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View Full Version : xv750 cdi performance upgrade



Wired1
17th January 2007, 21:06
I'm looking for a spare Yamaha XV750 tci/cdi unit to test a theory on...

:2guns: I just read an interesting article on the virago owners web site about the aging characteristics of the Yamaha (and probably every other) cdi unit capacitors. It argues very convincingly that the original capacitors were only rated for 15 years and after that will deteriorate with a resulting reduction in power and performance. Both my XV750's are pushing 25 so it stands to reason that they will be perfoming below par and could benefit from a boost of new caps in the ol' tickeroo (and we all know how that feels).
So this week's plea for XV750 parts is for a spare XV750 cdi unit that I can rebuild with the new components without risking the two I have that do actually work if not perfectly. The article also points out the Yamaha wouldn't have used the best components available in order to keep the cost down in the production run, so replacing with modern high quality capacitors will improve the performance of your bike even if it was still running OK to begin with.

This undoubtedly applies to all bikes with cdi or tci ignition which is all of them from the early eighties onward.

jaseman
26th November 2007, 21:05
Did you have any luck proving or disproving this? Sounds interesting.

Wired1
26th November 2007, 22:10
No I never got around to finishing it. I managed to get a spare CDI off ebay and I made a list of the capacitors required but then I sold the bike and got involved in another project. I does seem plausible though. If you wanted to do this and easy option would be to take your existing CDI to an electronic repair shop and get them to do it.

Pixie
29th November 2007, 10:12
Very few electronic ignitions are or were ever CDI's.The exeptions were two stroke dirt bikes and road bikes.

All others are Transistorised ignitions and dont store energy in capacitors to be dumped into the coil.

The manufacturer of these units will most likely to be Mitsubishi and they will not have the option of sourcing cheap components as the temperature requirements dictate high spec components and bulk buying minimises cost anyway.

Wired1
29th November 2007, 11:32
Yes of course he's right: http://www.sportdevices.com/rpm_readings/CDI_and_TCI.htm