[Arizoni]

IMO, unless a O-ring gets damaged during disassembly or assembly there is no reason to change it.

O-rings are quite resilient and can maintain their pressure tightness for years.

Earlier I mentioned lubricating the O-ring that slips into the filter bore but I should add that with the face seal O-ring on the oil pump inlet cover (on the bottom of the engine), both of the flat machined surfaces must be absolutely clean before assembling the parts.

A bit of dirt on either of those surfaces will greatly reduce the compression on the O-ring which could create a leak.

[singhg5]

singh5g's video shows the small o-ring on the stud in the wrong position.  It should go between the washer and the brass plate.   I found it very difficult to install it correctly and decided to buy the newer oil filter cap from Hitchcocks Motorcycles (see bottom of page 37 of the 2013 Catalogue Online at www.hitchcocksmotorcycles.com).  To quote the description, "On early EFI engines, the oil filter cap and associated parts are all separate and a real struggle to assemble when fitting to the engine.  This is the later set up which is screwed together so makes changing/cleaning the oil filter a much more simple task" (or to use better English, "a much simpler task" - and it was much simpler, so a worthwhile upgrade I think).

The small o-ring was on the stud from the dealer and I have continued that way for the last 4 years covering thousands of miles and many oil changes without any problems or issues related to oil lubrication or leaks or anything else that could be assigned to its location.  Lots of other riders have also used it without any issues.

Just curious to know how do you know the so called 'correct' position of o-ring ? Do you have any data that show that your 'correct' location give better results than so called 'wrong' position ?

Also your reference to 'newer' cap from Hitchcocks is nothing knew to members of this Forum. You will find lots of posts on this topic if you do a SEARCH. That cap has been sold in the US by CMW since 2010 ! It has been discussed many times over the years in this Forum.

[keithr]

The small o-ring was on the stud from the dealer and I have continued that way for the last 4 years covering thousands of miles and many oil changes without any problems

When I changed the oil on my bike (bought secondhand) it too had the O-ring in the wrong place.  If the O-ring is in the wrong place then I guess that means that more oil might leak past the brass plate and therefore not pass through the filter material, at worst meaning that a little oil won't be filtered but probably not making a great deal of difference (I hope not anyway!).

Just curious to know how do you know the so called 'correct' position of o-ring ? Do you have any data that show that your 'correct' location give better results than so called 'wrong' position ?

I downloaded a copy of the service manual and a diagram on page 03-14 shows the correct position of the O-ring.  Also it is evident from the newer design of cap that the O-ring goes between the brass plate and the metal washer.  By placing the O-ring on the stud between the washer and the base of the cap it is not going to serve any purpose.  It's meant to form a seal while allowing the brass plate to slide on the stud should the oil filter become blocked, therefore allowing oil to bypass the filter and still circulate around the engine - the spring tension determining the oil pressure at which the brass plate will move.  So as long as the filter doesn't become blocked it probably won't matter if the O-ring is in the wrong place (except it might increase the chance of oil leaking from the cover?).

Also your reference to 'newer' cap from Hitchcocks is nothing knew to members of this Forum. You will find lots of posts on this topic if you do a SEARCH. That cap has been sold in the US by CMW since 2010 ! It has been discussed many times over the years in this Forum.

Yes, I remember reading a bit about it some time ago, but I thought it was worth mentioning it in this thread.

[singhg5]

When I changed the oil on my bike (bought secondhand) it too had the O-ring in the wrong place.  If the O-ring is in the wrong place then I guess that means that more oil might leak past the brass plate and therefore not pass through the filter material, at worst meaning that a little oil won't be filtered but probably not making a great deal of difference (I hope not anyway!).I downloaded a copy of the service manual and a diagram on page 03-14 shows the correct position of the O-ring.  Also it is evident from the newer design of cap that the O-ring goes between the brass plate and the metal washer.  By placing the O-ring on the stud between the washer and the base of the cap it is not going to serve any purpose.  It's meant to form a seal while allowing the brass plate to slide on the stud should the oil filter become blocked, therefore allowing oil to bypass the filter and still circulate around the engine - the spring tension determining the oil pressure at which the brass plate will move.  So as long as the filter doesn't become blocked it probably won't matter if the O-ring is in the wrong place (except it might increase the chance of oil leaking from the cover?).Yes, I remember reading a bit about it some time ago, but I thought it was worth mentioning it in this thread.

I see your reasoning and all that makes sense theoretically.  In real life I have not seen anything remotely affecting the performance.  I think the reason that it did not make any difference is because the design has multiple back-ups that prevent any leaks to occur. The raised ring near the edge of the brass plate is pushed against the filter by spring on stud, stopping or minimizing  anything getting past it. And then there are more rings and gaskets to prevent leaks.

The small o-ring perhaps does nothing to stop anything because it is so thin it cannot withstand much pressure and it can be easily overrun or cut by the edge of plate.

I have attached 2 photos of 'NEW' cap obtained from CMW US. There are rings and washers even on the side of brass plate facing the filter - which is completely different from the 'original' cap. It is also different from the picture of the cap shown in the Hitchcocks catalog.

There is no evidence that one way works better than the other or one needs to buy version US vs. version UK.