XJ 650 ignition fuse keeps burning up

Hello everyone,

I just got a 1981 XJ650 bike. Nice bike, but my first ride today was filled with problems.

It seems like the ignition fuse keeps burning up. It lasts about 2-4 starts, then its gone. I went through several today and simply run out of spare fuses.

It seems like it was the problem with this bike before, since the previous owner left several boxes of fuses underneath the seat.

What could it be? Please help, since I want to drive a little more than a half a block this time. Thanks in advance!

 

Hello and welcome to you Lithdoc!
A bit of background on the fuse please, you should be using 10A fuses. Anything less will lead to the problems you are facing.
If you are running 10A, from the sounds of it you need to overhaul the starter, it's pulling way too much current. A quick refresh of the solenoid wouldn't be a bad thing either. Make sure all of your contacts are clean and tight. If the wiring is cheesy, make new lines.
Incidently, you might also want to invest in a new fuse block as the stock units are all dying right now (old age and corrosion are the culprits). Yours is probably in similar shape. It could also be lending a hand to the failures.

 

Thanks for the welcome and a quick reply.

Indeed, I am using a 10A fuse for the bike, but it burns up just after a couple starts. Ironically, the situation kept getting worse - at first, it held up to some 10 starts, then the number kept decreasing. My friend mentioned to me it could be the battery that might be old and causing short-circuiting. Is that also a possibility?

 

Doubt it's the battery - Robert is correct - too much current - starter or starter relay or both....

Pull the starter and clean it - not a hard job at all.

 

Thanks for your replies guys, you're the best. I can't wait to ride my bike!

Anyway, I'll try to improvise and pull the starter. Yesterday I ordered the Hayne's repair manual for the book, but that will take a while to receive, so I'll attempt today.

Thanks!

 

This may help

 

Hey - you bet it will!

Now, question. Do I have to take it all apart like in the picture. The "cleaning" that you're referring to - does that mean simply dust it off, clean off the grease and put it all together? Or should I change any parts? I've worked on cars before, but on bikes - not so much .Thanks!

Also, would it be possible to get a larger resolution picture for this? Thanks!

 

It actually disassembles easily. Once you take the 2 long bolts off the top and bottom cap basically fall off. You don't need to remove #s 4,5 and 6. I'm trying to remember but I think 7 just sits in the housing

I used brake cleaner to remove the grease from the gear end and regreased. Then used carb cleaner to clean the coils and magnet body. Clean the commutator to get brush dust from between copper strips then I used steel wool to clean the copper. Clean the brush dust from the top cap.

Measure your brushes 8.5mm is the service limit. When reassembling take care with the 2 end gaskets. The brush plate has locating tabs as do the the top and bottom covers. Take care to get them right. If the brushes are turned slightly the thing runs backwards!

 

One better on the larger diagram

http://www.4shared.com/dir/1570443/a2eb ... aring.html

you can download a PDF of the Haynes. You will need a print copy (which I see you ordered) so if you own one, I view this as a fair use copy for personal use.

 

Big big thanks to you, bill. Time to start working on the bike!

 

Nicely done Bill, I wish I could pull nice pictures out like that too!
I went so far as to purchase two Haynes manuals, one for the garage and one for the study (where the computer is).

 

Thanks. I cheat Robert- the PDF will not let you copy pics but our instant message system lets me cut a screen shot then save it to a file.

 

Thanks for all your help guys. Yesterday, I took out the starter, cleaned it all up (it was dirty indeed), put it all back together. Not a hard job at all, just like you said.

However, the problem is not gone. After about 15 starts today, the ignition fuse burned up again. Then, by accident, I put a 20A fuse instead of 10, so after some 10 minutes of driving slowly, the main 20A fuse started burning up.

Robert, you mentioned the fact that it might be the started relay or solenoid. Where are those things located? Do I change them, or just clean them up? Also, what role would spark plugs and wires play in that? They look kinda black, although the gap seems okay.

Thanks in advance.

 

Starter relay is just to the left of your battery. Direct connection to the battery then from the other post the wire to the starter.

Problem is it is a bear to take apart. you need to unsolder the very thin coil wires to get it apart and clean the contacts.

So let's back up a bit. If the fuse is going out while running then it is most likely a short of some type. The fact that the main fuse went seems to verify that. I would also guess the short is in the ignition circuit based on that fuse going.

