XR dies after 10 or 15 miles. Help!


21 replies to this topic
  • bkxl

Posted February 26, 2006 - 07:36 PM

#1

I have an 82 XL500 with a 79 XR500 motor. It has the same ignition system as the 650s, so you guys should be able to help me with this. I've had the bike for about a month, and I love it except for one thing.

If I ride it less than 10 miles, it works fine. More than 10, and it will suddenly stop running. If it sits for 20 minutes, I can restart it and go another 10 miles before it dies. If I restart it a minute after it died, It goes maybe half a mile.

So my guess is that the pulse generator is getting too hot and stops working until it cools down. I've never worked on electronic ignitions before, so please reply and let me know if this is the correct diagnosis. Also, let me know any good sources for a new pulse generator. I'm hoping some aftermarket company makes a cheap one.

And now a rant. I found this out while riding a twisty paved road in the mountains near some pretty big drop-offs, when the engine stopped and my rear wheel locked and skidded. Fortunately, I was upright and between corners, and I always cover the clutch lever, so I was able to get off the road and stop safely. The guy who sold me the bike a month ago told me everything worked fine, and it was a great bike but he needed the money, and he had another dirtbike he preferred to ride. I wish people would disclose problems with their vehicles which could potentially pitch the new owner off a cliff instead of pretending the bike is perfect to get a few more dollars.

Thanks.

  • HawkGT

Posted February 26, 2006 - 08:03 PM

#2

Sounds more like a fuel problem than an ignition problem [guessing].

A fuel tank that isn't venting produces the same symptoms as you're describing. Next time this happens slowly open the fuel filler cap and listen for air rushing in. If the fuel cap vent is clogged than gravity will only be able to pull so much fuel into the carb before there's too much negative pressure built up in the tank to overcome. Let it sit for awhile and the suction in the tank relieves itself and the cycle continues.

If that's what's happening then when it stops it will behave just like it's running out of gas--cause it is.

Check for spark next time it acts up to narrow it down between fuel or ignition trouble.

You say the wheel locked up though?!?! I can't imagine what would cause the engine to completely sieze and then start running again 20 minutes later.

  • targetdrone

Posted February 26, 2006 - 08:04 PM

#3

It sounds like an overheating problem. My XL600 used to do the same thing. Make sure your oil level is up and that the bike is not jetted too lean. Mine was incredibly lean and riding in the summer in Vegas didn't help either.

  • bkxl

Posted February 26, 2006 - 09:40 PM

#4

I don't think it was a gas cap venting problem, but if it happens again, I'll open the cap and see. Since it works fine for more than 10 miles at a time, I don't think that could be the cause. I once bought an Triumph Bonneville for $500 because it would only run for a minute before dying. I punched a hole in the gas cap, and it ran fine after that. Before I fixed it, it would sputter a little bit before it died, as it was running out of gas. The Honda engine cuts off suddenly like someone hit the kill switch. Hey, maybe there's something wrong with my kill switch.

When I say the rear wheel locks up, I mean it makes a big skid mark on the pavement. I don't think the engine is siezed when this happens. It's just caused by the bike being light, the weight transferring to the front wheel, and the resistance from engine.

Since the bike will kick over easily right after this happens, I don't think it's siezed. It even started and idled fine a minute after dying today, but then died again 2 minutes later.

The spark plug color indicates the fuel mixture is correct.

Have you guys heard of anyone having these symptoms happen because of an ignition component? Any ideas on what else might be causing it?

  • snaggleXR650

Posted February 27, 2006 - 06:02 AM

#5

In my limited experience, electrical problems are usually go or no go. In other words, if it quits working, it won't work ever again. The fact that it will start a minute later, seems to detract from your electrical theory. I've never experienced a fuel vent problem as described, but it makes perfect sense. An old bike like that could easily have a clogged vent hose. After a minute, there could be just enough fuel dripping into the carb to get the bike to run for another minute and then die again.

Remove the fuel line from your carb and stick a funnel or another long fuel line on the fuel valve. Make sure you have plenty of gas in your tank and then turn the valve on and let it flow into a gas can or something. See if the flow stops or comes down to a trickle after 10 min. If it does, pull the gas cap and see if the flow starts up again. This will prove the fuel theory without putting your life in danger. Good luck.

  • pigryder

Posted February 27, 2006 - 11:46 AM

#6

Question, will the bike shut off if it just sits and idles or do you have to be riding it? e.i. making more heat, possibly the valves gettin tight???

  • somecallmetim

Posted February 27, 2006 - 01:40 PM

#7

So my guess is that the pulse generator is getting too hot and stops working until it cools down. I've never worked on electronic ignitions before, so please reply and let me know if this is the correct diagnosis. Also, let me know any good sources for a new pulse generator. I'm hoping some aftermarket company makes a cheap one.


Thanks.


That sounds like a pretty good guess to me. FWIW I had an old ford that would do the same thing, that was the cdi getting hot then cooling off.. As others said, check for spark when it's hot. My Haynes for the 83-00 xr600 says that the pulse generator should ohm at 360-440 ohms.


