What resistor for COP conversion

[AMechEng]

What resistors are you guys using to convert to COPs. My stock coils primary is 3.0 ohms. My Denso sticks are 1.3. So what is everyone using? 2.0 ohm, 50 watts? I have a feeling people are using smaller resistors since it's not constant current.

 

[AMechEng]

http://www.newark.com/ohmite/b20j2r0e/resistor-wirewound-2-ohm-20w-5/dp/64K3770
http://www.newark.com/multicomp/mcprw0fwjw20jb00/resistor-wirewound-2-ohm-15w-5/dp/16R2068

The second link is what I ordered.

 

[alorio1]

Here is some info that might intrest you...........
http://www.vmaxforum.net/showthread.php?t=5427

 

[wildweasel_pt]

1ohm 20W is enough. I have an extra set that I can let you have for the price it costed me. Enamel resistors for heat resistance and good dissipation. I can email you the specs if you wish

 

[Bill Seward]

I never added resistors to my COP setup on my '85. So far not a problem, but your mileage may vary.

 

[AMechEng]

Thanks guys. I've got the stock coils out now so that I could use the space for my fuel pump. according to USPS tracking I won't have the resistors I ordered until Saturday and I'm taking the bike to the Keys Friday so I'm going to button it up without the resistors and see how it fairs.

 

[wildweasel_pt]

Be careful as early analog TCIs are prone to burn as current rises due drop in cops primary resistance.

 

[AMechEng]

Do you think 6 ohm power resistors will work temporarily?

 

[one2dmax]

I'm not sold that the CDI's need resistors. We do sell the resistor adapters for peace of mind but I just don't think it needs it. Besides, if it burns up then that's a good excuse to get the Ignitech CDI box which doesn't need them!


Sean

 

[AMechEng]

Cool

 

[AMechEng]

I never added resistors to my COP setup on my '85. So far not a problem, but your mileage may vary.

I laughed when I saw your mileage. I'm around 18000 miles on mine.

 

[AMechEng]

I've got the COPs on with no resistors. Bike runs great. Big improvement. Lost one of my bar end mirrors though.

 

[davesax36]

Lost one of my bar end mirrors though.

Well that's one of the other side-effects of no resistors.... :ummm:

(I run the resistor ones on mine because I bought my kit from Gannon)

 

[AMechEng]

Lol its a side effect of someone bumping into it and then me test riding the bike at high speed in the dark.

 

[AMechEng]

I put a few hundred miles on the bike this weekend with the COPs and no series resistors and the bike is running great.

 

[88vmx12]

I'm not sold that the CDI's need resistors. We do sell the resistor adapters for peace of mind but I just don't think it needs it. Besides, if it burns up then that's a good excuse to get the Ignitech CDI box which doesn't need them!


Sean

I think the main issue was what coils were being used, that is when failure occurred.

G

 

[dingy]

What resistors are you guys using to convert to COPs. My stock coils primary is 3.0 ohms. My Denso sticks are 1.3. So what is everyone using? 2.0 ohm, 50 watts? I have a feeling people are using smaller resistors since it's not constant current.

With a TCI the coils are continuously powered, except for brief interruption of current in negative side of coil circuit, which causes the coil field to collapse thus firing plug.

A CDI works the opposite, coil is triggered by a brief flow of current through the coil, majority of time coil circuit has no current flow.

With mostly constant current flowing through coil circuit, the power the resistors need to dissipate is higher than what would be needed with a CDI controller.

The Ignitech TCI has a dwell setting that compensates for the lower coil resistance. They recommend the dwell be shortened with coils that have a primary resistance less than 2 ohms.

Gary

 

[88vmx12]

With a TCI the coils are continuously powered, except for brief interruption of current in negative side of coil circuit, which causes the coil field to collapse thus firing plug.

A CDI works the opposite, coil is triggered by a brief flow of current through the coil, majority of time coil circuit has no current flow.

With mostly constant current flowing through coil circuit, the power the resistors need to dissipate is higher than what would be needed with a CDI controller.

The Ignitech TCI has a dwell setting that compensates for the lower coil resistance. They recommend the dwell be shortened with coils that have a primary resistance less than 2 ohms.

Gary

Thank you , we'll said..... I have been wanting one of those gizmos :ummm:
G