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Scott's D1/D7 Bitsa
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Scotto75
Bristol, UK.
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July 22, 2020 - 11:08 am
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Hello everyone,

I've just acquired a rather sorry looking Bantam from under a pile of junk in a corner of a barn, that appears to be made up of various bits and pieces over it's lifetime. Unfortunately the owner had no info or history regarding it so it's a complete unknown. Here's a photo of it after giving it a wipe with a soapy sponge.

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The frame is from a '52 D1 but the front forks, mudguard and headlight are from a later model. The frame and tank have a different red to the front end, which is slightly darker, but with green underneath all the paint. The engine off a '66 GD7 model, and the rear mudguard's been swapped out for an ali one. There's no battery or toolbox.

My first task is to assess the state of the engine. I'd like to see if it starts before I decide if I need to strip it. It has compression when kicked, the clutch moves and the gears change when rolled so it looks promising. It's missing its casings on the left side and the primary cover has a hole in it.

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I would guess that this is worn through from the nut and bolt holding the kickstart on. I'll drain any oil out of it which, judging by the hole I imagine is very little, and get the cover off to look for anything suspicious. Also, I'm going to remove the stator plate and see what lurks in there. Hopefully all I need is some new oil, points, gaskets and covers..... for now.

Please let me know if I'm missing anything. I'm no stranger to bringing old motorcycles back to dead, but I'm new to Bantam's and imagine there's a lot of dark art involved that I have yet to experience! Any advice is always welcomed. Thanks!

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cocorico
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July 22, 2020 - 11:37 am
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Looks as though it has been turned into a field bike at sometime. The hole in the case can be welded, or even patched using some thin aluminium and plastic metal. I wouldn't change the points yet - clean and set them, take the spark plug out and reconnect it, kick over and see if you have a decent spark. If not check plug, plug cap and capacitor finally a new mag coil (12£ on ebay). Then as you suggest, see if you can fire it up. I had an old D1 engine which hadn't been apart before which fired up easily and only got disassembled because there was a loose flywheel plate spinning like a turbine. Good luck with it.

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Scotto75
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July 22, 2020 - 2:44 pm
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Hi cocorico. Thanks for the reply.

cocorico said
Looks as though it has been turned into a field bike at sometime.

That's what I thought possible. There's no centre stand either. But not sure why it's still got rear pegs on and why they're so high up??

The hole in the case can be welded, or even patched using some thin aluminium and plastic metal.

I had thought that. I've got some JB Weld, but was concerned that the nut would knock it out again. I check what the clearance is like with the kickstart lever.

I wouldn't change the points yet - clean and set them, take the spark plug out and reconnect it, kick over and see if you have a decent spark.

I've got some time tomorrow afternoon. Will give that a go! Cheers.

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Scotto75
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July 24, 2020 - 12:48 pm
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Removed the plug and gave it a kick, but no spark. So I removed the stator plate and stripped the points, cleaned them and refitted, then tested the coil for continuity. Everything tested good, with the points breaking the continuity when open. I will try replacing the condenser with some I know work. I have an NOS Lucas Ford and old Intermotor one's off my Bedford CF.

Well in my quest for a spark, I've made another interesting discovery. The head has an 18mm size thread, and is currently using a 14mm Champion L82YC plug in an adapter.

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I'm unable to find a part number on the fins of the head to ID it, but the thread depth is 12mm, the same as the plug adapter. The plug seems to be sitting a mm inside the adapter, but at least it's not fouling the top of the piston. Looks like someone may have had a fight with a previous plug and lost and just tapped it larger, rather than helicoil it.

I also removed the 375/31 carb and stripped it down in order to run it through the ultrasonic cleaner, and made a couple more interesting finds. First off is the needle was bent just under the grooves.

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Maybe a previous owner had used a club hammer to get the clip back, or was trying to make a new groove? I was ordering a gasket kit anyway, so a needle has been added, along with a fuel filter.

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As it looks like the same gentle hands have been at work with this one as well!

