Triumph Bonneville T140 oil change and fitting a paper oil filter 

Dent Watkins 2 days ago (edited) @Songs From The Saddle , I'm not a great fan of the paper filter on the suction side of the pump. The pumps fitted to Triumphs, whether the original plunger type or the Morgo rotary type, are good for pushing oil round the system but work best with minimal restriction to the pump. They are not designed to suck through a filter, hence the wire mesh strainer. You mentioned somewhere here that there is atmospheric pressure pushing the oil through the filter to the pump but with the filter on the return line it is being pushed through by the scavenge pump which is a much safer option. Another advantage to fitting it on the return is that it takes any suspended particles out of the oil before they get into the rest of the oil system so it keeps the whole system clean. The engine is where those particles are produced so it makes sense to remove them at the earliest opportunity on the way out. The mesh in the bottom of the tank isn't the filter for the oil system, just a strainer or "bolt catcher" for any debris such as paint flakes, wayward springs, small family pets or whatever that might accidentally find its way into the tank. Filtration is carried out by the infamous sludge trap which is actually a very effective centrifugal oil filter. Just have a look inside the crank when the sludge trap tube is being removed for cleaning and you'll easily see how much carbon combustion by product and fine metallic particles it catches. The only problem with it is the fact that it requires a full engine strip to clean it and people are understandably not keen to do that. When the engine was first designed, routine maintenance was an accepted part of ownership but in recent years owners have become used to the longer service intervals with modern foreign machinery and want a similar thing with their Triumphs. If the engine is stripped, the sludge trap removed, cleaned and refitted, then a clean rebuild is carried out (engine, frame tube/tank and hoses spotless) with a spin-on filter fitted in the return line you should be able to keep the oil and the sludge trap clean too. Incidentally, Fiat 126s, those funny little boxy Italian cars made from the early 70s through to 2000, had a similar sized engine and were also fitted with a centrifugal oil filter. Theirs was a lot easier to clean though. It was inside the front pulley on the crankshaft where the fan belt ran and all you had to do to clean it was undo the ring of 6 bolts to remove the cover plate, hook the sludge out with a screwdriver, wash the last bits out with a paint brush/tooth brush (preferably someone else's) and some paraffin and it was time to put the cover back on. A ten minute job and no filters to buy. Easy life!

To complete an engine oil change on a T140, you also need to remove the crankcase drain plug, which incorporates the scavenge pick up strainer, allow it to drain, clean the strainer and refit. Once you have refilled the oil reservoir, you need to start the engine and run at idle until the oil can be seen returning steadily from the pipe inside the filler neck. For the first couple of minutes, the oil level will drop by a couple of inches, until all the oilways in the system are full and it's reached its natural level. Only then can you make a final top up and replace the cap. I installed one of those paper filter conversions on my T140 about 20 years ago, but I took it a stage further: as it is in the suction side of the oil circuit, to be absolutely sure there was enough oil flow through the filter, I modified mine with a longer piece of studding, so that it takes 2 of the elements, stacked one on top of the other. For the extra £10 a year, I think it's worth it for peace of mind. I make my own gaskets, from 1/32" (0.8mm) gasket paper, and fit them with just a smear of grease on both sides, so they won't stick the next time. They have never leaked and all it takes to clean the surfaces is a wipe. The filter elements were originally a BSA part, for the B50, etc. I believe the part number was 19-4589, also 99-1179.

I just went to Amazon and bought a pack of 100 mascara brushes for 5 bucks. Seems better than using my finger to put gasket sealer on. I just got a 78 T140 in a partial trade/sale. Doing some basic work on it, carb cleaning, replacing fuel lines, fluids and the throttle cable.

Perfect! I was just about to do this job on my '79 T140E and whilst I appreciate it shouldin theory be easy, I had a quick look to see if there was a video, just to be sure, and found this! Thanks!

Great video. I've just carried out the same mod to my 78 Bonneville. thanks for posting

