An appetiser, 74 TX650 rebuid.


Well-Known Member
I've done many, many mods to this bike, not much is standard: cooler, spin on filter, single points, permanent magnet alternator, cutch slave cyinder, manifolds, VM carbs, pcake filters, handbeaten side panels, tai ight, battery carrier, hdlight brackets, fue distributer, brake joining block, wiring harss x2, engine brackets, cable splitter, etc,etc, etc. All hand built in my workshop.

This is the cooler/spin on filter conversion I did.

The XS650 has two oil filters, well, strainers really, one in the sump and one in the right side cover. As said, they are strainers rather than filters and as such not particularly good at filtering the oil. The system works thus: There is an oil pump in the right side cover, it draws oil from the sump via a sump strainer, The pump pumps oil up a 10mm hole toward the front of the side cover, the 10mm hole is stoppered at the front of the cover via a 10mm bung. The 10mm hole from the pump is cross drilled from the right side strainer void, so, the oil is pumped through the 10mm hole then off at a right angle via the cross drilling through a strainer contained within the right side cover then on to the engine.

So to fit a remote spin on filter I removed the bung at the front of the side cover, mounted the side cover on the drill press table and angled it so the 10mm hole from the oil pump was vertical. The hole is set at an odd angle on two axis' to the cover, so setting the 10mm hole vertical was a job in itself. Once setup correctly, I drilled the 10mm hole out to 10.8mm then tapped it to M12 x 1.25 for 40mm so passing the cross drilling to the side cover strainer, I then countersunk the top of the hole to allow for an O ring and inserted a stainless spigot I turned up and threaded. This spigot covers the cross drilling leading to the side cover strainer.

Next I binned the side cover strainer cover and machined up a new one, which I think looks a lot better than just screwing a right angle, screw in fitting on the original part. Took a bit of doing this part as the outer side had to be angled to follow the angle of the side cover. Rather than use an ugly screw in fittings, I spun up a stainless barb and shrunk it in place.

Next came the spin on filter mount. I made this from a lump of 25mm ally, machined it to the desired shape, drilled and tapped the side for mounting screws, then mounted it in the lathe to machine the oil gallery recess, once done I drilled a central hole for oil output and a second hole through to the recess for the input. I then spun up a threaded piece on which to spin the filter and pressed it into the housing, turned up a stainless, threaded barb, screwed it into the spin on filter threaded piece, sandwiching the filter mount between. There was insufficient space for a screw in input barb, so I spun up a barb for an interference fit and pressed it into place.

I then fabricated some new engine mounts on which to mount the filter mount and oil cooler. The engine mounts were basically the same as the original ones I made, the right has been extended downward around 25mm for the filter mount and both drilled and tapped at the front edge for mounting a cooler bracket.

The cooler bracket is just a piece of 3mm ally bent at a right angle so the cooler mounts on top. I had to cut some 10mm ally tube to fit between the cooler mounting fins and recess the mounting bracket holes a little so I could install some rubber grommets to insulate the cooler from vibration. To hold it in place I cut some 6mm bolts to size and spun up some threaded positive stop, ally T nuts.
Last of all, I polished everything.

So, the system now works thus: The pump picks up oil from the sump via the sump strainer, pumps oil up the 10mm hole exiting the side cover at the front via the stainless barb. It then travels through a hose to the spin on filter then on to the cooler and then back to the side cover strainer cover via another hose, then into the void where the strainer once sat, then on to the engine.

It was quite a bit of work, but I enjoy working in my workshop, so, nothing is too much work for me.


