Hey guys and gals,
new to the forum, although I have been reading it religiously for the passed week.

Long story short, I bought a "project" 1995 GS500E that someone started converting into a cafe styled bike.
when I got it the carbs were terrible there were no hoses and the gas tank was off.

I cleaned the carbs up and installed them to see if I could get the bike to even fire off before dumping money into a rebuild kit. The bike started and ran pretty rough, to be expected. But it sounded like it was pulling a vacuum and the idle would shoot up without me touching the gas. It would also hang pretty long after i gave it a little throttle it would stay for 3ish seconds before idling back down.
I should note that he "jetted" the carbs, it has 145 mains and 40 pilot. it has no air cleaner so i threw on some 2.5" pods i had laying around. 
Is this all a carb issue? would a rebuild fix that? I only had 1 vacuum line connected to the carb going to the petcock.

this is also my first time working with carbs, so any help is appreciated.
Thanks!

The carbs/engine like the stock air box. It's almost impossible to tune them correctly across the rev range with pod filters. I would source an oem air box and filter and start with stock jetting so you know you have a combination that works.

I Talked with the previous owner and he said he ran a K & N "lunchbox" filter. I ordered one up and the bike started and ran a lot better.  I also rebuilt the carbs while i waited for the filter.
my issue now, is that i have bad hanging idle, i can spray starting fluid all around the carb and it doesn't idle up. The throttle cable isn't sticking, so i'm kind of at a loss of what to do. The only way i can get the idle to come back down is by adjusting the idle speed. It idles great at about 1100.

i did put new plugs in when i started this. the left side is running
rich, and the right looks almost brand new. i'm thinking theres more going on here than just a carb issue.

. 


Any help is greatly appreciated!

I tested the spark plugs against the block to make sure i had spark. Alas right bank is not firing.
I swapped the ignition coils and they both work on the left side. Looks like i'll be digging into the wiring to find the bad wire.

anyone have a good wiring diagram?
thanks,

Check the pickup signal generator.

one of the classic failures. Luckily there is a lot of info about it.

I traced back the wire after crossing some to test, and this is the guy that's failing. Its a black wire Green stripe.
To be honest, not sure what to do from here, not sure what this box is that its connected to.
I will take a look into the Pickup signal generator.
Thanks for the suggestion.

I am almost sure that connector is the TCI (input port) that receives the pulse of the signal generator aka coil pickup, so the TCI (black box) knows when to trigger(send a pulse ) the coils that elevate the voltage for the spark plug to fire.

I mean the connector that plugs there on the other side should lead you to the pickups.

Wiring diagram will be your friend, there is even a. Colored version of the Haynes manual book uploaded here and in multiple places across the web.

Clean everything thoroughly and get a multimeter to:
 
Check the pickup(there is a procedure) and test for continuity (lowest resistance) between each end of every cable, wiggle it, check it is firm while you are measuring.
While you are at it I suggest doing that to every connector on the bike.

To clean
You can use contact cleaner, a teethbrush, scotch Brite, even alcohol and to finish it it is best to put dielectric grease to protect the connections.

I don't have grease and I don't really know if it usual,I know it is not really necessary but it will prevent water getting in and corrosion build up. So do it if you can.

I found someone on Ebay selling the Signal generator new for $150 . Should see it next week.
I'll report back then!
thanks,

-Ebay link incase anyone is needing one https://www.ebay.com/itm/166116034907

Test it, be sure you identify the culprit of the problem before buying parts.

Or you can buy that and each following component of the ignition chain (from sparks plugs to battery) when the previous part you hoped it should had fixed the bike is unable to fix it. And so on.

Seriously,if you're going to do that, go to a mechanic.
Yes, you could do that with 5 buck parts, but no reason to buy unnecessary expensive parts.
It is not a PC either where the parts are compatible with a lot of other machines and are easy to sell or use in the future.

Unless you are a spare parts hoarder and plan to keep the GS for a looong time and don't mind wasting money.

If you can't manage to solve it then you would end up with 10%(or way more )of the bike value in parts that you don't need.

If you can buy a 150 dollar product, buy a 5-10 dollar multimeter.

Woah, calm down there.

Whether its the part or not at 30K on the ODO it was bound to fail sooner rather than later.
I value my time just as much as the next, and replacing a known failing part with a new one make me feel a lot more comfortable riding someplace further away than a couple blocks.

$150 for a part known to fail, or a couple hundred for a tow when it fails. 

Appreciate the input as always. 

Quote from: GreenoBeano on August 08, 2023, 10:55:43 AMWoah, calm down there.

Didnt mean to be rude, just straight.


I think its a good call.
I decided myself to buy a lot of new (lightly used salvaged parts from crashed bikes on ebay) parts in bulk and it was a good decision.
i had a 89 pickup , that was already repaired and it eventually failed. i replaced with no hassle because i already had the part.

The few things that failed were the ones i didnt replaced. 30 years are 30 years

I still think that making a diagnosis is good so you are really certain that the pickup is failing and how to properly test it.
A lot of folks came here throwing parts without too much sense. thats why i sent that message.

Quote from: GreenoBeano on August 08, 2023, 10:55:43 AMand replacing a known failing part with a new one make me feel a lot more comfortable riding someplace further away than a couple blocks.

Having faith on your machine not only comes from wrenching time, that could give you faith on being able to repair it.


Being able to use your bike without the fear of falling apart is other story. And i am not 100% there yet. But one step closer each time.

Well, the new signal generator fixed my right side not firing! so thats one problem down.
I'm still trying to figure out this really bad hanging idle/run away. Bike starts great idles okay, kind of choppy sounding but that could be from having straight pipes.

