plug wires

doug rooney · Post by **doug rooney** » Thu Mar 11, 2010 8:15 pm

I need to install a new plug wire on my TC250. can anyone recommend what I should get? Thanks

Buffalo-guy · Post by **Buffalo-guy** » Thu Mar 11, 2010 11:50 pm

Doug.
Any 7mm, wire core, non resister plug wire will do the deed. Should be available just about any where. If not, let me know, because I have a whole spool of the stuff, and could send you some. Don't forget to re-install the wire in the coil with some RTV silicone. How are the plug caps? Anyway, good luck with it, and I hope it cures your ignition troubles. Cheers.
Fred

doug rooney · Post by **doug rooney** » Fri Mar 12, 2010 6:22 am

I can find 7mm wire here and caps appear in great shape.
Thanks Fred!

H2RICK · Post by **H2RICK** » Mon Mar 15, 2010 1:51 pm

Doug, you definitely want to check those caps with your ohm meter. Looks can be deceiving.
IF/IF they are the original caps then they will be the non-resistor type and you should get a reading of zero ohms on your meter with the meter selector knob set at its lowest value.
However, if the caps been replaced at some time in the past with resistor type caps then you will get a reading of infinity or OL or 1 on your digital ohmmeter. Turn your setting knob on the meter to 20 K ohms or thereabouts and try again. If a cap is okay, you will get a reading of about 5 K ohms (4.6 to 5.2 is acceptable). If the reading is higher than that then the resistor inside the cap is faulty and the cap should be replaced.

TLRam1 · Post by **TLRam1** » Mon Mar 15, 2010 3:47 pm

What is the purpose of the resistor caps.

tz375 · Post by **tz375** » Mon Mar 15, 2010 4:11 pm

RF Noise suppression.

A non resistor system makes a lot of RF noise

doug rooney · Post by **doug rooney** » Mon Mar 15, 2010 6:11 pm

Thanks Rick, Tl, and Tz. Great tips and will check it out manana. Sundial folks come through again!! Hey boys....I'm gettin real close to cleaning her up and posting a pic. Week or so I think and this "old crotch rocket" will be on the road! I know, I know... been saying that for awhile.

TLRam1 · Post by **TLRam1** » Mon Mar 15, 2010 9:31 pm

tz375 wrote:RF Noise suppression.

A non resistor system makes a lot of RF noise

Did some of these come with resistor caps, why would you have resistor caps on these old bikes.

H2RICK · Post by **H2RICK** » Mon Mar 15, 2010 9:55 pm

Did some of these come with resistor caps, why would you have resistor caps on these old bikes.

This was right around the time that this type of cap was starting to become legislated in many jurisdictions. The "why" was because the polizei radios (and normal car and home radios and teevees) were beginning to receive more episodes of interference because there were more bikes on the road. Cage ignitions didn't bother radios so much because all the sheet metal acted as a shielding system.....of sorts. IIRC, by 1973 or so, even cages had to have built-in RFI suppression in their ignition systems.

doug rooney · Post by **doug rooney** » Tue Mar 16, 2010 8:14 am

Just did your test Rick and they have obviously been replaced as both look different. Meter at 20K, I got 10.1 on one side (side that was firing) and 4.1 on the other so appears I need 2 new ones. Thanks so much for the tips!!!!!

rbond · Post by **rbond** » Tue Mar 16, 2010 9:55 am

Check for after market coils, like Dyna S. They have a good range of coils that fit just about everything. Once you determine which ones, 'Google' that part number to see who has a good price on them. I put non-resistor wire and caps on mine and have not noticed any RF problems. These ignitions are weak sisters as it is, so any help for max power to the coils is a good thing to me!!!

doug rooney · Post by **doug rooney** » Tue Mar 16, 2010 11:12 am

Thanks Rbond. I have a pair coming (used but good) free of charge from a friend down in Ms on another board.