  • oil cooler and barbs.jpg
    oil cooler and barbs.jpg
    136.3 KB · Views: 11
  • tapping the side cover.jpg
    tapping the side cover.jpg
    166.9 KB · Views: 11
  • remote filter cooler fitted right.jpg
    remote filter cooler fitted right.jpg
    257.4 KB · Views: 10
  • remote filter cooler fitted right 2.jpg
    remote filter cooler fitted right 2.jpg
    214.6 KB · Views: 9
  • remote filter cooler fitted left.jpg
    remote filter cooler fitted left.jpg
    240.2 KB · Views: 8
  • remote filter coller complete top.jpg
    remote filter coller complete top.jpg
    254.9 KB · Views: 8
  • oil inlet cover outer.jpg
    oil inlet cover outer.jpg
    222.1 KB · Views: 8
  • engine mounts oil filter housing complete.jpg
    engine mounts oil filter housing complete.jpg
    176.5 KB · Views: 8
  • oil filter housing inner.jpg
    oil filter housing inner.jpg
    142.4 KB · Views: 9
  • oil filter housing outer.jpg
    oil filter housing outer.jpg
    111.3 KB · Views: 7
  • oil inlet cover inside comparo.jpg
    oil inlet cover inside comparo.jpg
    158.9 KB · Views: 8


Ultra Member
Cool work. Does the cooler have one way/check valve in the line somewhere? And if not is the oil from the cooler a problem when it flows all back down to the crankcase?

I've toyed with adding on an oil cooler to my 250 enduro/trail bike but have decided I need some sort of check valve in it once I determine the direction of flow!


Well-Known Member
Coolers are supposed to be mounted with the inlet/outlet facing up, so avoiding that problem, but some from the hose would find its way down I suppose.
Last edited:


Ultra Member
Coolers are supposed to be mounted with the inlet/outlet facing up, so avoiding that problem, but some from the hose would find its way down I suppose.
Even with inlet/outlet facing up I would think suction and gravity would pull most of the oil out if the cooler on shutdown.


Well-Known Member
Maybe a little suction. But with the inlet/outlet facing up, gravity wouldn'r affect it. Anyway I haven't had any problem, pressure is there from the get go.


Well-Known Member
Here’s a couple of small pancake filters I made. I originally had pods, but the rubber gromet in the pods that fits over the bellmouth is way smaller than the bellmouth, not ideal for air flow,

I cut a 15mm slice off the 101.6mm lump of ally and turned down one end to 97.4mm, then cut a piece of 1.7mm sheet to around 111-mm in diameter, stuck them together and bashed the overhang until there wasn’t one. I have to use my left hand now, as the right elbow complains. Sound easy, but it’s not, out of every 10 strikes, I think I miss about nine.

Once formed, I mounted it in the four jaw, and turned the overhang down to 3mm, then smoothed out all the scratches and what not with sand paper, finishing off with the random orbital sander with 240 grit.
Next, I mounted the 15mm slab in the three jaw using the turned down area and drilled through with a 25mm bit, machined the outer diameter to 101.4mm, machined out the centre leaving a 2mm wide lip on the periphery, 3mm deep, then bored out the 25mm centre hole to 57.3mm to fit the 57.4 mm carb bell mouth.

I flipped the slab over and mounted it in the four jaw again, then spent a couple of hours trying to centre the damn thing, then turned down the inner mounting ring so its 8mm wide and the flat body of the filter 2mm thick. Final step, turn down the inner mounting ring so its 9.8mm deep.

The cutting tool was then centred., spot on, and used to scribe a line across the back of the centre of mounting collar to ensure the holes were central to the 57mm hole. After removing from the chuck, I found the centre point of the collar using a calliper, centre popped it, mounted it on the mill and drilled the centre pops with a 4mm bit and tapped the 4mm holes with a 5mm x .8 tap. The plate was then turned on its side, and drilled and tapped in the centre of the mounting colar at 90degrees to the other two holes on the face. The piece was mounted in the three jaw again and using 240 grit any cutting ridges were smoothed over, then both plates were polished.

The knurled securing nuts were turned up from a piece of 20mm stock, tapped 5mm and then knurled using the scissor knurler I made a while back. These were mostly done by eye, so won’t be absolutely identical. You’d need a calliper to pick up the difference though.

The carb body was mounted in the three jaw and a file used to remove the ridge at the beginning of the bell mouth. The face of the bell mouth was pretty rough, so I took the time to smooth that with some emery. The turned piece was located over the bell mouth, the assembly was then stuck in the vice and pressed into place.

