Without any long, boring explanations.. think of a four cylinder Jap bike as two twins. Independent everything, little shared. Kinda' like losing one channel of a stereo amplifier. As for used parts, given the cost of new (if available) I don't see much of a problem. Electronics are go /no go items. Our shop has for a music system a 1971 Sony receiver that runs 9 hours a day, six days a week. Works great. It replaced a unit that failed after only a year from new back in 2000. For the most part, bike electrics most often fail from dumb stuff that could have been avoided IE; jump starts with incorrect polarity, bad grounds allowing voltage surges, etc.
--- On Tue, 6/2/09, oldschoolgwin <[email protected]> wrote: From: oldschoolgwin <[email protected]> Subject: [Nighthawk Lovers] Re: Formerly 700SC Carbs - now ignition To: "Nighthawk Motorcycle Lovers!" <[email protected]> Date: Tuesday, June 2, 2009, 5:29 PM Dennis, I have the exact same issue on my newly aquired 83 650NH. Went through the same diagnosis steps as you (confirmed by Dennis H - thanks Dennis). What does seem wierd is the loss of half the output (i.e. 2 inner cylinders loose spark) instead of loosing all output of the CDI. Does anyone have any experience as to how the CDI fails? Is it two independant circuits in the CDI where we would expect only half of the CDI output to fail? I am going to try and repair mine - because if i buy an old one ($50 to $100) how long will it last? I wonder how often the CDI's fail on bikes this old? If i'm succesful on repair I plan to write a BKM for others to use. Paul On Jun 2, 6:46 am, "Dennis" <[email protected]> wrote: > The Honda manual refers to it as the "Spark Unit". It says on it, > "Igniter". And I think they may also be called "CDI" and I'm guessing that > this is an acronym for "Capacitive Discharge Igniter". When you take the > tank off on a CB700SC, it is the square box mounted on top of the central > frame bar near where the rear of the tank sits. > > Dennis G. > - Seattle > > > > -----Original Message----- > From: [email protected] > > [mailto:[email protected]] On Behalf Of Graham Rogers > Sent: 02 June, 2009 01:44 > To: [email protected] > Subject: [Nighthawk Lovers] Re: Formerly 700SC Carbs - now ignition > > what's a spark unit? > > On Jun 2, 2009, at 12:24 AM, Dennis wrote: > > Dennis, > > Thanks for your help! The bottom of 19-4 says I'll be needing a spark unit > since all the other parts seem to check out. I'm guessing this part is no > longer available from Honda and I'll need to get it from a yard that parting > out a CB700SC? > > A general question to any and all - anyone have one of these or seen one go > by recently? > > Cheers! > > Dennis Gallagher > - Seattle > - one running CB700SC '85 and one half running CB700SC '86. > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Dennis Hammerl > Sent: 01 June, 2009 20:28 > To: [email protected] > Subject: [Nighthawk Lovers] Re: Formerly 700SC Carbs - now ignition > > Sorry.. your answer is at the bottom of page 19-4. > > --- On Mon, 6/1/09, Dennis <[email protected]> wrote: > > From: Dennis <[email protected]> > Subject: [Nighthawk Lovers] Formerly 700SC Carbs - now ignition > To: [email protected] > Date: Monday, June 1, 2009, 10:03 PM > > Dennis, > > I pulled the cable that runs from the ignition block to the pulse generator > and I measured the leads going to the pulse generator, as the manual > described, and on the wht-yel pair (cyl 2,3), I got 349 ohms and on the > wht-blu pair (cyl 1,4), I got 349 ohms. > > They didn't say how to test the ignition block. > > I'm going to put it all together again and see if it behaves the same. > > I'm most interested in your thoughts on "where to next" in this > troubleshooting. > > Cheers! > > Dennis Gallagher > - Seattle > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Dennis > Sent: 01 June, 2009 18:42 > To: [email protected] > Subject: [Nighthawk Lovers] Formerly 700SC Carbs - now ignition > > Dennis, > > OK. I pulled the coils out and the primaries measure 3.2 ohms and 3.2 ohms > and the secondaries are 14.9K ohms on the left coil and 14.7Kohms on the > right coil. I'm thinking that they are OK? > > Back to the manual now to see what's next. > > Dennis G. > - Seattle > > -----Original Message----- > From: Dennis [mailto:[email protected]] > Sent: 01 June, 2009 16:56 > To: '[email protected]' > Subject: Formerly 700SC Carbs - now ignition > > Dennis, > > I opened the screw on each of the four bowls and had gas in each. > > Then I pulled the four spark plugs out and attached each to its plug wire > and laid all of them on the metal fins and cranked the bike over. The two > inner plugs, which correspond to the coil on the right had spark. The two > outer plugs had no spark. I think the non-sparkers are both driven by the > coil on the left as you face forward. > > That's the news so far. > > I'm going to see how hard it is to remove the coils so I can check all their > connections and measure their primary and secondary resistances. But I am > open to 'what's next suggestions". > > Cheers, > > Dennis Gallagher > - Seattle- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en -~----------~----~----~----~------~----~------~--~---
