Bike runs good until it dies


XS650 New Member
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Chicago, IL
Hello forum, long time creeper, first time poster I need some haaalp!
I'm a new rider and this is my first bike. It's needed some work but I've been happy to dig in and get to know the machine.

The Bike:
1982 Heritage Special, stock pipes, jetting etc.
xscharge PMA, pamco ignition, ultimate high output coil from MikesXS

The Problem:
Well, I thought i'd finally got it running good until today. I've had the bike for a year now and its needed a bit of work to get good. The PMA swap helped big time and I thought I was in the clear though I haven't put a whole lot of miles on it since. The problem now is that the bike runs good until it doesn't-- and dies presumably when it gets up to temperature. It's not really a bogging down kind of dying feeling (like when I first got the bike a year ago!) When it starts acting up it gets a little stuttery, until it dies more or less straight out. After it cuts out it's difficult to start again, but after letting it sit for even just a very brief time it starts right back up and I can get a few more miles out of it.

Browsing around the web, some folks have suggested to other people experiencing similar symptons that it could be a failing ignition coil-- that the coil is cutting out when it gets hot. Which makes sense as the stutter seems like a definite misfire, until no spark at all. But the coil is new last Fall.

Full disclosure:
I'm a bone head-- just before this problem sprang up yesterday, I did make an adjustment to the timing with the pamco inadvertently over-advancing the setting before I underdstood the risk :banghead: --I don't wanna talk about it-- but afterwards didn't get the bike out of the parking lot before it died on me-- So I'm hoping I haven't done any serious damage. After properly restting the timing with a light it's better. I can get it around the block and a little more now.

It had been running good-- only other hiccup since I've had it running this season was a slight stutter after about a 20 mile or so ride but right as I was getting back home- I thought maybe it was overheating from riding in stop and go city traffic.

Whatchu guys think? What tests should I run? I'd been planning a big camping adventure for August so I'm hoping we can get to the bottom of this soon.. Are there tests I can do before I settle on rebuilding the enging? I was hoping I wouldn't have to dig in that deep this Summer-- but if that's what its gonna take I just want to rule out everything else first. What parts do I need to replace and inspect if I have to go that route? How bad did I fuck up? :doh: Thanks in advance
... After it cuts out it's difficult to start again, but after letting it sit for even just a very brief time it starts right back up and I can get a few more miles out of it...

Fuel delivery problems can also cause that. Search the forum for "tank vent", "gas vent", "vacuum petcocks"...
This same thing was just happened to me Thursday on the way home from work, turns out the gas cap was not venting. I dismantled the gas cap, cleaned everything back up and now she runs just fine. Even starts easier!

If there is no air coming into the tank, how can the fuel go out?:shrug:
Thank you both for a quick reply. I hope it really is that simple-- I've just been fighting with the thing so long, to have it give me a problem again I've just been expecting the worst.

BUT! After inspecting the gas cap, it seems likely that was the culprit! Looking at the cap theres a rubber grommet and spring keeps it with a tight seal, but where is it supposed to vent from? Oh there's a little tiny pin hole right in the middle which low and behold was covered right over when the previous owner kreem coated the tank. I peeled back the coating from the vent hole and will have to give it a good long ride later today.

I could not be happier with my xs650 as a first bike and I've really enjoyed getting my hands dirty with it, but with only a little over 13k on the clock she's begging for some miles and I'm itching to ride.
I also have a 82 Heritage Special that I'm working on, not my first bike but my first XS650.

Take the cap off the as tank by removing the screw at the hinge. Cover the tank opening and move the cap to your work area. Remove the 3 small screws on the gas cap and remove the center with the rubber gasket. There is a small washer behind there that needs to be checked and see if it's clogged or not.

I pulled the rubber off the center piece and used a steel wool pad and cleaned all the varnish of all the pieces. On the back of the center piece there is like a corkboard like gasket. Make sure the passage hole is not blocked, I used fishing line to check the passage.

Next I remove the lock by removing the 2 screws and flipping the center piece up. I used a vise to compress the spring to remove the clip holding the center. I did this just to make sure everything was clean.

Once everything was cleaned I put it all back together and blew through the small hole in the plunger and was able to hear the air flowing. And like I said before, once I installed it back on the gas tank the bike fired right up first try and idled smoother.

Hope this helps :thumbsup: