High idle...

[chandlerbingfl]

Hello fellow owners! Not well versed in bike mechanics but when I started my GZ this morning the idle was pretty high. Probably close to the 3k-4k mark when stopped. This never happened before and when I would turn off the bike it would pop/backfire. I checked the manual posted here but not quite sure what to check. Is it the screw w/ the white knob on it? That looks to be a stop for the throttle but when I tried adjusting it did nothing. I did turn it but put it back in the same spot, still no change in idle. Up till this the bike ran perfectly...

Any suggestions? Like I said not much experience so any help will be appreciated. I know the choke is in the "off" position and was wondering if this might be "on" even though it is "off"... maybe a stuck cable?

Thanks in advance!
chandler

[Easy Rider]

I know the choke is in the "off" position and was wondering if this might be "on" even though it is "off"... maybe a stuck cable?

Yes, could be. Also could be stuck or tight throttle cables, which sometimes only happens when the bars are turned to the extreme. Might try rotating the throttle grip to the slow direction and pointing the front wheel straight ahead.

OTOH, it could be a brain cramp too. Try it with the choke lever in the OTHER position. :biggrin:

Just as a refresher: GZ owners, for the choke, which way is OFF......????

[bonehead]

Choke is off in the foreward position(pushed toward the front of the bike)

[chandlerbingfl]

Thanks so far but I know I haven't cranked the bars to full lock in either direction. I'm wondering if the choke cable is stuck, maybe busted... I see how the throttle cable is attached but where does the choke cable run to and how does it connect / control the choke itself? Can I disconnect it somehow?

Again, TIA
chandler

[Easy Rider]

Thanks so far but I know I haven't cranked the bars to full lock in either direction.

Even when it is parked ??
When placed on the sidestand, the bars often go full left whether you want them to or not.

This conversation is beginning to have an old familiar pattern to it.....and that's probably not good.

You need to keep an open mind....and you need to check out other easy and equally possible causes and not be stuck JUST on the choke cable. It might be a choke cable problem but it might not too.

Is your choke lever pushed all the way forward ?? Does it feel about the same as always if you move it back and forth ?? Have you given the throttle a "test twist" or two with the bike off while watching the attachment at the carb ?? Does the throttle feel "right" ?? If you let it go, does it snap back like it should ??

[dhgeyer]

Does the bike start easily after sitting overnight with the choke lever in the OFF position? It shouldn't, even if the throttle is part way on. If it does, then the choke would be a good place to look.

The choke cable enters the carburetor on the left side, high up, at the front. There's a brass nut, and the cable goes through an elbow right before going into the carb. If the elbow got pulled out, it could get stuck, and that would cause the choke to be on. Also, the choke cable has an adjustment up near the choke lever. If the locknut came loose and the adjustment moved, that could cause the choke to be on.

If the bike doesn't start easily, cold, with the choke OFF, your problem probably lies elsewhere, very likely one of Easy Rider's tests might find the problem.

The white knob you mention is indeed the idle adjustment, but it's very unlikely to have moved by itself, and just turning the idle down using that would be a "Band Aid" solution, and probably not good for the engine.

Another possibility is something sticking inside the carb itself. Has the bike been sitting for a while? Doesn't seem to take long for these carburetors to gum up.

[alantf]

When placed on the sidestand, the bars often go full left whether you want them to or not.



And you really DO want them to go full left, or you can't lock the steering. :tup:

[alantf]

Does the bike start easily after sitting overnight with the choke lever in the OFF position? It shouldn't,

This must be something to do with the weak setting of the carb on the American bikes. The only time mine needs choke is when it's been sitting for 2 or 3 weeks (like when I've been on holiday) & even then, I can turn the choke off as soon as the bike starts. It's always been like this for the 3 years I've had it (from new) & it runs perfectly, with a decent mpg, so there's nothing wrong with the bike. I know that the temperature never drops below 10ºC/50ºF, but I assume that you still have to use the choke on American bikes above these temperatures. I wonder if any other European members can come in here & tell us if they need the choke or not. :)

[3-D Video]

I wonder if any other European members can come in here & tell us if they need the choke or not. :)

I don't seem to need it. But, the bike and I are still in the early stages of our honeymoon.

[Easy Rider]

Does the bike start easily after sitting overnight with the choke lever in the OFF position? It shouldn't,

This must be something to do with the weak setting of the carb on the American bikes.

