[thoresonr]

I recently purchased a pretty nice 77 Bonnie but I had some questions that I cant quite figure out. Previous owner was using Valvoline VR1 20W-50 in the grey bottle. He said "his builder recommends it" but I'm getting mixed reviews about using it. I have some Castrol Actevo 4T 20W-50 (semi syn) I could swap in. From what he said the oil only has 500 miles on it. I had a good ride on it after I bought it (about an hour at highway speeds) and the case, rocker boxes, around the jugs at the bottom were weeping. Not a terrible amount. Oil was at Max when I checked it and was just below the MAX when parked.
I've read that VR1 can/wont cause clutch slipping (I haven't experienced any). I've also been reading through where not to drain the crankcase (or primary case?) because the oil pump could potentially cause it to wet sump...
Mind is not made up on if to do a Norton remote filter or the internal to the sump filter with a BSA cartridge... I'd love to hear pros and cons for either if you got the time.

It has the earlier style battery covers (the shorter ones) and the Amal's are running pod filters (ugly to me) and I think the pancake filters would look better but do I get the ones that are offset or centered? I coulda sworn I read the offset ones were for monobloc's and centered were for Concentric Amal's but centered inlet filters seem like they would hit my legs with the carby's being splayed as it is.

It has repo early Smith's gauges (doesnt say Smiths on them) and they look good (no trip reset-or it's missing at least) but I'm really fond of the Smiths NVT arrow ones. Better mirrors would be nice too, as well as football grips.

 

[StuartMac]

Hi,

Firstly, welcome to CVV.

recently purchased a pretty nice 77 Bonnie

had a good ride on it after I bought it (about an hour at highway speeds) and the case, rocker boxes, around the jugs at the bottom were weeping.

clutch slipping
Valvoline VR1 20W-50
Castrol Actevo 4T 20W-50

If you intend to change oil brands, always check the packaging of the intended new oil for "JASO MA2" in the list of specs. it meets - that's the one that says the oil lacks the additives that can promote clutch slipping.

been reading through where not to drain the crankcase (or primary case?) because the oil pump could potentially cause it to wet sump.

We-el-ll ... The potential problem is owners who don't clean the outside of the drain plug and the crankcase around it before removing the plug can potentially introduce grit into the sump when they replace the plug; if the grit then gets sucked into the scavenge side of the pump, it prevents the pump scavenging the crankcase = "wet-sumping".

Norton remote filter or the internal to the sump filter with a BSA cartridge.

Never heard of "internal to the sump filter with a BSA cartridge"? The sump filter is small, the "sump" (crankcase below the crank throws) is small because it wasn't ever intended to contain much oil.

Aftermarket oil filters fit in one of two positions in the oil circulation system:-

. Between engine and frame, in the return line - in the event of a blow-up, they prevent debris reaching the frame. Examples of this type are:-

.. the spin-on canister types, similar to car oil filters ("Norton remote filter" is perhaps this type?);

.. contributor Dave Madigan (@DMadigan) has posted photos. of a couple of plate variations he makes - OIF AN Filter Base Plate and View attachment 773979 - he uses the HF116 filter element;

.. filter containers that use the Triumph Trident/BSA Rocket 3 filter element (e.g. https://www.tricor-andy.com/product/oil-filter-kit-t120-140-a65-oil-in-frame-fits-on-return-oil/ - mounts above the swinging arm pivot on an OIF - MAP in St. Pete sell a similar kit).

. Between frame and engine - prevents debris in the frame reaching the engine. OIF, these fit in the bottom of the frame tube; Tricor Andy does one of these too - https://www.tricor-andy.com/product/oil-in-frame-sump-filter-kit-paper-element/ but there are also a number of other suppliers.

has repo early Smith's gauges (doesnt say Smiths on them) and they look good (no trip reset-or it's missing

Uh-uh, it's been broken off. The repop speedo. trip reset isn't removeable (unlike original Smiths speedos.), takes some wrangling to get it into the rubber cup but it's do-able.

fond of the Smiths NVT arrow ones.

They come up on Ebay from time to time, look out for US seller "Dotler". Can't recall ever seeing repops with the NVT "wiggly worm" logo, probably because it was trade-marked and the current owner either wants too much money or has refused permission.

Better mirrors

Several posters satisfied with standard Hardly mirrors from Ebay - apparently many new Hardly owners, despite their new bikes being supplied with mirrors, feel the need to give Hardly more money for different mirrors and then sell the originals?

football grips

Depends what you mean ... If you mean the 'standard' "Gran Turismo" grips Triumph fitted '69-on, be careful what you wish for ... there are two types, neither of which is exactly what Triumph fitted, each has their own gotcha:-

1970'sTRIUMPH NORTON BSA 7/8" GRAN TURISMO NAVA TYPE HANDLEBAR GRIPS PN# 97-2125 97-2142

1970s Triumph Norton BSA 7/8" Gran Turismo Nava Type Handlebar Grips (2) PN# 97-2125 97-2142

www.thebonnevilleshop.com

... these are about 1/4" shorter than the originals so, unless you shorten the throttle drum, there's that size of gap between the widest part of the grip and the throttle housing. Note I'm not picking on TBS, they're the same from any spares dealer.

"Beston" grips also from many spares dealers. These are about 1/4" longer than the originals, so the grip overhangs the throttle drum by that much. They're nice soft rubber, which creates lots of drag on the bit of exposed handlebar under that longer bit of the grip ...

Fwiw, having dragged through the above about eight years ago, I used the shorter ones on my Triumphs - having shortened pattern throttle drums to suit - Bestons on my Japanese bikes, which have the throttle-drum length to suit ...

Hth.

Regards,

 

[thoresonr]

Hi,

Firstly, welcome to CVV.








If you intend to change oil brands, always check the packaging of the intended new oil for "JASO MA2" in the list of specs. it meets - that's the one that says the oil lacks the additives that can promote clutch slipping.


We-el-ll ... The potential problem is owners who don't clean the outside of the drain plug and the crankcase around it before removing the plug can potentially introduce grit into the sump when they replace the plug; if the grit then gets sucked into the scavenge side of the pump, it prevents the pump scavenging the crankcase = "wet-sumping".


Never heard of "internal to the sump filter with a BSA cartridge"? The sump filter is small, the "sump" (crankcase below the crank throws) is small because it wasn't ever intended to contain much oil.

Aftermarket oil filters fit in one of two positions in the oil circulation system:-

. Between engine and frame, in the return line - in the event of a blow-up, they prevent debris reaching the frame. Examples of this type are:-

.. the spin-on canister types, similar to car oil filters ("Norton remote filter" is perhaps this type?);

.. contributor Dave Madigan (@DMadigan) has posted photos. of a couple of plate variations he makes - OIF AN Filter Base Plate and View attachment 773979 - he uses the HF116 filter element;

.. filter containers that use the Triumph Trident/BSA Rocket 3 filter element (e.g. https://www.tricor-andy.com/product/oil-filter-kit-t120-140-a65-oil-in-frame-fits-on-return-oil/ - mounts above the swinging arm pivot on an OIF - MAP in St. Pete sell a similar kit).

. Between frame and engine - prevents debris in the frame reaching the engine. OIF, these fit in the bottom of the frame tube; Tricor Andy does one of these too - https://www.tricor-andy.com/product/oil-in-frame-sump-filter-kit-paper-element/ but there are also a number of other suppliers.


Uh-uh, it's been broken off. The repop speedo. trip reset isn't removeable (unlike original Smiths speedos.), takes some wrangling to get it into the rubber cup but it's do-able.


They come up on Ebay from time to time, look out for US seller "Dotler". Can't recall ever seeing repops with the NVT "wiggly worm" logo, probably because it was trade-marked and the current owner either wants too much money or has refused permission.


