Hi, I was hoping someone could help me. I'm a new motorcycle owner and am having a problem that I can't figure out. I've got a '96 gs500 with about 12000 miles that I got back in December for about $950. It starts strong every time and ran fine, and for $950 I figured it would be a great starter bike both for riding and working on (doesn't bother me if it's obviously been down a couple of times). So i get to ride it a couple times without any trouble, but then the rainy season starts so I have to wait for it to be sunny again. Unfortunately I don't have a place to garage it, and at the time I didn't have a cover for it. So the first sunny day that comes around, I put on all my leathers and go for a ride! I only make it about 3 blocks before I start loosing power, if I try to accelerate past about 4000 rpms the tachometer needle starts dropping fast... I tried to drive it home like that, but soon it sputters and dies. I thought maybe it was water in the gas tank so I drained the remaining gas, installed a fuel filter and took apart the carbs and checked for obstructions. Once I got everything back together and put more gas in it (I also replaced the battery because it wouldn't hold a charge anymore) I got the same problem, the bike will start just fine when cold and warm up but then after about two minutes of being warm (or riding) first it'll hiccup at about 5000rpms, then it'll sputter and die and won't start again until it's cooled down...
I only get to work on it on sunny weekends which until recently have been few and far between, and I'm really looking forward to riding instead! Anyone have any thoughts or suggestions?
''then it'll sputter and die and won't start again until it's cooled down...''
I dunno for sure but maybe it's a coil issue?? It seems that an electric part warms up and then stops working properly...
Or any carb issue?
Your new battery is ok, i mean is it charched properly from generator and from regulator?
When you say than the the bike sputters, can you tell if the one of the two cylinders has died?(maybe pick up coil problem?)
And first of all :sad: :icon_rolleyes:, your spark plugs are ok?
Hope you find out soon and fix it :thumb:
12,000 miles is when the 3rd (every 4000 miles) valve adjustment should take place. Do you know if it was done at this time?
You took apart the carbs, but did you clean them?
Stock jetting?
Thoroughly clean the carbs. While you've got the tank off and the airbox off for the carb clean, it's an excellent time to check the valves.
You say it starts fine and warms up.
So once it's warmed up and you've got it sitting on the side or center stand, can you rev it all the way through the RPM range?
Getting gas in your airbox or anything? Could be starting ok with the extra rich mix then dieing once it warms up a little.
Thanks for all the ideas everyone! As long as it doesn't rain tomorrow I've got lots of things I can try.
Quote from: sotomoto on April 29, 2010, 02:39:16 PM
''then it'll sputter and die and won't start again until it's cooled down...''
I dunno for sure but maybe it's a coil issue?? It seems that an electric part warms up and then stops working properly...
Or any carb issue?
Your new battery is ok, i mean is it charched properly from generator and from regulator?
When you say than the the bike sputters, can you tell if the one of the two cylinders has died?(maybe pick up coil problem?)
And first of all :sad: :icon_rolleyes:, your spark plugs are ok?
Hope you find out soon and fix it :thumb:
I'll check the coil, I'm pretty sure the battery is good, I had the dealer assemble and charge it.
The spark plugs were new when I got the bike, and they've been giving good spark.
Quote from: scratch on April 29, 2010, 04:38:19 PM
12,000 miles is when the 3rd (every 4000 miles) valve adjustment should take place. Do you know if it was done at this time?
You took apart the carbs, but did you clean them?
Stock jetting?
I'm not sure if the valves were adjusted, once I assemble all the tools necessary I'll follow the video and adjust them myself.
I ran out of daylight so I haven't cleaned the carbs yet, but I'll definately do that tomorrow.
I don't know about the jetting, how can I tell if it's stock?
Quote from: romulux on April 29, 2010, 06:52:52 PM
Thoroughly clean the carbs. While you've got the tank off and the airbox off for the carb clean, it's an excellent time to check the valves.
You say it starts fine and warms up.
So once it's warmed up and you've got it sitting on the side or center stand, can you rev it all the way through the RPM range?
Once I take the choke off I can rev it all the way, if I leave it on for another minute it'll hesitate at about 5000rpms.
Quote from: PachmanP on April 29, 2010, 07:26:59 PM
Getting gas in your airbox or anything? Could be starting ok with the extra rich mix then dieing once it warms up a little.
There is a little gas in the airbox, I'll try adjusting leaner...
Thank you all again I'll let you know how it turns out!
So the coils are good and the carbs are clean and the air fuel mixture is 1/4 turn leaner. That wasn't the answer.
I don't have all the tools I need yet to do a valve adjustment, but I checked them with what I have (I've got some feelers that are .038mm - .076). The ones in the front (exhaust?) were within that range but the left back was a little low and the right back was a little high... Could this be my problem or is there something else I should check out?