Yes, it absolutely DOES.
Go ahead, keep rubbing it IN. :skull:

:biggrin:

[dhgeyer]

Lots of people here in the States do things to their carburetors to make them run richer - rejet, shim the jets, and other mods that I don't pretend to understand. I've never been tempted to do this, for the simple reason that the leaner it runs, the less gas it uses. As long as it doesn't start knocking or running so hot as to do damage (unlikely with a 250), I say lean is good.

[chandlerbingfl]

Well thanks for all the input! I ride every day so this is the first anamoly I've come across. The bike sat during the day (I work noghts) and started as it normally would. Idle crept up a bit so I adjusted the idle screw and things leveled out to where it felt normal. Unfortunately when I got up to temp the idle crept back up to I'm guess 1500-2k rpm, rides normally shifting through the gears and all. Throttle adjustment appears to be ok.

I thought at first someone was screwing w/ the idle adjustment but I still think its choke related although the choke is not something I would normally use, lever action is normal..

Keep it coming - TIA
chandler

p.s. One thing I have noticed, when shutting it off I do get one pop of backfire?!?!?!

[blaine]

Your getting a backfire because the bike is revving when you shut it off.I to think it is choke related.Take it apart at the carb end and clean plunger and bore.Move choke lever to make sure plunger is operating.Fitting is 14mm.This is a common problem on suzuki models. :rawk:

[alantf]

I say lean is good.

Sorry, can't agree with that. Lean can do all sorts of damage, including engine running hot, & valve problems. I believe that the European model is set up as the designers designed it. The only reason yours is set up lean is because of American emission laws. Mine gives better performance, my valves need adjusting MUCH less often, & I'm still getting the same mpg as the American bikes. This is probably because I'm using less throttle in any given circumstance. :2tup:

[3-D Video]

A lean mixture will produce an overly hot combustion; not good for the engine. And, just like a rich mixture, produces less power; not good for mileage (kilometerage?).
You can smell the difference. Too lean has an acrid smell to it. To rich has a "heavy" kind of oily odor. If you adjust your carburetor by sniffing the exhaust, do that last… you may need to sit down for awhile :)

[blaine]

I say lean is good.

Sorry, can't agree with that. Lean can do all sorts of damage, including engine running hot, & valve problems. I believe that the European model is set up as the designers designed it. The only reason yours is set up lean is because of American emission laws. Mine gives better performance, my valves need adjusting MUCH less often, & I'm still getting the same mpg as the American bikes. This is probably because I'm using less throttle in any given circumstance. :2tup:
:plus1: :plus1:

[chandlerbingfl]

Your getting a backfire because the bike is revving when you shut it off.I to think it is choke related.Take it apart at the carb end and clean plunger and bore.Move choke lever to make sure plunger is operating.Fitting is 14mm.This is a common problem on suzuki models. :rawk:

I checked the choke and the plunger is operating so I know it's not a cable issue...when I pulled the plunger and started the bike still excessive rpms. I can be in 3rd and still no throttle and do ~25mph...

Could something in there be stuck or gummed up?

TIA,
chandler

[blaine]

:rawk:

I checked the choke and the plunger is operating so I know it's not a cable issue...when I pulled the plunger and started the bike still excessive rpms. I can be in 3rd and still no throttle and do ~25mph...

Could something in there be stuck or gummed up?

TIA,
chandler

Put some carb cleaner in the tank,SEAFOAM or BERRYMANS B12 work well.
http://www.postimage.org/templates/images/smiley/greetings/6.gif (http://www.postimage.org/)GO for a long ride,if it helps put some in the next couple of fill ups.

[chandlerbingfl]

How does the choke work? I see the plunger thing but does it work a butterfly valve or something?

chandler

[Easy Rider]

p.s. One thing I have noticed, when shutting it off I do get one pop of backfire?!?!?!

I think THIS might be important, as well as your statement that the idle "started creeping up".

All that can also be a sign of a vacume leak. Check the boots on both sides of the carb for loose, cracked, etc. Also the vacume line going to the petcock.

I'm kind of surprised that the problem hasn't affected engine performance when riding; if it gets worse, it probably WILL. If it is a vacume leak, it can cause the engine to run hotter than normal due to the leaner mixture.

[chandlerbingfl]

p.s. One thing I have noticed, when shutting it off I do get one pop of backfire?!?!?!

I think THIS might be important, as well as your statement that the idle "started creeping up".

All that can also be a sign of a vacume leak. Check the boots on both sides of the carb for loose, cracked, etc. Also the vacume line going to the petcock.

I'm kind of surprised that the problem hasn't affected engine performance when riding; if it gets worse, it probably WILL. If it is a vacume leak, it can cause the engine to run hotter than normal due to the leaner mixture.

