Sure, most early ignitions were set with the ignition advance fixed, then came automatic advance and retard, which were mechanical devices with springs and weights. problem was this advanced the ignition purely on RPM. This is not optimal as for driveability you need more advance for a given RPM when the engine is on light load. So they then introduced vacuum advance and retard, which was a combination of springs and weights, and vacuum control of the ignition. So at light engine loads,(which gave high inlet vacuum) the vacuum unit would advance the ignition further. Then came early electronic ignitions, which often had a crude advance curve... My old Jota was set at something like 10 degrees advance at tick over, then jumped to 28 degrees at 2000 RPM! modern electronic ignitions have a much smoother curve. on to 3D... this is where the electronic ignition receives an input from either a TPS (throttle position Sensor) or a MAP sensor, which measures inlet manifold vacuum. this is combined with engine RPM. Best way to look at it is in graph form... here is a 3D ignition map for a ford crossflow. I built a 3D ignition for my old Westfield many years ago and it transformed the way the car drove! 3D has hardly any effect on ultimate power, but makes it far better (and economical) to drive/ride here is a link to the ignition I made for the car... https://jtccc.wordpress.com/projects-2/megajolt-3d-ignition/
a little bit more progress... I am almost to the stage where I can take it all apart and have the frame powder coated. I have decided its going to be silver on the frame, the tank and seat colour can wait a while to decide. I have finished off the fuel tank plate. there are two outlets, going to the fuel tap, so I can have a reserve position, hence the varying heights of the outlets. that was an expensive piece of tube... £4.90! Sold to me
Thanks for the 3D explanation Buzzer. I’ve had the misfortune to fiddle with the mechanical advance type and combination vacuum and mechanical advance retard devices. I presume that although the modern methods are a big improvement, they are still somewhat compromised. Megajolt is such a great name for the ignition system. I was fascinated with the improvements you made to the Westfield .
here is the frame with all the modifications finished and welded, ready to go off to the powder coaters. Over the years I have used many… some good, some absolutely dire. For a few years now I have used a company called Redditch Shot blasting. the owner is a biker himself, and understands your requirements. They have a good selection of colours and I have never been disappointed with the results. they recently did a set of wheels for me, and when I collected them I noticed a ring around the inside of the rims… he saw me looking… he explained that the easy way is to hang the rims with a hook through the valve hole… but this he said leaves a mark, which looks poor, and also can affect the valve sealing. so he uses a long wire around the outside, which is under the tyre. Attention to detail, which I like.
while the frame is away I have cleaned up the carbs and fitted the Dynojet springs and needles which were for a Monster 900... However the jets wont be suitable for the twin plug 1000cc engine, and need to be a bigger. it will be a bit of trial and error, but for now I have increased their size... I know I will get some stick for this but for MANY years I have drilled jets out! A lot of people don't realise that some (but not all...) jet numbers refer to millimetres... so a 140 main jet has a 1.4 mm hole in it. A 70 idle jet has a 0.7mm hole. this is quite convenient if you have a set of Micro drills, as with a pin vice you can simply twist the drill through the jet. In the old days of Weber DCOE and Delortto DHLA carbs I did this all the time, as did many others! I always used to check the size of the hole in jets rather than rely on the number in case someone got there with the drill before me! I can hear people sucking their teeth at this! If you have a set of number micro drills, you can also do half size increments... To clean the carbs up, I bead Blasted them with glass bead. the secret here is use as low a pressure as you can to clean. I made the mistake for years to use a high pressure, which shatters the glass beads, turning them to dust, where they lose their peening power and you end up with a rough surface. I used a few bungs and duct tape to seal them, but of course they still need a full strip and rebuild after.
Here is the engine finished. I have welded some lugs on the sides of the inlet manifolds so they can be bolted together. the rod sticking out the top of the carbs is a rubber support mounting which bolts to the frame few days off now until the frame comes back
so the rebuild starts... the frame is back from the powder coaters and once again its a fantastic job. we have several companies local, but their performance in the past has been nothing but shocking! Instead I chose to travel a 40 mile round trip to Redditch Shotblasters as they are simply the best I have found for powder coat. the finish and attention to detail on the frame is amazing.
