cdi alternative?

GoldenMotor.com
Cabinfever1977

Cabinfever1977

New Member
Mar 23, 2009
2,288
1
0
Upstate,NY
i was on the other engine bike website the other day and saw that someone had replaced there cdi with a yamaha yz 80 cdi(78 model with 2 wires) and it worked for them.
im not saying to go and use one since are regular stock cdi's are only like $10 or so.
but that guy was having problems with all his stock cdis and he found that one at a local store and it worked better for his engine on his bike.i dont think he paid much for it either since he bought it used.

its possible that it could be used as a alternative cdi,maybe if someone tested it out.
 
Cabinfever1977

Cabinfever1977

New Member
Mar 23, 2009
2,288
1
0
Upstate,NY
$50,well maybe only if you really need one while youre waiting in the mail for a replacement stock one,but you could probally get a stock cdi from fedex or ups in a couples of days,but with shipping it would be close to $50

im guess im lucky my stock cdi still works.
 
Cabinfever1977

Cabinfever1977

New Member
Mar 23, 2009
2,288
1
0
Upstate,NY
i found some lower price cdi's online but there not the 2-wire ones.
i dont think motorcycle parts are good replacements for our bike engine parts because there high prices,unless you have some lying around.
 
Last edited:
M

matt167

New Member
May 20, 2009
420
0
0
usa
remember, you get what you pay for.. our CDI's are $10 but the spark ignition is probably not accurate when it comes to spark timing... with a motorcycle or dirt bike box, you will gain the ability for a real tachometer ( not the tiny tach with a 5yr non replacable battery and 2.5s response ) if you choose, as well as higher energy spark ( run wider plug gaps= jetted richer and more power )..

if your really looking for cheap, eliminate the CDI and run the plug wire off the mag just as your weed eater or chainsaw does
 
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
I just checked my plug gap I was at 40 thousands with a Direct hit From pulstar its was running just fine! Did not have my gapper handy when I put it in I was eyeballing for 30 thou....
 
M

matt167

New Member
May 20, 2009
420
0
0
usa
goat herder said:
I just checked my plug gap I was at 40 thousands with a Direct hit From pulstar its was running just fine! Did not have my gapper handy when I put it in I was eyeballing for 30 thou....
Click to expand...
doesn't mean it is a good consistant spark... 2 strokes will run with any kind of ignition, doesn't always mean it will run it's best... somthing that sells for $10 will never be as good as somthing that sells for $50.. you just can't expect it to
 
M

matt167

New Member
May 20, 2009
420
0
0
usa
I'v seen those... general consensus in the automotive world, is they don't gain anything ( dyno testing ), but on a 2 stroke who knows.. possible an old resistor plug could do the same gain tho
of course, average voltage on a car that would test on those plugs is 10-40k volts, and a little CDI may do 10k volts on a good day.. so there are some diffrences


BTW, the CDI is a coil... the magneto creates a 'pulse' and it induces energy in the secondary windings of the CDI, making spark voltage.. the spark is not directly magneto driven
 
Last edited:
M

matt167

New Member
May 20, 2009
420
0
0
usa
there are normal plugs available.. the plug numbers you can use are in the engine checklist thread
 
M

matt167

New Member
May 20, 2009
420
0
0
usa
not that I'm aware of.. truthfully, I have my doubts about those kinds of plugs and put them right up there with E3 an splitfire plugs as complete gimmicks.... no reason a resistor plug wouldn't do the same thing for what the end result will be
 
Cabinfever1977

Cabinfever1977

New Member
Mar 23, 2009
2,288
1
0
Upstate,NY
my regular plug works fine,im just happy if my engine stays on my bike and dont fall off.
id worry about good mounting brackets and stuff and not replacing whats working good already.
 
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
noobtard said:
so, the are no "regular" pulse plugs in our size I take it?
Click to expand...
No there is not Thats why in that post I left a link to the Direct hits.....Outperformance Shop - Pulstar DirectHits S100 S-100 50mm Universal Automotive I just got two more and will be using it with Norms light. To see how well that works. Nobodys gonna get hotter spark than this that I know of. Cabin guy here has a just Idea get it working first. However the subject on spark here was my two cents for the title of this thread..........
 
M

matt167

New Member
May 20, 2009
420
0
0
usa
goat herder said:
I would not be caught dead with a resister plug in one of these chinas......Resistance kills spark!
Click to expand...
Resistor plugs are actully common place in magneto ignitions.

In very old Magneto ignition automotive engines ( like Ford Model T's ). they used resistor plugs. when the mag saturates, the resistor still has held energy, and allows the plug to burn longer- thus somthing you may want in your China

they were also used up until the 50's in certin automotive applications producing weaker spark.. 12v ignitions pretty much eliminated the need for them, as they could produce 10-20K volts ( we are talking circa 1955, and not current day 100k volt ignitions )

lots of your lawn mower plugs are resistor plugs too..
 
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
The Chinas magnetos are way to weak for resistance in this subject. The pulse jig was works on this delicate scenario..
 
M

matt167

New Member
May 20, 2009
420
0
0
usa
goat herder said:
The Chinas magnetos are way to weak for resistance in this subject. The pulse jig was works on this delicate scenario..
Click to expand...
and Model T coils are cased in wooden boxes and very crude at best.. I doubt they are any worse than the CDI coil... the model T engine used a magneto in the same way the CDI does except it uses a series of points and contacts to control everything as there 4 strokes.. the magneto sends a 'charge' to the coil ( the CDI box is a coil ).. the windings are charged and then discharged, inducing a spark voltage in the plug wire.. just like any automotive coil.... so the weakness of the output of the mag really has nothing to do with the spark voltage, because the mag simply operates the primary windings of the coil..


If you see a diffrence between regular plugs and pulse plugs, there may be some monetary gain, it could be there just a hotter plug and burn better.. I still say a resistor plug will likely perform the same function as the pulse plugs, because the goal of each is the same and that's a longer spark dururation... I'm not saying theres any right or wrong, because there is little documentation on these engines that actully comes from the manufacture.. our suppliers have figured out what it takes to make them function
 
Last edited:
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
The pulse jig is a step up transformer when you look at the schematic. Yes I know the tricks for good old cars . How to start a flooded engine on a distributer system. you hold the coil wire a short distance from the coil when it jumps the gap it is a hotter spark. Fun mystery ignore the pulsing electricity running through your hand while watching observe. Whats funny to observe and research is the high breeds out there why are they using these things? What was the purpose why was the point of it gee they could have just put a resister plug in them and been done right? Or we missing something I saw one of these working on a display once I will never forget it. Any who I have yet one last thing to try. Have not dun it yet so I don't know , but will soon find out.........
 
You must log in or register to reply here.
Top Bottom