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cocorico
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July 24, 2020 - 3:39 pm
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Oof, that lot could go in "The Black Museum"! Obviously not a mechanically sympathetic PO. I think I'd look at a helicoil or a replacement head. A new plug wouldn't come amiss, though it should still run using the adaptor (with a sealing washer). You may be able to gently straighten the needle, but new is best. Hope you don't find too many other horrors lurking. Your choice of capacitor should be fine, too.

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sunny
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July 24, 2020 - 4:14 pm
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the  Brass insert  was  serposed to  glued  and  staked to stop it  coming  undone        so  look  up  Stake   NUTS    for help 

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Scotto75
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July 24, 2020 - 6:10 pm
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Hi cocorico, yes it doesn't bode well! The closer I get to it each time, the more I keep seeing other warning signs of botched work future me may have to deal with. I did try to straighten the needle but when I saw the state of some of the other bits, a repair kit was the only way forward.

Hello sunny and thanks for the info.

sunny said
the  Brass insert  was  serposed to  glued  and  staked to stop it  coming  undone

I was figuring that was the case after looking at pictures of other heads. On close inspection it would seem it has been fairly abused and may have come out a few times too often that it is now staked to the plug instead. I'll get the plug in a vice and see if I can either tap the insert off, or maybe file a couple of flats on it to use a spanner.

The thread of the insert looks metric and measures 17.9mm. I'm pretty sure the pitch isn't UNC. I can see on the internet there are 14mm to 18mm brass spark plug adapters, but they look quite wide around the nut end and can see it hitting the fins as it goes in.

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Scotto75
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July 31, 2020 - 6:40 pm
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In my quest for the elusive spark, I have removed the stator plate and done some tests. To start I have a S55 WiPac stator type 1452 (SN:1269) with an AC/DC flywheel.

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Here's the test results....

Primary coil - 0.9 Ohms.  Secondary coil - 5.5 kOhms.  Spark plug - 5 Ohms.  Condenser - 55 kOhms.

I tested the continuity of the primary and points circuit and confirmed it broke when the points opened. I had a couple of other condesers and tested one and found the Lucas DCB703C condenser had resistance of 260 kOhms, so used that one instead, under the assumption that the higher the resistance the better....?

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Scotto75
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July 31, 2020 - 6:44 pm
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This all seemed promising so wasn't certain where the missing spark had vanished to. I cleaned up the flywheel and found TDC with a screwdriver down the plug hole and a degree wheel on the shaft. I then backed it off to 19 degrees BTDC. On the flywheel I marked where the magnetic neutral portion was between a S and N magnet. I then reinstalled the flywheel so that magnetic neutral had passed the stator finger, which was sat under the north magnet pole. This was based on this info, albeit a Lucas chart....

https://www.bsabantamclub.com/wp-content/sp-resources/forum-image-uploads/mike-p5xbx/2014/05/magnetic-neutral.png

I double checked the gap I had set previously was still okay, and then made a minor adjustment to get the points to open. Didn't have a fag paper as my roll-up smoking days are well and truly behind me, but used a thin bit of paper as a rough guide. Put the plug in the cap and turned it over with my hand. Hey presto!! A very faint and intermittent spark. Suspecting the cap had seen better days, I pulled it off and stripped some bare copper, which I attached to the top of the plug, by screwing the top terminal down onto them. Kicked it over and BANG!! Some big bright sparks. Happy days!

I will order a new cap. I'll also make a TDC tool so I can clearly mark TDC on the case and flywheel and then redo the ignition timing more accurately.... but I've established I have ignition, so now onto the fuel side!

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The 375/31 carb is now in pieces and in my ultrasonic cleaner. Luckily my mrs isn't in for the moment so I'm doing this from the luxury of my kitchen with a cuppa, but she and the kids hate the sound the cleaner makes and so I usually have to do this from my garage. I have a gasket kit, new needle, fuel filter, etc, so will hope to get this back together very soon.

