Triple filter O ring.

[BlackJota]

Well if the OR 149 O ring is converted to metric, that would be: 72 x 76 x 2.4mm. That is not even close to Red's measurement of 45 x 52 x 3.5mm.

Now I need to remove the cover and see what size it really is.

Refer to the 2nd comment in this thread.

 

[1200ts]

Refer to the 2nd comment in this thread.

Yes I can certainly measure it. But was hoping to have the new O ring here before I did the oil change on the bike and not have to find one then. Looking at the size of the cover while still on the bike, it appears that Red's O ring size is the correct one as the covers diameter is not close to 76mm.

I found a pack of ten 45 x 52 x 3.5mm O rings for $6.74. I am hoping they fit when they arrive in a few days.

 

[arancia]

Yes I can certainly measure it. But was hoping to have the new O ring here before I did the oil change on the bike and not have to find one then. Looking at the size of the cover while still on the bike, it appears that Red's O ring size is the correct one as the covers diameter is not close to 76mm.

I found a pack of ten 45 x 52 x 3.5mm O rings for $6.74. I am hoping they fit when they arrive in a few days.

Lesson learned thank you - can't trust the Laverda parts list!

I measured it - suggests it's OR-133 at 1 13/16", 2", 3/32" and not the OR-149 as shown in the early 3C Operation and Maintenance booklet parts lists.

All the O-rings as used by Laverda in the bikes of that era are Imperial sized and the standard sizes used by O-ring manufacturers in the United States are defined by Aerospace Standard AS568A which has sizes in inches and talks about how 10% to 15% squeeze is needed for effective sealing.

The early Laverda parts lists for 750 and 3C had all the relevant OR numbers but now I'll be double checking with a measurement before believing.

 

[Rob]

Don't blame yourself - I looked at the RGS parts list and the OR149 error is carried through there! Think I would have paused when a purchase listing showed a 3 inch o-ring!!