Rocket racing CDI

[Deleted member 12676]

There are digital CDIs available but since they require an extra trigger input then only electronic technicians and engineers would be fit to figure something out that would work. I myself would like to design a digital CDI that uses the zero voltage crossover point from the stator coil as the "trigger". But my expertise is in analog circuits, not digital. Maybe a slow going long term project.

 

[Fabian]

The "arduino" concept looks interesting. Thank you for bringing it to the attention of the forum.

I'll make a new thread for "ardino", because it might be the anser to some peoples prayers.

 

[butre]

I could crank out analog circuits and follow instructions on digital ones all day but I've never been good at programming so the arduino has never been something I was willing to try. now that I've got a specific project in my head I might be willing to put in the time to learn.

I'll try to cook something up, for now just manually adjustable timing curve, soft rev limiter, and maybe a knock sensor. I know enough to know that I would have no idea what to do with any other data, so I'll leave that sort of functionality to the experts. I learned about timing on the drag strip so I can make full throttle flat ground power all day but anything else is pretty foreign to me.

 

[Deleted member 12676]

the less the throttle the more advance is needed.
For our uses an analog CDI is fine but what we mostly lack is its adjustability for throttle position if the riders ride without full throttle constantly.

 

[butre]

I know that much, I just don't know to what degree it should be advanced at low throttle. I suppose I could make it so that you input a base curve and then at every 10% throttle it retards the timing by a given amount that the user inputs. the only real challenge then would be figuring out a throttle position sensor

 

[Deleted member 12676]

Look at the RM250 CDI graph on my site.
Maximum and minimum should be adjustable by the owner, to set according to the engines needs.

 

[Fabian]

what we mostly lack is its adjustability for throttle position if the riders ride without full throttle constantly.

My engine only ever operates in two modes: idle and full throttle. At half throttle, the engine won't even get the bike moving.

 

[butre]

I'm generally at full throttle or idle if I'm not just cruising at low speeds

 

[HeadSmess]

I have never said that. Please show me where i have mentioned such words.

well, heres the most recent one...

I also completely agree with this statement, but from my experience the crowded needle roller design can safely rev to 4,800 rpm and will handle short bursts to 5,200 rpm, but is far happier with a max rev limit of 4,500 rpm to give long term engine reliability.
4,500 rpm is enough rpm to give a reasonable balance between longevity and power.



If you call my self imposed absolute maximum rev limit of 4,800 rpm slow, then we have different definitions of the term "slow rpm"..

short bursts to 5200. therefore, 5220 will cause irreversible and instant failure from they way you put things...

or is this crowded needles only? meaning a plain cage type could maybe possibly EXCEED this limit?


longevity and power... what? my 10,000 odd km or your 10,000 odd km ? sure...some engines do die prematurely. i put that down to the place i got em... and me. strangely, my skyhawk and zbox motors have lasted forever, when left alone. i have one of each. so, theyre still clocking up the km's without any of these dreaded failures. yes, i have a large box of dead engines as well. the forum abounds with quips of how ive blown engines... ALL MODIFIED. (except that one and only 66cc lemon pos)

i actually have not opened the skyhawk up, other than take the head off once. i even lent it to someone for several months, who used it daily.

all this cutting copying and pasting is too much, let alone why i should even bother replying in the first place. i have a good memory.if i read it, i remember it


maybe you meant you never said it in THIS THREAD???

you know, mufflers can be fitted and they work quite well

i know i may be on the other side of the border where the rules are slightly less draconian, but still...i have been stuffing around with motors on bicycles since the age of 16, and i have NEVER received any type of infringement notice for riding a motorised bicycle. ive been stopped, ive been questioned, ive been let go. again and again. and really...five times in total, max, isnt that bad in just under 16 years... sometimes with no helmet. sometimes being an idiot and doing the runner through the shopping center and surrounding streets. riding down BICYCLE PROHIBITED tollways....

then again, riding around in a world famous national park may have some bearing on the situation... yes, snobs with their heads up their...ahems abound.


12.54 per hour? i thought they were completely illegal down there? my, they must be relaxing finally


um...miles per hour? did you convert for the sake of our US friends? but that is still a strange 20.181 km/h so are you just making things up as you go?


youre already breaking the law with it. why not risk going a step further?

http://www.vicroads.vic.gov.au/Home/SafetyAndRules/SaferRiders/BikeRiders/PowerAssistedBicycles.htm

there is no speed limit if its the 200w version, and the sbp shift kit allows the engine to drive the wheel whilst the cranks freewheel. otherwise its a pedalec with a 25km limit and 250w... is the sbp kit unable to drive the wheel unless pedalling?


P.S. you know... continuous rating isnt the same as peak rating... you could get away with ANY horsepower but say it can only hold that for brief periods, therefore, it can only be 250W continuous... a lawyer could get that to stick in court, as well. just a thought. because that is a VERY BADLY WORDED PAGE< VERY CONFUSING>>>here it says 250, there it says 200, so whats the go? get a solicitor to read it and see what they think...

 

[Deleted member 12676]

Fab, HS, ya'll can argue via PM.
Here is my idea of what the perfect digital timing curve is for our engine if it peaks at 8500 rpm (in black) versus my analog CDI:

You can see that other than variation due to throttle position, my CDI is close enough.