Bike is in near new condition, only had 1200 miles when I bought it... no signs of damage to any of the hoses as I checked them already.... I posted previously... how does the choke work? Does the black plastic piece just slide in and out to restrict air flow so more fuel gets passed to the cylinder?

chandler

[Easy Rider]

I say lean is good.

Sorry, can't agree with that. Lean can do all sorts of damage,

my valves need adjusting MUCH less often,

You are taking his comment out of context.

An engine properly designed to run lean IS good.
Or, as it would seem that we have here, and engine that is tuned to run on the lean side of its design window.

Nobody is claiming that running ABNORMALLY lean is good.

Further, I think that your claim about valves is........mmmmm.....not based on actual data.
How is it that you think you have enough information to make that claim ?? :roll:

[Easy Rider]

Bike is in near new condition, only had 1200 miles when I bought it...

how does the choke work? Does the black plastic piece just slide in and out to restrict air flow so more fuel gets passed to the cylinder?


What does the bike being new have to do with anything ?? Clue: nothing.

The choke plunger works by opening up an extra passage for fuel flow. If it really is moving freely over it's whole range (might be hard to tell if it is going all the way back IN though) then it is HIGHLY unlikely that it is causing the problem. Gumout and Seafoam have spray carb cleaners.
You could get some and spray the plunger just in case it is gummed up.

I don't remember looking at it but isn't the OFF position for the plunger when it is IN ??
And you have never said explicitly if you have the choke all the way OFF when this happens......that is, the choke lever pushed all the way FORWARD. It might be possible that the handle bar lever itself is binding.

I still think you need to get OFF this choke thing.......at least long enough to check out some other things.......like the carb boots. On my GZ, they were so loose that I could grab the carb and twist it inside boots.......with very little effort.

You came here asking for advice and, except for the location of the choke mechanism, it doesn't seem like you are listening.

[chandlerbingfl]

Bike is in near new condition, only had 1200 miles when I bought it...

how does the choke work? Does the black plastic piece just slide in and out to restrict air flow so more fuel gets passed to the cylinder?


What does the bike being new have to do with anything ?? Clue: nothing.

The choke plunger works by opening up an extra passage for fuel flow. If it really is moving freely over it's whole range (might be hard to tell if it is going all the way back IN though) then it is HIGHLY unlikely that it is causing the problem. Gumout and Seafoam have spray carb cleaners.
You could get some and spray the plunger just in case it is gummed up. I don't remember looking at it but isn't the OFF position for the plunger when it is IN ??

I still think you need to get OFF this choke thing.......at least long enough to check out some other things.......like the carb boots. On my GZ, they were so loose that I could grab the carb and twist it inside boots.......with very little effort.

You came here asking for advice and, except for the location of the choke mechanism, it doesn't seem like you are listening.

Well even though I haven't had a bike in a long time I do know about vacuum lines, the boots, etc and I do NOT see anything wrong with them... Two mornings ago I did use the choke to start the bike in the morning just to get it to warm up a bit faster... that is why I am focusing on the choke. When I let the bike sit yesterday for several hrs it started and idle'd normally until it got to temp. If it was a leak or boot issue I do not think that would have been the case...

I DO appreciate the input and I AM listening... but I have checked out all the things put on the table at this point. If you want to insult me go ahead...

chandler

[alantf]

Further, I think that your claim about valves is........mmmmm.....not based on actual data.
How is it that you think you have enough information to make that claim ?? :roll:

I seem to remember many, many, years ago, an old mechanic telling me that it was wrong to think that you would gain anything with a weak mixture. This was in the days of leaded fuel, so it may not hold good today. He explained that the weaker mixture would cause more heat, which would cause the valve seats to pit. He also said that the lead was a sort of "lubricant" & helped the valve seats. I know for a fact, though, that at every service the mechanic who checked my valves said that he hadn't had to adjust them. At the 15000km service, he said that he had adjusted them SLIGHTLY. With all the posts about American bikes needing a lot more adusting, I think that the richer (slightly cooler) mixture may have something to do with this. Or, have you any other explanation?

[Easy Rider]

If it was a leak or boot issue I do not think that would have been the case...

I DO appreciate the input and I AM listening... but I have checked out all the things put on the table at this point. If you want to insult me go ahead...


No, listen, it is not intended to be an insult. It is insulting when one offers advice based on YEARS of experience and then the ensuing replies makes it LOOK like it is being totally ignored.
Are we on the same page there ??

And here's the problem: The WAY in which you are "checking" things isn't good.......and some assumptions you are making aren't good either. Pointing those things out is not an insult; it is necessary to bring the process to a good end.
Still on the same page......I hope.