Several posters satisfied with standard Hardly mirrors from Ebay - apparently many new Hardly owners, despite their new bikes being supplied with mirrors, feel the need to give Hardly more money for different mirrors and then sell the originals?


Depends what you mean ... If you mean the 'standard' "Gran Turismo" grips Triumph fitted '69-on, be careful what you wish for ... there are two types, neither of which is exactly what Triumph fitted, each has their own gotcha:-

1970'sTRIUMPH NORTON BSA 7/8" GRAN TURISMO NAVA TYPE HANDLEBAR GRIPS PN# 97-2125 97-2142

1970s Triumph Norton BSA 7/8" Gran Turismo Nava Type Handlebar Grips (2) PN# 97-2125 97-2142

www.thebonnevilleshop.com

... these are about 1/4" shorter than the originals so, unless you shorten the throttle drum, there's that size of gap between the widest part of the grip and the throttle housing. Note I'm not picking on TBS, they're the same from any spares dealer.

"Beston" grips also from many spares dealers. These are about 1/4" longer than the originals, so the grip overhangs the throttle drum by that much. They're nice soft rubber, which creates lots of drag on the bit of exposed handlebar under that longer bit of the grip ...

Fwiw, having dragged through the above about eight years ago, I used the shorter ones on my Triumphs - having shortened pattern throttle drums to suit - Bestons on my Japanese bikes, which have the throttle-drum length to suit ...

Hth.

Regards,

Thanks for your reply! I called them "football grips" as that's what I read they were called. More like American football shaped really. The ones on the bike currently aren't uncomfortable per se but without gloves on they rub off in the hand.

As far as the oil filters, the first one you linked I've never seen before! It was a Norton "spin on filter" for a 850 Commando. As for the second link, yes-that's the sump filter i've seen.

The Actevo oil I have on hand is JASO MA2.

 

[StuartMac]

Hi,

oil filters, the first one you linked I've never seen before

Fwiw, I've had Tricor Andy's "Pre-OIF" version on my T100 for years. I picked it because I also then had a couple of triples so having all Triumphs using the same filter element was a consideration.

As for the second link, yes-that's the sump filter i've seen.

I see where the confusion arises - it's referred to as a "sump filter" although it fits in the bottom of the OIF frame tube 'tank'.

BSA fitted the element to its singles '71-on, but also in a separate container; the 250 was also badged as a Triumph.

Btw, I've edited my previous post to include the return-line filter canister by Forum contributor @DMadigan Dave, that uses a Honda dirt-bike filter.

Hth.

Regards,

 

[rambo]

I have used VR1 oil. It has a lot of zinc in the formulation and is primarily for rally car use. It is a race oil as marked on the can. I had no clutch slip at all so run it until you need a change. You would possibly be better with a 20/50 V-twin oil designed for air cooled bikes. Your many oil leaks might suggest the engine build is not all that good but run it around to see where it is coming from. Might only be pushrod tube seal leaks.
Its not a bad looking modified bike done to the former owners ideas.

 

[tridentt150v]

The Charlies filter kit used a B33 filter........maybe thats the BSA 'sump filter' you mean?

 

[thoresonr]

That’s the one I’ve seen

 

[tridentt150v]

Yep, but you need the mounting kit for it, Generally it comes with another sump plate, a long stud mounted in the centre of the plate and a top and bottom filter disc. Like this:

Note that Motoashop also do this kit......this is actually a pic of theirs. Not even sure if Charlies is around any more, he was selling them more than 20 years ago, and the kit was always known as a Charlies kit.

I run one on my T140.

 

[TR7RVMan]

Hi thoresonr, The above is Motato filter. A nice filter. The drain plug will hit center stand. Allen head drain plug can be found which clears, but then fins will hit center stand. File to clear. A nice filter once you modify it to clear. Yes takes BSA filter. I currently have Motoa on my '73 Tiger. Modified to work perfectly.

