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I hear Chambers and TeeZee spent the day up at Johns dyno and Chambers bike makes the same power and torque curve as the two front running CB125 4-strokes.
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I hear Chambers and TeeZee spent the day up at Johns dyno and Chambers bike makes the same power and torque curve as the two front running CB125 4-strokes.
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Sorry to distract from the point of this thread Teezee, but I though we could all do with a bit of a laugh........
Following the thread link to youtube was the funniest thing I have done it months..... The following is a screen scrape from "Diospeedemons" description
A 28mm feeding a 30mm creating an ENORMOUS VELOCITY EFFECT at pinnacle of peak power. This is an experiment so far with synchronized throttle slides and blue-printed and balanced cylinder specs. The carbon reed valve is variably controlled manually, to optimize maximum intake and flow control.The reed cage has been radically redesigned to make the boyesen reeds emulate the function of timed valves. With this in place, an over-pressure condition can be created in the intake system, thus making True Supercharging possible. I have found a way to retard the ignition timing, under supercharged condition to minimize the effects of detonation.The vacuum guage will be installed to monitor overpressure and a K and N fuel/air meter with oxygen sensor built into phongeer exhaust, will monitor the best fuel-air ratio I can possibly attain. A Daytona electronic tachometer will help me fine tune the Boost Effect, then I will install on-demand Alcohol/Water injection using MCmaster-Carr brass misting nozzles at 1.5 gallons per hour. Water injection has been known to cool the intake incoming fuel charge, thus allowing more condensed fuel and air into the cylinder for a bigger bang= creating more horsepower. Denatured Alcohol with the water will increase the octane of the fuel while the water dampens detonation. A 2 liter Holley mini-fuel electric pump will be used to create enough pressure to maximize the atomization of the alcohol/water charge. I am using a computer model to work out this theory with all the variables to my particular bike. I am also customizing an SEF 98cc cylinder with a variable exhaust power valve, out of a 1984 Yamaha RZ350 two stroke engine. This valve will restrict or increase exhaust valve timing. Straight water injection misted into the phongeer exhaust,about three inches from exhaust flange, will modify the pipes sonic wave and make it more efficient. This Carburetion Theory has been successfully used on the 1932 Sterling "Silver Bullet" motorcycle. I have over 1000 highly detailed Honda Elite motor and bike building pictures on photobucket.com. Here is the link that you put in your address bar: http://s139.photobucket.com/albums/q2... ALL PHASES OF MY ELITE BUILDING IS COVERED ON THIS PHOTOBUCKET SITE. IF YOU LIKE MY VIDEOS , YOU NEED TO SEE THE PICTURES ALSO....check em' out!
I'm all for inovation, but, man that is some funny stuff he's smoking!
you can check out his "Duel carb" (note spelling): set up HERE http://www.youtube.com/watch?v=Ms7HA...e=channel_page
God I love the internet! Hours of fun!
Hi SS90, yes that's our thinking too. The 15deg retard RM125 ignition will most likely be better on Chambers bike as its head, pipe and porting is a good approximation of an early RM.
With John C's help we spent the whole afternoon trying different modules on my bike looking for less retard and trying to optimize the ignition.
By mix and matching different stators and black box’s the best we achieved was a retard of maybe 8 deg but have know idea of where in the curve that is. The curve was close to the original fixed ignition for HP and shape. The initial part of the power curve looked much the same but had worse over-rev. It just didn't work or we couldn't make what we had to play with work.
And to make things worse, I got all my dyno graphs on a disk and when I got home I could not open them. So I don't have a record of all that hard work.
The interesting thing was Chambers bike made much the same power and shape of power curve as the two 4-Strokes that normally run at the front. Chambers curve neatly fitted between theirs and almost exactly matched their shape. Mine was much steeper and made more power but was really peekier compared to theirs.
I run the same pipe as Chambers and could quickly fit a barrel the same as his but Dave who rides my bike occasionally likes the point and squirt clutch action. He can make it slingshot out of the corners on the clutch, this works very well on tight circuits. He prefers it to Chambers bike which is easy to ride but mine has the snap needed for quick passing or to jump forward to block an attempted passing maneuver.
To make any headway with a mapped (retarding) ignition setup for my particular motor I need to use a programmable digital ignition that I can map myself. I think my combustion chamber setup needs its own particular ignition map and to find something that will just drop in was a bit of an ask but it was worth a look.
I remember the clip you posted showing a retarding ignition in action, we need to make ourselves a setup like that, with a decent timing light that will fire from a CDI at 12,000 rpm, a degree wheel and RPM counter. With the KX and RM CDI's Our timing light turns off at about 8,000rpm.
