New CDI and coil combo for racing available!

[kr1x]

Nice debate guys. You can run stock cdi to 15 000 rpm, if you want to. With correct portmap and enough retard on magneto. I think its more about what power figure goes to rear wheel with improved CDI unit on same setup. So i hope there will be same setup tested with different CDI-s like HD, Jaguar, stock and compare dyno with timed light video would be good.

When I look, at last Timing curve which Jaguar posted here, 6degree @ around 9600-9700. Thats too much retarded for that RPM. Around 20 degrees would be OK.

Retarded timing is good, but too retarded is not. Hotter gases go to pipe and hotter exhaust gases have more sonic speed which improves scavenging from intake. But it heats up engine more, which would be problem for these chinese engines which have small heatsink area.

 

[mapbike]

Dodge, no "facts" have been thrown at me. I keep asking for them but Huffy, in his attempt to cover the fact that his is just a copy of my old Jaguar CDI (with a smaller timing capacitor), refuses to demonstrate any proof that he has a better design or a more unique design. My new design approximates a digital CDI which is what all good racers use. That is because at high RPM the ignition timing of a regular analog CDI quickly retards too much which in effect is an RPM limiter.

Bahramu, the HD is the same as my old Jaguar but with a smaller capacitor in the timing circuit which makes it better for high RPM engines. But not as good as my new model which has a newly invented design upgrade.

Mapbike, it sounds like you have a modified engine that revs high (over 8000). My old Jaguar was not designed for race engines, only for stock or slightly modified engines. Only the new one which I am just starting to make is made for race engines. And bringing a bike to the races will not prove anything becuase, as I am now repeating, each engine is different. You have to try the two CDIs on the same engine. Headsmess has the best idea with testing the two with a dyno.

Looking at the graph below of ignition timing curves you can see how my new design extends the RPM by 1300 (assuming the engine power greatly lessens with less than 6 degrees BTDC ignition timing)
View attachment 50867

I agree Jag, the only way to know what the facts are regarding which CDI performs best at high RPM's will be to use both on the same engine in the same conditions, you are correct in saying that there is no way a true comparison test can be done if two different engines are used.

Yes, I do have a well ported engine that has a better balanced crank which allows for much high RPMs than a stock china girl engine, my tach has registered 9400 RPM at it maximum, because of the quality of the tach which has recently died on me I cant swear that the reading was completely correct, I can say that the engine was no doubt screaming at that point.

Jag if what you say is true and you have made an improved version that will allow higher RPM's then that is a good thing and now people will have the HD Lightening as a choice as well as your new improved version, personally I'm not a "racer" because I live a long way from any such events that I could be a part of, but I do like to get the most I can from my engines and so far the HD Lightening CDI and the Stock CDI have proven to give me the most RPM capability.

I say honestly that anyone who, does the work and goes to the expense to bring a bigger and better product to market for those of us who want it, deserves credit for what they have done, as with any product or service, when something comes to market and is good, someone or several will look at it and try to make their version in some way or will see if they can improve on the idea, that is just how it is in every free market environment, there is really no need for hate or mud slinging, but instead that is a chance for the person or company with the best marketing skills to win, many great products over time have gone away because they were out marketed by a lesser product and vise versa, I say there is room for more than one version of High Performance CDI in our motorized bike culture and actual unbiased Dyno test will show which is king of the hill as far as performance is concerned and this has yet to happen, but when it does several arguments will be laid to rest and then people can choose what they want based on those results.

As a by stander and as someone who really enjoys my motorbikes whether it be the fast ones or just the 30mph cruisers, I can honestly say that I wish all involved in this debate the very best and hope it all ends with a virtual handshake when its all said and done.

