O-Ring Spec

[kcscout]

2000 R1100RT

Engine oil filler cap o-ring that seals the cap.

Is this the right spec?

17.5 to 18mm X 4 mm

 

Any thoughts if it might be available at the local hardware store or if it needs to be special ordered?

Thanks.

[ShovelStrokeEd]

O-rings are typically sized by ID and cross section.

Get those dimensions from the original groove in the cap.

Note that there must be room for expansion so the cross section area is better obtained from the depth of the groove than the width. Figure the depth of the groove to be about 80% of the cross section.

 

That said, given your specifications, an M3.5x18 would probably be what you are looking for given a 4mm groove width.

 

If the O-ring measured 4mm in cross section, the groove should be about 3.5mm deep and 4.5mm wide.

 

Go HERE for some reference as to sizes.

 

Doubtful you'll find it at your local hardware store unless they stock metric assortments. A hydraulic supply store might be a better source.

[Sailorlite]

The BMW part no. is 11-14-1-340-902 and is described as 18x4. I rode over to the dealer and bought one 2 days ago, but that was mostly just an excuse to take a little ride.

 

I haven't checked but it's possible that a BMW automobile dealer would have that part number too - might save you some travel time. (I didn't even try at my local hardware store).

[Big_Gray]

I went to the local dealer and asked the parts guy for both O-rings for the filler cap (the one on the cap and the one in the valve cover) and he knew the numbers off the top of his head. They replace a lot. I believe the pair was under $5.00. Cdn.

[kcscout]

Thanks all. I tried my local hardware store - not one of the chains, but an independent owner. They had at least 50 O-Rings there. The closest I got was 17x3mm and 19x3mm. Dang! So close.

 

Guess I'll be making a midweek run to our local dealer to see what they have in stock.

[breyfogle]

....Guess I'll be making a midweek run to our local dealer to see what they have in stock.

 

An alternative would be to order the correct size from one of several on-line web-based O-ring supply houses. I replaced my cam sprocket cover O-rings that way.

 

Google is your friend .