Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 350 Talk => Topic started by: Stoneman on May 25, 2022, 12:48:03 PM

Title: Installing New Condensers?
Post by: Stoneman on May 25, 2022, 12:48:03 PM
I have a new set of condensers to install on 350 GTR. Looks like the leads coming from inside the dynamo must be unsoldered and then soldered onto the new condensers? Guess I can do this but looks like a pain. Any advice?

By the way, looks like existing condensers are original to the bike which has less than 5000 miles on the clock. Am I correct in assuming they ought to be replaced? Multi-meter readings for Ohms and DC voltage look weak compared to new condensers.
Title: Re: Installing New Condensers?
Post by: mrjones on May 26, 2022, 08:32:16 AM
 The leads from the generator go to the points and should have a "U" shaped end on them the condensers are mounted with a screw and also have a u shaped end on them which goes to the points, i use Kawasaki z650 condensers but im sure many others will fit, they dont cost much and even though yours are low mileage they are old!
Title: Re: Installing New Condensers?
Post by: Stoneman on May 26, 2022, 09:08:00 AM
Thanks, MrJones.  I don’t have the U connectors on the dynamo leads but I’ll put them on when doing the condenser change out. Will at least be easier next time.

It crossed my mind that I should look into electronic ignition and forego the points and condensers altogether.
Title: Re: Installing New Condensers?
Post by: OldSwartout on May 26, 2022, 10:11:57 AM
You are correct that the condensers must be unsoldered/resoldered in the original design. The originals do go bad after this much time has passed.  Mrjones is correct that there are various replacements available meant for other bikes.

A different solution is to unsolder the originals, remove them, cover the bare wire sections going to the points.  Then buy new condensers intended for older autos with points. Some have a bracket and lead with a spade connector. Then mount those under the tank with the lead connected to the coil terminals coming from the points.

Electronic ignition is a good way to go but takes quite a bit of time to do.
Title: Re: Installing New Condensers?
Post by: Stoneman on May 27, 2022, 10:51:38 AM
Thanks, OldSwartout! Guess I’ll be warming up the old solder gun; not that much trouble really.

I also have a new set of points. Any reason the originals would go bad from age? They look to be in good condition, at least no pitting on the contact surfaces. Again, 4,700 miles on the clock.
Title: Re: Installing New Condensers?
Post by: czmike on May 27, 2022, 08:07:11 PM

Hi Stoneman,

Ignition condensers on a two stroke motorcycle have a hard life, for an electronic component.
They are subjected to peak voltages of around 250 volts each time the points open.
This voltage is cyclic at a fairly high frequency so the condensers have to charge and discharge somewhat about 3,000 times a second each time the points open.
This rapid charging & discharging current heats them up and so does heat from the engine and the dynamo.
They are subjected to a wide range of vibration from the engine, dynamo & road shocks.
The materials they are made from (paper, wax, aluminium foil, etc.) age reasonably well but eventually fail.
Even sitting on the shelf for years.

They are difficult to test thoroughly.
You need to apply a high voltage (at least 300 volts) to them to check for leakage properly.
Multimeters use only very low voltages for their tests although many of these can measure the capacitance value for you.
Old school condenser testers are the best things to test them with as they usually contain a high voltage source.
Being an ignition nut I restored one (photo attached) and it is an amazing thing which has caught failed condensers that otherwise tested good.
Even new ones!

Ignition condensers are cheap enough and quite plentiful so get new ones and perhaps get an old ignition guy to test them if you want (it is a good idea!).

Best Regards,

Mike Munday
Title: Re: Installing New Condensers?
Post by: Stoneman on May 28, 2022, 11:18:47 AM
Thanks, Mike, thorough explanation and all the more reason to change these old ones out. Plan on doing it today.
Steve the Stoneman
Title: Re: Installing New Condensers?
Post by: Stoneman on May 28, 2022, 02:02:27 PM
Mr. Jones, I see quite a few similarly configured condenser sets for the KAWASAKI Z650. Some refer to 1978 model, some say ‘79. Does it matter? Or could you tell me the model year condensers you are using?

The new condensers I have, bought from Richard in 2013 have the mounting bracket that also holds the oil wick for the points lobe assembled backwards. It just won’t work and doesn’t look like bracket could be removed and turned around.
Title: Re: Installing New Condensers?
Post by: mrjones on May 28, 2022, 06:45:43 PM
 i read on this forum that z650 points and condensers will fit so i just got the ones that looked the same!