Peace, Map
http://ts1.mm.bing.net/th?id=H.4838969052955201&pid=1.9&m=&w=300&h=300&p=0

 

[Deleted member 12676]

as 48ccbiker on the other forum pointed out, it may just be a question of which carb is used. The stock carb does a poor job of fuel atomization and so needs more spark advance since large fuel droplets burn slower. I chunked my crappy NT carb almost immediately and put on a Dellorto. Then after being tired of having to southern engineer it for jetting changes I switched to a 18mm Mikuni. So I dont think I have ever tried my CDI with a standard carb.
Also I think that low engine compression causes a slower burn, correct me if I am wrong. I also upped my compression right from the start, but not too much, always near 130psi. I think stock is 90-100psi (at sea level).

 

[keatonx]

the dyno is on its way. had issues with using even a trucks 24 volt alternator as the load... at 100amps, thats still only 2400watts...(just over 3hp). i need twice that power rating so the thing doesnt fry itself, at least! so i has been fiddling with eddy current brakes with good results much easier.

I built a simple dyno to test some experimental 2 stroke engines I built (from weed eater motors with less than 2hp)
It uses a band brake from a chainsaw's chain brake.
I can use a square rod to connect the outer clutch bell's square hole and the square hole on the weed eater's crank/clutch.
Then just hook up a tach and do torque (ft lbs)*rpm/5252 and you have your horsepower (at that rpm).

I haven't tried it yet, but I'm guessing the band brake will get hot really quickly so I might have to spray it with water.






Hey look, my hands aren't black with grease in that pic! A very rare occurrence indeed!

Anyways the band might not make enough friction, but I spent less than 15 mins making it so it won't matter anyways

But here's my best idea for a super simple dyno for a motoredbike- get a bathroom scale, and put it between a brick wall and your bike's front tire, so it's being squeezed between them and only being held up by friction. Then hook up a cheap 10$ small engine tach, and rev the engine to WOT and slowly feather the clutch so the bike starts pushing on the scale and giving you readings. Do this for only 1 or 2 seconds at a time. Let out the cluth out different amounts so you can get readings for 5000rpm, 4000rpm, 3000rpm, etc. Calculate the engine torque from the scale's pressure by factoring in your gear ratio and tire radius (simple math, divide the lbs of pressure on the scale by your gearing, and multiply that by the amount of feet that will fit into your tire diameter (exactly 1 on a 24" wheel) and you have your engine torque readings. From the different readings you can draw out a simple torque curve, and from that calculate hp at different points using engine shaft torque*rpm/5252.

Sound like good idea? Anyone would easily be able to do it and the clutch will only be slipping for a few seconds max.
I haven't tried the above because currently my only bike with a manual clutch is my lawnmower bike which has a belt slipper clutch and I don't want to overheat the belts (the belts are 10$ each; they're special notched ones with no wrapping!).

 

[Deleted member 12676]

very inventive. I like that!

yes heat is a very important concern when it comes to ignition timing. Compromise is very common in 2 stroke design. What is best for engine power is often not best for engine reliability. So that may be one reason that all racing motorcycles have a retarded ignition timing at high RPM. All the power in the world does no good if it cracks the head or melts the piston.
So along with a dyno readout there needs to be head temperature readings on long WOT straights.

As to the 6 degrees around 10,000 RPM, that seemed to be normal from all the ignition maps I could find on the internet.

 

[MotorBicycleRacing]

We have a really good dyno at Socal Motor Bicycle Racing events and the dyno builder
is a good friend.

Ryan recently dynoed a stock 66 cc China girl at 2 1/4? HP

I intend to dyno my new 69 cc "balanced" motors, stock and with various mods such
as different CDI units.

It may not happen until the big April 12th 2014 race at the Willow Springs go kart track.

Dyno pic before it got fancy stuff like covers.

 

[sublunacy]

what about the gt2a and gt5a? is everyone just pretending it doesnt exist?

soliciting and asuming diplomas much?

 

[bahramu]

I realized the December race is on an oval track so I won't be racing the HD Lightning this December. Maybe I'll hit the oval someday... Next race on a GoKart race I'll be there.