I buy my oem stuff from www.ronayers.com

they dont have online microfische for older bikes,but if yours is the same as an xl650 I'd say thier price is good...

Part Number: 30300-MY6-671
Description: GENERATOR, PULSE
Source: HONDA
Price: $39.81

  • khelton

Posted February 27, 2006 - 01:46 PM

#8

Sounds like a heat related spark problem to me, had some bad coils once that did that..when it stops, take the plug out, lay it on the head, turn it over , if the plug sparks, you have a fuel problem..my bet is it won't spark.

  • khelton

Posted February 27, 2006 - 01:49 PM

#9

Actaully, with the wheel locking up...don't know what else that could be except the engine locking up from heat....not good....

  • tomshell

Posted February 27, 2006 - 09:04 PM

#10

Check the coil aasembly when hot.I had that happen to me years ago and it drove me nuts.Coil would get hot and open up,cool off a bit and it was good to go till hot again.

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  • bkxl

Posted February 27, 2006 - 09:23 PM

#11

Thanks for all the replies! This forum sure is active.

I'm surprised a pulse generator is so cheap. I'm going to replace that first and see if the bike stalls. It seems to be heat-related, but also speed-related. I can go 11 miles in stop-and-go traffic to and from work without stalling, but if I'm going fast without stopping for an extended period of time, it will stall. Maybe it's hotter then, but I can't tell how hot.

XRs Only sells an oil dipstick with a thermometer built into the cap. I may buy one so I can see exactly how hot it's running. I used to have one on my Sportster, and it was surprising how much the temp varied. At night in the rain in the winter, the oil temp would never get over 150 degrees, and it would get up to 220 in the summer.

I don't think the engine is siezing when it stops because it kicks over easily without much resistance if I kick it right after it stops running. If it were siezed, it would probably be hard to turn over. I think the rear wheel skidded because of the high compression piston and the sudden loss of spark, and due to the fact that the engine was revving kind of high in a low gear when it happened.

If I kick it a minute after it dies, it will start up and run perfectly, but it only runs for a minute or two before dying again. If I wait 20 minutes, it will run for 10 miles. I haven't tried letting it sit in my driveway and run to see if it will die under those conditions, because I'm afraid it would overheat and cause more problems if I let it idle for 20 minutes without driving anywhere.

I'll post the solution when I figure out what the problem was.

  • bkxl

Posted July 29, 2006 - 09:22 PM

#12

It was a pulse generator problem, and Honda has discontinued the part. It took me 5 months to find a used one at a junkyard. I rode the bike 170 miles this week without any stalling, including one 45-mile non-stop trip. I thought I'd better post this because I couldn't find anything in the forums about intermittent heat related pulse generator failure. It's real, and it could happen to you. And it's easy to fix if you can find the part.

I bought a 1981 XR500 pulse generator, but it didn't work. It bolted in nicely and looked good, but Honda changed the CDI system in 82, which is the year of my electrical system. Not sure if a pulse generator from after 82 would work or not. So be warned: If you're buying an electrical part for an older XL or XR500, and it's from a different year of bike, make sure it will work before going to the trouble of paying a lot for it and installing it. Also, if you buy one from an XL from the right year, but your bike is an XR, make sure they're compatable. The XL has a more powerful alternator, so it may not work.

My bike is a bit of a Frankenstein job, with a 1979 XR500 engine with a 10.5 to 1 Wiseco piston in it. It has the alternator and CDI parts from a 1982 XL500R in the body of a 1982 XL500R. It runs great now, and hope it will for a long time.

  • InternalCombustion

Posted August 02, 2006 - 06:55 AM

#13

Mucho thanks for the update, BKXL, I am having that identical problem with my street-legal 01 XR650R. Exact same problem, and it only started maybe two months ago. I thought I was loosing my freaking mind trying to find the problem, even went so far as to replace the crapo E-Line black box that came with my dual-sport kit (God forgive me for not getting a BD dual-sport kit!!).

Anyway, have just finished the re-wire job, replacing the E-Line black box with real electrical components and am going to do my first road test tomorrow. I will let you know if the problem is still there. If it is, that b$@#&tard pulse generator is getting tossed out.

Glad to hear you're back in the saddle again. Nothing worse than a mystery glitch!

Ride safe,

  • SniperTeamBravo

Posted August 02, 2006 - 11:00 AM

#14

Actaully, with the wheel locking up...don't know what else that could be except the engine locking up from heat....not good....


I doubt his motor is locking up, the ay he describes it it is due to compression, try it yourself, go along in 4th gear or third and hit the kill switch without pulling the clutch in, youll experience exactly the "rear locks up" deal he is, I gaurentee it! Shoot, My 1996 XR600R supermoto wont let the rear wheel do anything BUT lock up if I try to push start it, and this is wiht the thing in perfect ruinning condition! It has too much compression.