The lead into the bell mouth is flat, so not a perfect shape for induction. I could have recessed the filter collar lower on the bell mouth, creating a bit of a lip on the outer periphery of the bell mouth to improve induction, but realistically the improvement in induction wouldn’t be worth the time.

Both filters fit well and the hoses from the fuel distributor block lead over the filters nice and neatly. Happy with the outcome, except the inner knurled nuts are a little difficult to get to, probably due more to the fact my fingers are fused, but I can turn them with a little bit of messing around. I’ve yet to get some perforated sheet metal to replace the stainless crap I used to keep the foam in place.


  • 1.jpg
    516.3 KB · Views: 7
  • 2.jpg
    203.2 KB · Views: 6
  • 3.jpg
    219.5 KB · Views: 4
  • 4.jpg
    376.3 KB · Views: 4
  • 5.jpg
    616.4 KB · Views: 4
  • 6.jpg
    500.2 KB · Views: 3
  • 10.jpg
    339.9 KB · Views: 3
  • 11.jpg
    375.4 KB · Views: 3
  • 12.jpg
    497.6 KB · Views: 3
  • 13.jpg
    473.8 KB · Views: 4
  • 15.jpg
    371.5 KB · Views: 5
  • 20.jpg
    341.1 KB · Views: 5
  • 25.jpg
    415.1 KB · Views: 6
  • 26.jpg
    377.7 KB · Views: 5
  • 27.jpg
    357.5 KB · Views: 5
  • 28.jpg
    485.1 KB · Views: 6
  • 29 (1).jpg
    29 (1).jpg
    357.9 KB · Views: 6
  • 31.jpg
    401.1 KB · Views: 6
  • 32.jpg
    370.5 KB · Views: 8


Well-Known Member
You've probably noticed the aluminium manifolds on the bike. The bike was fitted with BS38 carbs originally, they are CV type carbs. The diaphragms were holed and as I couldn't get new ones at a reasonable price I opted to replace them with VM34s. The VMs came with manifolds and rubbers, but sited the carbs such that the throttle cables interfered with the petcocks, necessitating leaning the carbs over at an angle. Rather than do that, I machined up a couple of new, longer manifolds that sited the carbs behind the petcocks.

The manifolds were made up of two pieces, the mounting flange and the spigot and then pressed together. I also turned up a couple of brass barbs for use with a manometer I made, and presed them into place.


  • c.jpg
    556.2 KB · Views: 5
  • d.jpg
    575.4 KB · Views: 4
  • e.jpg
    516.6 KB · Views: 3
  • f.jpg
    283.9 KB · Views: 3
  • k.jpg
    362.1 KB · Views: 5
  • WIN_20211224_14_58_32_Pro.jpg
    524.7 KB · Views: 5
  • WIN_20211227_14_31_41_Pro.jpg
    470.8 KB · Views: 5


Well-Known Member
A reed valve engine breather I machined up. Petal was taken from a pit bike read valve and cut in half, two holes drilled and screwed to the base plate. Base plate was tapped M3 10mm deep to take the petal. Not fun tapping this small, but, this time around the tap survived.
Main body was carved out with an endmill to give the petal room to move and air to flow. Base plate has a channel on the engine side for any oil to run down back into the rockers. Topside was channelled either side to get the Allen heads level with the top surface. Stainless Allen's were turned to make them shiny, I do like shiny baubles.
Outlet spigot is 16mm with a 10mm hole. If it's not big enough I can take it out to 12mm later on.
On the pistons downstroke, air from the engine enters the main body of the breather, through the reed valve and is channelled upward, does a U turn and travels downward to the outlet spigot, losing a little oil on the way. Any oil trapped before the reed valve is channelled back to the rockers. The reed allows some air to leak past into the engine on the piston upstroke, thus maintaining a slight negative pressure in the crankcase. The outlet wil be plumbed to the air filter - when I get around to it. In essence, it's just a PCV valve that all modern engines have.