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Scotto75
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August 6, 2020 - 10:50 am
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Having run the carb through the cleaner, I've rebuilt it using new needle, gaskets, filter, etc. The carb was reinstalled (without the tufnol spacer, but one is on its way) and I connected up to a temporary fuel tank. 

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I clamped a screwdriver to the frame with the end slightly down the spark plug hole and, with a degree wheel on the rotor, marked where TDC was. I then also marked 19 degress BTDC, and redid the points timing a bit more accurately than the first time. Once all connected back up, I gave it a few kicks with 32:1 fuel mix and the engine came to life, albeit pretty smokey and a with a very loose and rattly exhaust. A little adjustment and it's idling away and revving nicely!! I did notice a little fuel come out of the insert in the head so will order a new insert, and some 18mm crushable plug washers to see if I can resolve that. I've also ordered a new plug and cap. With the engine sounding promising, I am prepared to continue sorting the rest of bumps and scrapes out with a view to registering and riding it myself.

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Scotto75
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August 6, 2020 - 11:17 am
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Having resurrected the engine, I now need to get the silencer fixed to the frame and resolve the issue with the bent up footrest bar and odd spacers. There's a threaded hole on the silencer with an internal diameter of 0.26" so at a guess I'd say it's 5/16" BSW? Does anyone know what thread it is?

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I did a search for this specific bolt and got a double threaded 'silencer support stud' with a part number 35-1030, but it doesn't appear available. I will have to order a 2" bolt and a few nuts and make something to come off the frame.

I also removed the footrest bar and rebent it straight as it had two bends in it, but the spacers appear to be random bits of thicker pipe, the brake pedal was sliding about and the piece for the exhaust was on the wrong side. It looks like the foot rubbers have taken a considerable beating, and were hollowed out to fit over this larger wall pipe. I'll order a pair of new footrests, some 1/2" washers and a length of pipe with an I.D. of 1/2" to make some new spacers. I would imagine that the spacer with exhaust pipe groove is the correct O.D.?

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There was a bush inside the brake pedal sleeve, and the below piece, which had brass shims inside the frame tube, which I can only assume was to stop the bar from moving inside the frame when standing up on it or under impact?

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Also, the brake pedal is bent and has cracked where it meets the round sleeve. For now I will leave it and see what it looks like when I can mock it up with some new spacers. If it works, i'll just weld the crack and leave it as it is as it's still part of the bike's story so quite like that its showing its history.

Please let me know if I'm way out or missing anything. I'm hoping I can do a reasonable job of getting this roadworthy without having to replace every part I come across!

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Scotto75
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September 12, 2021 - 9:05 pm
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Well, I'm afraid it's been a while since I have posted, and not a great deal has happened. I have managed to complete the footrest, without the centre stand. I've ordered the missing parts to complete the rear brake linkage, but have hit another hurdle.

I'm having difficulty getting the rear wheel off because one of the nuts has seized itself onto the spindle.

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The other nut's off on the left side, but it won't budge on the right side. I'm figuring I'll either need to find a way to stop the spindle from rotating (double nuts on the left side maybe) and heat up the stuck nut. Otherwise I'll have to get me nut splitters out.... or the cuting disc!

Is there an easier way to get the nut off so I can remove the rear wheel? I have a feeling I may be missing something fairly obvious 🙂

Thanks.

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stubaker58
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September 12, 2021 - 10:21 pm
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Great work so far. Nice to see someone not simply replacing everything but keeping the bikes history intact.  I’ve always found locking two nuts on one end of the spindle sufficient to get a stubborn nut off.  Keep us updated with progress.

regards.

“There’s nothing new under the sun”.

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Scotto75
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September 12, 2021 - 10:34 pm
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stubaker58 said
Great work so far. Nice to see someone not simply replacing everything but keeping the bikes history intact.  I’ve always found locking two nuts on one end of the spindle sufficient to get a stubborn nut off.  Keep us updated with progress.

regards.  

Thanks for the reply. Appreciate the words. Somethings are a bit Heath Robinson, but I’m trying to keep it as I found it, but safe for the road!

