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Hi there. It is a normal right-hand thread. (Turn the pulley anticlockwise to loosen it while one of your chuck adjusting pins is through the main spindle and holding it to stop that from turning.) I just loosened mine to double check because I haven't had it off for a while (and my memory is terrible). Mine was tight but I managed to undo it simply with a firm handgrip on the pulley sheaves. You may need to use a rag on your sheaves to stop them cutting into your skin if yours is tighter than mine was. Good luck - Tom

Thanks (High praise indeed.)

It's worked out well. I'm still using my Unimat 3 regularly and all the time I have it powered by the scooter motor (so I'm now just holding my original Unimat 3 motor as a spare). 😊

They're certainly far more durable than the original rubber belts. 😊

Gosh. With such little use your DB200 must be in good nick! I use my Unimat 3 roughly once a month but when I'm making a model steam engine it's many hours per day. 😊

Beautiful scenery around there. (My camera is a just a basic car dashcam so you should do a lot better.) I look forward to seeing what you come up with. 😊

I'm glad you found my video useful James. I just searched for information on your particular power supply and downloaded its data sheet. Unfortunately the data sheet shows your power output is rated at only 90W (while the motor you intend to drive with it is rated as 150W). I thought I was cutting it fine by choosing a power supply with a rating of only 200 W but in practice it has never even felt warm so it appears to be ideal. (Some people recommend your power supply has double the rating of whatever you intend driving with it.) 90 W on the other hand I'd say is DEFINITELY too low. Sorry to disappoint you with this bad news.

Many thanks for your reply. It looks as though I will have to buy the power pack that you have used. By the way, I couldn't agree more with your policy of keeping the Unimat as original as possible. All the best and thankyou again Jim Lake

Hi Ian Thanks for your kind words. Unfortunately I bought this Score engine complete with its reversing gear from a second-hand shop many years ago. But having made a number of 10V models and a D10 (that all have similar componentry), I can say that there’s no strict rules as to which sides to have your inlets or exhausts and neither is there a standard direction of rotation for that matter. In fact, I like to vary all these things so I end up with no two models the same. I did however make up the reversing gear for one of my D10 models. It was back in 2022 and I used the latest Stuart drawings that I bought direct from Stuart Models. (These drawings include assembly instructions.) I did however find serious errors in those drawings relating to how the eccentric-pairs should be pinned together (which I alerted Stuart to at the time) and I studied this Score engine in great detail in order to figure out how to get it all correct and working. I’m no genius so without having this Score engine to copy from I doubt I would have succeeded. (Or if I had, it certainly would have been harder and taken longer.) Good luck & best wishes. Tom in New Zealand

Thanks Tony.

Thank you. Unfortunately you won't find many new videos appearing. I'm still enthusiastically working on projects but it takes me a tremendous amount of time to do a video and other things are much more pressing at the moment. 😊

Thanks Philip. I really appreciate you taking the time to comment. I'm in the early learning stage as far as making videos is concerned. Truth is, I hate seeing myself on screen and am not keen on hearing my own voice either. Putting words on the screen seemed the only solution but then I found there was too much I wanted to say here. BTW - I'll be 72 this year so we're around the same age. Wishing you all the best for the new year. PS. You're well ahead of me in being able to design and build your own carbide-tipped cutting tools! That would certainly ne worth seeing.

That headstock pulley should easily unscrew off the headstock spindle. Just use one hand on that pulley and one of the two little steel rods you use to adjust the jaws on the 3-jaw chuck to hold the spindle from moving.

Thank you!

I'm glad you found it useful. It makes doing it feel worthwhile. 😊

Thanks Francisco. I was at first keen on going brushless myself but then the low cost, availability, and mounting bolt pattern of the MY6812 brushed motor made me decide otherwise. For measuring I either use a little 150mm/6inch rule or vernier calipers. I can't remember the last time I used something other than this. - Best wishes - Tom

I'm glad you found my videos helpful James. (Most of the ones I found on TH-cam were from people trying to sell their own versions and gave away very little of the important detail.) I bought my motor direct from China via AliExpress. It was listed as "MY6812 150W 24V high speed small scooter brush motor" and my vendor was "XINHUANGDUO Automation Store". The speed controller I bought locally here in New Zealand but I've seen the same one for sale on Amazon. (I don't like dealing with Amazon.) My seller called it "60A peak Forward/Reverse DC speed controller Case Fan & display 10 - 55 V 1800W" (Heaven knows where that power rating came from because it seems greatly exaggerated to me and obviously his wording is designed for search engines rather than for a logical mind.) Hope this helps.. Best wishes - Tom

@@downunder4087thank you Tom. Still helping out. Greetings from a new 55-year old unimat 3 owner in the Netherlands.