You don't have additional lights or other devices attached to the bike do you?

 

Indeed, the manner in which the fuses are going out seems to be strange to me too.

The ignition fuse seems to be going out when the bike suddenly stalls when releasing the clutch too fast. The subsequent start won't happen, since the fuse is out. I'm not an experienced driver, so it has happened quite a few times. The main fuse went out both time while i was idling and trying to turn the bike around on foot.

I don't think there are any additional lights attached, but it seems like the previous owner messed with the wiring a bit, since the turn light and main headlamp wires don't look so orderly as if they came from the factory.

 

Interesting when I get a minute I need to look at the schematics. The bike will cease to run when the ignition fuse goes so it could be as you rev up the fuse is blowing - may not be you at all...

Under about 3k rpm the bike is running off the battery then the alternator takes over and charges the battery. Could be in that circuit. there are so many options.

Can you read a schematic and use a multimeter? We can help you through it but will probably have to do it piece by piece.

Anyone else have better ideas? This one will be hard to figure out remote.

 

You say that the fuse blows when you pop the clutch. First thought is a chaffing or hanging wire. That would be harness related not the solenoid or starter. I agree bill, this will be a bit difficult but since we have only one circuit to worry about, we're in pretty good shape all things considered.
I would start by ohming out all of your connections to ground and doing a visual on every inch of the harness.

 

Okay guys, my bike is now officially not driveable.

While I was able to make a few loops yesterday, today I was unable to even start it. First of all, I drove all around south chicago looking for 10A fuses. It seems the 10A is quite a desirable commodity, since they were almost impossibe to find. I ended up finding 10 of those fuses, thats all they had in the 5th store I visited.

This morning, I was unable to start the bike. The fuse burns up as soon as the key is turned to ignition. I looked through all the circuits, changed some wiring, but no help. Burned up some 5 fuses just trying - they simply turn red and burn up in 1 second after the key is turned.

I checked the current flowing through the mutlimeter - it is more than 20A, since the reading on my multimeter was maxed out.

 

Not to state the obvious but you have a short. The good news is it sounds like it is solid so should be findable.

Checking connections that should not be ground to the ground should be a good place to start as Robert suggested. I would also unplug all relays the TCI, disconnect the starter relay etc. Then you can plug back in one at at time and maybe see what circuit the short is in.

 

The easiest thing is going to be to get out the wiring diagram, get a multimeter, and get a couple of alligator jumpers.

Use the gators to connect the mulitmeter to measure resistance between the R/W side of the fuse and ground (with the fuse out). Turn the ignition on. The resistance will probably drop to 1 Ohm or less.

Then start disconnecting things that the R/W or L wires lead to and see if/when the resistance jumps to a much higher value. I'd start with the TCI module (under the left side cover).

Whatever you disconnect right before the resistance jumps is going to be the offending component.

 

I'm not too good with these things, so please explain some of the details to me.

First of all, multimeter, has only two leads. So do I connect one lead so that it bridges the fuse and the other one to ground? Ground being things like the engine block, right?

What exactly do the letters R/W and L stand for? Also, what is TCI and what does it do?

Next, when I disconnect any component, to my understanding, the resistance should become infinite, since the circuit is interrupted. How do I avoid this?

Thanks so much guys for your time and patience helping me with this. I'm not a bike guy and while I can deal with mechanical stuff, electrical stuff is completely new to me.

 

SQLguy's method is the opposite of mine, either will work. R/W and L/W are the wire colors - Look at the connector to the starter relay. You will see a red wire with white stripe (R/W) and a Blue wire with white stripe (L/W) The schematic in the Haynes detals all this for you.

At the fuse panel you will see a R/W on both sides of the fuse - Remove the fuse. One side goes to the ignition switch the other to the kill switch then on to the rest of the start circuit. Try each side to ground (the engine or better the minus terminal of the battery). Ideally there should be infinite or very high resistance. We are betting at least one side will be near zero.

Then start unplugging stuff to see it jump up - what you unplug is the problem.

The TCI is the ignition module. Located behind the left side cover. The pickups send a signal to it and it fires the coils.

Just post your questions and we'll work through it.

 

Two questions:

First of all, Hayne's manual. Which filename is the one for that manual in the link you sent? Because I downloaded the x650 service manual and that did not seem like it was it.

