New boots! Still won't idle.

[UncleMike]

Keith,

Thank you, thank you, thank you. I'll check the spark plugs and coils next, and then figure out how to check the ignition.

Scary, uncharted territory for me, but it's gotta be done.

Thanks,
~Mike

 

[KEITH KRAUSE]

OK. Checking for poor connections is fairly easy and straight forward. It just takes time and a little effort.
Checking the advancer is easy too with a gun. You just watch the marks move/line up. I'm not sure what your parts look like but if you check several times at different rpm's and it advances smoothly, at least you can eliminate it as a possible problem. Quick and simple to do.
As for the 17 volt problem, the Stator Papers will explain better than I can. All I can say is that needs to be fixed regardless if it's your problem or not. You did say that the bike seemed to start stalling as you watched the volts climb on your meter, if I'm not mistaken.
I don't want to send you down the wrong road, but at this point, considering your carb work, I have to believe it's electrical and not carb related.

 

[UncleMike]

OK. Checking for poor connections is fairly easy and straight forward. It just takes time and a little effort.
Checking the advancer is easy too with a gun. You just watch the marks move/line up. I'm not sure what your parts look like but if you check several times at different rpm's and it advances smoothly, at least you can eliminate it as a possible problem. Quick and simple to do.
As for the 17 volt problem, the Stator Papers will explain better than I can. All I can say is that needs to be fixed regardless if it's your problem or not. You did say that the bike seemed to start stalling as you watched the volts climb on your meter, if I'm not mistaken.
I don't want to send you down the wrong road, but at this point, considering your carb work, I have to believe it's electrical and not carb related.

As you said, it's worth looking into regardless.

Thanks again for everything,
~Mike

 

[Matt]

Mike, I read through this thread today during my lunch break at work. It seems that we have a similar level of competence when it comes to mechanics. I try but don't have as much experince as I could really do with. I truely understand your frustration. Although I can't offer you any practical advice do understand that you are not the only who has problems like this. Be strong brother, and I'm sure I speak for others here, our thoughts are with you. Good Luck:-D
Matt

 

[UncleMike]

Does it help solve the issue if I tell you that when the bike was FULLY warmed up yesterday during my ride, the bike started idling at 2000rpms and it was a strong idle, too?

BTW - Same thing this morning. Started her with 3/4 choke, she started up and idled at 900, then slowly climbed to 2500 and held there before slowly and smoothly losing rpms until she started to stall. I blipped the throttle for a little bit but she died.

I tried again and got the same thing. But then I tried with no choke and she started right up and idled at 1100rpms.

I hadn't touched the idle knob since she was idling at 2000 yesterday.

~Mike

 

[t3rmin]

Have you checked your gas cap? I've read that if the cap isn't breathing right, the tank will build up enough negative pressure (from gas being extracted) that gas flow will stop/slow down. This process can take a while, so you'd be able to start the bike fine but it would stall once pressure built up. I think this was happening to me last night. When I took off the cap, it ran fine. I cleaned the cap out with carb cleaner and now it's happy.

 

[UncleMike]

Have you checked your gas cap? I've read that if the cap isn't breathing right, the tank will build up enough negative pressure (from gas being extracted) that gas flow will stop/slow down. This process can take a while, so you'd be able to start the bike fine but it would stall once pressure built up. I think this was happening to me last night. When I took off the cap, it ran fine. I cleaned the cap out with carb cleaner and now it's happy.

Yeah, I checked it out a while back. Cleaned it twice just to be sure, but the problem still exists when the cap is off the bike.

 

[t3rmin]

Ok. This thread is getting so long I might have read it here! ;-)

 

[KEITH KRAUSE]

Does it help solve the issue if I tell you that when the bike was FULLY warmed up yesterday during my ride, the bike started idling at 2000rpms and it was a strong idle, too?

BTW - Same thing this morning. Started her with 3/4 choke, she started up and idled at 900, then slowly climbed to 2500 and held there before slowly and smoothly losing rpms until she started to stall. I blipped the throttle for a little bit but she died.

I tried again and got the same thing. But then I tried with no choke and she started right up and idled at 1100rpms.

I hadn't touched the idle knob since she was idling at 2000 yesterday.