  • WIN_20221003_16_06_39_Pro.jpg
    398.8 KB · Views: 5
  • WIN_20221003_16_08_18_Pro.jpg
    351.3 KB · Views: 4
  • WIN_20221003_16_03_05_Pro.jpg
    812.4 KB · Views: 4
  • WIN_20221003_16_09_04_Pro (1).jpg
    WIN_20221003_16_09_04_Pro (1).jpg
    168 KB · Views: 5
  • WIN_20221011_11_04_46_Pro.jpg
    269 KB · Views: 5
  • WIN_20221011_11_04_56_Pro.jpg
    326 KB · Views: 5
  • WIN_20221011_11_05_05_Pro.jpg
    419.2 KB · Views: 4
  • WIN_20221011_11_03_19_Pro.jpg
    251.4 KB · Views: 4
  • WIN_20221011_11_03_30_Pro.jpg
    264.7 KB · Views: 5
  • WIN_20221011_11_09_37_Scan.jpg
    573.6 KB · Views: 5


Well-Known Member
After converting to VM34s, there was a jumble of hoses, adapters and joiners under the tank, very untidy, so, I made a fuel distributor block that sits under the front lip of the battery carrier I made a while back.

The VM carbs have 8mm fuel inlets and the petcock outlets are 6mm. I chucked a lump of aluminium and turned up an 8mm barb either end, then drilled through to join them up. Two 6mm brass barbs were then turned up and pressed into the front of the distriutor block, they are drilled through and join up with the through hole joining the 8mm barbs.

This has the effect of joining the two sides of the tank, so when the fuel level gets below the tunnel, one carb doesn't run out of fuel and starve.

The original BS38 carbs had the fuel inlets joined by a hose between, thus joining the two side of the tank.

Sure neatens things up: a 6mm hose from each petcock plugs into the two brass barbs on the front of the distributor and the outer two, 8mm barbs connect the distributor to the VM carbs, interupted by a couple of 90 degree filters.


  • WIN_20230111_13_07_02_Pro.jpg
    335.4 KB · Views: 7
  • WIN_20230111_13_07_10_Pro.jpg
    523.3 KB · Views: 6
  • WIN_20230111_13_18_33_Pro.jpg
    681.7 KB · Views: 7
  • WIN_20230122_11_30_28_Pro.jpg
    427.1 KB · Views: 6
  • WIN_20230122_11_31_12_Pro.jpg
    452.7 KB · Views: 6
  • WIN_20230111_13_43_28_Pro.jpg
    370.7 KB · Views: 5


Well-Known Member
Singe point conversion.

I grew up in the 60s riding Brit twins, hated setting the points, a real PITA, So when it came to the TX I had two choices, make a hall effect trigger for the ignition system from parts I had in my electronics collection, or, convert the bike to a single set of points. I much prefer mechanical items to electronic so settled on a single points setup.

There was a cam available for this conversion, but apparently they weren't very accurate and they were withdrawn. So, I decided to make one myself. First order of business was a backing plate which I made from some 3mm thick steel, shaped it on the lathe, filed cut outs for the mounting screws and drilled and tapped the plate for points and lube felt.

I then made up a few timing LEDs: One with a resistor to run off a 9 volt battery, one without running off a button battery and a third with alligator clips and resistor to run off the bike's battery.

Next I turned down some stock to 18mm, bored it 8mm, filed the ramps, then cut the keyway. Nope, timing was way off. Did it this way for a few attempts without luck. So, I decided to do it in reverse: Cut the keyway, mount the round stock on the advance rod, gap the points, time the engine, set the points at the midway position and mark where the heel of the points contacted the round cam and filed the ramp. Success, I managed to get the timing for number one cylinder spot on with the correct dwell after only a few files. Next I rotated the engine 180 degrees and did the same for the other ramp, success again.

For this conversion, the two single outlet coils don't work, so I bought a twin outlet coil for a CB750, made an ally bracket and polished it and mounted it to the original tab on the frame.

I've since removed the original coil mount and welded on a couple of tabs to mount the CB750 coil.
When I got around to starting it up - perfect, bike started up straight away and ran like a beauty!
In the future I may have to make another cam, depending on how this one wears. I'm thinking of bronze as I have a little in my scrap bin.


