1986 XL600R No start

Hi everyone I just purchased a 1986 XL600r that was running ok when I bought it two days ago, but would bog down around 1/4 throttle. I drove it around some yesterday staying off the throttle, and she did fine , but not running quite right.  At one point after shutting her down in town, had a real hard time (10 minutes) trying to restart her. I finally got her started and got her home. I tried to fire her up the next day in order to try and tune the carb for the altitude Im at. 

Long story short, she just wouldnt start (wheras before it was very easy to start) - almost like she wasnt getting spark. Well I pulled the plug wire boot and the wire was completely disconnected from the coil! I figured this wire having been super loose while riding was likely the poor throttle issue I was having. Well reconnected to the plug wire to what I think was the coil, then pulled the plug to check that it was super black and sooty. I replaced with a new plug and.... still nothing. Not even close to turning over.

Whats going on here? My next step is replacing the ignition coil and wire with a new one, but anything else I'm missing here? Thanks.

edit: this bike had a new stator installed last summer.

Edited by Jonathan Wall

Alright checked a couple circuits:

 

Alternator/ignition (black/red wire) : 290 ohms , in spec

Pulse generator (blue yellow to green white) : 340 ohms, out of spec should be 450-550

getting strange readings trying to test the CDI so not sure I have the right multimeter for that job

Also confused on how to check for resistance on the primary and secondary ignition coils..do I just connect both ends to each prong with my the multimeter probes and then swap the probes from one side to the other or?

Edited by Jonathan Wall

you never mentioned if you did a basic spark test by grounding the plug against the engine and kicking it over. if not the pulse generator would be next guess after a new wire a coil. If you have a good blue spark and it still doesnt start you will have to check the timing and valves.  I have a couple of 83 xls and have rebuilt the top ends of both and stripped one right down and found many small issues that could have turned to big ones. Do you know what type of stator was put in? If you dont get a lot of responses post your question on the xr 600/650 forum 

Carpenter, thanks. I haven’t done that. how do I ground the plug to check for spark? No idea on the type of stator put in , as the work receipt doesn’t say. 

insert the spark plug into the boot   Rest the plug up against the cylinder making sure metal is touching metal and with the ignition turned on give it a couple of kicks while someone watches it and see if you get spark. Works better in dim lighting also a word of caution do not have your fingers near the metal part of the plug while it is being turned over, it can bite. You can google how to test for spark on an engine and there are a few videos 

Alright, so I have blue spark.

...this means I should be looking at valves and timing ?

Edited by Jonathan Wall

if you dont have one get yourself a manual You can usually find a honda shop manual on ebay or get a clymer manual off amazon. Check the basics  .is the air filter clean, get your self a spray bottle and put a bit of gas in it and spray a bit through the airbox into the carbs. How many miles and is there signs that someone else has had it apart (paint off the bolt heads, silicon squeeze out between parts) Like i said before post this on the honda xr600/650 forum there are a lot of guys over there with a lot of knowledge. It is a 30 plus old bike. The first winter after buying mine i stripped the motor down and found a cracked rocker, a out of round cylinder and a tiny chip if the 5th gear. All of these little problems could have caused big problems so what i am saying it would not hurt to at least pull the top off and head and have a look inside

just one thought ,Is the choke turning off all the way ? the cables could be getting a little sticky

Sounds more like carb issue then electrical at this stage. If it WAS running ok, then its more likely that something has changed since you've had it.

  IE, meybe you stuck stale fuel in it, or a bit of crud has been dislodged into the fuel bowl, pilot etc.

         meybe someone has been fiddling with adjustments?

    Start at the basics,, when you kick it over a few times,, does the exhaust smell like fuel?

         Yes, then meybe its just flooded and needs a plug clean again.

Sometimes winding up the idle screw and not touching the twistgrip takes out the guesswork.

      NO? Time to start at the fuel tap and work your way down, checking for flow.... 

            There is a difinate knack to starting big 4strokes,, usually a fair bit of choke and no throttle when cold ( dont gas it when kicking,, easy to do!)

               No throttle when hot.

                     kick from TDC  like your shin depends on it ,, then get your leg up real quick in case it backfires.

One thing worth mentioning is after pulling the plug and seeing it showing a rich condition I turned the pilot screw in to about one turn out , i have since moved it all over the place trying to start her , but could that be preventing starting ? I tried moving it back to the 2 turns out baseline per the service manual too. 

I was thinking of turning the idle screw all the way in to get a really high idle to help start the bike too and then adjust from there. 

one other piece of info is seems like hitting TDC compression takes more kicks than others sometimes...almost like I have the compression release engaged until it finally catches....is there a way to check that the compression release is sealing/functioning properly?

Alright, so I got her started!  I did have the plug out and gave her a bunch of kicks to purge the cylinder...another thing I did was use the manual compression release to go down a couple degrees from TDC, before going up for the kick, which I wasnt doing before as I heard that was optional and only to prevent kickback. Anyways she started, so will be trying again in the next day or two, as well as installing that new wire and coil.

Edited by Jonathan Wall

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