HELP bike keeps dying on longer rides

My bike is always stay on a trickle charger, but sooner or later the battery goes bad. To check the alternator output you need a cheap multimeter. Set it on 20 volts DC, start the engine, touch the negative post on the battery with the black lead from the meter, and the positive battery post with the red lead from the meter. At about 2000 rpm you should see a reading of 13.5 volts or higher. I'm told that the alternator doesn't really kick in until about 2000 rpm, but I don't know why.

 

@tabaka45 good point check this NicoRx.

https://xjbikes.com/forums/threads/testing-the-feild-coil.119720/

 

You don't "have" to plug the vacuum line actually, Only if the diaphragm leaks (rare) would that even really help. I just have seen people do it anyway.
Unless he hacked at the petcock guts , On would not make it flow gas, RES would. Maybe he hacked it. If you pull the tube off the petcock, you will find out.
If your ONLY running the bike with the petcock ON and its a vacuum type then he hacked it or it was leaking anyway.
If I were you, I'd pull the hose off the petcock output, then run a new hose to a gas can or container and find out which setting produces flow and which one does not.
Post pics if you can.
Once you know how its flowing, you can eliminate the petcock.

 

Well and now I replaced the solenoid and it is just clicking one time when I try to start. I will have to do a work up for this ugh

 

Battery reads 12.66 and solenoid 12.3 v

 

Is that with the engine running at 2000 rpm or better?
Also, the battery can read 12.66 but not have enough power (amps I think) to actually turn the engine and fire the plugs. Regardless of your fuel issue, I think you have a weak battery, or perhaps battery connections.

 

^^^^, yup, battery voltage will drop during start/load. More the drop, the worse the battery.
Battery tester will look at voltage when its starting and tell you if its good or not.
I have a cheap amazon one cause of all the vehicles I own and all the lead batteries I have.

 

So I attempted to short the solenoid and the bike did not turn over and I have no resistance from the negative terminal to the crank case. Would a weak battery still cause those symptoms?

 

That is with the bike completely off

 

Battery should show greater than 12.5 volts sitting there doing nothing, load it with a starter motor it should drop down to say 10.5 volts while cranking if it's fresh & strong. The resistance drop between the negative terminal of the battery and the engine itself should be a big-fat zero. Cranking the engine with the voltmeter between the negative terminal and the engine case should show less than a volt if the cable is good. This will also hold true for the positive battery cable between the battery terminal and the starter motor lug bolt while cranking, if the solenoid is bad it will show near the battery voltage.

 

I bought two back up solenoids and tried each one. The negative to the engine was near 0 and positive to solenoid was also near zero. Also zero when pressing in the ignition but all it did was cause the solenoid to click and continuity went up .002 for both. Bike voltage went down to 12 but after 5 mins of sitting was back above 12.6v

 

Battery ground/black to engine case, you using resistance setting (ohms) and not voltage correct? it should be from 0 ohms to maybe an ohm or two. Many meters may show an ohm or two when touching the meter terminals together. That is your offset.
Shorting the 2 big bolts of the solenoid should make starter run. One bolt should go direct to battery, other bolt goes to the + terminal of the starter motor. Shorting with a conductive metal would make starter move.

 

it was set to the continuity/diode test and was buzzing. I did not set it to ohms

thinking of attaching the + end of the battery to the starter connector and the negative end to the starter body while in neutral to see if it turns

 

This will bypass the solenoid and any other issues that may be lurking behind the scenes such as a bad starter which is not hard to rebuild, Amazon has the brush block for under $20.00 and I had mine done in half an hour... yes this proves a caveman like myself can do it. The extra cranking may have worn the brushes down to the nub causing it to turn slowly or not at all, the other alternative is to buy a rebuild outright and they're outrageously expensive for what they are. Either way you will need a starter motor to continue with the diagnostics and after going back to the start of this thread maybe another bike-nerd-tekky-guy to further assist you, another set of eyes never hurts. Unfortunately I'm about six maybe eight tanks of fuel away from Columbus depending on how hard I push it.

So here's the what I know about these fuel systems and all the related having put my XJ750 back together, it's the bike in my avatar that I got in several milkjug crates with the disclaimer of "Some Assembly (and much cleaning) Required" and the fuel system was no exception. Overall they're quite simple but they have a few quirks, my vacuum petcock leaked right away so it was replaced with a hand only shutoff piece and it works. I've always been in the habit of turning off my fuel since my dirtbike days so it's a no-brainer for me. Down the line are for super-small hat shaped screens over the fuel inlets of the float needle seats, they are the last stop for the crud that always manages to get past that Checkpoint-Charlie filter screen on the petcock. That being said brings up the question of super-fine "rust-dust" and other sediment in the tank that may be building up on the inlet screen and reducing the fuel and stopping the bike only to disperse a short time later when the flow stops. Think of a window screen with a fan blowing into the house at night, all the bugs accumulate and stick when the fan is running and eventually fall off when stopped. It only takes a little of that super fine crud to build after say 20 miles to reduce the fuel flow to a trickle or less and put you on the side of the road. Sure the fuel may flow like a fountain when checking it in the driveway but how about 30 minutes later?