Charlies filter is similar. Actually Charlie developed it from modified original plate. Now others have reproduced it with a dedicated casting. It hits center stand also. The acorn nut is too long. It must be replaced with a thin lock nut & the threads sealed. End of day takes less modification that Motao, but casting is a little flimsier. Not really a problem though. The "Charlies" & Motao take exact same filter. Placing a rare earth washer shaped magnet under top not works really well. Use nylock for top nut on either Charlies or Motao.

Truth be told even with filter the frame bottom collects sludge. So, if you use Norton spin on or Tricor filter in return line you should still pull frame sump plate & clean screen. If you use Charlies or Motao you will pull sump plate to change filter. Screen is not used. So really if you use the filter inside the frame it's a good thing. Plus you are sucking oil through filter before it enters oil, so particulates inside frame will be trapped by filter. Plus you don't have to mount an outside filter or add the hoses required for that. I feel the in frame filter is best choice. The frame of '71&72 bikes is different. It has oil pipe inside frame that prevents use of the in frame filter. But '73 on, the in frame filter is the filter of choice in my mind.

The actual filter paper is similar in the in frame, spin on, Tricor, so that's not a factor in filter choice. The filters are all similar in price. About $10-11US.

First photo shows what a good job the in frame filter does. (The other ones clean well too though).

Here's exploded view of the Charlies & Motao.

End of day my opinion is Motao has a much stiffer plate. It is less prone to leaking/seeping. Much more work to properly fit. Charlies version is still a good filter. Much easier to modify. If you use plenty of red loctite or better yet Loctite 574 it will not leak at stem. The modification is basically just getting rid of acorn nut. But this brings on bad leaks if not properly sealed. I've fitted both brands.
Don

 

[TR7RVMan]

Hi All, Think the filter doesn't actually clean that well? Here's T140 sump plate that had the later screen with anti sludge band fitted. 1500 miles on oil. I've seen this many times. The in frame paper filters work! I get mine from Motao. They are glued together better that some other brands. Same price.

Compare with last post using filter to the screen in these photos. Sludge passes right through screen!

Oh, one more thing. Never ever use 3 bond on the sump plate gaskets! Talk about a fight to get screen out. Hylomar Blue is a good sealant for sump plate.
Don

 

[tridentt150v]

As I said, I have a Charlies and never ever had an issue........no leaks and all I've ever used was the gaskets installed dry. And the centrestand doesn't hit at all....never did. So TR7RVMan I guess the issues you had aren't endemic.

 

[StuartMac]

Hi,

The Charlies filter kit used a B33 filter

"Charlies" was the long-time Bristol Triumph dealer. When owner Reg Hall developed his 'kit' for the OIF 650 and 750 twins, he used filter part number 99-1179.

First use I can find of 99-1179 is on the '71 Triumph and BSA 250 singles. @DAVE M has previously posted a photo. of a B40WD (i.e. armed forces version of the pre-'71 BSA 350 single) with a similar-looking filter container. I'm not able to find use of 99-1179 on pre-unit BSA singles (but that might be because I'm not looking in the right place?).

you need the mounting kit for it

E.g. also the previously-linked https://www.tricor-andy.com/product/oil-in-frame-sump-filter-kit-paper-element/

The above is Motato filter.

Uh-uh, it's the Motao filter - TRIUMPH OIL FILTER KIT OIL IN FRAME BONNEVILLE 650 T120 750 T140 TR7 BILLET CNC

Charlies filter is similar. Actually Charlie developed it

"Charlie" didn't "develop" anything ... What's now become the generic name for all the inlet filters that fit in the OIF stems from the long-time Triumph dealer in Bristol (England), "Charlies of Bristol".

Hth.

Regards,

 

[TR7RVMan]

Hi thoresonr, Nice bike! Somebody put some time into it. '77 is a good year.

Mirrors is a personal preference. Whatever you feel gives you safest rear vision. I prefer the old school big round ones on long stalks. They would look out of place on your bike. Again whatever you feel is best. No question good rear vision is a large safety issue. Even that is personal preference. Safe is in modern car!