Nice job, the fitting of a proper disposable paper oil filter is certainly the number one most worthwhile modification that can be done to most old British bikes. The standard factory design of a simple mesh strainer at the bottom of the oil tank or sump with the oil pickup sitting below the strainer right at the lowest point, just where all the muck and particles are heading as most of it all passes through the mesh strainer, is the worst possible setup regardless of how often the oil is changed. Just because BSA, Triumph and others chose to do it that way doesn't mean it was much good. Personally I prefer the oil filter to be fitted on the oil tank return line, this not only fills the oil tank with effectively filtered oil that protects the feed pump, big ends and any plain type crank bearing used on some old Brit bikes, but it also filters the oil flowing to the rockers which drains onto the cams and followers. Plus the oil is forced through the filter by the scavenge pump. But the paper filter in the bottom of the oil tank that you are using is still a very good established method, and it is the simplest way of improving the oil filtration on a bike such as the T140, I seem to recall these becoming available in the very early 1980's. I would just ensure that the oil does flow freely through the filter, particularly in very cold weather, when the bike is first started. After an oil change there can also be a pocket of air trapped below the filter when the oil tank is refilled, this can also sometimes happen with the standard steel mesh strainer, which causes a slight delay in oil reaching the pump and big ends. After refilling the oil tank I used to remove the drain plug again, and there would often be a short delay as the trapped air escaped before any oil appeared. I bought my first T140 way back in 1983 when just an 18 year old lad, BKW 167T with just 1200 miles on the clock. I made a steel housing to take a small paper oil filter that was used on Suzuki's GS125 model. I plumbed the filter housing into the oil tank return line before the take off point to the rockers, and it was small enough to just fit under a side panel. Breaking open the paper filter element after just 800 miles revealed an alarming amount of particles trapped there, some relatively large, that had all passed straight through the useless standard engine sump strainer. The amount of particles caught in each paper filter decreases over time as more of the crap is removed at oil and filter change and is not left in the system to simply recirculate. Sorry if I have blabbed on a bit too much, but carry on the good work, I've always been a fan of the T140 having owned three over the years, the second was an ex police bike with the AV frame with rubber mounted engine, the last was a nice untouched electric start model JHE 310W. Ah! Fond memories of them all.

I was watching a RU-vid awhile back & it was said that on automobiles at some speeds the oil actual bypasses the filter? I have a 1973 Tiger 750. I put on an Oil cooler years ago. I.use original oil screens & one at bottom of tank has not been removed or cleaned in years. I figure if the oil drains it is ok. I change oil every 1000 miles or before winter storage. I have 63,500 miles & it still runs good.

Nice video! I just put one of these on my '79 T140 and realized that when my centerstand is up it hits the acorn nut in the center of the plate. And it actually smacks it pretty hard when you take the bike off the centerstand, not just a slight rub. Anyone else run into this? Or am I missing a stop for the centerstand that would keep it from hitting? Any suggestions?

They have these great little things these days called "funnels" which are great for pouring liquids like oil and not spilling them all over the place. Go down the hardware shop and get one, you won't regret it!

I thought when you use the old gauze sump you were supposed to use that Golden oil type as it is designed to sludge and drop the impurities into the bottom of the sump. The holes in that gauze were much bigger than the paper filter you have now fitted. That paper filter is designed to run with the best modern oils all of which contain about 20% additives with the paper filter designed to catch the particles. I am not sure it is a good thing to rune the paper filter with that oil as it may completely block up. Your thoughts and anyone else's much appreciated as I have just ordered a paper filter and a modern 10/50 synthetic oil that will reduce wear when starting up.

I just bought a 78 Bonnie this year, had it about five months and recently did this job, just ordinary filter and change, and am interested in doing this change. I've had Triumphs before, but it's been forty years, mine seems to burn a good bit of oil, I'm thinking I might need to re-ring it. I've been i Harleys for fifty years, and that was the usual answer. I reckon I'll have to do it this winter, if I can't come up with a better explanation of oil consumption. I would welcome any comments. I had a 64 TR6R back in the seventies, and it didn't burn much oil at all, not much experience with the 750's.

Why go to paper filter from reusable stock mesh one , what benefits are gained ? New to the English bike scene , i Just won a 1977 Bonneville with 6,000 orig mi , @ Brit jam bike show here in Connecticut two weeks ago & she's a beauty... The best $10 i ever spent lol , winning !

Should this be motorcycle oil due to a wet clutch can cause slipping

How do you feel about this setup vs an external oil filter?

What do you use to seal the drain plug? Fiber washer or O ring?

Oil level needs to be rechecked after running the engine as the new filter will hold oil so level will drop.

Will that oil in frame model still wet sump if you leave it unused for a while ?

Hi...how are you finding the paper filter?..all good?

The only thing is the manufacturer and number on the oil filter. Thank you for the idea 💡 On my 79 T140V.

Hi; so you change that filter every 1500 miles? I have an external filter but I will remove it soon. I almost sized the engine 2 times with these stupid hoses and filter touching the frame. Was a thing from PO. The problem that I see with these others are that I put plenty of kilometers per year on this 79. I use it as a transportation so around 10000km per year or more. I change the oil like manual says so there are like 5 changes per year. Is not good in my book to remove those nuts etc very often. You can let that filter there you can say. I say what is the point to put one if you do that? Filters would be removed every oil change.

Obviously doesn't possess a funnel!