Featured Engine Oil Filter Design, Pre-oif

Hello everyone, I’ve just become a member of The Triumph Forum and this is my first post; I hope I can do it properly.

As all of us owners of old classic Triumphs know, these motorcycles desperately need some decent engine oil filtration, and several years ago I decided I absolutely needed to install something on my ’68 Bonneville. I looked around on the internet but didn’t see any kits that I felt were satisfactory, so I decided to create and install my own design. This was 3 years ago and maybe there are some better kits available now – I’ve had no reason to keep looking. I’ve always intended to share this design with others so that they may duplicate or maybe even improve on the design, but I’ve only just now gotten around to doing that, so this will be a test of my memory.

Please note that this is for a 650 with the original twin carb/air filters setup. Assess for yourself if your bike is different, such as you want to install on a 650 with a single carb (air filter clearance?) or a 500 cc machine (overall clearance of parts?). If it’s a 500 (or any size other than a 650), find out if the oil line routing is the same or different from what I’ve illustrated for a 650 before proceeding.

My design criteria were as follows:

1) Oil filtration efficiency that is at least equivalent to today’s car engines.

2) Extremely reliable design: No chance of things shaking loose, hoses coming off or prone to leaking oil. No chance of engine oil starvation: For this reason, I wanted the filter to be in the oil return line, which is virtually the standard convention when adding engine oil filtration on classic Triumphs.

3) Easily serviceable.

4) Uses inexpensive, readily available oil filters.

5) Does not require any modifications to any of the original parts of the motorcycle (e.g., drilling holes, cutting metal).

6) Will not interfere with servicing/accessing any other part(s); will not potentially rub other parts.

7) A “filter pointing down” design so as not to just depend on the anti-drain-back valve in the filter. This also allows for cleaner used filter removal, plus I want to completely pre-fill a new oil filter before screwing it on as lubrication to the rocker gear is after the filter (see oil line diagram). (In this case, these last two reasons for the “filter pointing down” design really don’t apply since the filter mount and filter are disassembled/assembled off the bike.)

8) Be hidden from view as my bike is stock and I want to keep that look.

I was able to meet all my design criteria and the oil filter adds another 3/8 of a quart to the oil capacity, which is a “plus” in my opinion.

As noted above, for quick reference I’ve included a sketch showing the motorcycle’s engine oil lines and the location of the oil filter.

As the one picture shows, the filter mount/oil filter is hidden behind the left panel/toolbox, under the battery tray, in front of the rear fender and is attached to the motorcycle’s main frame tube. While the mounting method is not a particularly elegant design, it provides a very secure vibration-resistant mounting, is out of sight so as not to detract from the original looks of the motorcycle, and yet is easily serviceable by simply removing the motorcycle’s left panel/toolbox. Perhaps some clever person can come up with a filter mounting design which directly clamps to the motorcycle frame tube so that it stays in place and the filter is simply spun off (hint, hint). (Maybe somebody already has and, since I haven’t been searching, don’t know about it.)

Below is a list of the parts used along with notes. It’s been a few years, so hopefully the list is complete and the notes are thorough and helpful.



PARTS LIST, WITH NOTES:

12” x 12” x 1/8” thick sheet of black Nitrile (also known as NBR rubber and Buna-N), cut down to size.

Black zip ties. For securing the Nitrile sheet to the motorcycle frame tube.

Norton Commando 750 850 spin-on oil filter mount. Available from The Bonneville Shop, PN# 06-3139, as well as from other sources. This item is also sold with a filter included, but if you are going to use the oil filter adapter (see next item below) this is NOT the filter you want. I recommend taking some fine sandpaper to remove the black finish from the raised “IN” and “OUT” markings to make them much more obvious.

Oil filter adapter. Available from Colorado Norton Works, SKU #0500-01. An oil filter is included with the adapter. (You may need to search around on their site, this item does not seem to readily pop up even with the part number.) This converts the oil filter mount from 16 mm x 1.5 thread pitch to 20 mm x 1.5 which allows for use of more readily available and less expensive oil filters in the U.S.A., and I recommend using it. If you live elsewhere, you’ll have to determine whether it makes sense to change the thread size or not. If unsure, you can always decide to add the adapter later.

High strength thread locker. For securing the oil filter adapter to the oil filter mount.

5/16” I.D. hose. Length as needed. This is the standard size for the motorcycle’s oil lines.

3/8” I.D. hose. Length: 3 inches. The connections on the oil filter mount are 3/8” hose.

Brass 90-degree barbed elbow, 5/16” hose to 3/8” hose. Qty: 2. I reduced the length of the 3/8” barb (and carefully smoothed where I cut) in order to get maximum clearance from the left air filter. While I wanted to keep the 3/8” hoses as short as practical, I made sure that each 3/8” barb had a small amount of distance from its corresponding oil filter mount hose tube so there would be no metal-to-metal rubbing. I did NOT want to shorten the smooth hose tubes on the filter mount and there was no reason to. Both of my 3/8” hose lengths ended up being precisely 1 ½” long.

Crimp-style & screw-type clamps for 5/16” I.D. hose (9/16” O.D.). Qty: As needed.

Crimp-style clamps for 3/8” I.D. hose (5/8” O.D.). Qty: 2. Use on the 3/8” side of brass barbed elbow.

Screw-type clamps for 3/8” I.D. hose (5/8” O.D.). Qty: 2. Use these where the oil line hoses connect directly to the tubes on the oil filter mount. This is where you remove the hose connections in order to remove the engine oil filter along with the filter mount to change the filter. I very much recommend using crimp-style hose connectors in the other areas near the filter mount (see picture) so that it’s totally obvious which hose connections to remove. The hose connections on the oil filter mount are smooth (as noted earlier) whereas the other nearby connections are barbed.

Approx. 4” dia. stainless steel hose clamps. Qty: 2. Trimmed to length for a cleaner looking installation. Smooth the trimmed ends.

“IN” and “OUT” labels for hoses connecting to the oil filter mount. Homemade. This keeps the hose connections identified to help prevent accidental swapping.

Oil filter mount holding tool with (2) 5/16” x 24 tpi bolts, see picture. I made the tool from material I had on hand. After the oil filter/filter mount is removed from the motorcycle, this tool is used to hold the filter mount for unscrewing the old oil filter and installing a new filter.

Label for inside of left panel/toolbox. Homemade, see picture. Please note that this filter information is based on using the filter adapter. While this label is certainly not necessary, for me it provides a quick reference when I go to change the oil and filter. In any case, keep your filter information handy – it’s not a simple look-up in the operator’s manual or filter catalog, obviously.



So, there it is. Hopefully others will adopt this engine oil filtration method and prevent further unnecessary engine wear on their classic Triumph motorcycles. I know I feel a whole lot better having this installed on my old ’68 Bonneville.

 

Thanks Iron, Sandi and Eldon for the warm welcomes and for the nice compliments regarding my first post. To answer Eldon’s question, the ’68 T120R is my only motorcycle.