So I got about 100 amazing miles out of the new top end before I ran into serious trouble again.
I'm sitting at a stop light on the offramp of the freeway when the GS just dies...like I turned the key. Couldn't get it started and had to truck it home.
Just pulled the fairings off. Definitely getting a spark and it seems like I'm getting good compression. Maybe I should invest in a legit compression tester to really see.
Also checked the petcock to make sure fuel was getting to the carbs.
I really don't know what is wrong this time. It had been running so amazingly great since I rebuilt it. Seems weird that it would just decide to jump timing or something sitting at idle when I've had the thing up to 90 mph.
Anyone got any ideas (simple things that could be wrong) before I go drop some $$$ on a compression tester or another top end?
I thought I was ready to start having fun again with this bike, but I guess it has a different agenda for me :technical:
I got a compression tester :icon_lol:
THink I could borrow it? I would ride the bike over and use it in your bike cave but....the bike is broken!
Yep.
PM me what's convenient for you.
Given the work you've done on it, I would suspect mechanicals first, but if it died like you turned the key and you didn't notice anything obvious happening (loud grinding, misfire), take a look at the electricals. Did you pull the engine to do the head work? Maybe your ground wire isn't secured tight enough?
I woukd doubt compression suddenly went out. The bike would do something even with bad compression.
Like mentioned, most likely electrical. Or the timing chain could have jumped. Or the timing rotor slipped.
Too bad you can't bring it to the Bike Cave.
I agree it's likely electrical as well. One of your connectors might've just come undone, although you did say you were getting spark.
At least no one said "the only 3 things you need for a motorcycle to run are compression, spark and fuel", haha as if that's ever any help. If all you had to do was throw some compression, spark and fuel in a bucket to power a motorcycle I'd making hand built motorcycles in my basement. I completely understand how those things are relevant and important, but still.
Curious, you said you've had it up to 90 MPH. When I was rebuilding my top end some of my research and the BF said to treat it like a new engine. I.E break in period like it says in the manual. I know Flick didn't touch 90 until he had a 1000 miles in or two weeks. Think you might of been to hard to soon?
Mary
Its possible I rode it too hard to soon. I thought the break in thing was only for bottom end work, but what do I know?
If something had gone wrong at that speed I wouldn't have been too surprised, but it happened at idle.
I installed a manual chain tensioner during the rebuild, so that could have something to do with it, but again, if it was good up to redline, it seems weird the timing would get off at idle. I should be able to borrow adidasguy's compression tester soon. If the compression is in spec ( which I doubt ) then I can start figuring out whats wrong. I doubt it is electrical, because I am getting a spark.
What is the proper method of doing the compression test? Or do I just attach the gauge and hit the starter for a few seconds?
We've got a video for that :laugh: http://www.youtube.com/watch?v=6PH0BnemyPQ&context=C3d5e5a0ADOEgsToPDskKg71t1i6d-OmLfjzOfzpWY
-Jessie
Thanks for the video link!
One more thing.
The spark plug is emitting a yellow spark. It should be blue? Any chance that this is the problem? Probably just weak because the battery was nearly dead from trying to turn the engine over many times.
It could be the condition of how you're looking at the spark. Wheel it in the garage/shade and check it out in a darker area.
I agree on the break-in period that it's only the bottom end (including pistons/jug) that needs to break in. If you just did new valves, you lapped them already, so nothing there needs time to expand and sit properly like it would need to in the bottom end.
I never thought I would be happy about this, but it looks like my bike is having fuel delivery problems! :woohoo:
lol....
So I got some aerosol engine starter and sprayed it into the air box while cranking the engine and she started right up.
So, maybe a ripped diaphragm in the petcock? Could be something carb related but I don't know anything about carbs so I don't know where to start. Maybe bad gas from sitting for 3 months while I worked on the bike?
The good news is, it looks like the engine internals are fine. This is just a huge coincidence that it happened within 100 miles of the rebuild. I'm not afraid to get down and dirty with the carbs, I just don't know where to start (help ;) )
Dies it work in PRIME? If not, then you have a kink in a fuel line or blockage somewhere.
Do you have gas in the tank?
Did you add a fuel filter in-line?