@@aerobill8554 I love my Unimat. I spent at least 4 hours over the last two days making parts for the clutch on my old 1951 Matchless motorcycle. There must be many others just like us around the world making the most of these well-designed machines. 😊

Thanks Dave. I prefer the idea of using nice thick phenolic spacers when you can do so. But on my bike they'd push my carbies too far backwards and this would create problems at the airbox end. Using them would also require me to use different/longer manifold studs. In support of my fat O-rings though, I suspect the air gap produced by them is more effective per millimetre of thickness than you can get using your phenolic spacers. 😊

I'd like to help you. But unfortunately making these videos takes a lot of time and I'm too busy with other things right now.

Thanks Dennis. I did look at using a sewing machine motor myself but I couldn't find any at all available, let alone find one of the dimensions and power rating I wanted. The new technology used in my scooter motor involves very powerful permanent magnets so I'm hoping they don't attract swarf to it! But at least its well sealed if they do.

Thanks. I'm often disappointed with TH-cam video quality and I've never been sure how many countries are affected by it. I wasn't even aware I could alter it at my end until now. 😊

The flywheel doesn’t run perfectly true. But then perhaps I’m getting too fussy in my old age. 😊

@@downunder4087 Its pretty hard to notice, I think I could put up with it 🙂

I was surprised that the ambient temperature didn't seem to have too much influence on my carburettor overheating problem. That day when my slides seized was actually rather cool. (From memory, maybe only 14 degrees Centigrade.) So based on this, I suspect your gaskets were of sufficient thickness to do the same job as the thick O-rings I later fitted to cure my problem. 😊

Thanks for your comment. It would have been easier but it wouldn't have achieved as much. By taking the metal off the rear faces of my manifolds, every time I remove and refit my carburettors I'll not only have full thread-engagement with the entire depth of my nuts but I'll also automatically have the same width of air gap at my O-rings. To put this another way: If I'd just skimmed metal off the front faces of my nuts (as you suggest), any time in the future I remove and replace my carburettors I'd have to carefully work out once again exactly where to leave those nuts to achieve the right air gap, avoid warping my carburettor flanges, and avoid over-crushing my O-rings. (There are shoulders at the end of the threaded sections of the studs that my nuts and washers should ideally seat against and I've achieved this by taking metal from where I chose.)

@@downunder4087 Yes those shoulders are a pain in the @@@@! I’ve found that apart from being extremely difficult to access the inner nuts they also are awkward to mount on the studs which protrude so far that you can’t get the full height locking nut past the body of the carbs. On my Bonnie the stud shoulders stop you nipping the nuts up the flanges. Last time I serviced the carbs those nuts had locked onto the studs and unscrewed them from the head. That was fun. It seems rediculous that you have to remove all the fuel piping from both carbs and potentially the tank as well just to wield a spanner removing one carb, even one cut in half. Ask me how I know. Those shoulder bolts and o-rings would be a good idea if manufacturing control was present but in the 70s I think a thick gasket and plain studs are better. Not my favourite job …… down there with front sprocket changing and valve guides!!! I also think the two bolts holding the carb against an o-ring is just asking for them to wobble around with little heat insulation if the ring is squished.

