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CB350Cafe first build
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393 Posts
Discussion Starter · #1 ·
Been Chasing some electrical gremlins and wanted to know if anyone had some experience or could share their thoughts with the following:

The bike has had aweful performance. Idles fine, steady, perfect sync, 1100rpm...but under load she craps out. sluggish, rpms fall off, she stalls...I have been chasing fuel as the symptoms are identical to a bike gettin ready to run on reserve...

Some measurements I have taken of the coils...
Primary: 4.6 ohms according to Clymer's (in spec)
Secondary: 22.6 Kohms and 23.2 Kohms Range in the Clymers says 10.6 to 15.8 Kohms ( I think mine are high...is this ok?)

Also Stator readings with the bike dead cold...stayed at 0.9 between all 3 leads, and they were all infinity relative to the ground/negative terminal on the battery.

Clymer's says these should be around .34 ohms. (my numbers again are high, but they are all equal) I am not getting the voltage I would expect revving the motor at 5000rpm (confirmed with digital tach) I never get above 13V. Battery is fresh, and cold bike not running I pin a 12.54V.

Tomorrow I plan to clean up the grounds and look up some of the ground mods/improvements as it seems these bikes are known for week grounding.

What do you guys think?
 

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Is my bike ok?
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15,025 Posts
Cleaning up the ground is not a bad idea. Also clean all the connectors. Especially those concerning the charging system!

Weak Ignition feels just like starving for fuel.

You could check and make sure the ignition advanced is working correctly. Not frozen or stuck. That will definitely cause poor acceleration.

Could be the voltage regulator now allowing the bike to charge. Or the rectifier. Not sure if your bike has a one piece R&R, or if your regulator and rectifier are seperate.

If it has a seperate voltage regulator some of those are points operated and adjustable. I had a bike that wasn't charging one time. Five minutes adjusting the regulator and it was good as new.

Sent from my SCH-R720 using Motorcycle.com Free App
 

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CB350Cafe first build
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393 Posts
Discussion Starter · #3 ·
working through the details. Thanks for posting Shinyribs...

The R/R on this bike is inbetween the resonator and frame to gain access...the grounds on this bike are typically poor at best...so I plan to add another ground from the negative post to the frame, AND drop the resonator and inspect the R/R, its ground.

Also found that the wire plug/caps have resistors in there that pinned at 9,550 ohms...these should be 5000 ohms. This certainly adds to the coil secondary resistance.

I will try to get the stock 5kohm resistors clean up the grounds and try the bike again.

Need to try and find a new R/R if ones even available, and check how much that will set me back.

The R/R on this bike is not servicable other than checking its connections and ground.
 

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I would say r&r if your battery is only getting that much voltage
 

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CB350Cafe first build
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393 Posts
Discussion Starter · #6 ·
I would say r&r if your battery is only getting that much voltage
thanks 94...
so by the numbers...
0 rpm bike off, 12.50Vdc
1400 rpm 12.33Vdc
3750 rpm 12.65Vdc
4950 rpm 12.75Vdc

never seen the Volts above 13...I know these TCI systems need probably 14 to 14.5V.
 

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CB350Cafe first build
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393 Posts
Discussion Starter · #7 ·
well as a follow-up I am going to add an additional ground as recommended by those that own Virago's, pull the existing r/r and check all of the connections as well as clean up its ground.

Also found a guy with a spare 87 xv535 r/r and going to test the bike to see if that's actually what is wrong!

hope that is it and I can call this one done...starting to run out of things to check.
 

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CB350Cafe first build
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393 Posts
Discussion Starter · #8 ·
Additional ground added, and replaced the R/R with an aftermarket. Back up to 13.76V running, and there is now residual charge on the battery when I shut the bike off!

Performance is still not 100%, but it is much improved.

The secondary resistances of the coils were high, so I removed the resistors and springs, and replaced them with .138" diameter aluminum rod cut to 1.400" long. This brought the resistances back into spec.

Will swap out the plugs with resistive types so I can still filter any electrical noise.

Will post some pics later. Feels good to have narrowed it down to what was actually needed instead of guessing and throwing money and parts at it.

Thanks for all your help.
 
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