Poor Idle Continues (Voltage Problems?)

[zexus]

I have been having some issues with my bike over the past few weeks and posted up in a couple of threads about my issues. After getting a bunch of advice from many great people I tested my stator and r/r and didn't find any problems. I replaced my battery but still seem to be having the same problem...the bike idles poorly when at warm idle and seems to stumble when the fan kicks on. The following are the voltage readings in various states. Maybe someone can tell me if these look suspicious.

Bike Cold:

Nothing on = 12.8v
Lights on = 12.3
1000rpm = 13.4
1000rpm + Fan = 12.87
2000rpm (no fan and still cold) = 14.31
4000rpm (no fan and still cold) = 14.25


Bike Warmed Up:

1000rpm (no fan) = 14.5
1000rpm + fan = 12.6
When fan turns off voltage increases to 13.3

When fan turns back on for second time it drops to 12.4
When fan shuts off for the second time it again goes up but to only 12.7

When fan turns back on for the third time drops to 12.3
When fan shuts off for the third time it goes up to only 12.5

What I see here is a continual drop in power after each cycle of the fan. As the bike got warmer the rpms started to falter (poor idle). I figure that by the fifth cycle of the fan the bike would probably stall. What I am seeing is the voltage dropping from 13.3 to 12.7 to 12.5. Is this normal? Is it possible this battery is bad? Or maybe I got coil problems?:bang head:

 

[naughtyG]

Have you performed the crimp fix yet? There are a lot of crimps in the MAx harness that could increase in resistance with heat, but the main one is the one under the seat near the battery that crimps all the positive wires from RR, Battery etc.. Soldering it helps a lot!

 

[zexus]

Have you performed the crimp fix yet? There are a lot of crimps in the MAx harness that could increase in resistance with heat, but the main one is the one under the seat near the battery that crimps all the positive wires from RR, Battery etc.. Soldering it helps a lot!

I by-passed the r/r crimp by directly wiring the r/r to the battery positive terminal.

 

[mr.maxx]

try an extra ground wire from the battery to one of the bolts to the mount that holds the rear coil mount. 10 ga. sand off all the paint 4 a good connection. that helped my bike .

 

[zexus]

try an extra ground wire from the battery to one of the bolts to the mount that holds the rear coil mount. 10 ga. sand off all the paint 4 a good connection. that helped my bike .

Okay, I'll give that a try. Thanks.

 

[zexus]

It sounds like people really believe my problem is with the r/r. I'll try grounding the r/r to the negative battery terminal and if that doesn't help then I guess I should pick up a new style vmax r/r (finned) or one from a zx14.

 

[sdt354]

I've not had much luck with early R/R's and consider the ones you mentioned superior and a good upgrade. And, it's probable the charging system isn't up to snuff. But, just my 2 cents, you might want to look at the fan motor for excessive currant draw? Voltage drop through the fan circuit? (dirty connections or pinched wires) Check play in the motor shaft? Just to eliminate the possibilty before spending the $$.
Steve-o

 

[jfeagins]

It sounds like people really believe my problem is with the r/r. I'll try grounding the r/r to the negative battery terminal and if that doesn't help then I guess I should pick up a new style vmax r/r (finned) or one from a zx14.

+1


I originally cleaned up all the R/R mounting points and ran a ground specific wire from where the R/R bolts to the footpeg assy and ran it straight up to the battery, and at the same time I did the bigger battery box mod to my 85, and in doing so, added some reserve voltage for those times stuck at a light or in traffic idling. It helped somewhat, but in the end, I had to upgrade to the new style R/R too.

I got a deal from Sean Morley (One2dmax) here on the forum. My bikes' ran great ever since.

 

[Miles Long]

I've not had much luck with early R/R's and consider the ones you mentioned superior and a good upgrade. And, it's probable the charging system isn't up to snuff. But, just my 2 cents, you might want to look at the fan motor for excessive currant draw? Voltage drop through the fan circuit? (dirty connections or pinched wires) Check play in the motor shaft? Just to eliminate the possibilty before spending the $$.
Steve-o

+1. Probably just a smoking gun, but eliminate a failing fan as a cause of the dropping voltage readings as the bike warms up.
With the bike off, disconnect the feed wires, jumper the fan to your spare battery, do a current draw test, with your multimeter set up to measure amps. Run the fan for a while, see if amperage ramps up. Not likely, but an easy thing to do.
Based on my own recent experiences, and given the fact that you have already installed a new battery (another PC680?), I would suggest upgrading the regulator to a newer style. Not a large expense, easy to do,and a valuable upgrade, even if not the root cause of your problem.
Cheers!

 

[MANA1]

Just curious if your bike ran poorly at idle as if running on three cylinders. Unfortunately I have the same type of problem that you had. Still debating on getting a rr off a r6 from ebay or another oem finned unit.