I owned a 650 pre-unit Triumph as a teenager and now as a "senior citizen" owning this Bonneville I've developed a new respect for their engineering. I think it's mostly to do with having more time to plan my work sequences and having better tools for reaching barely-accessible fastenings. Unlike when I was a teenager, my bike is no longer my one and only form of transport too so I'm not under the same pressure to get work done fast. 😊

@@downunder4087 me too, but it’s still no fun wrestling a nut on a twelfth of a turn at a time 😜

Thanks Mark. It’s not without its defects but then I’d hate to own a showroom bike because I’d get even more annoyed than I do now every time I accidentally add another. (Of course I do try very hard not to.) It still had the blue painted centre-stripe on the chrome rims and the grey hammered paint on the hubs when I bought it. I don’t regret getting rid of those features. BTW - I got a shock a couple of years ago to see a Silver Jubilee in a local bike show that appeared to have hardly been ridden since new. (I think it may have had 69 miles on the speedo but my memory's not the best.) What struck me most was its Avon tyres. They looked so skinny that I assume the first thing many owners did was to beef them up. I run a “Michelin Road Classic 100/90-19 Front B19” on the front and a “Bridgestone 110/90-18 Battlax BT46 Rear 61H TL” on the rear and I very much like the looks and performance of this combo. (I don't subscribe to the view that you must always use the same brand/model of tyre front and rear and tyre-availabilty issues in this part of the world tend to stop you from doing that anyway.) It makes me feel very safe on the road and adds to the looks (ignoring the fact that my rear tyre comes within millimetres of touching my brake master cylinder and I dread the consequences of getting a rear tyre blowout - not that I think such a thing is ever likely to happen). 😊

Ha ha. .....You reckon 😂

That statement sounds odd coming from "someone within the profession”. I would have expected it more from someone such as myself who’s owned a British bike way back in their past and worked on it back then with plenty of enthusiasm but a shoestring budget, minimum tools, and minimum engineering expertise (and who’s made that statement based on their distant memories). I’m somewhat embarrassed to recall making a comment (probably about 5 years ago now) on someones TH-cam video about how these bikes are horrible to work on and require long drawn out dismantling processes just to gain access to where you want to start. Unfortunately that comment was based on “memory recall from my youth”. My attitude now, after having begun “restoration” of this bike about 2 years ago and with decades of engineering experience under my belt, is completely different. I have a newfound respect for them and the people who made them and realise that so many of my past criticisms were based purely un ignorance.

My bike refuses to even start on 91 octane fuel so I go for the maximum octane rating I can get (which is 100 octane and probably roughly the same as your "premium"). However I always like my fuel to remain relatively "fresh" too. (I'm lucky that year-round riding is easy in this climate we have here.) So I resist using any fuel that isn't either "fresh from the pump" or "from my own fully-sealed storage container". I won't add any oil to my fuel except for the benefit of my 2-stroke chainsaw and scrubcutters where I use lower octane fuel anyway. But this doesn't mean that I don't understand your reasoning for going down this route (of using 2-stroke fuel in your 4-stroke engine). I just think it's overkill. 😊

@@downunder4087 I use 93 octane premium as rated in the USA Michigan. Not too many people use premium, so I think it comes with some kind of additive to make it last longer? I also add some Marine Stable that is also good to combat the affect of 10% Alcohol that most of our gas has in it. I was told years ago that Premium has detergents in it that keep the engine cleaner too? I started using gas with oil, just to use up the gas in my 6 gallon boat tanks. If I have an empty tank it is easy to get mix ratio correct. I always drain gas from the motorcycle before winter storage & spray with WD40 to prevent rust inside tank.

@@chamberizer Thanks for sharing. It's always good to know how others are tackling things.😊

thanks 😊

Yes. I've read some owners like to swap to Mikuni.

@@downunder4087 The main problem when switching to Mikunis is the routing of the fuel lines. The Amal carbs share fuel to the bowls with banjo fittings. The arrangement preserves the main and reserve taps. On the Mikunis the main tap feeds one carb, the reserve tap feeds the other. You could find yourself running out of gas when you least expect it.

@@jeromebreeding3302 That's useful to know. I'm not considering swapping to Mikunis anytime soon though because I'm happy with the performance of my Amals right now. 😊

@@downunder4087 Can't fault you there . Once the design flaws of the Amal carbs are resolved plus tuning exercises they work exceptionately well, until the pot-metal slides wear on the carb bored, then the carbs must be replaced, or bored oversize. Lineing the carb bored with a brass sleeve might help. Or even better machine a brass slide to match.