I'm liking that very much Looking at it, I wonder if the mudguard is too shiney? I wonder if it can be sanded so it looks more of a brushed nickel look, toning down the shiney to match the frame/forks/ etc?
As an aside from bike building I have been doing some work on my old milling machine... A while ago I treated myself to a new one, well almost new... It had a lot of the features I wanted and while not as big as I would have liked, it seemed to fit the bill. Well after using it for a month, I decided it was crap, and no where near as good as my old one! It was nowhere near as accurate, struggled to make decent cuts, the adjustment on the vertical was so course it was almost unusable! good job I kept the old one! So I placed the trusty old miller ( i bought it 40 years ago, that makes me feel old!!) back in its place and gave it a bit of love. One of the reasons I like the new one was it had a full set of collets, my old one had just three, which was very restrictive. over the years I had tried to get more, but its an unusual size and I have never seen any. The miller must be from the 30's I think! I bought a set of ER25 collets and set about converting the headstock to accept these. An accurate bit of work, it took a while to get the miller spindle in the lathe to run with zero run out. I managed it though and carefully turned the internal taper, finishing off with a fine stone in the tool post grinder. Its worked a treat! I also replaced the threads and nuts on the bed with some off Ebay, which has taken all the slack out, the old threads were badly worn as you can imagine from probably 90 years of use! the bearings in the headstock were remarkably good though, they may have been replaced before I got it. So its here to stay, and I will be converting it to accept some digital readouts which are cheap these days. years ago I converted my lathe to digital using some digital calipers, this transformed its ease of use. I may treat the lathe to some proper ones as well
I do love a bit of engineering. My Dad was a toolmaker and he had a workshop equipped with drills, a lathe and a milling machine etc. He turned out ('scuse pun) some lovely work, mostly models, and was working on a rotary engine before he got too old to continue. He liked and owned many bikes down the years, and it's a pity he didn't take on a build like yours - if it had turned out half as nice as yours I'd have had a very nice motorbike out of it.
A bit of accurate filing and drilling… I drilled and tapped the end of the throttle spindle and filed a register on it to fit an adaptor for the TPS. This links directly to the new Ignitech ignition. from previous experience, adding 3D ignition greatly improves drive-ability and fuel consumption.
Here are the finished home made inlet manifolds. They have a slight register so an “O” ring separates the carbs from the manifold, I didn’t want metal to metal. I also cross braced them...
Although based on a scrambler, I thought this might be of interest? http://www.dpccars.com/blog/jay-leno-2015-ducati-umc-038-hyper-scrambler-review-video/
I like the look of that... here are the last couple of photos for a while... I will be doing some small jobs and the wiring, something I love doing... will be making the loom from scratch as so much has changed! Also taking a break over the holiday (unless she goes out !) then in the new year it will be colour decision...
As the battery will be below the tank and no longer on the side, will you be having some leads coming direct from the battery, outward for things such as a battery charger, accessory power supply
yes, I will add a charging lead, but wont bother with an accessory lead.. That brings me onto the wiring... I looked at the existing loom and realised SO much had changed that it was redundant... So I am going to wire this from scratch, using my own design of loom. I priced up the wire new and it was a LOT of money , and although I had some wire from past rebuilds it was limited in different colours. So off to the scrap yard with a big pair of side cutters. I came away with this lot for £5! should keep me going. it took a while to separate it into single strands of wire, but there is now a right mix of colours! its bigger than it looks in the picture
I don't envy you your task, but that's just me projecting my electrical ignorance. If you know what you are doing I can imagine it must be very satisfying to create your own loom, knowing each and every wire and its function. I've seen a new loom loom being made in a TV documentary. They used a large board with every component spaced around on it, and then ran and pinned the wires between them. Is that your approach too?
not quite as this is a "one off" loom. I tend to build the loom on the bike... Its actually not that daunting a job. My approach is is to break it down into sections. First I might do the lighting circuit, where I would lay all the wires out on the bike and connect them up. I use Velcro cable ties as a temporary measure to keep everything in place on the fame, and to keep the wires together in bundles. then I would do another circuit, say the ignition, and do the same. this is where the velcro ties come in, you undo them and add the wires. when all the circuits are in place I either remover the loom and wrap it, or what I tend to do these days is use the split corrugated conduit which looks neat an can be put on with the wire in place.
