Ever burn a CDI box up with a NON-Resistor?

MikeT

~SPONSOR~

Jan 17, 2001

4,095

11

• Apr 21, 2004

• #1

I know everything that has been said about why you should use a Resistor spark plug but other than a recent issue of MXA where they used and aftermarket ignition system, I have never heard of any one burning up a CDI box or any ignition system by using a Non-Resistor plug. Maybe there is someone out there. The reason I am asking is because I want HARD proof and not just hearsay on this issue. Also, when I bought my "new" bike, the guy handed me a full box of non-resistor plugs (8 total) and said don't believe everything you hear. Well, I've heard use a Resistor and that's all I ever used in my post 1990 bikes. Pre 1990 I used non-resistor and never has a problem myself.

Although this issue has been rehashed several times, I want to know if you KNOW of anyone who has had problems that can be tied to the fact that they weren't using a resistor plug on a stock ignition.

 

D

dirt bike dave

Sponsoring Member

May 3, 2000

5,348

3

• Apr 21, 2004

• #2

Mike,
I don't think the issue is burning up the CDI. The issue is the electrical interference preventing the bike from running at its full potential. Most the warnings from the mags say Honda's are most prone to electrical interference.

If you have ever had non-resistor plugs in an old car, you can hear major electrical interference on the AM band. Resistor plugs will largely prevent this.

From my '99 CR250R manual:

"The use of a non-resistor spark plug may cause ignition problems".

Note that it says 'may cause problems', not 'will cause failure'.

But why take a chance if your bike calls for a resistor plug? You are not going to gain any performance by using a non-resistor plug.

 

D

Dewster

Member

Feb 4, 2002

216

0

• Apr 21, 2004

• #3

For what it's worth, I've used resistor plugs in my bike since day one and my CDI went out. :think:

 

Last edited: Apr 22, 2004

Rich Rohrich

Moderator / BioHazard

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Jul 27, 1999

22,839

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Chicago

• Apr 21, 2004

• #4

The Wolf CDI boxes that FMF sold under their own label were prone to puking on non-resistor plugs.

The most common problem I have seen is high rpm mis-fires from the use of non-resistor plugs, but the exact cause is unclear to me. There is enough evidence in my mind that changing to resistor plugs can cure those issues to warrant their use. There is no logical, or performance related reason to run a non-resistor plug.

 

MikeT

~SPONSOR~

Jan 17, 2001

4,095

11

• Apr 21, 2004

• Thread starter
• #5

Believe me, I don't think there is a performance issue either. I just have a full box (that was given to me) of non-resistor plugs and I want to be sure my bike isn't going to have a costly malfunction because of them.

 

Rich Rohrich

Moderator / BioHazard

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Jul 27, 1999

22,839

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• Apr 21, 2004

• #6

1 box of non-resistor plugs tossed in the garbage = $10

The value of knowing you didn't hurt your bike while acting like a cheapskate = PRICELESS :)

 

B

Bizerk

Member

Feb 28, 2004

142

0

• Apr 21, 2004

• #7

Resistor

At the moment the spark jumps the gap it causes a high frequency burst of energy, this is known as RFI')">RFI (radio frequency interference). This is why resistor spark plugs were introduces in the mid 1960's. Placing a resistor within the spark plug suppresses the RFI')">RFI. Without resistor plugs in your car you can experience static on your radio as well as interfere with other sensitive electronic equipment. Some later model vehicles as well as newer Powersport engines must use resistor plugs for a proper "talkback" to the electronic ignition. Outboard marine Capacitive Discharge Ignition (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor ( as used in NGK Z-type spark plugs). Use of non-inductive resistor type plugs on these motors can cause misfire and poor performance.

 

V

VB Racing

~SPONSOR~

Jan 26, 2004

117

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• Apr 21, 2004

• #8

I can second what Rich said, I was at an ice race a couple years ago, fouled a plug, and threw in a non resistor for the heat race. I had an FMF ignition on the bike(awesome ignition, by the way) . The bike missed at high RPM, and had a dramatic loss in power. Switched to the proper plug after the heat race, problem solved. I also know that a non resistor plug WILL mess with the signal from the TP sensor on the carb. You have to remember with electronics you are working in milivolts, and they are easily manipulated by stray voltage. God forbid you get a voltage spike, then you will see smoke coming out of the CDI.
I work with electronics every day in an automotive environment( I am a driveability specialist at a local shop). I have seen some very strange things happen because of stray secondary ignition voltage. I once had a Ford Thunderbird in the shop that had a faulty processor. Whenever the car was running , all the radios in the shop would blink out. It was because of a stray signal from the vehicles processor.
I hope you get the idea.
My 2 cts

 

D

Dewster

Member

Feb 4, 2002

216

0

• Apr 22, 2004

• #9

VB Racing said:

I once had a Ford Thunderbird in the shop that had a faulty processor. Whenever the car was running , all the radios in the shop would blink out. :p
My 2 cts

Click to expand...

Ok, now thats borderline "erie". Ever see the movie "Christine"?

 

bclapham

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Nov 5, 2001

4,340

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• Apr 23, 2004

• #10

CDI boxes are >>>>$200- just not worth the hassle if you ask me- so the other question, how come the dude had a box of 8 plugs? i take it no one else wants to buy them either!

 

R

Rcannon

~SPONSOR~

Nov 17, 2001

1,886

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• Apr 23, 2004

• #11

One time, at band camp, I had this happen.

Look at many of the "box-o-plugs" for sale on that auction site, CBAY. Lots of them are from salt lake city. There is a local freight damage place that gets loads of sparkplugs. The plugs have been handled in a questionable manner. many of the containers have been wet or dropped.

There is one particularly lazy (and smelly)guy that uses this place as a way to make some sort of living. He rounds up all the crap he can carry and dumps it off as new on C-Bay.

I dont mind buying the crap for personal use or giveaway, but be darn careful of "new plugs" from Salt Lake City.

 

S

Studboy

Thinks he can ride

Dec 2, 2001

1,818

0

• Apr 25, 2004

• #12

Ha, MPS. I can't believe that somebody would be sleazy enough to pass off anything from that place as "new".