Fj1100 dies when hot

PolskiFJ · September 09, 2012, 02:38:26 PM

Hello everyone,

Still trying to figure out what's going on with my bike. Swapped out the Coils and the resistor that's on the battery over the weekend. Took out the bike and again it died on the side of the road. I have now found out that my battery is not getting charged when the bike is running. under heavy load it drops to running on two cylinders, then stops running altogether. I can put the battery on a charge box for a mere 30 seconds and it will start right back up, but when you put a voltmeter to it, you will see that the battery is not getting charged. Just getting some opinions on what it could be? Stator?? Alternator?? so sad, as i have struggled to get it running all summer long, and would really like to get it up and going for some nice fall rides.

Thanks everyone!

rktmanfj · September 09, 2012, 02:56:08 PM

Quote from: PolskiFJ on September 09, 2012, 02:38:26 PM
Hello everyone,

Still trying to figure out what's going on with my bike. Swapped out the Coils and the resistor that's on the battery over the weekend. Took out the bike and again it died on the side of the road. I have now found out that my battery is not getting charged when the bike is running. under heavy load it drops to running on two cylinders, then stops running altogether. I can put the battery on a charge box for a mere 30 seconds and it will start right back up, but when you put a voltmeter to it, you will see that the battery is not getting charged. Just getting some opinions on what it could be? Stator?? Alternator?? so sad, as i have struggled to get it running all summer long, and would really like to get it up and going for some nice fall rides.

Thanks everyone!

First thing I would do is check all the grounds, especially the one at the back of the engine.

Pat Conlon · September 09, 2012, 03:03:00 PM

Are you sure it's electrical related? Did you put your voltmeter on the battery to check the charging voltage?

It could be fuel related:
A common problem on the gravity fed 1100's and 1200's is a pinched fuel line which will give the exact symptoms you are describing.
Proper fuel line routing is critical and you should have a picture on your air box or back fender, if not, let me describe:
As the single fuel line leaves the petcock, it should run *under* the 2 branch lines which feeds #1/2 and #3/4 carbs.
If the single fuel line is run over the 2 branch lines, the bike will start and run for awhile, then as the engine heats up the (now warm) fuel line gets soft and pinches, starving the carbs for gas.
So you stop.....wait for awhile, gas slowly flows thru the pinched line, refills the carbs and your bike will start again and run for a short while 'till it happens again.
Also, some folks have mistakenly installed a fuel filter on this gas line. A high flow screen filter is fine, but a paper filter will restrict the gas flow, even when new.
Paper filters are fine with a fuel pump pushing fuel through it, like the '89+ FJ's, but are a problem on the gravity fed "84-"87 bikes.

Hope this helps.

RichBaker · September 09, 2012, 08:05:26 PM

What is the battery voltage:
1) Ignition off?
2) At idle?
3) Revving over ~2500 RPM?

Have you had the battery on a charger overnight? If not, do so before making the above measurements...

What year FJ?

PolskiFJ · September 10, 2012, 09:09:41 AM

I did put a voltmeter to the battery, and even with the bike running it was at 11.92-11.95 and it was not climbing, even when you increased the rpm. I have not ruled it out as a fuel issue either but i think that with the battery not getting charged this is where i should start. I unfortunately travel for work, so i do not have the ability to look at it during the week, and am too stubborn to give it to a mechanic for an issue i'm confident i can fix.

Yamifj1200 · September 15, 2012, 03:39:45 PM

"I did put a voltmeter to the battery, and even with the bike running it was at 11.92-11.95 and it was not climbing, "

For some reason your alternator is not charging the battery. Fj's like a good hot battery and a good charging system. There may be a problem with the wiring between the alternator and the battery. I would also look at the plastic two wire connection to the alternator. I don't know if the alternator will charge if the regulator is working or not. Have you charged the battery to see if the motor runs properly with a good battery?

Eric M

PolskiFJ · September 18, 2012, 10:22:54 AM

Quote from: Yamifj1200 on September 15, 2012, 03:39:45 PM
"I did put a voltmeter to the battery, and even with the bike running it was at 11.92-11.95 and it was not climbing, "

For some reason your alternator is not charging the battery. Fj's like a good hot battery and a good charging system. There may be a problem with the wiring between the alternator and the battery. I would also look at the plastic two wire connection to the alternator. I don't know if the alternator will charge if the regulator is working or not. Have you charged the battery to see if the motor runs properly with a good battery?