  • SniperTeamBravo

Posted August 02, 2006 - 11:04 AM

#15

It was a pulse generator problem, and Honda has discontinued the part. It took me 5 months to find a used one at a junkyard. I rode the bike 170 miles this week without any stalling, including one 45-mile non-stop trip. I thought I'd better post this because I couldn't find anything in the forums about intermittent heat related pulse generator failure. It's real, and it could happen to you. And it's easy to fix if you can find the part.

I bought a 1981 XR500 pulse generator, but it didn't work. It bolted in nicely and looked good, but Honda changed the CDI system in 82, which is the year of my electrical system. Not sure if a pulse generator from after 82 would work or not. So be warned: If you're buying an electrical part for an older XL or XR500, and it's from a different year of bike, make sure it will work before going to the trouble of paying a lot for it and installing it. Also, if you buy one from an XL from the right year, but your bike is an XR, make sure they're compatable. The XL has a more powerful alternator, so it may not work.

My bike is a bit of a Frankenstein job, with a 1979 XR500 engine with a 10.5 to 1 Wiseco piston in it. It has the alternator and CDI parts from a 1982 XL500R in the body of a 1982 XL500R. It runs great now, and hope it will for a long time.


From what I read allot of guys buy an XL stator for that reason, that it is more output, and thats a good thing. The pulse benerators are also all the same after 87 or so as far as I've been told. I asked at Ricky stator if a stator off of a 1989 XR600R may work on my 1992 XR600R and he said it is idnetical except for the plug on the harness end. I lost out on it on ebay so I am buying two new stators for my 92 and 96 because they are both plated and need more watts for the mondo lighting I have on them.

  • bkxl

Posted August 03, 2006 - 08:31 PM

#16

Glad I could help you diagnose your problem, Internalcombustion. In your case, I hope it's not the pulse generator and you're back on the road, or in the dirt. The internet is a place where you can find the answer to any question, and it's great to be the guy with the answer every once in a while. The problem was driving me nuts and making me really scared to ride the bike, but now I'm really enjoying riding it. And it gets 62 mpg when I commute with it.

You guys are right on about the compression being enough to lock up the rear wheel when the spark cuts out, especialy with the 10.5 to 1 piston I have in it.

As long as I'm posting, here's how to kickstart an XR or XL500, so if anyone searches the site for it, they'll find it. I've read some posts where people are really scared to kick old XRs over after getting bruised or broken feet. I had a pretty bad bruise on the bottom of my foot when I first got the bike and the pulse generator stopped working at a gas station, and I kicked it 50 times :thumbsup: before giving up and letting it cool off. I was careful about the procedure for the first 40 kicks, then I got sloppy and got hurt. So here's how to kick start a Honda XR500, or kickstarting a Honda XL500.

1) It's a good idea to check the automatic compression release mechanism and make sure it has the correct tension. Do this every 6 months or so.
2) Make sure the bike is in neutral, the ignition switch is on, and the choke is all the way out.
3) Kick the lever slowly a few times until you get to a point where you feel a lot of resistance. You're not trying to start the bike with these kicks, so just push the lever slowly and gently.
4) Once you've found the spot where you feel a lot of resistance (TDC on the compression stroke) lift the lever up once and gently press it down once.
5) Now kick it hard and it should start.

  • InternalCombustion

Posted August 08, 2006 - 06:53 AM

#17

It was a pulse generator problem...


How were you able to verify the pulse generator was overheating? I know you said you replaced it and you went 170 miles with no glitch and that certainly would seem to indicate the source of the problem.

Like I posted before I am having the identical problem with my XR650R. I am not much of an electronics guy and I am trying to figure out why a pulse generator would overheat. :thumbsup:

My consern is that on the 650R's the pulse generator is not a separately stocked item from the dealer, my understanding is that to get it you have to order the stator: big bucks. That's why I want to be sure its the pulse generator before I go and spend that kinda money.

On an earlier post one of the guys reminded to check the spark to verify it is ignition and not a fuel issue. Problem is, with the 650R, holding the plug and kicking it at the same time is a bitch. Or else I am a wuss. :ride:

  • chrisb421

Posted April 06, 2012 - 05:10 PM

#18

i'm having a simular problem. my xr650l runs fine for 2 miles and just dies. its like a bad/dirty carb. i live in the caribbean, so i'm basically at an elevation of 10 feet. there's some elevation setting that i tried messing with - but its only supposed ti turn a 1/4 turn, but it just spins, so i don't know if thats the problem or what. anyway. i'd appreciate any imput. thanks

  • rogervize

Posted April 07, 2012 - 01:50 AM

#19

Presume you refer to the PG(pulse generator) on the RHS under the clutch cover..for timing the ignition?
..not to be confused with the ignition exciter(energy source) ..LHS ..note that this is also a 'pulse' generator.
I believe I had a faulty PG ..but I ended up replacing everything so not sure now...it definitely works fine on the bench.
BTW..all the electricals are subject to heat unless you put them in an environmental chamber...and inside an engine is not the ideal place for these.

  • CHUCK_DEMPSEY

Posted April 18, 2012 - 03:25 PM

#20

Call the shop @Xr's Only and ask for Jr. He will trouble shoot it for ya !!!!!!





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