~Mike

I was about to ask if you had any other symptoms than stalling.
The only things I can think of (it's late and I'm tired/about to sign off) that can cause the rpm's to rise as you describe above are...
An intake leak...
A sticking throttle valve(s)...
A mal-functioning ignition advancer...
Voltage problem effecting spark/combustion.
I doubt that it's a sticking throttle plate. A plate can stick or be binding but you can usually see a problem by checking them for smooth operation when you have the carbs in your hands. Only you know if they are operating smoothly.
An ignition advancer can fail too. There are a few designs out there. Some better than others. I've never had a problem with the older mechanical units, such as used on my '79, and the newer '80's models seem even more reliable. I just mention it because if the rotor that contains the sensors/magnets starts to slip or spin separately from the shaft, the ignition spark will be erratic and it has the same effect on combustion as a very lean mixture. Erratic sparking will cause the rpm's to rise erratically and return slower than normal. Blipping the throttle can change how the rotor slips on the shaft and the degree of the problem changes too. The old Martek ignitions used rotors that were held by a single set screw that often came loose. My bike had one of these and when it came loose the idle jumped around and acted similar to what yours is doing. One moment the bike was fine, the next moment it was having a problem. It took me a while to figure out what was going on. I don't know if your ignition advancer is failing, but taking off the cover and checking the advance action SEVERAL times under different rpm's should be a good enough test to see how it's operating. Normally, the advancers are reliable. But I only mention it as a possibility, no matter if it's not that common a problem on your model.
Most likely possibility is an intake leak. Intake leaks can sometimes be very constant in how they effect performance. Other times they can "change" and get worse or better...for awhile. Your description makes me think intake leak, but it's up to you to eliminate any chance of that. What have you done as far as intake leaks are concerned?
Lastly, voltage problems, low or high, can cause all kinds of strange problems, as we all know. A lot of electrical related trouble shooting is difficult to understand. I know 17 volts, as you have, is a serious problem. That must be fixed. I believe you said you have a replacement reg/rec that's working fine? I think you should install it and check all the electrical connections as I said before and re-test. If your voltages are as your manual/Stator Papers say they should be, then you know any problem isn't related to high/low voltage or poor connections.

 

[UncleMike]

Pat's going to come over sometime soon and help me diagnose the electrical problem, so I won't bug you again until then.

As for intake leaks, I have replaces all eight boots with brand new OEM, I have replaces the seal on the airbox filter lid, I have replaced the clamps between the airbox and the secondary airbox because one wasn't closing all the way, and I have done the spray test multiple times.

Not sure where else to look.

Thanks,

~Mike

 

[RacingJake]

Still sounds like a carb problem.

Pull the fuel line from the carbs and turn the fuel one and it should pour out like a garden hose

Start the bike up for a few seconds then turn it off and feel each exhaust pipe for heat. If you have a cold pipe then check that carb and plug.

Check the throttle plates with the carbs off the engine. Open them up and let them close to see if one has a bigger opening or is sticking.

Clean the slow speed curcit and fuel bowl level

PS it's something simple........ that's the way Murphy works :???:

 

[Jethro]

I think I posted thise earlier, but the most wacky intake leak that I had the displeasure to experience on my bike was at the float bowl gasket. The gasket was fine, but I had forgot to tighten up the float bowl screws. You would think that gas would leak from there, but I was just tuning while on the centerstand. Took me hours to figure out. Air was getting sucked in through there, and either messing with the mix or the fuel delivery.

You have a new vaccum line, so that shouldn't be it.

Have you tried hooking up a auxilary fuel source? Sometimes the petcock can operate properly, shut on and off with vaccum and generally seem fine, but it actually leaks a little air into the #2 carb. I would probably try to hook up some other fuel source while it's in the driveway being tuned to rule out a bad petcock. Barring that, put it on prime to run and block off the vaccum port with a short section of 1/4" line that is plugged.

The spray test is not always a clear indicator of air leaks, but you have new boots, so that shouldn't be an issue there as long as they are installed correctly.

As Keith said, the advance unit is a good thing to check. Suzuki suggests lubricating the unit from time to time. If it's sticking, you'll never get it to idle well. If you have a timing light, it would be a good idea to check if it is timed correctly, and advancing properly. This will also tell you if you are getting consistant spark on all 4 wires.

I'm with Keith, I don't think we are dealing with a valve/compression problem. I think the electrical system is questionable for sure. I hate electrics...