Regarding oil, I use Mobil1 V-twin 20-50. Many of my local friends use it. Works good for us. Any of the quality motorcycle oils are fine. 20-50 is weight of choice.

Regarding leaks, British bikes have a deserved reputation for leaks. However a T140 can be assembled to be basically bone dry for 5-7 or so years. They really can & synthetic oil won't leak on them either. We've proved that long term over several thousand miles. But the push rod tube seals have a service life of only about 5-7 years with viton seals. A few years tops without viton seals.

Specifically, tighten your cyl base nuts pretty darn tight. Then clean area well. See what's leaking. If it's just nuts, trust me they can be very successfully resealed with loctite 574. I've done this on many bikes. Haven't failed yet. But if base gasket still leaks after tightening nuts, it will need to be replaced. Using 574 on base gasket will insure no leaks/seeps, but... you must reseal 4 inner stud bottoms as well. Also base gasket must be fit tension free without binding on cyl spigots or any of the studs or oil feed dowel.

Retorque cly head. Adjust valves after tightening base gasket & head torque.

Use Hylomar blue on both sides of valve cover gaskets. Hylomar allows easy removal of gaskets later.

Same with primary cover gasket. Must not bind on any screw shanks. Elongate holes as needed. Use Hylomar blue on both sides of gasket.

If your oil is from push rod tubes you must reseal them. Use viton orings only. I've stuck a strip of black t-shirt behind PRT until I got around to fixing leaks. Change it as needed. There is orings on tappet blocks where they go into cyl. base. The intake seldom leaks. The exhaust tappet block has full oil pressure around it. If oring hardens or cracks it can leak very bad. A cup a mile in some cases! Again viton orings only. Rocker shaft orings can leak, yes, viton only.

One of the root causes of leaks/seeps is not flat gasket surfaces. All mating surfaces must be checked. You can offer up covers, housings & use feeler gauges. Try for .0005 or less gaps. Warped covers, especially rocker boxes will usually seep. 574 on covseal gaskets for rocker boxes works quite well to stop seeps. Many studs go into oil space, so oil seeps out threads. 574 on threads is good choice.

The first part of stopping leaks is accurate diagnosis of where leak is coming from. Wind while riding blows oil in the oddest directions. Not just backwards.

Regarding air filters, do search & look over Vstevens posts. He fitted the old version chrome filters. Do not use paper element filters. Only use original wire/gauze type. Paper filters can modify mixture in odd ways that can be very hard to tune around. The good wire/gauze are still made by CAW in UK. They made them for Triumph factory. Still made! Clearance to fuel taps can be a problem. Various taps & elbows will allow them to fit. I'm not a fan of the cone filters you have now.

Chain guard might be good idea. Just in case.... These bikes are not prone to breaking chains, but you never know & it somewhat contains the fling off of chain lube.

Oil level on these bikes is not straight forward.... From cold in garage to after 50 mile ride on 100f day oil will expand about 1". City riding will put more oil in primary case. Freeway riding removes oil from primary case. The primary is "self leveling". Bu the level is variable. The primary oil circulates with motor oil via the left main bearing & 3 tiny holes. Any change in oil level in primary the oil will be seen in frame oil level. So it takes some miles & observation to really determine oil consumption unless it's pretty bad.

This is important! The fill amount of empty primary is only 150cc!! You put 200-350cc in primary case. The extra will end up in frame! Doesn't take much extra & you remove filler cap to check oil & it overflows. If you stick a 1/4" wood dowel or screw drive down filler hole behind chain, reach to bottom & pull it out. Normal oil depth in primary is about 1/2" with bike level. Again it will vary. Over fill comes into tank in about 10 miles ish. Under fill takes 15-20 miles to level. So if in doubt think about using a "dip stick" & look for about 1/2" as "normal average".