Pinched line?
if PRIME does work, then check vacuum line to the pet chicken. (and be sure there is gas in the tank)
Could the in-tank petcock fuel screen be clogged up?
Did not work on PRIME (first thing I tried on the side of the road).
Yes, gas in the tank.
No in-line fuel filter, just the stock setup.
Not a pinched line.
I'll go see if the in-tank fuel filter looks okay, but gas comes out just fine from the tank-mounted petcock.
Given how abruptly it happened, I'm with adidasguy on the vaccum line being torn/off. You've lost vacuum somewhere, a bike wont just shut off if you've got bad gas.
Carb diaphragm could have ripped, air filter could be clogged, pet c.ock clogged, or carbs just too gunked up.
Does fuel flow from the float bowl drains? If not, look for a restriction in your fuel lines/petcock. If it does, check for clogged jets.
-Jessie
Man, I wish you could limp it over to the Bike Cave. I'd love to help solve this. Got petcocks and whatever else needed to being it back up to snuff. I LOVE solving problems!
A little progress...
Took the tank off and started messing around with all the petcock and carb lines. Seemed like the vacuum line had been pinched by the air box. I thought it was weird that it took 100 miles for the problem to manifest after the rebuild, but whatever, the bike started drinking the fuel in my temporary tank.
So, I put it all back together and started it up. But the bike will only run for <5 minutes before it dies and refuses to start. Next day I try to start it, same thing. Runs fine for a few minutes at idle, sounds mostly normal then dies and refuses to start. Next day, same thing.
At least I sort of got it running. Anyone got any ideas why it won't stay that way?
Shot gunning it I would guess that you are getting insufficient fuel flow.
-Jessie
I am not sure if 5 minutes is enough to create a vacuum in the tank, but could it be the vent in the tank lid is blocked? Will it run ok with the tank lid open?
Probably running off the gas in the carbs. 5 minutes is sort of the limit for running that way, and considering a little fuel might be dripping in.
I'd suggest you look for your fuel line pinched or did you put a fuel filter in? (Take out the filter)
Something is making fuel flow very slow. Over night, the carb bowls fill up again and give another 5 minutes.
I'm sure you tried the usual of PRIME, RES fuel cap open and making sure there is gas in the tank.
Those fuel lines around that air box are prone to getting pinched or bending too sharp and pinching off the fuel.
Thats what it seems like, so I guess I'll take the tank off again and make sure there are no kinks or anything, but I was very careful last time. I need to come up with a better temporary tank so I can test everything without the tank blocking view of it all.
Quote from: Bluesmudge on March 04, 2012, 11:07:59 PM
Thats what it seems like, so I guess I'll take the tank off again and make sure there are no kinks or anything, but I was very careful last time. I need to come up with a better temporary tank so I can test everything without the tank blocking view of it all.
Got one here in the Cave. Works great. Just don't have it higher than your regular tank or gravity puts too much force on the fuel and the floats can't close (hence gas comes out of the carb intakes)
Its by MotionPro. You see the white tank here - hanging a couple feet too high.
(http://i1206.photobucket.com/albums/bb442/adidasguy/GS500/trey_on_IV.jpg)
Okay, maybe I'm on to something.
I don't think the problem was ever fuel. My problem is nearly identical to what this guy is describing:
http://www.apriliaforum.com/forums/showthread.php?235576-No-spark-for-a-few-minutes-after-stalling-06-SR50
Twice now I've waited for the bike to die after it idles for 5-10 minutes and then pulled the plugs and checked for a spark. Both times, no spark. Seems like an electrical problem, which makes sense because when it first happened the bike turned off like the kill switch was hit, not like it was running out of fuel.
I'm not very good with electrical stuff, I'm more mechanically minded. So if you have any suggestions, please keep in mind that I probably don't know any of the electrical terms or what everything does.
Was thinking yesterday you had an ignition problem. I've never had a problem with the pickups or modules on bikes but I had a 75 Mustang V-8 that did the same thing. The Mustang would die after a few minutes running and wouldn't restart for 5-10 minutes but then would restart and run all day including starting and stopping after that, was a bad module.
There's some simple resistance tests in the manuals you can check your pickup with but the easiest way to check the module (ignitor) that I can think of is to replace it with another known good one and see if that fixes it. Maybe you can find one in a cave somewhere?
