aluminum threads. Ugh.

A brief stop at the pub might be in order, just to cool off a little. Since I have to go downtown anyway. :cool:

Glens way works 99% of the time.
But I always have a fresh can of Gasgacinch on hand for the nasty gaskets that won't stay put. Think of it like liquid elastic. I also use it on the tubeless tires on my TXT. A very light coating is all it take for most applications.
IMHO a must have. Great product.

http://images.motorcycle-superstore...._Sealer_--.jpg

Thats odd, why should there be nikasil in the holes? does the base and head deck surfaces have traces of coating too?

No. The base and deck looked fine. Maybe it has nothing to do with replating. But it's just another Friday the 13th aspect of today's work.

I got the cylinder on the first time before realizing I hadn't placed the base gasket yet.

Then, I found I had done a stupid thing by torquing the studs to YZ250 spec. That's because the studs sit too low if you do that. Plus, I hope I didn't do some terrible thing to the bottom of the holes. I reset the studs to optimal height and left it at that. The other way was clearly wrong.

I think I will wait until tomorrow, the 14th, to use my new tap.

Some days are definitely better for drinking beer than working in the shop. When I start fumbling everything I usually call it a day if it isn't something that needs to get done immediately.
When the time comes make sure the o-rings are nice and warm before streching them. They'll hold their stretch better that way. Use a drop-light to warm up the cylinder and the head. Lay it on them (not the o-rings though) for an hour before you go to do the job. With everything nice and warm it will be easier to keep the o-rings in place. And do all that GMP says too.
If it makes you feel better the last time I put my cylinder on I forgot the base gaskets also :o

+1 - only mine folded over at the corner and leaked like a sieve.

I'm having a little troubles trying to comprehend this. http://www.cafehusky.com/smilies/excuseme.gif

Don't the two just go together. Thus the saying 3-4 beer job...OK even if it turns into a 5-6 beer job...well you know what I mean...http://www.cafehusky.com/smilies/cheers.gif

Thanks everybody. Yes, it does make me feel better that I'm not the only one to forget the gasket.
I figured I was probably not the first one to snap the post off of the powervalve actuator plate either. I found out later that the trick there is to heat the nylock nut before trying to unscrew it.

Anyway, the top end is done. Head is on and torqued.

I taped, then tapped.

Thanks again folks!