Well assembled & maintained these bikes are very reliable & pretty trouble free. My local friends & I ride these all over northern California. Far from cell service. They really can be quite reliable. Where are you located?
Don

 

[TR7RVMan]

Hi, Tricor Andy's filter is same casting as the filter Classic British Spares is selling. That casting is the same all the sellers are using. It differs from a factory plate, but having a cast on nipple for the 3/8 feed hose. Meaning plate & nipple are same casting. The nipple is quite sharp on some & should be smoothed before use. Motao screw in feed pipe is quite sharp as well. This can peel rubber which ends up in pump or tends to seep. The original Triumph sump plates have nice smooth steel pipe inserted into the casting. Apparently the original Charlies were made from original sump plates. I've never seen one in person or photos. I've seen several the Charlies type with oil feed as part of the aluminum casting. Lots of people use these to good results. Thing is once you modify the filter if/as needed, it's good to go forever. Now you just remove the 4 nuts, swing out filter with feed hose connected. Counter hold filter top plate with large pliers as this prevents stem from unscrewing (yes even if loctited). Then remove lock nut from top. Spin off top plate. Remove filter. Wipe off bottom plate with lint free cloth & parts wash or the like. Clean gasket surfaces. Install new filter. Spinning filter will snug top plate. Then snug lock nut to top plate. Install gasket & bolt it up.

The Motao filter has an oring on bottom plate. This is very prone to popping out. I don't use the oring. They came out with modified plate & oring. Not really any better. The plate fits perfectly flat so no real need for the oring. The filter itself has 2 large flat rubber seals glued to it. I've never had problems with them or seen them come loose.

There is more to the Charlies type filter than drilling hole in base & sticking in a stud. You need the bottom adaptor plate for filter to nest into.

Filter hitting center stand is bike to bike. Every bike I've seen either Charlies or Motao filter fitted the stand hit the acorn nut or drain plug. 3 friends said it didn't. When they checked, it hit. The 4th friend's didn't hit. The exhaust was modified & the center stand was using exhaust pipe for a stop.

To be fair to Motao though, they recommend you put oil feed hose facing rear wheel. Then run long hose from rear around up over crossmember of frame to steel feed pipe. That's just stupid!! All's they had to do is offset the drain plug. I install with feed pipe facing front. Then stand hits. On an aside, throw the rubber orings in kit in trash & only use copper rings. The orings have no area to nest it. They will eventually fail & you'll loose oil. Either motor will run out of oil or the oil soaked rear wheel will throw you in a turn. Either way you lose.
Don

 

[TR7RVMan]

Hi Tridentman, Good you stand doesn't hit. What year bike do you have? I've not been that fortunate on any I've installed. My personal experience is two '73s, '76, 77. My friends have '78 & 79. It seems these bikes all had original stands.

The gaskets I get from Rabers, Bonneville Shop, British only, & a few other places when installed dry don't leak too much. But... they stick very tightly to the surfaces which means scraping with razor blade. I then started greasing them to prevent sticking. Then they tended to seep, fairly bad.

My frame is not perfectly flat on bottom. I've seen this not flat on many bikes. So I started using Hylomar from Rambo's recommendation. Stopped the seeping & allows easy removal. Just pull down hard on plate with fingers or a screw driver, but no prying. A quick shot of parts wash dissolves the Hylomar & wipe dry with rag.

Scraping the gaskets installed dry would take 30 minutes with a razor blade.

I've tried to flatten bottom of frame 3 times. I think I made it worse each time! I finally used bluing on the sump plate. Scraped & filed sump plate to conform to frame bottom. Sounds wrong & stupid, but actually worked good. I did this to friend's bike also. If I had frame upside down I could remove studs & file it flat. Laying under bike with studs out, I cannot! I've tried emery cloth on a steel plate. No help. The weld bead is very hard. The rest is very soft. A thick oring would be ideal. I'd like to cut groove for oring in plate, but the plate is so thin I don't think it'd take the pressure of ring without warping. So normal gasket with Hylomar is what I've been successful with before & after the scraping.
Don

 

[thoresonr]

Just to keep you all updated (vs starting a new thread). I ordered the CBS oil filter kit, just waiting for a time to add it. The chain guard is still off and after reading another thread (76 t140v thread) I currently have mounted Avon Roadrider tires in the 4.00 x 18. Im guessing the PO couldnt fit the chain guard as it would likely rub. As it sits just looking at the bike the chain seems very close to the tire, and it chain guard mind need some trimming (it's also powdercoated black like the frame) so not sure if I wanna trim it up (probably should if chain guards are easy to find).