If it just dies with no spark, check 2 things:
1. At the battery, monitor the voltage. What is it at starting and at the time it does? What happens when you rev it? Could be defective regulator. After dieing, can you still crank it? Are lights on?
2. I'd try swapping the ignition unit. Possible it heats up and dies. I have extras you can try. If battery and voltage OK then possibly ignition unit. You can try unplugging it and plugging back in if dirty contact. Also check plug for the ignition timing pickup. Its under the seat back of the battery next to the neutral switch.
3. Just thought of another: defective side stand switch and neutral switch or the dual diode (or connection - connectors under seat back of battery box). This circuit will kill the bike. Lights will work. But bike otherwise is dead AND the starter will not work. Same effect as the kill switch.
Quote from: gsJack on March 06, 2012, 08:09:57 AM
Maybe you can find one in a cave somewhere?
Cave has spares of everything he needs.
After it dies I can still crank it and lights are on. Clutch and side stand switches are working as they should.
Sounds like it is the ignition unit. I'm not even sure what that is. Sounds like I need to become a caveman.
Let me know when you want to come by for some parts. Borrow them and if they work, pay later. If not the fix, return them later.
Sounds heat related so unit would have to run 10 minutes to heat up and flake out.
You can borrow ignition, regulator and whatever else anyone thinks might be a possible cause.
To save the battery, I would change everything first. If it runs fine, then put back original parts one at a time until you get it to die again.
As it warms for 5 mins it dies right ... more than likely the crank trigger, not the ignitor.
Cool.
Buddha.
After some more research, it looks like the buddha is probably correct. The crank trigger (aka pickups, aka signal generator) sounds like the culprit.
Here is a really good thread on the subject:
http://gstwins.com/gsboard/index.php?topic=46028.0
So if adidasguy has the part I'll meet up with him and hopefully have this all sorted out!
When its an electrical problem and heat related, it could be nearly any component.
Any electronic circuit can be subject to an open circuit or short as things heat up and expand.
If heat, the problem spot can be found by cooling it.
If the pickup, have the cover off. When it warms up and dies, cool it down. use some freeze spray or a can of air held upside down and freeze that thing. See if things work. You can do the same with the ignition unit and regulator. Do it one at a time to see which is subject to heat failure.
It could be a break in a wire or poor connector that opens up when heated.
When you visit the cave, take one of everything just to cover all bases.
when it heats up and dies, do a resistance check on your coils. Sometimes you can cook them, they are right over the top of the engine.
just a thought. could be 100% wrong.
open the drains on the bottom of your carbs with the petcock in prime... if gas keeps flowing out constantly then keep looking elsewhere... if gas doesn't keep flowing then you found you have localized the issue...
looks like someone only read to the bottom of the first page... :icon_sad:
Ah damn, I need to read more...
He visited the Bike Cave tonight. Took home a regulator, ignition unit, 2 coils, timing pickup and 24"x32" color wiring diagram.
Out of all that, the bike should be running soon. There's not much else electrical that can make the bike die but still turn over with the starter.(Which rules out side stand, clutch, neutral and associated relay and dual diode.)
The Bike Cave likes visitors! :tongue2:
For those of you following along at home:
Tried the ignition unit: still wouldn't turn on
Voltage Regulator: nothing
Signal Generator: BINGO
The let the bike idle for 25 minutes without incident. Then tore into the engine to check the torque on the cylinder head bolts from the rebuild and fix a minor oil leak from the valve cover.
Then I put it back together and let it idle for 20 more minutes. Looks like its good to go. I'm about to go on a test ride to be sure.
Thank-you everyone for your suggestions and a HUGE thank-you to adidasguy for the assistance with parts and everything else.
I'm wondering, was the signal generator going kaput just a coincidence or is there any possible connection to having just done an engine rebuild? It just seems weird that it happened only 100 miles after the rebuild. Maybe I should put an extra signal generator in my tool kit if I go on a trip.
Rare to go out - there is nothing electrical hi-techie in it. Its just a coil and a piece of steel. Most likely it was damaged during your rebuild. Most common part to go out is the regulator/rectifier and I think second id the stator.
Save it. I'd like to rip it apart and see what is really wrong with it just for giggles.
Glad to have helped! The Bike Cave to the rescue!