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Anderzander's D1
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November 17, 2011 - 1:27 am
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I picked up a set of hole punches for a few quid dead handy for making gaskets, the other way is to lightly tap with the ball end of a small hammer or have a collection of balls out of old bearings and place that over the hole with a light tap of the hammer.
I quite often make my own gaskets can be a lot quicker than searching around for one with the dealers etc.

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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November 17, 2011 - 8:22 am
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By the way your careful gasket preparation should yield at least a 0.1 BHP increase and you you that vital edge when challenging twist and go scooters at traffic lights !!!

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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Anderzander
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November 17, 2011 - 8:47 am
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Lol. The gasket was only to help see where I need to go with the grinder. More pics later tonight 😉

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November 17, 2011 - 9:09 am
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Blimey grinder next, serious stuff then ? I take it it's not an angle grinder ten inch diameter ???
Amazing little tools those Dremels, have one with all the attachments and use it only once in a blue moon but then its worth its weight in gold.

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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Anderzander
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November 18, 2011 - 12:01 am
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Made a start on the grinding:

00b9d3fa-1.jpg

Here is a close up of the unmodified side, you can see the sharp edge of the liner's cut out and the unmodified corner of the transfer tunnel:

e8255d99.jpg

Here are a couple of close ups of the modified side:

2f524455.jpg

13b3f385.jpg

Still more to do - but if I was a column of gas I'd be much happier to go down there now 🙂

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Anderzander
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November 18, 2011 - 12:05 am
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Also done a little work on the inlet.

Here is a before shot and you can see a chamfer where the internal diameter changes:

807985a9.jpg

So I have removed that and worked quite deeply into the port to reduce the 'ramp' that steers the gases away from the port opening inside the liner.

Here's a picture with a torch lighting the liner:

a70f3156.jpg

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Anderzander
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November 19, 2011 - 12:14 pm
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Done a little more fiddling - checked the clearances to the ports with the barrel and head on with no gaskets. The piston just clears the bottom of the transfer ports when at bdc, it also just fully uncovers the top of the inlet port at tdc.

Even without a base gasket or a head gasket the piston comes nowhere near the head either - I put a cross of 3mm solder on the piston crown and ran it through a compression cycle and it never touched it :0

So the plan is to use a minimal base gasket and run it without a head gasket - not to tune it, but just to make it run a little more efficiently.

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Anderzander
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November 23, 2011 - 8:58 am
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A little more progress: I finIshed grinding the other transfer tunnel and then worked them over with a smaller stoner to get a finer finish. I also did a very small amount of work on the barrel side of the carb to match the inlet diameter a bit better.

Then a big clean of the barrel with paraffin and a blow through with compressed air. Made a new base gasket, a slip of 2t oil on the piston rings to help them in - and mounted the barrel and head.

I just need to check over my wiring again and tape it into place then the tank can go back on and we can try starting the old girl. 🙂

Routing the wiring from the brake light switch seems difficult to do in a hidden way - any suggestions on a plunger frame would be appreciated?

Anyone know what the torque settings for the head are? I've always just done it by feel, but this time I'm using liquid gasket and would like to make sure I'm consistent across the four bolts.

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Sprung Chicken
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November 23, 2011 - 10:54 pm
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Cylinder head nuts, the torque setting is 18 - 20 ft/lb.

I ran the rear light wires down back of reg plate and along the nearside mudguard stay then along the frame.

Dougie;Glasgow ;Scotland.
1955 D1, 1970 B175

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Anderzander
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December 4, 2011 - 12:04 pm
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I seem to have lost an update off this thread too .... I'll see if I can't make a fresh one later on.

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December 5, 2011 - 5:03 pm
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Some progress and some questions ....

Sorted the front number plate for the D1. It was two pieces bolted through the original number plate and looked pretty scruffy, so I've removed the original for later attention and in the mean time glued the two halves together and reshaped them with the dremmel. A touch of paint and it looks fine.

eafff479.jpg

Refitted the exhaust and the tank etc and the big moment had arrived... time to start with the new ignition.....

However it wouldn't start .... 🙁

Very nice big healthy spark at the plug, fuel (eventually) coming out the float bowl having been pumped through - but no joy. Just to eliminate the electrical side of things I tried a quick spray of easy start through the filter and it started imediately - which was very encouraging and it sounded great, really crisp and healthy - until it died again.

I would welcome input on sorting the carb out though please....?

I'll put fresh petrol in, as the fuel has been in for some time and may well be a little stale, I'll also strip and clean the carb and blow some air through and see what that yields.

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December 5, 2011 - 9:49 pm
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One thing which would have made more of an improvement would be to ensure that the transfer ports in the cases were perfectly smooth and polished, I have found this alone makes a good deal of difference.

If you want more, make a reed block for it.

