XJ650 not starting, coils/plugs ok, alt brushes okay

Hey everybody,

Got the new coils from mikesxs.com, which as it turns out are a drop in replacement for XJ coils, and only $32 each. Well, in terms of resistance and fit, anyway. I would like to gush over them, and tell you how smooth and wonderful the ride is...

But it still won't start. The plugs were carbon fouled, so I tried my best to clean them up with with a wire brush and some rubbing alcohol. I read you could do that somewhere. Didn't expect it to work wonders, but I thought maybe it would help it start.

Anyway, tomorrow I guess I will replace the plugs with fresh new ones, and try to push start it. (Battery is dead, but good.)

Also had a look at the alternator brushes again as I went to replace them. This time instead of measuring I looked at the wear line -- practically new. Anybody want to buy some alternator brushes?

So, coils, wires, and caps are all good, brushes are good, battery should be good (if it wasn't dead). I'm hoping that I'll put the new plugs in and everything will work fine. If it doesn't, where should I be looking next? Something else in the ignition system to check? Or should I move to the carbs? Is it weird that the plugs were super carbon fouled and yet it wouldn't start without the choke in? Given the history of running rich, should I adjust the idle screws in a little bit? That's the lean side, right?

Summing up my previous posts about this bike, I had some electrical troubles with the fusebox and a melted connector that I cleared up. Bike was backfiring and gutless when accelerating at that point. Is it possible that the earlier problems screwed up the plugs to the point of no return?

Sorry, lots of questions... I'm tired and rambling. I need to fix this damn thing so I can take it to work!

 

Oh yeah, it shouldn't matter which lead goes to 1 and which goes to 4, right? It's a wasted spark system, I think...

 

The battery being dead might have something to do with your problem. On the XJ's the battery delivers power to the TCI Unit which in turn is reponsible for the timing of the spark, amongst other things. A weak battery on an XJ does give problems at the spark end of the works. An enterprising XJer here should be able to provide the link to the XJ Electrical page on the web, which has a lot of useful electrical/coils/plugs/battery etc. information.

Simplest test would be to crank the engine (I know, can't do that 'cos battery is dead) and take one of the plugs out of the engine, hold it against the block to ground it and see if it sparks at all.

Might be best to get the battery fully charged up and then try - if that fails then the problem is elsewhere. Intermittent or total electrical failure on the XJ when I first got mine made my hair turn grey trying to hunt down the cause...

 

(Battery is dead, but good.)???
A dead battery is dead and useless until you get it charged up!! As redcentre003 pointed out, these bikes need juice to run. You may be able to turn the engine over with a low battery, but there's not enough juice to get the ignition to work.

Here's the link to the XJ Electrical page mentioned.
http://www.geocities.com/MotorCity/Speedway/7795/

 

...dead, but good.....

They don't stay good very long if you let them sit around dead.

 

Ah, I see. I'll work on charging it then. I was able to push start it with a pretty much dead battery the other day though...

 

Well, I guess I'll pick up this charger today unless you guys see a problem with it:

http://www.canadiantire.ca/browse/produ ... earch=true

 

Oh yeah, how long should I charge the thing to get it going?

 

I would not charge a motorcycle battery at more than 4 amps, but if dead you might start with 6 for a half an hour or so. Not saying you can'y use higer currents, but the batter will last longer if you charge it slower.

Most battery chargers will either cut off or or have an indication when fully charged. If the charger only has an ammeter then fully charged is when the charging current drops down to less than an Amp.

 

Okay. This one is a 1A manual unit, so I might just chuck it on there for an hour and see how it goes.

 

A 1 amp charger will take more like 10-12 hours on a dead motorcycle battery.

 

Awesome.

Just awesome.

I pulled the plugs again today after having it running with Seafoam in the tank last night. Got pretty funky looking old gas out of one of the float bowls, as well.

Thought I'd check the gaps... turns out the mechanic who certified my bike didn't gap them correctly at all. Gapped to more like .5 mm instead of .7 - .8. ALSO! Totally wrong kind of plugs. NGK 7HS, not 7ES. Thread is waaaaay longer on the 7ESes... so I replaced them with the plugs I picked up the other day. I guess it's my fault for ruling that out as part of the problem, but I thought I could trust the mechanic just a little bit.

I will now charge the battery and try starting it again in a little while. Maybe tonight I can take it out for a ride... I know a motorcycle mechanic who really needs a brick through his shop's window...

Oh yeah, ended up picking up a 2A/6A manual charger instead of the 1A job. I can just read the ammeter to figure out when it's done.

 

Re: XJ650 not starting, coils/plugs ok, carb cleaning time?

Alright.

Starts up a little easier now. Idles weird, dies when I give it throttle. If I let it idle, starts making it's way up to 3000rpm before it calms down. I attributed this earlier to Seafoam doing its thing. Dies after about 3 minutes. Trying to start again right away doesn't work. Have to let it cool for a few minutes.

I manged to let it idle for about 5 minutes. Checked the headers. 1 and 2, hot. 3 and 4, ice cold. Pulled the plugs. 1 is a nice tan colour. Perfect. 2 is a bit less tan, but looking okay. 3 and 4 are totally clean. Checked spark on 3 and 4, both working fine.

I should mention that I started fiddling around with the idle screws, and put them all about 3 turns out. Adjusted 3 and 4 a little further out, but still seem like they're doing nothing.

When I drained the float bowls I got quite a bit of gas out of 1 and 2, and not so much out of 3 and 4. I guess I should pull the carbs next, hm? I have the rebuild kit and a decent selection of tools. I'll have to see what's open tomorrow and Monday so I can get some gauges to bench sync and maybe make a manometer. Got the rebuild kits already...

Any input?

 

You don't need "Gauges" to "Bench Sync"

The easiest way to get the Throttle Plates ALL ~~> "Mechanically Synchronized", is really quite simple.

Cut a 1/4 Inch WIDE section of somebody's regular, old "BUSINESS CARD."

Using the IDLE ADJUSTMENT ROD below and between #-2 and #-3 ... adjust the THROTTLE BUTTERFLY of #-3 to give you some nice drag on the strip of Business Card.

(The Business Card Strip will bend to conform to the curve of the Throttle Plate and the Carb Body.)

Get the nice drag going for you on 3-Carb and leave the Strip in #-3.

Now, just cut yourself another strip and adjust all the other Butterflys EXACTLY like the nice job you did on 3.

Bingo.
They're IN!