I am having the same problem as well. I should check my valves as well, just be sure
Have you tried running on Pri and/or with the gas cap open? Pull the black caps off the top of the carbs and make sure your needles are straight? check over all your vacuum lines for any that may have gotten disconnected or cracked? Checked to make sure the choke is functioning properly? Just some ideas.. hope you get it figured out so you can ride instead of wonder wtf.
(Full of fresh clean gas? Did you check the fuel sock in the tank petcock? Is the tank petcock open correctly?)
I have tried running it on PRI with the cap open. The needles are straight as much as I can tell by eyeballing it, is there a specific method I can use to be sure? I haven't checked all my vacuum lines so that'll be next. The choke seems to be working fine... I make sure that it engages and disengages properly every time I reconnect it to the carbs before I put everything else back together. I only put a gallon of fresh gas in after I drained it all, that's all my gas can will hold. Also I didn't want to put too much in in case I just had to drain it again, or if it sits too long while I try to fix it. Should I try filling the tank up, do you think that might help? I haven't checked the fuel sock either, I'm not sure what that is but I'll figure it out and look into that as well.
Thank you for all of your help, anything I can try that gets me more familiar with my bike and one step further from having to take it into a mechanic is much appreciated! :)
When you pull the tank off there is a petcock bolted directly to the tank. If you take it off there is a fuel sock or strainer in there.. it could be possible that it is clogged up.. I would pull that out and clean it out real good.. couldn't hurt to do it even if it's not the problem. Then make sure that petcock is all the way open when you put the tank back on!
Yeah, I've had that off before, I just didn't know what it was called. How exactly do I clean it?
Probably just poor some fuel through it backwards to make sure it is flowing okay.. I would imagine some carb cleaner spray would work just fine as well.
Alright, cool! I'll give that a try, thank you.
I think you've got electrical problem, being the signal generator assy othw known as the crank trigger. My 96 had the same exact symptoms. Replace the pick-up assembly which plug into the electronic ignition black box and now all is well
So I haven't posted in awhile because I had a line on a used signal generator for $15 on craigslist. I've been trying to get a hold of this guy all week and come to find out this morning that he already sold it! T-T So before I spend $150 on a new one, can anyone explain how to test the one I have to make sure it's the problem? For $15 I'm willing to give it a try, for $150 I had better be pretty damn sure...
Maybe you can use this: http://www.bbburma.net/Documents/JohnBates_ChargingCircuitTests3.pdf
And make sure the wires to the coils are tight. The coils will test ok even if the wires are somewhat loose, but they will fail when they get hot because the wire contracts.
The coils tested fine when the bike was cold, for some reason I didn't think to test them while hot... :embarassed: Anyway, thanks for the pdf, my roomate is an electrician so hopefully together we can figure it out! Thanks again!
I can't say what the exact problem is, but I'd also like to throw my vote in for something fuel related. If you're only getting 3 blocks down the road the engine isn't going to be fully warmed up anyway, but it doesn't take long to run out of fuel, and you probably wouldn't notice at idle because it's not taking much. Have you checked your fuel likes to make sure a good amount of gas is coming out? If one of the lines is clogged, or you have an inline filter that's slowing it down it might just not be letting enough gas get to the carbs.
At least you've got your roommate. Electrical work is the end of the world to me.
So I finally found a signal generator for a reasonable price on ebay. It was pulled off a '92 gs (mine's a '96). The part number is the same, but when I switched them out my bike wouldn't even start anymore! After a little coaxing I could get it to turn on, but then if I give it any gas it immediately bogs down and dies. I put the old one back on and my original problem came back. I put the new one back on just to make sure I hadn't done anything else wrong, but it reacted the same way. Is there any other adjustment I should make with the new signal generator? Do you think it's just bad and I should try an purchase a new one? Is it time for me to just admit defeat and take it into a shop? Any feedback you have would be greatly appreciated.
Thank you!
Quote from: Adar on April 29, 2010, 02:02:29 PM
the bike will start just fine when cold and warm up but then after about two minutes of being warm (or riding) first it'll hiccup at about 5000rpms, then it'll sputter and die and won't start again until it's cooled down...
I had a problem like this and it ended up being the vacuum on the petcock so i blocked it off and put an inline on off switch on for the time being just my 2 cents :thumb:
Yeah, that's a good thought. I forgot to mention that while I was waiting for the signal generator to come in I did this conversion:http://gstwins.com/gsboard/index.php?topic=40919.0. Unfortunately it didn't seem to help much.
There really is no adjustment to the signal generator. with the part I received to fix my '96, the male spade terminals in the connection block were somewhat rusty/dirty and I cleaned them the best I could with fine wire brush. changing the SG did fix my problem for good. It could be that you rec'd a bad signal generator.