I've ordered a grab bar from a UK supplier so I'm just waiting for the Post to deliver it. It was a nice cool 65F today so I went out for a 1.5hr ride. The front brake grabs but the lever slowly pulls all the way in. I've downloaded the AP Racing PDF (from the same 76 t140 thread) and haven't yet tried to bleed it but I do have a vacuum bleeder. Would that work in this application? The Master cylinder I was told was newer.

Ive fitted some bar end mirrors and I'm quite happy with them. The only other thing I noticed today during my ride was some slight popping getting off the throttle out of the right side silencer. I'm assuming that means it's a bit lean on that side? Looking for a good video or book on tuning Amal 930 carbs.

 

[thoresonr]

One thing that does get me is the speedometer cable. I greased it and it works but if I really hammer on the throttle the speedo stops reading all together until I ease up on the throttle and it catches up to my current speed.

Can the cable unravel itself due to torque? It does look like a long coiled spring. That’s my thought anyway. It unravels and then the cable catches up with itself when I ease up on the throttle.

 

[tridentt150v]

Nah, probably means your worm drive ring or the spindle drive is worn and skipping.......you will need to remove, clean, and inspect. Undo the rear axle, slide it out, drop the wheel to the side, then the speedo box can be removed. Solution is a new drive.
Other possibles are the cable is broken and so only catches/works at low speed, hence a new cable. Or your speedo gauge is worn - most Instrument/gauge shops can fix it. But my money is on the speedo drive.

 

[thoresonr]

Nah, probably means your worm drive ring or the spindle drive is worn and skipping.......you will need to remove, clean, and inspect. Undo the rear axle, slide it out, drop the wheel to the side, then the speedo box can be removed. Solution is a new drive.
Other possibles are the cable is broken and so only catches/works at low speed, hence a new cable. Or your speedo gauge is worn - most Instrument/gauge shops can fix it. But my money is on the speedo drive.

I’ve pulled the cable completely out and it was bone dry before I applied grease. I’ll look into a new drive and cable as well. Speedo is aftermarket and but no telling how accurate or well made it is.

Current setup.

 

[Mick Barratt]

Just to keep you all updated (vs starting a new thread). I ordered the CBS oil filter kit, just waiting for a time to add it. The chain guard is still off and after reading another thread (76 t140v thread) I currently have mounted Avon Roadrider tires in the 4.00 x 18. Im guessing the PO couldnt fit the chain guard as it would likely rub. As it sits just looking at the bike the chain seems very close to the tire, and it chain guard mind need some trimming (it's also powdercoated black like the frame) so not sure if I wanna trim it up (probably should if chain guards are easy to find).

I've ordered a grab bar from a UK supplier so I'm just waiting for the Post to deliver it. It was a nice cool 65F today so I went out for a 1.5hr ride. The front brake grabs but the lever slowly pulls all the way in. I've downloaded the AP Racing PDF (from the same 76 t140 thread) and haven't yet tried to bleed it but I do have a vacuum bleeder. Would that work in this application? The Master cylinder I was told was newer.

Ive fitted some bar end mirrors and I'm quite happy with them. The only other thing I noticed today during my ride was some slight popping getting off the throttle out of the right side silencer. I'm assuming that means it's a bit lean on that side? Looking for a good video or book on tuning Amal 930 carbs.

The popping is much more likely to be an air leak at the exhaust into the head.