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Machine got hot at one time. Also Pull Starter was broke. Stator wires were broke and repaired-tested ok at .4 ohms each (Yellow to Yellow). I am trying to determine if bad CDI, Voltage Regulator or Stator/Exciter Coils. I hooked up a snapon computer to obtain the attached trace with 4 lines. Key on (Red/White) and Power to the CDI both appear around 14 VT but with many spikes. The input to the coil GREEN shows negative output to the primary side of the coil where I would have expected positive. It also exceeds 50 volts negative at times (off the scale). The exciter coil BLUE did not show consistent 12 volts (not sure if it should be)?

Can anybody shed some insight as I am new to looking at this type of output. Bad Voltage Regulater causing all of this? Would a bad CDI cause the no start? Are the voltages shown normal? TIA Norm
 

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Discussion Starter #3
Model and Vin

The number of our machine is 4XACH50A*4B395435 while some digits were difficult to see the S/N looks to be 395435. Would this make it an early or late (2004.5) model?

The model is Sportsman 4X4 500 HO
 

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The VIN is actually 4XACH50A54B395435 - it was purchased 09/30/2004 - it is shown as a SPORTSMAN 500 HO BLUE '04.5, but the date of build is not given - it has a model designation of A04CH50AS - the warranty expired 3/30/2005 - there have been no recalls on the product.

Only the build date can determine if it early or late, but typically 04 is early and 04.5 is late

The subject is "2004.5 Dies when hot. Elec trace help needed."

Let's start at the beginning; how long does it run before it dies? How long does it have to set before restarting? Was the problem sudden or has it been happening, but is now worse? Did you add any accessories to it or have any service performed just before it started happening.

The more details the better.
 

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Background of Problem

The VIN is actually 4XACH50A54B395435 - it was purchased 09/30/2004 - it is shown as a SPORTSMAN 500 HO BLUE '04.5, but the date of build is not given - it has a model designation of A04CH50AS - the warranty expired 3/30/2005 - there have been no recalls on the product.

Only the build date can determine if it early or late, but typically 04 is early and 04.5 is late

The subject is "2004.5 Dies when hot. Elec trace help needed."

Let's start at the beginning; how long does it run before it dies? How long does it have to set before restarting? Was the problem sudden or has it been happening, but is now worse? Did you add any accessories to it or have any service performed just before it started happening.

The more details the better.
A friend of mine has a Auto/Truck repair shop he owns which works on just about everything. He has also worked for a tracktor dealership so he knows his way around motors. I have helped him with the computer and electrical stuff on the newer cars. We have worked on several ATVs and Bikes over the years I am still trying to determine how to know what to replace based on the symtoms.

This machine came to us not running at all. The pull starter was broke and the assembly contained in the area of the stator wires wore out the bushing and then messed up the insulation on two of the three yellow wires. He was able to repair the insulation using black tape (not the best solution but the wires ohm'ed ok and also Voltage at low RPM was around 30 VAC. The other coil also ohm'ed out ok (do not remember exact number). We have considered if we should use shrink wrap with crimp connectors for better insulation.

So now we can at least get it started. It runs less than 2 to 3 minutes. Has good power initially, then sputters, stalls and will not restart until it sits for 15-30 minutes. The owner indicated it overheated on the trail (with flashing dash pointer, etc). I am not sure if that is when the problems started or not. The machine is used on a dairy farm and is not shown any TLC;).

I also wondered if a gap somewhere could be off? BTW compression is about 60PSI after 4-6 cycles.

I hate to sound stupid but I just don't know what to expect to see on the scope. Should I be seeing all the spiking?? Why is the input to the coil showing as negative on the White/Blue wire? Is this normal? Is it normal to see it going past 50 Volts? Should I be seeing a one to one spike on lines 2 and 3 (Green and Blue lines) (Pulsar coil and Ignition coil)?

