No Decent Spark Until You Let Off The Start Button.

82 XJ550 stock everything is cleaned tuned up and it runs excellent, once you actually get it started. Brand new battery one week old (and every battery before this)same thing. It has a tiny random not visible spark or no visable spark when I press the start button and crank it over but EVERYTIME I let off the start button it Sparks blue and snappy once and only once, sometimes this single spark is what fires it up.(Even jump starting still no spark until I let off) Carbs have been went over 5 times by me (Have been baptized in the Church Of Clean) new intake boots, throttle shaft seals, plugs etc..checked stand switch, clutch switch, cleaned start switch, cleaned starter + brushes (helped it turn over much smoother and quick). Still a tiny barely visible spark once in a while or no spark until I let off..... then only strong spark you'll see.

 

Are the spark plugs new?

 

Spider, you say it runs excellent once started. Is that just idling or going out and about heating up engine, going through all gears /rpm range and coming home 1 1/2 hours later and does it still run excellent after all of that?

Have you checked what the battery voltage drop is when cranking?

 

What happens if you boost it off your car?
I see you have a new battery but it sure presents symptoms of a weak one.

 

Sounds like your starter circuit is draining electrical power that should be going to your CDI or "spark generator" I forget the term. When you release the starter button, generous power is restored quickly so you get enough spark and engine turnover momentum to start. Try starting without pushing starter button (connect wired across the starter solenoid). Check amp draw of your starter. If it's over-amping, might be robbing all available power. Not probably but maybe. I'd say its upstream of your plugs if they ALL exhibit the same issue. NOt battery if it's new and same symptoms with the old battery.

 

Check the connections to the starter motor. Sometimes they start to fail near the terminals.
Other possibilities: spark plugs (as mentioned above), high resistance in the plug caps (if they are 35 years old, replace them), or weak coils. The stock coils were never that powerful, lots of us upgrade them.

 

^^^ and check/ clean all of your ground connections also. 30 years ago everything was fresh, clean and new.

Spider - How long have you owned this bike?

Just noticed we are neighbors - I work in Merrill.

 

Often an indicator of a weak battery. But---if you've been able to verify that it is NOT the case of what you describe (and it would seem that you have been able to verify that.....)then my next direction of thought is to the brushes in the starter. If tat still doesn't solve it, my next line of. Defense would be to go after the coils.

 

I have the same bike, 2 issues come to mind.
I removed and disassembled my starter about 700 miles ago (I have 11,000 total miles). It was all gummed up. The old grease had solidified and the brushes were all gummed up. I cleaned it up, re-greased, and put on a new gasket. That helped starting a bit.

I recently did the fuse box modification and had my fuel tank off. While I was standing there just sort of looking everything over I noticed my left ignition coil had a crack in it. I got the new coils ordered from XJ4ever.com, the green Dyno coils. Got them installed and also found a bad (open-no continuity) spark plug cap, so installed a new set of those too. Man, it starts immediately when I press the start button. I really didn't notice any performance increase but it used to always be a hard starter. Works great now. I just did the install on my 550 and sent Len lots of install photos to include the cracked coil pictures. Contact him and reference TJ's 550 and he will share info with you.

 

And you don't know lectricity? That's a very good suggestion as the high current starter cannot only pull down the battery, but if any resistance on the ground side exists it could reduce the available voltage to the coils by floating ground slightly. You could check the voltage at the TCI R/W wire and black wire at the TCI while the starter is spinning. If a voltage drop is being produced in the ground circuit the voltage would appear abnormally low. Check from the R/W wire to battery negative to evaluate the high side.

Here is a recent link on the 550 battery ground scheme for their locations:

http://www.xjbikes.com/forums/threa...ires-clarification-please.112042/#post-563157

Note that the 550 uses the extra frame ground, which is not necessary if the frame to motor, motor to battery grounds are in perfect working order. However, with the added frame ground in good working order, any unwanted voltage drop in the starter high current ground side during starter engagement will not affect the ignition and lighting circuits.

And for one other ground to inspect and clean is at the ignition coil. There you should find the main harness eyelet terminal that supplies a common ground through the coil mounting hardware for the ignition, signal, and lighting circuits.

And, even though you have a new battery and used jumper cables, always start by measuring the voltage at the battery cables and ensure you are supplying at least 10v when the starter is spinning.

 

The ignition coil ground is located on the right coil, under your fuel tank.

 

@Rooster53 - thanks, I read a lot here and some of it sticks.

 

Ok sorry for the delay in my responses, though I might have found the solution...(and I wrecked some shit in the process.
Here we go:
New plugs:YES
Starter was degummed, it helped it turn over much faster and much less drain, but this was done previously.
Hello Stumplifter: You are my neighbor what a small Jap bike world we live in!
Bike runs great through all temp ranges and started amazing once warmed up
When it was jumped a tiny bit more spark but no start!
Chopped plug wires back a bit, still nothing.
My fuse box is totally garbage (understatement), but it is not restricting anything at this point, I replaced the ignition fuse holder.
Never checked the grounds....not gonna lie (planned on it though )

ANYWAYS...Sometimes I do stupid shit so . I took the TCI out of my XJ 650 threw it in my 550 and it fire up instantly every time, spark when you crank it over and everything, its not rideable with that TCI pretty sure the timing curve is totally different so it sputters out quite a bit. But I think its the TCI ..
NOW here is the part where I broke some shit. I went to disassemble the old TCI (I Repair Electronics For A Living) and I busted the board up in the process...sooooo there just happens to be one of the coolest 30th annual European and Japanese bike swapmeets about 15 miles from me starting Friday and Saturday, so I am gonna go down and see if I can get a used TCI for cheap.



P.S.Its also for sale... for too much, tons of new stuff on it. 10,000 miles, hasn't been registered since 1990 I ride it with those plates hoping to get comic relief from the police.
Almost to embarrassed to admit those are Harley pipes on it ($40). Ive got two caps you can pop off to give it a screaming demon like sound. Don't worry, I own a totally bone stock 1980 XJ650, I will never deface.