I synced the carbs the best I could with the idle fluctuating the way it is.
I can blip the throttle, and the revs hang for a long while, like 5-8 seconds before coming back down.
Sometimes i'll blip and they'll continue to climb.

I've double checked that my choke doesn't stick, and since i don't have my tank on i can clearly see my throttle not sticking either.

It has new intake manifold boots, w/ some Black RTV to make sure its not drawing air from there.

The hose clamps are all tight.

I'm not sure where its drawing in air from to continue to climb.

I thought i cleaned the carb well enough with new gaskets and all.

Could this be a valve issue? I've yet to check those.

Any insight is appreciated/thread links to similar problems.

thanks,

Hi there, I'm having the same problem.
My revs will go out and won't come down when choke is off.

I've 25 pilot
68 mid
150 main

And cheap air intakes which I'm planing to replace with a straight exhaust, it's also a cafe racer project.
Im 3 turns out on the air/fuel mix.
The bike got black smoke during idle and no smoke under power but seams too lean when under power and when the revs go up and won't come down, I have to put a gear on and let go of the clutch slightly so it drops. Also sometimes when this whole drama happens the exhaust will after fire (aka back fire) with actually FIRE not just the popping. Kinda cool but scary.

Revs not coming down is usually because the idle speed is set too high, usually it was set high to to compensate for bad carb jetting/settings or to compensate for a vacuum leak (or sometimes just because people aren't used to carburated bikes anymore and don't know it takes a few minutes of choke before the bike will idle without it, so they crank up the idle speed to make it act like a fuel injected bike at startup but then the idle runs away once the bike warms up). Make sure the valves clearances are in spec, then start with stock airbox/filter/exhaust/jetting with all new o-rings, gaskets and rubber parts between the airbox and intake. Once the bike is started and warmed up, set the idle to ~2,000 rpm to vacuum sync the carbs and then finally set the idle to 1,200 rpm.

Quote from: Bluesmudge on August 17, 2023, 03:44:38 PMRevs not coming down is usually because the idle speed is set too high, usually it was set high to to compensate for bad carb jetting/settings or to compensate for a vacuum leak (or sometimes just because people aren't used to carburated bikes anymore and don't know it takes a few minutes of choke before the bike will idle without it, so they crank up the idle speed to make it act like a fuel injected bike at startup but then the idle runs away once the bike warms up). Make sure the valves clearances are in spec, then start with stock airbox/filter/exhaust/jetting with all new o-rings, gaskets and rubber parts between the airbox and intake. Once the bike is started and warmed up, set the idle to ~2,000 rpm to vacuum sync the carbs and then finally set the idle to 1,200 rpm.

I appreciate this, i'll try adjusting my idle speed down. How long does a bike typically take to "warm up" before adjustments can be made?

It can take a full 5 to 10 minutes to get up to operating temp. I've heard people even say at least 15 minutes of riding but I think idling for 5 minutes should get you close enough and then you can fine tune the last 200 rpm's once you take it for a long ride on a hot day. You can reach the idle adjust screw at red lights for that last little bit of fine tuning.

By the time you are done syncing the carbs, it will be up to operating temp for the final idle speed adjust.

25 Pilot could be too much also

Alright,
I need some more help, cause i'm going crazy 

Maybe i'm running to small of jets for the lunchbox, but no matter what it will not get rid of the hanging idle/climbing issue.

I bought new jets from sudco 40 pilots 145 mains, and i'm running a K&N Lunchbox filter.

I sprayed starting fluid all over to see if there is any leaks,

I plugged the vacuum ports on the side of the carbs since i'm using an auxiliary tank right now.

I started with 3 turns out, and then with the choke fully on I can get it to idle around 3k-3500, But if i blip the throttle it jumps up and just hangs there and slowly climbs. The only way to get it down is to let off the choke some.

Float levels are correct using the U bend method,

Maybe I didn't clean the carbs well enough, and theres something sticking inside.

I also pulled a plug and it looked slightly wet, so not sure if thats unburnt fuel or not. I lost my sense of smell a long time ago, so i can't confirm if its oil or fuel.

I'd love to start fresh with stock exhaust, air filter and jets, but finding those in the budget i set for the bike isn't there at the moment 

Appreciate any help, I read through the Idle hovering - trouble shooting guide, it did have a lot of good information in it.

Thanks,

Stock exhaust Isnt that important. But stock air box/filter and jets is though and  shouldn't cost much on eBay and those will get you to a running bike a lot faster and maybe cheaper because it is a known working combo.

Did you adjust the mixture screw for highest and best idle? 3 turns out is on the high side and implies that the idle jet isn't large enough. I'll admit I don't know much about what size jets work with different air filter and exhaust combos. I've just brought a lot of non running bikes back from the dead by setting everything back to stock. With modern gasoline, plug pulls are almost useless so it's nearly impossible to tell if the bike is running lean or rich. If you actually want to tune for the K&N filter  It can be worth paying someone with a Dynometer so that you can actually see your air/fuel ratio. The problem is the]at filter flows too much air and not enough velocity, so you have to make a ton of adjustments to get it running right across the rev range. It's a little better than pod filters but still messes with all the variables. It's hard enough to get right when you start with a running bike. I can't imagine doing it with so many possible variables that could be slightly off or way off.

Spending $100 on a used air box and stock jets will save you hours and hours of guess and check workingmpulling the carbs over and over and ordering more jets.
Adjust the valves, set everything to stock/clean carb and check and make sure all rubber components are crack free and pliable, sync the carbs, adjust mixture screw for highest and best idle, double check carb sync, then adjust final idle speed to 1200 rpm on a warmed up bike.  Do these things and the bike will run. Doing it one piece at a time is a recipe for madness.