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Anderzander
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December 5, 2011 - 10:24 pm
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Thanks Al - I'm not really after modifying it beyond a tidy up. Any tips for sorting the standard carb would be very welcome though! 🙂

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December 6, 2011 - 4:04 am
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After all your good work you have reached one of the usual sources of problems with the D1 that is the tiny carb, If you have read the thread about Ultra-Sonic cleaners you will most likely understand why I ended up getting one. The floats on these are usually far from perfect condition also the carbs have some tiny drillings and passageways, the one at the bottom of the float chamber for example. Unless you are extremely fortunate and have a rust free fuel tank (inside) then you will need not only a gauze filter on the fuel tap (should be one there but often long gone) and an inline fuel filter even with those in place don't be surprised if a fine sediment still gets through, mine does. Quite often the float needle does not seat well I lapped mine in with some Brasso which improved things a bit, definitely check the float, no leaks etc.
The bike should start ok without use of the strangler by the way, just flood the carb and give it a go, mine starts ok like this even when covered in frost in the winter. I find a fairly hefty amount of throttle helps when starting.

Phil

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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December 6, 2011 - 4:46 am
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One more thing, actually more than one, as you have found the float is a one piece job, check the small locating boss in the bottom of the float chamber is clear of sediment etc, thats the one where the bottom pin of the float locates, if this is not clear then the float level will be wrong.
Amal has been telling us they will start re-making some parts for these carbs but as yet nothing, maybe one day. Most of us seem to have a carb made up of the best parts from a collection of others, there are some spares around with the dealers, you may have to phone around C&D, T&G and a few others may be able to help, I'm sure somebody on the forum will help there for possible sources.
As you said probably best to put some fresh fuel in, even with correct pre-mix two-stroke oil you can get a build up of oil in the float chamber so thats another good reason to give the carb a periodic clean say one a month, thats what I do, and throw it in the cleaner as well.
One more thing with this ignition set up I have found it better to use a standard type spark plug and not one of the Iridium ones, someone who knows a bit about ignitions told me they are not suitable and from experience it seems he is right.
This next bit is only my personal opinion and everyone one has to make their own decision but I find running on a lesser fuel/oil ratio improves running and starting, somewhere around 30/32 to one seems ok, I have been using this for two years now and all fine, the original spec for 20 or 24 to one or thereabouts is a lot of oil and modern oils of a good quality are nothing like the gunge folk were using 40 50 years ago.
Hope you get it sorted sounds as if you are on the last hurdle !

Phil

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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December 6, 2011 - 9:30 am
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Part three, another place to have a good look at is the cap nut for the jet holder, that collects water and sediment too, as for the main jet you can see how tiny it is and therefore how susceptable to blocking up fully or partially, this is where the Ultra-sonic cleaner does a good job, failing that before I used to put it on the end of my high pressure bicycle pump. The main jet can actually look ok but still have some residue in it, I know you are not supposed to poke things down them but need must sometimes and something like a piece of wire from a wire brush fits down there. as my Bantam was not used on a regular basis before I had it I did a lot of carb cleaning for the first month or two I had it, frequent use like for a lot of things works wonders, I used mine all last winter as my normal transport in all sorts of weathers and off it went whether covered in frost or been out in torrential rain all night and never once doubted it would let me down.
Think I have gone on enough now !!!!

Phil

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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Anderzander
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December 6, 2011 - 9:43 pm
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Cornish Phil - thank you for you replies. Lots to go at there 🙂

I just need to make a decision about where to start - I'm tempted to start with the carb, given that the tickler flooded the float bowl. So perhaps something has blocked stopping the fuel getting from there to the venturi.

I agree that modern oils can run a much leaner mix - so will be doing that when I mix up the next lot of petroil.

I'll feedback with results / more questions after the next fiddle.

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December 6, 2011 - 11:32 pm
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A late night sojourn has seen me stripping the D1 carb - and what delightful little thing it is 🙂

d22225c7.png

The main jet was largely blocked by some liquid debris that blew out with the airline -not sure what it was? but hopefully that's was the issue. I've also cleaned the carb body out pushing a little copper wire through both holes from the float bowl.

I didn't try to start it until I've put some fresh petrol in and I may drain out what's in now too.

One thing I do fancy doing at some point is replacing my rubber fuel line with a copper one. Does anyone know the fitting size? they look around 1/8 BSP or NPT. The fittings are readily available for capillary oil gauges and it would be a simple matter to solder them up.

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December 7, 2011 - 7:13 am
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Seem those bits a few times ! Your float looks reasonable as far as I can see from the photo, liquid in the jet was probably two stroke oil residue I think. There was a post some time ago on the old forum regarding union nut sizes on these carbs, it appears to be some odd ball size very close to 1/8 th BSP but 1/8th tubing should be ok, was thinking of doing this on mine with a curly pigs tail like old style bikes always seemed to have, would look good I think.
David re: cleaning jets, I do believe you can get " prickers" to clean carb jets, bit like the sort you get for cleaning the nozzles on oxy-aceteleyne cutting nozzles, might be worth investigating some time.

Phil

BSA Bantam D1 "150" in use regularly often as general purpose transport, quite a few other bikes as well. Cornwall Area Rep. 

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December 7, 2011 - 9:37 am
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Hello Phil, was it you I sent the black plastic Qualcast float to to see if it would fit the D1 type carbs ? If so, did you receive it or had time to try it out ?
Would be interesting to find out if they are a possible substitute for the brass ones. People who are supposed to be re-making parts for these carbs certainly seem to be dragging their feet, David.

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