It's not hard to find a bike that vibrates less than a 70s British one Dave! 😊 It's supposed to be another beautiful day here this morning so I'll be going for another ride. But getting my bike out from my garage and ready to hop on involves pushing it up a sloping driveway through a narrow gap between a parked vehicle and a stone wall, pushing it through a narrow gap between vehicles, and then pushing it up another slight slope of muddy grass etc. I've scratched both the parked vehicles and bike in this process before. I've even lost my balance once when I was using my silly teenage-acquired technique of "leaping into the air and coming down with full body-weight" for kickover. (That was most embarrassing! Lucky my wife was standing there watching me with amusement at the time. It was only the addition of her miniscule effort that saved me from smashing my blinkers!) To avoid repeating incidents like these I find I've got to focus on always using the best techniques. For instance, to put my bike on its centre-stand I now try to always roll the front wheel up onto a short piece of 4x2 timber first, stand on the left side with my right foot pushing down hard on the stands foot lever, and pull it backwards with my left hand on the left handlebar handgrip and my right pulling up and backwards on the frame under the seat. (Or at least that's how I think I do it. ) Above all, I've got to remind myself that my difficulties probably aren't age-related at all. You see I tend to forget I lost my balance and dropped this bike once before 30 years ago (and in full view of onlookers/neighbours too). Ha ha.

@@downunder4087 Maybe we should write-books...I've done similar-things . I'm rural, hr-ish nth-east of PN . We are the Poor-People on our road , our drive is gravel with a steep-slippery-section up to 'the-shed', which a previous old-guy built (very-Heath-Robinson!) I have the-same-issues with center-stand (and have employed your exact-methods) I also have another-bike, 1982 Yamaha XV1000 (roadster, not virago)which I was going to sell due to its weight , but I wanted-one for years, bought a 'dud' then finally found this-one (12yr-obsession) .Now I have parts-forever and a cheap-reg-bike . I started-doing very-light-weights and it's helped a lot . The thing that changed-everything was doing exercises called The Tibetan 5-rites (5 different-moves) i struggled with the first-one (spinning-clock-wise and the 3rd ) but now I never suffer from motion-sickness of any-sort (could never go on a boat,fishing etc ) It's changed lots of things that I would never have believed if I hadn't done it , balance is improved too . Dave

@@kdsowen2882 Our biggest danger to our health is the other idiots on the road. I got taken out by a Freightliner petrol tanker on the south Auckland motorway a few years back. Lucky I was in my 40-series Landcruiser at the time and not on my bike or I'd be dead now. (The police charged a different truck driver to the one who actually hit me because it was a complicated multiple vehicle pileup.) Stay safe and keep enjoying life. I pick lonely roads and avoid riding altogether on weekends when more people tend to be on them. 😊

@@downunder4087 Agree , I got taken-out by letting a bike-shop fit fork-seals (wrong-size,too-tall,clip wasn't seated) wrecked bike and me (5hrs surgery) I ride the same as yourself, yesterday was a cracker ! Dave

That's astonishing! Thanks for sharing.

Thanks Simon. I can see you work meticulously to get things right and this is what I always aim to do. When I was at college it was my dream to own a Norton. My best mate owned a 350 single, 600 dominator and a 500 single, all at different times. I was locked into fitting my “new standard Amals” back in 1995 when I purchased them and set them aside in storage along with the bike. It was only recently I became aware of the existence of premier versions. Knowing what I know now, I’m very jealous of your “hard anodised slides”.

@@downunder4087 The Premiers also come with removable pilot jets in various sizes for optimum tuning - also easy to clean out ! Not intending to wind you up - hope the standard Amals are working well.

I especially value posts like this one of yours here (that supply good info) and I'm certainly not getting any bad vibes about it. For most of my life I've never had the Internet available and I truly appreciate the advantage it gives me now (as a learning resource) when I work on this bike. If I ever need to replace my carburettors again I'll go for premiers. But this is based on longevity rather than any other factors. I doubt I could do anything to improve how my bike is idling and running right now with its standard Amals.

I think my problem was more to do with errors made by previous-owners of my bike (and/or the bike shops they may have used to work on it) because I believe my bike originally left the factory with the thicker carburettor O-rings fitted. I also believe that while our carburettor slides run dry most of the time, on occasions they get somewhat "washed by fuel" during normal operation. So I don't think adding any sort of anti-seize lube would work. Furthermore, the clearances are so tight in a carburettor that's in good condition that adding any grease-type lubricant would simply serve to stiffen up our slide-movement rather than freeing it. 😊

Thanks. Good work and greetings in return from far--away New Zealand. (I have a brother living in Germany.)

