Hitchcocks Forum

Hi all,
I just changed the oil and filters on my B5 bullet for the first time. All went smoothly with the servicing kit from our hosts (90032) except that I have one small rubber O ring left over. It's about 10 mm in diameter and was in with the oil filter box. There was no existing O ring of that size on the assembly when I removed the old one, and no obvious place for it to go. Is it for a different style of assembly I wonder or am I missing something? The oil suction filter also looked like someone had been jumping up and down on it, so I'll need a new one of those if I can't straighten it out. Amazing what you find when you start to service the bike yourself...

AFAIK you don't need it. I''ve wondered the same thing myself every time I've changed the oil on my 2015 C5. I believe it's a hangover from the days when the filter assembly came apart. I believe it was a right PITA getting it back together and installed against the spring pressure. Whatever, my engine hasn't blown up yet. As an aside, my engine is painted black, being an LE Dispatch. Although the filter cover appears to be symmetrical, on mine it only fits properly if all three bolt holes in the cover are in their original place. Otherwise unpainted machined alloy is visible. I doubt that it matters, other than visually, but it does make me wonder how accurately the covers are made.

I'm wondering the same as you Rattlebattle after one of the lugs snapped off my oil filter cover. I tightened all 3 bolts evenly and the lug snapped off when I attempted to torque load the second bolt. I've got a new cover waiting to be fitted and the bike is running quite happily with a penny washer (on top of a small washer being used to fill the gap) transfering the load from the bolt into the cover. I'll fit the new cover at the next oil change.

That small O ring is for inside the oil filter cover assembly. If it fails then most of the oil that should go to the big end doesn't. Certainly worth checking it every now and again as it could get damaged due to the stepped shaft it fits on.
Every time the filter cover assembly expands after Allen bolt removal the O ring is moved to the smaller end of the shaft. When the assembly is compressed again the O ring is forced back over the shoulder of the step onto of the larger section of the shaft.
If the assembly is compressed squarely my thoughts are that the ring shouldn't be damaged at all by this abysmal design. Of course REI may have actually improved the design again since its introduction and put a chamfer on the shoulder.

That's what I did at the last oil change.
I noticed that the small o ring is forced over a sharp edged shoulder on the filter cover.
I dismantled the filter cover, one screw, and used a needle file to chamfer and round off the shoulder.
The O ring has an easier transition when replacing the cover now.

The filter kit covers a number of models. Hitchcocks only have part numbers up to about 2010, as I found by asking them. The post 2011 models are different spec to the models in the "Parts Book Online". Hence there are an excess of odd-size O-rings in the kit (unless Hitchcocks have now revised the set, do ask H). Check the sizes very carefully against the ones you take off; the old O-rings may have to be reused. O-rings can be bought individually and very cheaply (Amazon/Ebay).

The one on the little suction filter is too small for the depth of the groove, it is 30mm OD and 25mm ID, the original is barely 1.5mm thick and needs to be at least 2.5mm thick to make a good seal, 3mm thick (30mm OD) will squeeze in if 2.5mm does not seal. The suction filter has to be inserted carefully so it slides all the way in square or it will get crushed, try-fit it with your finger.



With the little bottom suction filter, the cover plate may become warped. I had to judiciously re-flatten it around the outside with a fine file (that's when I mic'ed up its groove); the filter sits over its magnet when pushing it back up its hole, be careful it does not tip over.

Thanks for the info; I'll check mine next oil change.

Having taken the filter out to have a look at it, I can certainly confirm that there is no small O ring needed on a 2015 B5 bullet...

Not normally needed, but it is still in there.
Under the spring loaded round plate.
Mines a 2016 c5.

Item No.30


http://www.hitchcocksmotorcycles.com/pa ... e_Cover_RH



There is detailed history (elsewhere) of severe engine damage due to failure to fit this particular O ring during reassembly of the earlier type of multi piece filter covers. I don't think it too unfair to believe its failure would not offer the same result on the more recent pre-assembled [Allen bolt] variety.