I cannot seem to find voltage regulators for the 2004.5 or 2005 model on the net. Do you know of a good source?
Thanks
Norm
 

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The CDI sends about 100 volts peak to the coil each rotation of the crankshaft. The pulse gen and coil should be basically in sync - just milliseconds apart and only milliseconds long.

The problem is probably either in the carb or fuel delivery to the carb. If the fuel in the tank is ethanol blended and over 21 days old, it should be dumped - best fuel to use is 87 octane ethanol free - if you are going to use the fuel up in 21 days or less you can use 89 octane with no more than 10% Ethanol, 7% MTBE or 5% Methanol as an additive.

Since the engine runs, I doubt an electrical gremlin - run the engine until it dies and immediately spray starting fluid onto the air filter while trying to restart - if it will run with starting fluid (not necessarily a steady stream, but a shot once in a while to keep it running), then the problem is definitely fuel instead of electrical.

Do you have the service manual? I can email you a copy in PDF if you would like - just PM me an email address and I will get it to you in short order.
 

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But NO VOLTAGE at Ignition Coil during NO Start Contradicts your answer

The CDI sends about 100 volts peak to the coil each rotation of the crankshaft. The pulse gen and coil should be basically in sync - just milliseconds apart and only milliseconds long.

The problem is probably either in the carb or fuel delivery to the carb. If the fuel in the tank is ethanol blended and over 21 days old, it should be dumped - best fuel to use is 87 octane ethanol free - if you are going to use the fuel up in 21 days or less you can use 89 octane with no more than 10% Ethanol, 7% MTBE or 5% Methanol as an additive.

Since the engine runs, I doubt an electrical gremlin - run the engine until it dies and immediately spray starting fluid onto the air filter while trying to restart - if it will run with starting fluid (not necessarily a steady stream, but a shot once in a while to keep it running), then the problem is definitely fuel instead of electrical.

Do you have the service manual? I can email you a copy in PDF if you would like - just PM me an email address and I will get it to you in short order.
I need answers to the electrical questions I asked as I explained I am new to using the lab scope on these machines before I can move on. I also need to point out I have NO VOLTAGE at the IGNITION COIL during the no start episodes. I got 2 of the 4 answered so far, can we address the other two? In particular:
Should I be seeing all the spiking?? and Why is the input to the coil showing as negative on the White/Blue wire? Is this normal? Isn't the other post a negative 12 volts?


We have checked and cleaned the fuel subsystem including rebuilding the carburator (including ultrasonic cleaning), pressure testing the fuel pump and replacing the fuel filter. We also have 'wet' plugs after we have 'lost' the spark (i.e., after running it for the few minutes needed to go from full power to no start condition.

I have also asked " I cannot seem to find voltage regulators for the 2004.5 or 2005 model on the net. Do you know of a good source?", I find them for other years but not late 2004 and not 2005 models VR's

Thanks for letting me focus on the electric for just a bit longer as I do not have a warm and fuzzy feeling that all is well in that area...
 

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During your no start/no spark condition, if you have good voltage from the stator up to the cdi but none coming off the coil its a pretty good bet the cdi is bad. Had a CR500 many years ago that would loose spark when it got hot. You could pop the cdi in the freezer for a few minutes and plug it back up and the bike would run fine for about 5 minutes till it got hot and quit again lol.
 

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Yes, you should be seeing spiking and is makes no difference if it is positive or negative an long as it is either pos or neg consistantly - I have never used a trace tool, but I have used an oscilloscope to measure amplitude and duration. The input to the coil is a single spike about 100 volts peak - the output of the coil is about 30 to 40 thousand volts peak to peak and it will go both directions for about 100 milliseconds.

Isn't what other post 12 volts? There is no voltage to the coil until the CDI discharges. One post receives a spike and the other post is ground.

The rec/reg (i.e. Sure Power ECM) is part number 2203348 (superseded from 4010937) $150 from Polaris or sources.

What is your concern about the rec/reg? It is not part of the ignition circuit.
 
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