Thanks for your input. 😊

Thanks for sharing.

I don't think that would be enough for my bike. My 1.2 mm air gaps from my fat O-rings seem to work much more effectively than my 1.3 mm thick gaskets (but then I don't know how much more effective mica is than paper/cardboard). 😊

Glad you enjoyed it. 😊

Thanks. I believe the correct nuts for my bike could possibly be less deep than those I've chosen to use. (Cleveloc nuts?) However I often use stuff that's more easy to lay my hands on rather being a stickler for using exactly what's specified .... unless doing so would adversely affect appearances of course.) 😊

Thank you kindly!

Thanks heaps. I love feedback on other people's experiences! As you've no doubt seen from my videos. I had both my slides jam up from overheating after riding hard on an unusually long uphill incline. (BTW- I shouldn't have written in that video on "tuning" that I'd turned the bike off TOO SOON because I could have left it idling for an hour and the carbies still wouldn't have cooled enough to free my slides.) I am leaning towards the opinion that, because the skirts of our slides aren't of uniform thickness, our slides (and perhaps the necks of our carbies as well) distort under these high temperatures to cause the seizures we experience. I noticed burrs on my slides when I got home and dismantled my carburettors and I later lightly sanded these areas (as well as applying a bit of light oil as I mentioned doing in that video). Since installing those fat O-rings I've never experienced any more slide-sticking. It still amazes me how, when I restarted my bike at the top of that hill, it didn't scream its guts out at full revvs (as was your unfortunate experience). I even stopped my bike more than once on my way home and each and every time on twisting the throttle I found my slides were still jamming. (I was gentle on the throttle grip though because I knew the danger I would be in if either slide were to jam SOLID.) Somehow my engine-vibration and piston-suction seemed to help my return-springs enough to make my slides behave themselves for the successful trip home!!!!!

Hmm. The next time this occurs I'd stop and check if it's comfortable to hold your bare skin against the upper bodies of your carbs. (The petrol manages to keep the bowls cooler so that's why I'm saying the UPPER bodies.) If you can then it'll rule out overheating as being the culprit. (I would tend to be more suspicious of whether your carburettor slides are properly synchronised throughout their travel - including in their at-rest positions.)

On the commando that symptom usually means the mixture is a bit lean at idle. When you open the throttle, initially the mix tends to go leaner than at idle before fuel makes it out the needle jets....so need to dial in more richness at idle to help smooth transition to needle phase. If mixture screw (idle air control screw on concentric Amals) doesn't richen enough, then consider lowering the needle clip to the next lowest ring on the needle (therefore raising needle initial position, making it richer throughout its range).

thanks

I try to do it with only one push on each but sometimes the operation seems to take so long that I mistakenly feel I can speed the process up by using multiple pushes. Ha ha. (I must check out whether I have a restriction in the fuel feed into my RH carbie because it AWAYS takes longer to flood its bowl.)

@@downunder4087 2 explanations I can think of for that - if the bike is on its side stand, the left carb is lower, so will probably have a higher fuel level to start with, or there could be a difference in the length of the tickler (mine has about 2mm difference between the two, and takes longer to flood the left one)

@@rickconstant6106 Thanks a lot. I hadn't thought of either of those factors. 😊

thanks Dave. I didn't know the brand of my bike boots because I bought them in a second-hand shop (same as my helmet). They're actually a bit small for me and I can't put them on unless I have bare feet. It took me a while to get used to the sticky feel of the previous owner's foot-sweat too. But after applying a lot of my wife's talcum powder it's now bearable. Lucky they're sheepskin-lined on the sides eh. LOL.

@@downunder4087 Funny ! My gear is ALL op-shop including my-gloves that I bought in the late 70's . I re-purpose and modify anything that 'works' though I'm not having much-luck with gluing my soles on my op-shop boots . Dave, older and also nz

@@kdsowen2882 We must be very much alike. I recently ditched my op shop gloves in favour of a pair that cost me an arm and a leg new. I guess I must have fallen for the advertising blurb because I'm not convinced they're any better. 😊