xj550, seems so close, but still so far

So it has been a while everybody, I have been reading a lot but not posting. So here it is. I had problems getting the bike to start last year and spent a whole hell of a lot of time cleaning the carbs. Ended up putting on a whopping 25 miles last year....

Was able to store it in a garage where I could work on it over the winter. Got the valve spacers back into spec, cleaned the carbs again and did a bench sync. Checked the brushes (was having battery issues) and looked into a few electronic issues I was having. Many of which have not been resolved, I think I just need to replace the fuse box (old style box with circular fuses) and many wires/connectors. The PO made it so the headlight can be shut off with a toggle switch...

So onto my problems as they exist today. Took the bike out last night for a ride. Ran great except occasionally I would get some "bogging down" when giving it gas, but it would eventually catch up. Went ~35 miles making my grand total for this year double last! But as I was taking a left into my development, the bike lost all power, I opened the throttle all the way and was able to limp it home. Threw it into neutral and put the kickstand down, went from 2000 RPM to nothing very quickly, but not as though by kill switch.

Today I took it out for a ride, made it 4 miles and it turned off while going 40 mph. Couldn't get it to start, ran my errand, came out and got it to start again. Any time I try to idle it it dies once hot. I suspected low gas so I opened petcock to pri and drove home like that, made little difference. I could only get it to start (once hot) when the throttle was open all the way.

It starts hard, but once it gets going it will idle at around 1200 rpm. After driving it for a while it idles at 2000 rpm.

Anybody have any ideas?

End temp for the engine today was ~200f, last night I measured it at 290 in places on the engine. Is this thing running super lean and killing itself? And if so is it air leaks or could it be exhaust?

 

"Lost all power" and "2000 rpm to nothing" sounds like kill switch. You said you had concerns about electrical...

Did it actually die, or am I taking you too literally? I had an issue with a flaky run/stop switch once, bike would die and I had no idea why, was running great otherwise.

 

It was not like it wasn't getting a spark, it was more like it was gas depraved. I was always able to get the starter motor to go right after it broke down too, it just wouldn't restart. I am running between the driveway and my computer, I only have one more day till work begins full time again. I can go check the switch but from what I see that doesn't look like the culprit. Plus the starting after hot too points to it more being a gas problem, or a leak problem, since I would have to keep the starter running for 10-15 seconds with the throttle all the way open to get it to start. Then I would have to be super aggressive to keep it running when in gear.

 

So to add to this thread. I found that when my bike was on, it was spilling gas on the ground. After further inspection I found that one of the float needles was missing its rubber tip... So that is ordered. Beyond this I also found that the PO had 2 types of spark plugs so those have all been replaced.

I spent some time looking into how to check the kill switch, but got sidetracked by the gas. I am wondering if anyone has some tips for checking it? Chazmati how did you figure it out? Also the kickstand and neutral sensor, are there easy ways to check those as well? While it is in the garage this weekend I will be pulling it apart. One step closer, I hope

 

You seriously need a service manual or this is gonna be one heck of an uphill fight. There is a way to check all of that and more; and you've got a lot of work to do.

Find a manual so we can be of serious help.

 

I have the service manual, was just wondering if someone had a trick to checking the switch.

I have it in the garage now without the carbs on it, so I will be taking the wheels off in prep for brakes arriving as well as checking some of the electronic issues I have been seeing. Really the major one was a bad battery, I have been through the charging system and a new battery fixed it. Occasionally the start button does nothing, I am assuming it is between the kill switch, kickstand and neutral sensors. This was mostly caused by low voltage from the battery before but it has happened once since I got the new bat. Will be looking into some of this today

 

No real trick, you throw a meter on the leads and operate it.

The original solenoid isn't "solid state" the contacts get burnt/carboned up and it can become intermittent.

The problem with the starter button can also be the button contacts as well.

Here's a "quickie" guide to checking the various switches, etc: http://xjbikes.com/Forums/viewtopic/t=27543.html

 

I'd wonder if you have fuel in the bottom end too. Having the float not close can keep accepting fuel, then it gets down into the lower end, seriously mucking up the abilities of the oil.

Open your oil fill cap and smell. If it's gassy ( gasoline smelling ), then replace oil before you burn something up down there.

 

One other thing to keep in mind:

"Starts fine cold, hard to start once hot" is a classic symptom of too-tight valve clearances...

 

I have found that the ignition coil that runs cyllinder 2 and 3 has a broken secondary coil (inf. resistance).

Just to make sure, if I throw the multimeter on the other coil it will jump to 11 Kohm then pops back to infinite (11 +-20% so in spec). Is this okay or should it be staying at a constant resistance. I really know little about how the coils work. Both primary coils were right on target.

Also no gas smell from the oil, good tip though, I would not have thought to check for that.

 

So the bike has been running great! It seems like the largest problems I was having stemmed from the coils and caps. The only problem I have now is trying to find where the PO's toggle switch went to. This controls the headlight.

I have 3 versions of the wiring diagram and I am finding it hard to understand. One side of the switch is tied into the fuse box I don't really understand where the other side could go. Anyone have any ideas or experience with this wiring. Sorry Im being very vague... The diagram is very confusing. Hopefully Ill figure it out shortly.

 

There are TWO diagrams you need to make sense of this, the wiring diagram and the circuit diagram. Without both it truly is a nightmare.

PM me with your email address and I'll send you the factory wiring AND circuit diagrams; plus the headlight and other fault isolation diagrams.

The original configuration for the headlamp circuit was to have the light come on only after the bike had started. Then, the light would stay on even if the bike stalled, until the ignition was switched off and back on again. I suspect your PO was confused, or decided to out-engineer Yamaha and eliminate the latching relay. Bad idea. The way it was originally designed works fine.

 

Here is a photo from when we did the valve spacing this winter
http://www.chrisstraitphoto.com/photos/ ... 3Zk-XL.jpg

the two grey wires are the ones from the toggle switch, this would suggest that the wire went to the dimmer switch. It is just a question of which wire...

In the picture you can see it moving up there. The Yellow, Red Yellow and Green seen on the right are the power to the light. The wire is not long enough to go any farther than the left cluster.

I agree with you Fitz the PO was a bit of a cobjobber, as it seems most of POs are. Thank you for your ongoing support and help. I think that I have both of those but will PM you.

 

It has been fixed! I found where the switch goes, I am going to work towards reverting it back to its original state, the headlight does, however, turn on whenever the key is turned. So for now I will be using the switch, later reversion.

Another question I should have asked while I had it all apart. Is there a way to calibrate the spedometer? Mine is off by as much as 15 miles per hour.

 

Not calibrate; how about clean and lube? See: http://xjbikes.com/Forums/viewtopic/t=15303.html That's usually the fix.