Mark, out of interest how close to the bearing journal are you going to be able to weld?
There seems a lot of meat/metal on the full case where the stator sat that would get in the way of welding close up to the journal. Will you remove more prior to weld?
Great question Jon.
The welds get quite close with the exception of the rear and underside (where the vertical webs get in the way).
If you can imagine, there will be another section of crankcase welded behind the left cylinder. This is for the outrigger gearbox bearing and also acts as the point at which the left engine cover is mounted to. So that section is almost welded twice.
The underside is near impossible to access, so its welded as best as it can be.
Some of the webs are then machined back and a support plate is bolted in place bridging the join for added strength. The plate goes over the lower crankcase studs and is held by the underside nuts when the engine is assembled.
The last option is to v out and weld internally where the left lab seal sits, but as the cases need to be apart, the danger will be distorted crankcases.
Hope that all makes sense, but all will be revealed soon
What way will the crank pins be spaced man ? I mean how many degrees apart ?
Kev, 120 degrees mate, should run pretty smooth
Ah , just wondered . I never had any engineering training . And when I got my first few bikes never really had any tools either . Generally I used a Vise-Grips and a rock for routine maintenance . Thankfully I've learned a bit since those early days . Keep up the good work , cant wait to hear how she goes for you . Oh , and how will you organize the ignition ??
Last Edit: Mar 26, 2016 19:27:19 GMT 1 by KevtheRev
Interesting yamark about your plan for the triggers.
I know what you mean about the smooth running of a triple. I have a V6 golf, which being a four stroke is effectively the same timing between firing. My colleague at work also has a speed triple, which is very smooth.
My first guess around this problem would have been to machine off the Hall effect triggers of an LC flywheel, and let in 3 at 120 degrees apart. You could even adjust the pickup to further away if they were taller.
Thanks Kev, I hope you didn't squash your fingers when using the rock .
The ignition is tricky, but the plan is to use three trigger coils (generator area), and three secondary coils under the tank.
To explain it would bore the tits off you, so I won't,
You could bore the tits off me as i find it interesting.
Couldn,t you use some kind of programable ignition, on the ignitech i had to ground the ignition coils, and the cdi is replaced by the ignition unit?
I would just like to say all things electrical are a little bit like black magic in my eyes
Hi Tobyjugs, at the risk of boring everyone.
The LC works by charging a capacitor in the cdi box. Half a rotation of the flywheel is needed for the 2 coils to charge the capacitor(these are the high/low speed windings, their outputs are combined to give a constant output across the rev range).
With the capacitor charged the magnet on the outside of the flywheel passes under the pickup coil and signals the capacitor to discharge in the cdi box.
This charge(like a pulse of electricity) goes to the secondary coils under the tank.
On the LC the coil has 2 output leads which means both spark plugs fire. One piston is at BDC so this spark is wasted, the other piston at TDC makes the bang we all like. A second magnet 180 on the flywheel makes both plugs flash together 1/2 a rev later.
So the limiting factor on the LC is the generator source coils(high/low coils), they need 180 degrees to create energy, I need 120 degrees.
Both of Harry's triples use the Dyna S system, so he has solved the problem.
I understand Cinder is going over to the same system for his 700cc LC four as the LC's capacitor struggles to fire 4 plugs.
Harry uses a cbr600 generator and flywheel, then 3 Dyna S coils with 3/ 3ohm secondary coils. This gives 35,000 v at the plugs and is the system I'll probably adopt.
Hi Mark It's all dutch to me, but I know you know what you are doing, and I know it will work when it's all fitted. This is the thing with specials - so much work is done beneath the skin that often never gets seen or thought about, all the more with your unique build. It's gonna be an awesome bike for sure
cb250g5, while your maths seem logical, im not sure it works like that.
You see it's more about trying to get enough charge from 1 revolution of the crank rather than 2. This is irrespective of RPM.
I would have also thought the limitation is with the original system. I'm not an expert on the latest ignitions, but thought they got power from a battery to exite the secondary coils once a trigger is given.
I've no doubt that a modern battery powered ignition would be the best, if not cheapest way to go.
However alternators, and this is a simple single phase alternator, all be it with a slow speed & high speed winding, don't produce more power just because they spin faster, the frequency of the AC waveform just increases.
Take a google for "alternator power vs rpm" & you'll see plenty of graphs of the rectified DC voltage quickly reaching about 90% of max & then not really gaining much more for revving higher. One reason alternators have replaced dynamos. So you will have enough power at lower revs to handle the number of sparks that is needed at higher revs, in my humble opinion, based only on theory, not having seen the circuit diagram of the yam CDI.
I bet the cap is just charged from a half wave rectified version of the AC coming in. 1970's electrics.