Topic: replacing capacitors

[Johnny V]

Trying to make my bike (cb750) ride able. My points are shooting sparks so probably my capacitors are worn/bad.
because original/after market capacitors are about 8$ a piece I was wondering if I could replace them with normal capacitors as they would be only about .50c

[cookindaddy]

I would say that you could. They should be film type, like the ones you have shown. I am not sure of the value though. Does anyone know how many microfarads the regular caps are?

[bollingball]

Seem like I read they were 24mf TT or HM will know for sure.

                                            Ken

[Eddie]

Hmmmm...as long as the values are more than the orig I'm not sure that it maters....?? Would mean that there is more filtering involved and a higher voltage would be better anyway..

[bollingball]

I just went out to the shop and found two new Daichi caps no rating on them any where but the Honda part # on the box is
#30250-300-154. I don't know where that 24mf came from just brain cells firing off but I have a lot of dead ones. Maybe HondaMan or TT will see this Bump. I don't have any thing to measure them with. I just change them at the 3K tuneup.

                                     Ken

[cookindaddy]

I'm not sure they act in this case as filter but rather as snubbers, to keep the coil reaction from excessively arcing the points when they open. They should probably be in a range since too small won't be effective and two large might change the timing?

[ekpent]

Maybe these are more in your budget. Not that big of price to pay to keep things stock and simple.  http://www.z1enterprises.com/Ignition-Condenser--Honda-CB750-CB550-4444.aspx

[Johnny V]

It is not really about the budget. Found a post from Hondaman in this topic, http://forums.sohc4.net/index.php?topic=31534.0

 

Fortunately, the Honda condensors (or whoever it is that makes them) are manufactured to the tolerance range of .22-.26uF. I first stumbled on this whole thing when working on the Suzy Water Buffalo, famous for eating points in 6 months or less. It turned out that the coils were mismatched at anything below 3000 RPM, and the arcing was pretty at night, nasty on parts. We ordered an entire box of 144 condensors and I measured them with a pulse and VOM recovery (fixed resistor, fixed pulse, time the decay to 63%, all standard electronics stuff). We found the box had mostly 0.24uF (good thing!) and lots of 0.26uf, a few 0.22uF, so I installed those 0.26uF on the 750-3 bikes when they came in for tuneups. The parts fit all the Suzy Threes, and the Honda Fours, so using them up was no problem in a year. The spark on those bikes went from a bluish green to a bright blue with the 0.26uF, and that go me started on the whole "coil tuning" bit for other bikes as well. It became one of my "great tuning secrets" in those days. I used the 0.22uF on my 750 when racing.

Seems 220nF is the way to go, going to order a few caps soon and try it out.