Eric M

Thats the thing, when the battery is charged it goes like a bat out of hell, but the battery drains during the ride and it dies under heavy load. I am going to replace the alternator on friday, along with the headgasket that seems to have blown during the ride on Saturday. It's starting to smoke like crazy, and when I bring it back in i see steam coming from the motor where the headgasket is

By the time i'm done with what i thought was a simple problem i'm going to have a brand new FJ

PolskiFJ · September 18, 2012, 10:27:08 AM

and on that note,

does anyone know where i can get some inexpensive, good quality valve stem seals, rings, and a head gasket?? ALSO, what oil do you all recommend???

ribbert · September 18, 2012, 10:36:49 AM

Quote from: PolskiFJ on September 18, 2012, 10:27:08 AM
and on that note,

does anyone know where i can get some inexpensive, good quality valve stem seals, rings, and a head gasket?? ALSO, what oil do you all recommend???

Now you've done it. The forum will be clogged up for the next 6 mths, again.

Randy @ RPM is your man for engine bits, check the banner ad at the top of the page.

yamaha fj rider · September 18, 2012, 11:13:23 AM

Quote from: PolskiFJ on September 18, 2012, 10:27:08 AM
and on that note,

does anyone know where i can get some inexpensive, good quality valve stem seals, rings, and a head gasket??

Seems like it's one or the other, not both. Like Noel said call Randy at RPM. Hope this helps.

http://www.rpmracingca.com/

Kurt

fintip · October 11, 2012, 03:01:58 AM

It is said on the XJ forums by a guy who knows much more than I (and no one contests it) that "dies when hot" is a classic valve shim adjustment warning sign indicating that the valves are way too tight.

Given you are also replacing a head gasket, it leaves me wondering...

Also, I must have missed it, but surely you replaced the battery recently, right? Ruled out a defective battery?

ribbert · October 11, 2012, 08:34:58 AM

Quote from: fintip on October 11, 2012, 03:01:58 AM
It is said on the XJ forums by a guy who knows much more than I (and no one contests it) that "dies when hot" is a classic valve shim adjustment warning sign indicating that the valves are way too tight.Given you are also replacing a head gasket, it leaves me wondering...

Also, I must have missed it, but surely you replaced the battery recently, right? Ruled out a defective battery?

I wouldn't be too sure about that. If they're tight enough to "die when hot" it sure aint gonna start cold. And, they tighten up VERY slowly over many 10's of thousands of Km's.

Noel

fintip · October 11, 2012, 10:06:17 AM

The idea, I believe, is that when the engine warms up, the metal expands a little bit, making it even more tight than when cold.

Also, this is primarily a problem, it is said, when you get a bike that has a history of having *never* had its valve shims changed--many XJ's were neglected like this. The engine is just bulletproof enough to put up with it. I get a feeling this is less common with FJ's, as they are performance bikes, and people treated them as such a bit.

If the OP doesn't know the history of the valve shims on this bike and has never done it himself, though, just something to look into.

fj11.5 · October 11, 2012, 03:24:41 PM

trust me, if the valves have tightend up, she won't want to start, and if they have become that tight, they will be burnt out, , if the pics are still on here of mine, check out the FJ head , take a close look at the exhaust valves, , they are fuuuuckeddd from never having the shims serviced until it was too late, , easy way to find them, , compression test, , or easier , a leak down test, mine wouldn't even hold air , could hear it blowing through the exhaust system , no matter what position the cams were in, the valves were closed ,, I've also owned an xj 750 , awesome bike no work done by any of the 3 po , and. she never stopped when hot 45,000 klm

fintip · October 12, 2012, 11:33:18 PM

Well, the guy generally know his stuff, but I don't know any better--never dealt with it myself, personally, so it's all a guess to me. Electrical does sound more likely.

I have a friend who just bought an XJ750 two days ago, pretty excited for him. Got a great deal on a runner for $600 up north in fair shape. He does touring, and found a guy bobbing one a few states away who is getting rid of the factory touring stuff that comes on it for $50. Altogether it's quite a steal. Was talking to his son and he tells me it's pretty fast. Those XJ motors last forever though... Just wish they didn't have the flat spot between 4 and 7k on the tach. Still, good bike.

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Fj1100 dies when hot