 

I’ll have to get my thread gauges out and confirm what I have. My understanding is that as mine’s a plunger and not rigid, it’ll be a 9/16 BSF thread, not 7/16. 

We’ve got tubs of old nuts at my work, but doubt many’s be BSF. 

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cocorico
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September 13, 2021 - 7:57 am
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I've not a lot to add (apart from 'keep up the oily rag work'), just keep on dousing the seized side in release oil between periods of heating.

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stubaker58
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September 13, 2021 - 8:58 am
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I’ll look out some likely nuts and send them if you PM me an address. I seem to have gathered a few over the years but I’m not enough of an engineer to know what thread they are! 

“There’s nothing new under the sun”.

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larryc
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September 13, 2021 - 10:55 am
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Re the wheel nuts that are stuck fast; I always try heat from a blowtorch, shield the surrounding area, when hot put some penetrating oil on, re-heat and cool a few times with oil between, they usually do finally give. Just be careful with the oil and blowtorch you do get some small flames so have a wet rag handy.

Great project and methodical approach to getting it going!

Larry

D1 plunger 2 x D3 plunger projects and a 1953 Hungarian Csepel 125 plunger

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Scotto75
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September 14, 2021 - 9:50 pm
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Thanks for all the posts. I appreciate all the kind words (and offers of nuts stubaker58).

I went back to it tonight and really tightened up the other side, then with a blowtorch and a can of plusgas slowly managed to work it off a flat at a time. I think the spindle end must be slightly mushroomed, but I will run a tap through the nut and check the spindle is flat..... but the wheel is off!! Thanks again.

I can get the ancient Avon Speedmaster off and clad the flaky wheel in new rubber. Before that I need to address the state of the rear brakes. So I have removed the plate off the drum and quickly inspected the parts and can see the shoes have plenty of life left, but not sure how long they've been sat there. The shoe linings are green which I haven't seen before.

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The brake lever was spinning round, so now the plate's off I removed it and could see the star hole had completely rounded out. I will have to order a replacement.

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I'm hoping to keep the momentum going, but I have three other bikes that always need attention, a gearbox rebuild for my Bedford CF, and an Austin mini estate that I'm supposed to be restoring, as well as a family and a day job!!

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cocorico
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September 15, 2021 - 7:52 am
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Scotto75 said
... as well as a family and a day job!!  

Wow - sounds like you have a big garage, too! Well done in your persistance with the nut. Don't worry about the green brake linings, they were normal. Flaky chrome will often yield to wire wool and oil - though wear gloves as some flakes can be painful. Looking forward to seeing more progress. A gearbox rebuild on a CF is probably a doddle in comparison.

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Scotto75
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September 16, 2021 - 9:26 pm
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cocorico said

Wow - sounds like you have a big garage, too! 

I’m lucky to have my single garage in this city, even if I am always tripping over motorbikes, but will never stop dreaming of that bigger garage! Got the mini in the in-laws garage and the Bedford on the street. Welding that over the winter was fun! 🙂

I’ve stripped the wheel down completely now, removed all the dried up grease and can see I need to order a few bits, mainly the felt washers. Bearings felt and look good so will reuse them. Don’t see the need to replace something that’s old but well made and with plenty of life left just for the sake of having new parts that may be poorer quality. Don’t know about the quality of Bantam bearings being sold on the various websites, but will see what these feel like after a few miles and replace if necessary then.

I’m planning on putting a load of these old parts in my ultrasonic cleaner, then blowing with some compressed air and then regressing before assembly. Would anyone have any concerns about the Speedo drive having bath in some warm degreaser? I’ve tried flushing it with some brake cleaner, but it was thick with gunk so fancy leaving it to soak for a bit.

As I need to order some bits for the rear wheel now, I’ll get the front wheel off as well this weekend, and with any luck dismantle the plunger springs to check the condition of the rubbers in case they need ordering too.

As soon as the wheels are back on with new rubber and brakes all sorted, I’ll actually have a rideable motorcycle!! Can’t wait!!

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