Rough running first kilometers

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panhead
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Rough running first kilometers

#1

Post by panhead » Thu May 10, 2007 12:27 pm

I have the following problem: starting and idling is no problem. First 1 - 2 kilometers the motor is running rough (one cylinder, coughing and spitting) and the generator light is on. After 2 kilometers everything is back to normal. I use electronic ignition. What could be the cause of this?



fourthgear
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#2

Post by fourthgear » Thu May 10, 2007 1:16 pm

Panhead
The fact that the Gen. light is comming on is a clue thats its probably electical in nature, sounds like low voltage at first and then the charging system brings it back up after running a bit. The voltage has to be above your running voltage for the coil and of course your electronic ign. system , they are real picky about voltage .How old is the batt. and try to take a volt reading before and after you first start her up ,before you take a ride. Another thing is , some times coils act up when they are going bad or cracked , some seem to get worse when warm or the other way around .

panhead
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#3

Post by panhead » Thu May 10, 2007 1:21 pm

I will check the voltage before & after starting. The coils are over 15 years old, so that might be a problem.

DuoDave
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misfiring

#4

Post by DuoDave » Fri May 11, 2007 11:45 pm

It could be the coil breaking down, try another coil if avaialable. However, I would expect the coil problem to show up when the bike is hot. I would try another battery first and see how that goes.

panhead
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#5

Post by panhead » Fri May 11, 2007 11:55 pm

It's not the battery, I changed that one already. If weather permits I'll check the voltage this weekend.

lockdoc
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#6

Post by lockdoc » Sat May 12, 2007 5:43 am

I also have an electronic ignition with a new Accel super coil that exhibited the same symptoms as yours but only for a day. The second day I only had output on one leg of the coil. Replacement on the way. My generator light would flash but I assume it was only because the rpm's dropped so low. I'm hoping it was just a defective coil and not something with the charging system blowing it out. Battery is good and seems to be charging fine so we will see.

panhead
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#7

Post by panhead » Sat May 12, 2007 8:26 am

What I forgot to mention is that I have two coils (dual plug STD's), I can't imagine they are both breaking down. And why does it only happen in the first kilometers? If it is a defective coil I assume it would happen more often.

panhead
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#8

Post by panhead » Sun May 13, 2007 12:24 pm

volt reading before and after you first start her up
Before starting: 12.40
After starting: 11.80 (idling)

Panacea
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#9

Post by Panacea » Sun May 13, 2007 3:51 pm

Did you polarize? Mike

panhead
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#10

Post by panhead » Sun May 13, 2007 4:31 pm

No

fourthgear
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#11

Post by fourthgear » Mon May 21, 2007 1:18 pm

panhead
Bring up your idle to see if you are charging while taking a voltage reading . You will probably need to polarize ( after disconnecting batt. )if you are running a mech. regulator as has been said. 12.40 volts is ok ,but if I don't see over 12.50 ,I think some thing is not right. I always have around 12.83 on mine and always over 12 volts @ idle.

panhead
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#12

Post by panhead » Mon May 21, 2007 2:21 pm

It is charging above idling speed. I now suspect the (electronic) regulator as sometimes the generator light is on if I'm riding.

fourthgear
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#13

Post by fourthgear » Mon May 21, 2007 10:16 pm

Check all charging circuit and batt. wires , you may have a wire loose or damaged. Even corrosion on bolted surfaces( grounding ) may give you problems. How do you Gen. brushes and commutator look?

panhead
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#14

Post by panhead » Mon May 21, 2007 11:38 pm

fourthgear,

Wires etc. look good, but I haven't had a look inside the generator yet. But why does that play a role only the first kilometers? I would assume it would occur moe often.

fourthgear
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#15

Post by fourthgear » Wed May 23, 2007 1:10 pm

panhead
The Gen. light is supposed to come on when the Gen. voltage out put is lower than batt. voltage. I say supposed to because I have seen them come on with a shorted wire too. The fact that it goes away after a few miles could mean when warm it is all working correctly and your voltage out put is above batt. voltage . I have seen where the outer bearing has been over lubricated and grease has accumulated on the commutator and caused charging problems. This is not saying you don't have an ign. problem , there may be a plug or coil or some other part of the ign circuit that is causing the problem. If you are getting low voltage out put from your Gen. , it will affect your electronic ign. , until you get the right voltage to operate and perform correctly.It may or may not effect both cyl.. Since you have duel plug heads and have separate coils , you may look more closely at the cyl. that is miss firing , if it indeed just affecting one cyl.. Have you tried to switch coils , just switching the wires and see if it affects the same cyl., that will give you a test for the coils.

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