 

[KEITH KRAUSE]

Are you positive the manifolds were installed correctly? Meaning, are they all the same or was each manifold meant for a specific cylinder? All four manifolds sold under the same part number? Are they genuine Suzuki or aftermarket? Any manifold o-rings involved? Sorry if I'm bringing up any questions already answered. This thread is long and it's easier this way. Just trying to eliminate possibilities.
New question. Was the bike OK before/at one time? Did you inherit this problem? If it was OK, did it start doing this after you did some work on it? Did it start doing it after sitting for some time or ?

 

[Clone]

You know Mike, you are a saint, SERIOUSLY I would have put a rag in the gas tank and lit it with the zippo and walked away A LONG TIME AGO.](*,)

Keep going guy[-o< for ya.

 

[UncleMike]

Are you positive the manifolds were installed correctly? Meaning, are they all the same or was each manifold meant for a specific cylinder? All four manifolds sold under the same part number? Are they genuine Suzuki or aftermarket? Any manifold o-rings involved? Sorry if I'm bringing up any questions already answered. This thread is long and it's easier this way. Just trying to eliminate possibilities.
New question. Was the bike OK before/at one time? Did you inherit this problem? If it was OK, did it start doing this after you did some work on it? Did it start doing it after sitting for some time or ?

All the boots were the same part # and genuine Suzuki parts. It's a 16v, so no manifold O-rings.

When I inherited the bike, it required starter fluid to start after sitting for more than two days. A little carb cleaner in the tank stopped that, but the stalling issue was still there.

 

[UncleMike]

Here's something new. I was testing the r/r again, just to be sure, and it's definitely sending way too many volts, although it's not really warming up all that much. After trying for 10 minutes or so, it was still only a little warm, not hot at all.

Anyway, I noticed that when I rev it up, the brake light goes out. WTF does that mean?

~Mike

 

[Jethro]

Here's something new. I was testing the r/r again, just to be sure, and it's definitely sending way too many volts, although it's not really warming up all that much. After trying for 10 minutes or so, it was still only a little warm, not hot at all.

Anyway, I noticed that when I rev it up, the brake light goes out. WTF does that mean?

~Mike

Sounds to me like you have a short or shorts somewhere, that has probably fried your r/r

The brake light could go out by either vibration or a short that heats up too much with the major voltage, probalby will fail altogether at some point.

If your r/r is fried, you could boil your battery. Check and see if your battery is actually holding a charge (make sure it's showing 12.8 volts and then check it the next day) and then take off the headlight and the tail light, and begin checking voltage at the bulbs with the ignition switch on. You shouldn't drain much voltage with the bulbs off while testing circuts, so you can leave the ign. switch on for a while.

I feel for you, man. I HATE electrical issues, but you definitely have them, and can for sure cause the problems you are having with the idle.

 

[UncleMike]

Sounds to me like you have a short or shorts somewhere, that has probably fried your r/r

The brake light could go out by either vibration or a short that heats up too much with the major voltage, probalby will fail altogether at some point.

If your r/r is fried, you could boil your battery. Check and see if your battery is actually holding a charge (make sure it's showing 12.8 volts and then check it the next day) and then take off the headlight and the tail light, and begin checking voltage at the bulbs with the ignition switch on. You shouldn't drain much voltage with the bulbs off while testing circuts, so you can leave the ign. switch on for a while.

I feel for you, man. I HATE electrical issues, but you definitely have them, and can for sure cause the problems you are having with the idle.

Sweet. Pat's coming over next week to help diagnose everything. Should be a good time. I've got a honda r/r I'll slap on.

BTW - I've got a sealed battery. Something else I should look out for?

~Mike

 

[Jethro]

Sweet. Pat's coming over next week to help diagnose everything. Should be a good time. I've got a honda r/r I'll slap on.

BTW - I've got a sealed battery. Something else I should look out for?

~Mike

If you have a sealed battery, it should be fully charged at more like 12.9-13 volts. Just make sure it's holding this voltage before getting into testing all the electrical circuts.

Make sure you check the grounds in the headlight assembly. Set your meter for checking continuity, and check all the plastic connectors by testing the circut through the connectors. You don't have to disconnect them, just touch the leads to the metal on either side of the connector. Then make sure the wires directly around them aren't showing continuity with a wire they shouldn't. I had a connector that looked brand new, not melted at all, and would disconnect and connect just fine. All looked well, but one neighboring wire in the harness was arcing. Took me months to find, and melted a lot of wire in the harness.

 

[81gs750bagger]

mine won't idle either

mine won't idle either

81 gs 750 ,carb clean per this site. bike starts and over revs t 4000-5000 rpms then dies will not idle, does airbox have to be on to even get bike to start ?