Second, once again, when I disconnect ANY part of the circuit, shouldn't the resistance jump to infinity right away, since I interrupt the circuit? Or am I simply thinking too hard and its all connected in parallel?

 

Nope you will be looking at the short (which is not a natural condition) as opposed to looking at a circuit you would interrupt.

My apologies I thought I got my online haynes from that site - now I'm not sure where it came from. I'll try and figure out where I got it from.

This doc from that site has the schematic though..

XJ650J_maxim_suppliment_xj650j_.pdf

 

Lithdoc, a little more info is needed like maxim or seca a 81 i think should be a H but i could be wrong
once we get on the same page, these guys will figure something out
i'am going to go out on a limb here and say look real close at the places where you said the last owner taped some stuff up

 

good point Polock. The H is the 81 maxim and there is a separate schematic but all can see is a couple of different wire colors .

Lithdoc PM your email and let me know your exact model - or the VIN if you are not sure and I can figure it out. I'll Scan a usable schematic and send it to you.

 

Okay, because of all your help I do have some progress report to make, although still no cure.

If motorcycles were humans, I would call the condition "idiopathic paroxysmal power surge." Anyway, that diagnosis is of little relief.

Yesterday I did just what you guys suggested - started going through all the components, pulling them out one after another. After putting it all back, I check the current flowing through the ignition fuse - around 0.3 Amps. I think - PERFECT! Maybe it was some stupid water that was condensed, but now its gone and its cured.

This morning I'm about to go out for the ride. As I'm backing out, i turn the wheel left-to-right. The bike starts choking. Then I turn it again some more, eventually the engine shuts off. I look at the ignition fuse - its out.

Okay, so I think the short is somewhere around the steering wheel. I first connect the alligators across the ignition fuse, set multimeter to current, and start fidgeting with all the loose wiring. I find the wiring connector where I think the short takes place - since moving it increases current from 0.3 amps to 20+

Playing around like this I almost drain the battery, but I see NO PLACE WHERE THE SHORT COULD BE! I start moving the connector in the picture - seems like the surge might be happening there, but inside and out it looks clean. I start dissecting the rubber hose covering all the wires, thinking the short might be there, but again - a disappointment, since all the wires look clean and intact.

Here is what I discover a little later. When the connector in the picture is just connected, multimeter indicates a power surge. Move the wires around - current goes down. If I carefully connect and then disconnect, again there is a surge. Simple logic would say that there should be no surge, since I barely moved the wires.

It seems to me that there might be something wrong with a piece that controls the current. However, since my knowledge is limited, I cannot tell you more.

Thanks for reading my long essay

 

Interesting - try these two things

Repeat your plug/unplug of the connector with the kill switch off. This switch is "adding" more circuit when on. Problem could be farther down the wiring.

With the connector unplugged measure the l/w wire going to the start switch to ground. It should show wide open. Try the lowest ohm scale and the highest ohm scale on your meter. Should show open on both scales. If it doesn't clean it till it does. Also you can press it and see it go to closed as an additional test.

I'll let you know if I come up with more ideas

 

Just to let you guys know. The previous owner had disabled the start button and relocated it to be on the battery cover. It is somehow bypassed, and the started spins even with the key and kill switch off. Of course, engine does not start till you turn on the key and put kill switch to "on."

Regarding the kill switch - it does shut the current completely off when the switch is off.

 

I assume you mean it spins when you press the new starter button - not spins all the time?

 

Yes, thats what I mean

I don't know how other bikes are, but this one, the starter will go when the button is pressed irrespective of what the status of the key or the kill switch. I don't know whether that is normal or not, because all I've worked on were cars.

 

Nope not normal - he has it hot wired but that should not be a problem. Normally the R/W wire is interrupted by the kill switch which removes the starter and 12 v to the coils too.

Check my PM...

 

EUREKA!

Well, I found the short. Took only 20 hours of frustration, but oh well - one has to make sacrifices to enjoy their bike!

Anyway, a piece of a connector for the lights had chipped off and would eventually touch the ground. Wrapped some tape and - done! All this frustration is evidenced by 20 burned fuses.

Thank you all guys for taking your time. Now I feel smarter and more of a "biker"

Now I noticed a new problem - the handlebar is not inline with the wheel. How do I adjust that?