Cylinder base o-rings

[MikesBike]

I'm putting an engine together and am ready to slide
the cylinders on. In my gasket kit, there is a cylinder
base gasket and 4 large-diameter orange o-rings.
I'm having trouble fitting the o-rings into the slots
at the base of the cylinders, the diameter seems to be
too large and they are not staying in the slot.
Is there a trick to keeping the o-ring in place while
the cylinders are installed? Are they really needed?
I currently have the o-rings in the freezer trying to
stiffen them up a little...
Thanks
Mike

[John]

Mike, you might try a little bearig grease lightly smeared on the O rings help keep them in place. They are needed. They prevent crankcase gasses from escaping between the steel sleeves and the aluminum of the jugs. I recently did my engine, but I had no trouble with the O rings. What brand gasket set did you get? Vesrah? That's what I used.

[ratbyk]

O Rings

Mike, when I have trouble with O rings in situations like you have described I tack them in place with some weatherstrip adhesive.
It is a super glue for bonding rubber products to metal. Should be available from virtually any automotive parts store. This should hold them in place until you have the barrels located onto the crankcase.
Ken/Sooke

[TopCatGr58]

Hey Ken/Ratbyk,

When I did my rebuild 4 years ago, the machine shop/motorcycle racing shop mechanic/owners told me I didn't need the O-rings, and so I put mine back together without them! Just where do these gasses leak to from the crankcase into the cylinders/jugs??

Mine has been fine for past 4 years and many several thousands of miles, still has plenty of compression, and no oil leaks around the bottom of the jugs! Just wanted to post another person's experience who didn't replace the O-rings!
T.C.

[Ken Talbot]

I didn't put the o-rings in either when I rebuilt Tsunami about 25000 miles ago....

[MikesBike]

I put a little high temp silicon glue into the groove
with an acid brush, placed the offending o-ring into
position and held it in place with a large o-ring from
my o-ring replacement kit. I'll give it a chance to dry
overnight and remove the large ring just before I
slide the cylinder over the pistons...
If it looks like it won't cooperate, I'll just leave them out.
Thanks for the help!
Mike

[strom]

Hope you got new ones... u gotta have new ones. They brake fast. Got no problem with mine, got em in with no problems. New ones. They are still avaliable from yamaha. Got a new set with a complete set of gaskets for the XS too.

LP

[MikesBike]

Yes, I had new ones from the gasket set I had bought.
The glue trick seemed to work OK as I put the cylinders
on this morning without any problem at all. I used a
couple of spacers and head nuts to secure the cylinders
in place while I do a little work on the head... Looks like
I have at least one bent valve.
Mike