Starter : Rebuild, buy salvaged, or buy new

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Have you actually checked to see if you have a spark? Shouldn't be too difficult but you will need to raise the tank. If you haven't got a 'spark detector' just pull one of the HT boots and insert a spare plug, make sure it is grounded and watch for a spark when you operate the starter.

Don

 
Have you actually checked to see if you have a spark? Shouldn't be too difficult but you will need to raise the tank. If you haven't got a 'spark detector' just pull one of the HT boots and insert a spare plug, make sure it is grounded and watch for a spark when you operate the starter.

Don
Agreed, unfortunately I've run out of time. Have to get the house prepped for an upcoming move and that's killing all my time for the forseeable future. Hate to do it, but will have to pay to get this taken care of... :(

 
Thanks to everyone for the help. As promised I'm updating the thread with the results so others can understand what happened / why. I'll try to keep it brief, with the full diagnostics below for the intrepid reader...

SPOILER - Not the starter or starter relay, culprit was the battery. Less than a year old it would mean then the battery was not the best when I got it or that I didn't charge it correctly upon receipt and set a low 'memory'. Replaced with a Motobatt given reviews on this site.

Things I still don't understand at this point, but could be I was using the electrical test tool or testing setup wrong:

- The battery read a good charge at rest, and the drop when attempting to start appeared to be in the 11's on my tool (but obviously I wasn't taking the reading correctly)

- Why when the marine battery was attached the starter cranked but the bike would not fire. When the new battery was put in it immediately fired. Maybe there was too much power and it spun the starter too fast for an ignition?? I would be pulling that out of a piece of my anatomy I am currently sitting on.

Tech Details:

1) 12.61 DCV Cold start battery

2) Test light = no current draw

3) Meter = .50 MA on hookup then goes down to .06MA

4) Big load tester = good

5) Charge rate = 13.90 peak DCV

6) When cranking drops to 9.1 to 9.2

7) Yuasa tester = Bad battery 67% health

Replaced with Motobatt

1) Charging peak of 14.0 DCV

2) Cranking DCV drops to (lowest) 9.80

3) Starts freely and easily

4) Amp draw on tester (requested by me to verify): Peek = 97MV (9.7A), constant at 56MV (5.6A) **Tested with 14G solid copper shunt in 15" length

 
Glad you got it resolved. Going back through some of the original posts was enlightening - it's too bad you didn't replace the battery first thing. But live and learn. This will be a good thread to reference in the future when somebody else has a similar problem.

Lesson learned: The FIRST thing that needs to be done is put in a KNOWN good battery.

Glad all is well in your FJR world again.

 
OK, now I'm confused....
sad.gif

...Scenario 1 Reading at Battery at rest: 12.3 Volts...Scenario 2 Reading at Battery at rest: 12.46 Volts
Both batteries were undercharged. Anytime you are diagnosing a starting problem one of the first things that you should do is charge the battery over night then check the battery the next morning. Here is something that may seem strange, but it's true. A voltage reading of 12.4 volts indicates that the battery is only 75% charged. A reading of 12.2 volts indicates 50% charged and 12.0 volts is only 25% charged. A reading below 11.9 volts the battery is a fully discharged and entering a point where it may be damaged. Any reading below 10.5 volts indicates a damaged battery that should be replaced. A battery's state of charge is not a linear scale between 0 and 12.7 volts.

An engine needs a certain minimum cranking rpm to start. The coils need a voltage around 8.5 volts or higher to have enough energy to create a spark hot enough to start a cold engine. At what voltage does the ECU stop firing the injectors? I dunno, just throwing that out; the ECU does monitor battery voltage for the fuel injectors.

 
Last edited by a moderator:
Both batteries were undercharged. Anytime you are diagnosing a starting problem one of the first things that you should do is charge the battery over night then check the battery the next morning. Here is something that may seem strange, but it's true. A voltage reading of 12.4 volts indicates that the battery is only 75% charged. A reading of 12.2 volts indicates 50% charged and 12.0 volts is only 25% charged. A reading below 11.9 volts the battery is a fully discharged and entering a point where it may be damaged. Any reading below 10.5 volts indicates a damaged battery that should be replace. A batter's state of charge is not a linear scale between 0 and 12.7 volts.

An engine needs a certain minimum cranking rpm to start. The coils need a voltage around 8.5 volts or higher to have enough energy to create a spark hot enough to start a cold engine. At what voltage does the ECU stop firing the injectors? I dunno, just throwing that out; the ECU does monitor battery voltage for the fuel injectors.
Thanks for the V = charge level specs, very handy!

Another reason the ecu monitors voltage (at least in automotive) is to vary the on time of the coils so adequate spark can be delivered in a low voltage situation.

 
Top