  • 2points.jpg
    315.2 KB · Views: 6
  • points plate disassembled.jpg
    points plate disassembled.jpg
    794.9 KB · Views: 7
  • points plate assempled.jpg
    points plate assempled.jpg
    576.7 KB · Views: 7
  • points plate fitted.jpg
    points plate fitted.jpg
    402.1 KB · Views: 7
  • 3 timing lights.jpg
    3 timing lights.jpg
    265.7 KB · Views: 5
  • polished points cam on rod.jpg
    polished points cam on rod.jpg
    226.6 KB · Views: 5
  • polished points cam2.jpg
    polished points cam2.jpg
    290.5 KB · Views: 5
  • single points cam.jpg
    single points cam.jpg
    214.3 KB · Views: 6
  • led 1.jpg
    led 1.jpg
    426.2 KB · Views: 6
  • coil bracket and coil and engine mount fitted right side.jpg
    coil bracket and coil and engine mount fitted right side.jpg
    546 KB · Views: 6
  • timed left.jpg
    timed left.jpg
    255.3 KB · Views: 6
  • timed right.jpg
    timed right.jpg
    230.3 KB · Views: 6


Well-Known Member
The original tail light on the TX, like all Jap bike tail lights was massive and just didn't fit in with my build criteria so I decided to make one. I tried bending up a tail light at first but couldn't get the side tabs to mount the light on level, so I welded one up from a number of parts I cut and shaped. Because the tail light bracket was to be polished the bracket had to be made in two sections.
The original mounting hole in the guard had rusting cracks radiating out, so I enlarged the hole to remove them. This left a 48mm hole in the guard for mounting the tail light. To remedy, I inserted a 48mm grommet in the hole and turned up a large aluminium T bush and inserted that in the grommet from underneath. The tail light sits above that and a bolt is inserted from underneath and engages a nut inside the tail light. A hole through the bolt provides cable egress.
To stop the tail light from rotating on the guard I welded a tab to the rego plate bracket and attached that to the lower tail light hole in the guard via a grommet and T nut.
The light itself is an LED and although smaller than the original tail light is much brighter.


  • ally parts.jpg
    ally parts.jpg
    618.4 KB · Views: 4
  • unpolished parts.jpg
    unpolished parts.jpg
    266.9 KB · Views: 3
  • tl5.jpg
    297.5 KB · Views: 3
  • ally side.jpg
    ally side.jpg
    669.2 KB · Views: 3
  • ally mounted 2.jpg
    ally mounted 2.jpg
    258.9 KB · Views: 3
  • ally bung.jpg
    ally bung.jpg
    436.5 KB · Views: 3
  • gromets in guard.jpg
    gromets in guard.jpg
    437 KB · Views: 4


Well-Known Member
The rear brake controls had seen better days, not rusted, but not looking very tired, so, I fabricated/machined some stainles and aluminium goodies to spruce it up a bit.
Yamahas brake anchor and clevis left me totally underwhelmed, so I fabricated an anchor from 10mm aluminium and machined a clevis from stainless. The rod, adjuster and pivot are also turned from stainless. Together with the polished rear wheel, it looks quite 'sanitary'.
The brake lever has since been painted black.


  • 311825052_3387984964794859_8660863492506112213_n.jpg
    130 KB · Views: 7
  • 311829430_3387985011461521_4295905161747681361_n.jpg
    132.9 KB · Views: 5
  • 311924041_3387985084794847_3633466748907459175_n.jpg
    195.9 KB · Views: 5
  • 311914498_3387984928128196_7240297514843683754_n.jpg
    184 KB · Views: 6
  • 311869876_3387985128128176_7735073725385128436_n.jpg
    200.1 KB · Views: 7


Well-Known Member
I think there are some shots of the bike in here somewhere. But here's another couple.


  • WIN_20220412_15_43_49_Pro (1).jpg
    WIN_20220412_15_43_49_Pro (1).jpg
    246.2 KB · Views: 11
  • WIN_20220412_15_44_21_Pro.jpg
    224.5 KB · Views: 11