Electrical... Battery might be going down during the ride, enough to stop the ignitor box from making a hot enough spark, I did a test with my ignition so time back to check the accuracy of the tachometer and also reduced the running voltage and found the cutoff to be just over 8 volts. 20 minutes is about the right amount of time to run a 12v battery down to that point with the electrical load of the XJ bike. I have the 750 SECA and with the stock headlight, two taillight bulbs and ignition the total demand is just over 10 amps of current once the battery has reached its 100% charge point. The alternator in these is only good for just shy of 20 amps and will not produce anything below about 2000 engine RPM, this is due to the threshold of the internal regulator transistor, a lengthy explanation for later. Weak brushes or corroded connections to the regulator box and the alternator is compromised. One of my brushes was broken when I got it so they were replaced, not difficult but a something that must be done. These use a special long length brush and our vendor Chacal has them. There are are also solder connections inside the alternator housing for the brushes that can go bad, something to consider.

While I don't know the specifics of the Maxim electrical the output of the alternator has to make its way to the battery and eventually the rest of the bike, have you checked the integrity of the fuses? How about the bond between the engine and the frame itself being these are rubber isolated engines? How about some of the other electrical connections? Those spade terminals do get crummy over time and the female side can lose its grip. I poked each and every one of mine out of their shells one at a time to sand the spade with a 320 wet & dry and carefully squeeze the female end to restore the grip, mating a 6 terminal connector now takes some effort but they're absolutely solid.

Since reassembly of the bike I have accumulated 7868 miles as of this post and will be adding more later today. I absolutely trust this bike to take me anywhere I want to go, it has been rock solid dependable and I ride it every day. The only major service so far has been a re-lining of the clutch and removal of the swingarm to address a side play issue. I have spanked S&S powered Harley Sportsters and a few "ninja" bikes on stoplight drags and done 500 miles interstate runs averaging 85 MPH with passing peaks in the triple digits. The only real bitching points I have are with the high-strung gearing and that ATARI game console speedometer that is so far off it's in another dimension... if anyone has a 0-120 speedometer I'd be interested. It runs Kenda Challenger rubber and handles well, there are no chicken strips on the back tire. Given the sheer simplicity of the Yamaha bikes I'm quite confidant the problems you're experiencing are lurking in plain sight, sometimes it takes another set of eyes to see what has blended into the background.

 

Took it to get tested and the guy said it was at 200 cranking amps and it was good despite being 2 years old

 

Well that's a start.. pun intended. So you've bypassed the solenoid, checked the wiring from the battery terminals to the engine and starter lug and still no crank? My money is on worn down brushes in the starter or the clock springs that push the brushes have lost tension, either way you're looking at either another starter motor or repairing it. Again they're not difficult to work with if you have some mechanical experience, the thing you have to be careful of is getting everything "clocked" or positioned correctly inside as they index into slots which are not always obvious being covered in slimy grease. I worked at a rebuilder in my youth and screwed a few up along the way. They're quite expensive on the evil-bay used, I don't know what the rebuild price is but the brush block is just under $20 from Amazon and not difficult to replace. They used to be $45.00 when I was rebuilding them in the late-80's with a $20.00 core... times have changed.
So until you address the cranking issue everything else is on hold, 200 cranking amps is about right for these batteries so while it has the juice to turn it over that doesn't mean it can run a marathon, you will need to get the engine running and back to the diagnostics of why it has a limited running range be it electrical, fuel or mechanical.

 

As Brhatweed said they are quite expensive.

https://xjbikes.com/forums/threads/how-to-test-your-starter-circuit.7828/

https://xjbikes.com/forums/threads/replacing-your-starter-motor-brushes-w-pics.45727/

 

It’s frustrating, I replaced the starter brushes I think a couple of years ago and this bike has only gone 300 miles since Ryan and only had 5k to begin with. I will open up the starter and take some pics for sure. Lots of work to do but excited to fix these problems on the bike

 

I get where you're coming from, it's very frustrating but an unfortunate fact of our throw-away world of chinese made junk. I do my own work and have never taken my car to a shop once in 235K miles so I spend just as much time looking for quality as I do the work itself. The cool thing about the XJ is they're quite simple and easy to work on, a 10MM gets most everything done, the brushes in the starter are short & thin to begin with and pass a lot of current for a short time, the added cranking of the problems & diagnostics all adds up to more wear. To me a $20.00 brush block is a half hour opportunity to clean things up and make it right so it's reliable, I live in a very small town do put on a lot of rural miles with Minneapolis just over 90 miles to the south so reliability is paramount and I'm not known to compromise. 300 miles in a couple of years? Dude you gotta get out and ride man.
Bikes are a lot of work but I take things as challenges and learn things hands-on, don't take it as a frustration as you will figure things out. That big sh!t-eatin' grin on your face going down the road comes from knowing you did it yourself, sure better than some store bought ninja bike or potato mashin' Harley cruiser covered in yards of chrome... only one grinnin' there is the cleaning products companies.

I will say those are great tutorials that Franz pointed out.

 

Hard to believe it would be the brushes again....... but never know.