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custom ignition maps are definitely the go. I spent time ages ago with Chris Sayle(Dynotech) doing run after run with careful adjustment of ignition timing between runs. I was using a YZ80 ignition that I think Darren has now. It did not retard enough for the TS100 I was running. If it was set for max power at max revs we had a handy 19.9hp. If we then tuned for peak power at lower rpm we ended up advancing the timing with the result that "peak" power dropped off. I was looking at something like 5hp increase round 5-7000rpm. This was on a motor that had a pretty respectable power curve anyway.
This reminded me of a story I heard at Johns about TZ750's and the AMA's attempts at restricting their power. The story goes, that they required them to breath through a standard orifice plate. This was supposed to limit the air supply but some clever engineers/tuners figured a way of adapting a diffuser to it and changed the vena contracta effect. Eventually the TZ's made more power with the orifice plate than they did before. This story interests me because of the 24mm carb restriction and it would be interesting to see if the TZ approach could be used. I would like to know more if anyone else knows something about TZ750's and the FIM's orifice plate restrictions and how the tuners got around them.
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The problem is the carb position on a rotary disc engine. You need ~7deg taper & yes this is what I ran on my 125. You can shorten it by machining the taper starting in the carb.
Don't you look at my accountant.
He's the only one I've got.
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70's-80's car motorcycle hot up book.
http://www.bgideas.demon.co.uk/tmanual/
Chapter-1 about power and how its measured
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch1.pdf
Chapter-2 An interesting read about carb sizes, max port flow and shape 2 and 4 stroke.
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch2.pdf
Chapter-3 combustion and the power stroke
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch3.pdf
Chapter-4 the exhaust system and expansion chamber
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch4.pdf
Chapter-5 the camshaft
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch5.pdf
Chapter-6 Ignition
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch6.pdf
Chapter-7 Supercharger or Turbo
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch7.pdf
Chapter-8 Pistons and Rods and balancing
http://www.bgideas.demon.co.uk/tmanual/Tm_Ch8.pdf
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I think that you will develop your ignition very quickly with a degree plate. I think it would be the best value tool I have (I made it for €2)
I am not 100% sure what curve would be "ideal" with your combustion chamber (with the dished piston), but my experience with tests on ignition curves Vs head design suggests to me that what you are suggesting is correct (start at say 25 deg, advance 5 degrees more up to say 5000 RPM, then retard gradually back to maybe 14 deg at 10,000)
Essentially, I believe a "non linear" curve is in order for your particular requirements.......... but I don't know of any method of calculating a map, and it will certainly be a "test and run" situation.
An advantage you have is that your exhaust port width is limited to about 70%, and you won't suffer any localised heating of the crown that you will get with a larger bridged (or auxillery) port situation in the event that yo run "too much retard"
At work I have a mapped curve from a company that make an ignition specifically for a squish head situation, I will take a pictiure and post that tomorrow, as it may be of some help in seeing what does work in a similar situation
My experience is that on an air cooled 133cc (cast iron) engine making around 20 PS
(with a Squish head) getting the ignition map correct is good for an all over gain of 1PS (all through the range) about 2 NM and about 750 RPM more over rev...........
Non squish head on the same cylinder, I have regularly seen 2 PS gains (over a "static" set up....but of course the curve used with this head design is dramatically different to the one for the squish head!
Strangely, my experience has shown that if it is just a little out of "optimum" the power curve is much the same as a static ignition, and I have heard MANY people say that there is no gain...... not true, it is certainly worth persevering with!
Strangely, with the 125cc aluminium sleeved cylinders that I do, the gains with the ignitions are still there, but not as big as I had expected (or compared to the all cast iron cylinders)....... I put it down to the superior cooling of the aluminium compared to the all cast iron cylinders
Diverging. so 14 included. I think I hinted at this a little when we were still talking about rotary discs. I tried both ends of the carb but was surprised that the ugly Mikuni entry in this case wasn't the problem area. I'd made a belmouth with kneedit & a slow taper in with a blunt entry (as opposed to the airbox std fitment). A bit of silicon spray & it was easy to test it on or off.
The idea is that the velocity increases & then decreases gradually with no eddying.
Possibly more important on a reed block with it's vast area compared to the small carb.
Don't you look at my accountant.
He's the only one I've got.
The mikuni round slide 24mm carb is 28mm in diameter at the bore exit. This carb is used on some of the 60/65cc motocrossers.
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