1982 XJ 550 Crank No Start - I'm lost

Hey everyone, I'm at a loss, and seeking some help.

about a year ago I picked up a non running 1982 XJ550 maxim and have been messing around with it here and there.
when I got it is was in this condition:
- no crank (bad starter)
- dirty carbs
- been laid down.
- "last ran 5 years ago"
-15,000 miles

Things I've tested, and things I've done
- cleaned carbs thoroughly
- replaced starter (cranks nice and fast)
- tested compression (120-140 throughout)
- checked spark, strong on all 4
- replaced plugs
- brand new battery

my problem I can't get the damned thing to start. I got it to start once or twice after cranking for a several minutes. when it started up I ran/idled, albeit like crap, and reved with some hesitation. and I haven't gotten it to start since then. It has zero reaction to starter fluid or gas in the carbs. I'm lost on what I should check now. bad coils under compression? valve lash? timing? thank you all so much in advance! I just want to get this ready for riding season!

TLDR: It has fuel, spark, and compression but is near impossible to start. I'm wondering what I should do next.

 

A few things.
Compression is great and that is what sucks the juice in.

1. Valve clearance
2. Dropped... Did it damage the reluctor or twist something on the left hand side of the crank
3. Air leakage... All encompassing issue carb wise.
4. As another chap in a current thread noticed, the carbs had the wrong pilot jets.

 

Zero reaction to starter fluid, well then have to look at spark again. Making sure you have a really good battery or even jumping the bike from another bigger battery is a good way to make sure low voltage is not an issue. As @css1984 mentioned, if the intake vales are not allowing spray or fuel in, then the bike will not run.

Clean all the plugs again. Test the plugs for spark with the lights off in your area if you can. Hope that you get a good blue spark on the plugs. If the spark is red that is not the best but having any spark is a good thing. If there is any corrosion on the contacts? Have you checked what the spark plug cap's to the wire connection looks like. If you remove them and see green or chalky white, clean them up. You can even remove a very small portion of the plug wire to get to good copper wire again.

Good luck and keep the updates for the troubleshooting coming.

 

hey guys thanks for commenting, and sorry for the late update. I retested my compression and got good numbers. 140, 130, 145, 140 and the bike has only 15,000 on it so I may rule out valve lash for now. I ended up inspecting my coils and both are cracked!(although they seem to not be wildly out of spec) I checked the spark again, and now I'm having second thoughts. My friend owns this exact bike and says they can be very temperamental when the ignition system is not dialed in or if they get a slightly weak battery. Is that something a lot of people experience? I'm thinking about just ordering a set of DC-1 coils as I've read on this forum they can be a good upgrade. I'll keep ya'll in the loop on what happens

 

Yes on the battery, have to have a very good battery that will hold close to 12V when you push the starter button. Once the battery starts to get weak, the brain box does not like it and will not throw voltage to the coils. Has to be close to 12v with the bike trying to start. Starter button pushed. Others will add the exact voltage.

 

Couple thoughts..

The 82 has the YICS intake, so if your carbs aren't sync'd well it wont want to start or run much at all. Use a guitar string (High E string, ø0.010) as a feeler gauge to bench sync the carbs so they are as close to each other as possible. Then on the bike you'll want to sync them with vacuum sticks/manometer.. on the YICS head this is a hassle because you need to install a YICS blanking tool to isolate the individual cylinders.. When I had the 82XJ650, I just installed the YICS tool and left it in place.. the bike ran a lot better with it in, even once sync'd ¯\_(ツ)_/¯

Concerning coils...
Right now your stock setup powers the coils & ignition box like this:
1 battery -> 2 red wire -> 3 battery connector -> 4 red wire -> 5 main fuse (usually 1st position) -> 6 red wire -> 7 key switch connector -> 8 red wire -> 9 key switch -> 10 brown wire -> 11 key switch connector again -> 12 brown wire -> 13 fuse box again (usually 4th position) -> 14 red/white wire -> 15 kill switch connector -> 16 red/white wire -> 17 kill switch -> 18 red white wire -> 19 kill switch connector again -> 20 red/white wire -> 21 splice -> 22 red/white wires fork to -> 23 ignitor box, 24,25 coils, 26 neutral relay -> 27 start switch.

I typed all that out to illustrate that its a lot of wires, switches and connectors to pass through to get from the battery to the coils and ignitor box. Especially if the bike was ever stored outside, there is gonna be a ton of resistance along that path to the coils & ignitor box, which will lead to weak or erratic spark. You should, of course, check and clean each and every switch and connector for best possible performance....

Beyond that, if the coils & ignitor box are getting (some) power and you suspect spark may be weak..... Before replacing the coils outright, consider an ignition circuit relay mod to deliver max battery volts/amps to the coils & ignition box with the least possible connections & resistance. Check my XS850 Master Thread for general details on this Ignition Relay Mod.... The XJ and XS wiring have a lot of overlap, so all the same principles apply. Happy to field questions if you do go this route.

Side note if the coils are cracked and still throw good spark, get some epoxy or JB-weld and fill up the cracks. Just make sure they are perfectly dry (free of moisture) before filling them in & let the compound fully cure before running the bike.