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Discussion Starter #1
hey guys i have a 2003 rc51 and need a little direction or advise if you can help please chime in.

1. the bike is not holding a charge. with new battery completely charged. the bike will start and run fine. the bike charges the battery just fine but when you turn the bike off for 30 min to an hr the battery is drained and bike will not start. so back on the charger and it shows 72% when an hr ago it was at 100%. a couple weeks ago i found my rectifier plug fried i replaced with some connectors for a quick fix. so i am thinking its the rectifier but others are saying maybe starter. i have traced every plug and cleaned. as well as every ground i could find. and the kill switch is in the run position

2. i was riding the bike to a friends house to try and diagnose this problem and another one occurred. i was stopped in his driveway. bike was idling and then just cut off. i restarted immediately and it idling for about 2 min and cut off again. now when i turn key on the fuel pump is not cutting on. the kill switch is in the run position. also when key is on the power commander is no longer lighting up. can anyone help? downloaded the manual and tried trouble shooting what i could but had no luck.


so i have ordered a fuel pump. do i order a rectifier?
all advise will help thanks guys.

also i want to do the repairs. so taking it to the shop isn't in my price range right now. unless its a last resort
 

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What is the battery charging at? Is this a new battery after the fried reg/rec connector or a battery before? If it's before is it the same battery? Can you take the battery somewhere to be checked?
 

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Discussion Starter #4
Yes new battery after the fry. Its at 13-14 with bike running before my fuel pump issue. So I fugure I get that sorted and ill be closer to figure out why battery is draining.

No sort of alarm on the bike only thing is the pc
 

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The manual shows you how to test for a battery drain. Have you done that?
Have you checked your fuel cut-off relay? I cant say for sure, but you should be able to feel it click when you turn the key on and it throws power to the fuel pump. I think you can swap the headlight relay (in the front fairing) if you suspect relay failure. Or you can simply test if power is coming into the pump when you turn on the key.
Have you measured the AC voltage on all three legs coming from the stator?

I would highly recommend getting rid of those butt connectors and replace with solder and shrinkwrap. The vibration of our bikes is hard on twist or crimp connections.
 

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Discussion Starter #6
i have not measured the ac voltage. not to sure how to quiet yet. i havent found the part that tells you how to test for batt drain. i downloaded the manuel and its 470 pages so i have been just scrolling in the garage. need to just order an org manual. i have checked the relay. looks good but did not know i could swap out. going to try that when i get home.


and when the bike shut off the 2nd time i turned key off then back on and usually when the fuel pump kicks on it was clicking pretty lound it kinda startled me so i turned the key back off and now when turn key on there is no sound at all.
 

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That clicking could have been the relay on it's final failure.
The Current Leakage Test is on page 16-7
16-8 shows you a way to test the stator (alternator)
Here's another way that Makis explained to me recently.

Have a very good charged battery.
Start the bike and disconnect that white plug.
Use your A.C. Voltmeter and measure the 3 yellow wires by pairs.
At idle they should give you 12-14V A.C. and near 4000rpm about 40V or so.
If that is the case in all 3 pairs then your stator is fine.
Alternatively you can measure Ohm resistance between each of the 3 yellow pair of wires.
It should be 0.2-0.5 Ohm at room temp
 

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Discussion Starter #8
thanks jondog ill look into it more this weekend and let y'all know whats going on. also already ordered a fuel pump so that will be installed Monday when it arrives
 

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Why? If the failure turns out to be the relay, then return the fuelpump and get your coin back.
Besides, it's no easy task to replace the fuelpump. It's straight forward, but you have to remove it from the bottom of the fuel tank, and you may need a new gasket. And if you're in there to replace the pump, it doesn't make much sense to not replace the fuel filter too.
I think you're getting the cart before the horse with the pump. At least until you do some further testing.
 

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Discussion Starter #10
Ordered the seal to. No filter though. Well I'm going to check relay tomorrow and if its that everything will end up getting returned or just stored for the future.
 

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Discussion Starter #12
Sorry guys. Swapped delays and nothing. So i had all fairings off except the nose fairing. So I took it off and starting checking the front side of the harness. And there was ths problem. On the top front right side of the bike were 3 wires that have rubbed the cladding off of eachother and were grounding out. One was completely broken. So I fixes them up and shrink wrapped. Bike starts everytime no problem now and holds a solid charge. So I have a fuel pump for cheap if anyone needs it.

The previous owner did not take care of this bike. I've been slowly getting it back to what it should be. The whole wiring is a joke
 
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