Featured Engine Oil Filter Design, Pre-oif (rev'd Filter Specs)

Discussion in 'Vintage Classics' started by Kraig, Jun 4, 2022.

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  1. Kraig

    Kraig Well-Known Member

    Jun 4, 2022
    Webster, NY

    IMG_3237.jpg IMG_3240.jpg

    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.


    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.
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  2. Iron

    Iron Elite Member

    Dec 29, 2021
    Bob Ross Studios
    Welcome Kraig.
    A really informative first post. Looks a really good job. Thanks :)
    • Agree Agree x 5
  3. Sandi T

    Sandi T It's ride o'clock somewhere!

    Dec 3, 2018
    Tucson Arizona
    As @Iron said, a really informative first post, @Kraig. I think you win the award (if there was one) for best New Member First Post. ;):) I hope you stick around and share more of your knowledge with us here on the forum. Thanks!

    TTF welcome.png
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  4. Eldon

    Eldon Elite Member

    Nov 14, 2018
    North Yorkshire
    Welcome, nice first post with a helpful well thought out solution which makes a pleasant change to the " I have a problem, can someone help" intros that some others post and then disappear once resolved.
    Hopefully you'll hang around, have you any other bikes or just the one?
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  5. Kraig

    Kraig Well-Known Member

    Jun 4, 2022
    Webster, NY
    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.
    • Like Like x 2
  6. Pegscraper

    Pegscraper Elite Member

    Jun 12, 2020
    Welcome. I'm not that interested in the old classic Triumphs TBH but a very useful and I would say essential mod for enthusiast owners. I could never understand why bikes of the era ran such poor oil filtration and often no air filtration at all! Crazy.
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  7. Vulpes

    Vulpes Confused Member

    Mar 14, 2018
    Hi and welcome. Great first post.
    • Agree Agree x 2
  8. Markus

    Markus Crème de la Crème

    Oct 28, 2020
    Wow! What an interesting first post! Hi there and welcome to the forum!
  9. capt

    capt Elite Member

    May 8, 2016
    western Australia
    I did something similar on a BSA M20 , I used the fuel filter setup from early Landrover's , they had a fuel filter which was a small housing with a paper cartridge inside.
    I put a tap inline to stop wet sumping too. The filter fitted under the oil tank.
  10. Kraig

    Kraig Well-Known Member

    Jun 4, 2022
    Webster, NY
    Hi everyone, I’ve just realized that there are 2 errors in my post. My preference would be to revise the posting but I don’t see a way to do that, so I’ll just do a reply to my own post, and it looks like I can change the name of my post so I’ll try to add “(Rev’d Filter Specs)” at the end of the post title.

    First, I misidentified the filter screw thread that results when using the Oil Filter Adapter. This error shows up in the text and in the picture of the filter information label that’s inside of left panel/toolbox. The correct information is that it’s a ¾ -16 inch thread.

    Second, the number for the NAPA filter shown on the filter information label was incorrect. The other filter numbers are correct.

    I am posting a new picture showing my revised filter information label. It shows the correct filter screw thread, the correct number for the NAPA filter, plus two more filter brands that can be used.

    My apologies for the errors.

  11. Kraig

    Kraig Well-Known Member

    Jun 4, 2022
    Webster, NY
    Here's a better picture of my revised Filter Information Label. IMG_3444.jpg

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