SUPER CONFUSED!!

Ok, I've been working on a 1982 Xj550 Seca that I bought a couple weeks ago......it's been a major work in progress because the bike had been sitting for approx. 4 years. Anyway, I finally got it running good and tuned up nicely, lined the gas tank......it was awful. So I put the Gas tank back on it yesterday moring and fired up the bike and it ran BEUTIFULLY, sounded great, smooth, started super easy, everthing was great. I killed the bike went and got more gas came back put the gas in and started the bike up again, and again flawless, perfect idle everyting was FANTASTIC, so I decided to take the bike for a small ride.....since it isn't tagged yet I kept it short, probably about a 2 to 2.5 mile ride. Pulled the bike back up into my Garage and shut it off, and just for kicks thought I would see if it started up good again...........and.....well, it wouldn't start, the engine turned over but it wouldn't start for nothing. I thought I heard a bit of a clunk sound at one point right when I started trying to start it. So I kinda wondered if it had jumped time, or something. I checked the plugs and all plugs are still getting fire....kinda weak but getting fire, has a brand new battery, that is fully charged, carbs have fuel in the bowls, everything seems right, but it won't start for nothing..........ANY SUGGESTIONS?????

 

Have you tried it since it has cooled down? Same result?

 

NEW battery doesn't mean CHARGED battery. How is the voltage on the batt (with the key in the off position)? Check your charging system output. A bunch of idling and a 2.5 mile ride would drain a battery if the charging system isn't producing any voltage.

 

Ok, Guys, here's an update and a new deminsion. I went home today at lunch and checked the battery with a volt meter and it read 12V. I turned the key on choked the bike and it started up and ran GREAT....so I took it around my subdivison a couple times, probably rode it for 7-10 minutes or so, it was running great......but I pulled up to a stop sign and went to pull away and apparently the bike was in 2nd instead of first and I killed it....well.....it was time to push it back home from there. I tried it all the way home....while pushing it and it wouldn't start. LUCKILY I was only about a 1/4 mile from my house, and it was all flat terrain. So, I tried it when I got it back to the house and it was turning over but wouldn't start up. So I let it sit and cool off for awhile, while I ate and mowed the lawn and went back and tried it again and still the same. So I left if for about another 30 minutes or so and went out turned the key on and tried it and it was dead in the water, wouldn't even turn over. I pulled out my volt meter checked the battery, it had 12V so I opend up the seat hatch and found that the "main" fuse was blown, replaced it and it blew instanly. So I pulled the hot side of the battery replaced the fuse again, went to put the hot lead back on the battery and it blew again......?????? Obviously there is a short somewhere. Ya'll got any suggerstions of where I should look first? Also why is it not starting back up after it gets warm? Are these two problem connected?

 

Get a wiring diagram. Does it blown when the key is turned on? When the starter is pushed? Try to observe behavior to see which circuit you need to start going down. I would guess that the two problems are related.

 

Do you know where I can find a wiring diagram? I looked all over the internet for one a couple weeks ago and couldn't find one. As far as your question, No the key doesn't even have to be on for it to blow. It started blowing the intstant I put a new fuse in.

 

Ok, revision on that last post. I just got back home from work and I put a new fuse in the "Main" fuse spot and it didn't blow until I turned the key on.

 

Well I THINK I MAY have eliminated the shorting issue....for now atleast. Any I just took the bike for another spin around the neighborhood and pulled back into the Garage killed the bike and again same thing, I wouldn't start. Obviously something isn't working right when it gets warmed up but I don't have a clue what. You guys got any direction for me to look in?

 

My friend's Maxim did the same thing awhile back.. I don't remember exactly how he fixed it, but you may want to sync your carbs and use a Colortune to check your fuel mixture. The only other thing I can think of is that his compression was down quite a bit due to bad valves.

 

Ok, the carbs are pretty well synced, the bike runs great while you have it running but if it gets warm and you kill it....it ain't starting till tommorrow. To new to this bike deal to know what "Colortune" is. What's that?

 

PM me and I'll email you cable and wiring diagrams.

 

If ONLY the main fuse blows when you turn on the ignition, it can only be 2 things.

1.) Your Brown wire from your regulator/rectifier is grounding to frame somewhere.
2.) Your brown wires inside the harness are grounding out to frame somewhere before the fuse panel.

Check those two things first. If it's a harness issue, it should be fairly easy to see if the harness has rubbed against the frame and is shorting out. IF it's an internal short within the harness, i'm afraid it may involve ripping the whole harness out of the bike and unwrapping it to find the short.

It could possibly be found easily right behind the ignition, where the wires come out of the key cylinder.

 

Thanks, KrS14, I got it to stop blowing the fuse...for now. But your suggestions help me confirm what I was thinking. A couple nights ago I starting looking everywhere in the wiring for a short but I didn't find any bare spots. But I kinda keyed in on the brown wire and really moved it around and checked it out good. If It happens again I'll probably try and run a whole knew wire for that one. I'm thinking maybe moving it around like I did checking it, made it make temporarily connection. At least if it happens again I'll know what to key in on for sure. You got any clue what might be getting to hot that would cause it not to start after I kill it from a short ride???

Thanks Again.