As for the vacume leak, looking and even touching maybe is NOT a sufficient test. Pulling on the boots or twisting them might be good enough.....along with checking the clamps for tightness.....but the best method is to spray a small amount of carb cleaner or WD40 or starting fluid (but it can be dangerous) around each of the boots and vacume lines one at a time.......while the problem is evident. If the engine speed or sound changes in any way, there IS a vacume leak. Often they can't be detected with the naked eye.

AND vacume leaks often DO GET WORSE as the engine components heat up.

That's all I've got to offer. Unless new evidence comes to light, I'm done.

P.S. Where did you buy the bike? If it was a dealer, you should be able to make an appointment to have them look at it while you wait; you might want to consider that even if you didn't get it from a dealer.

Like a lot of technical problems, the actual repair is likely to be minor and with their experience they might be able to go right to it and the whole thing might be very inexpensive.......or maybe even free if you bought it there.

Good luck!!

[Sarris]

Hey Chandler, I suggest a couple of tanks with fuel system cleaner (amount per mfgr's recommendation), then take it out and run the crap out of it for 50 or 60 miles a few times. It really sounds like a partially gummed up idle circuit. If it were me, I would do this first.

GeeZers seem to get gummed up carbs fairly often when not used regularly. I don't know what year yours is, but with only 1200 miles it doesn't sound like it's had a lot of use.

My two cents worth.

:2tup:

[Easy Rider]

Hey Chandler, I suggest a couple of tanks with fuel system cleaner

Blaine beat you to the punch on that one.......and I agree with both of you.

Gummed carbs are very common.
Vacume leaks are fairly common too.
Sticky choke and throttle cables less common.
Actual choke (enricher) trouble IN the carb is pretty rare.....but that still could be the problem.
Hell, it could even be a head gasket that needs to be torqued down but that is rare too.

[Water Warrior 2]

Further, I think that your claim about valves is........mmmmm.....not based on actual data.
How is it that you think you have enough information to make that claim ?? :roll:

I seem to remember many, many, years ago, an old mechanic telling me that it was wrong to think that you would gain anything with a weak mixture. This was in the days of leaded fuel, so it may not hold good today. He explained that the weaker mixture would cause more heat, which would cause the valve seats to pit. He also said that the lead was a sort of "lubricant" & helped the valve seats. I know for a fact, though, that at every service the mechanic who checked my valves said that he hadn't had to adjust them. At the 15000km service, he said that he had adjusted them SLIGHTLY. With all the posts about American bikes needing a lot more adusting, I think that the richer (slightly cooler) mixture may have something to do with this. Or, have you any other explanation?
Yes, lead was used as a lubricant among other things. Combined with a slightly richer mixture there would be a cooler running engine in most cases.

[Easy Rider]

Or, have you any other explanation?

Yes. I think you assume way too much.
What makes you think that "american" bikes need the valves adjusted more often than is your experience ??

I don't think there is any evidence to indicate that is the case.

My GZ when checked around 3K miles needed no adjustment; don't know if that was the first check or not. I didn't keep it long enough to need a second check.

Now, are you ready for this.........
That was the FIRST bike in about 35 years that I ever had the valves checked on.
About 10 different bikes over ~35 years and never touched a valve; never.

The first check on my Shadow needed some adjustment on about half the valves. It ran better after. As long as it runs good, I don't intend to check them again until 2X the recommendation ......or more.

I'm not necessarily saying that your assertion is wrong, just that I suspect that it is a guess based on scant little real evidence or data.

[alantf]

What makes you think that "american" bikes need the valves adjusted more often than is your experience ??



Because of what people post on this site? right? ;)

BTW, I am talking about GZs, & I notice that you didn't keep yours long enough to do a second check. :whistle:

[chandlerbingfl]

Well thanks for all the input... was the choke... bit of cleaner and Seafoam and problem resolved!

Thanks!
chandler

[blaine]

Well thanks for all the input... was the choke... bit of cleaner and Seafoam and problem resolved!

Thanks!
chandler

http://www.postimage.org/templates/images/smiley/signs-and-flags/23.gif (http://www.postimage.org/)

Put some Seafoam in 2 or 3 times a season to pervent any more carb problems.Maintance is key. :rawk: :2tup:

[Viirin]

When i first got my GZ the choke cable was seized in the "on" position but i had never ridden before so i didn't know any different - cost me about €25 to get it replaced and brought the frequencies of fill-ups way down as well as the running temp i imagine.

For Alan's earlier post i have a European spec GZ but i need the choke to get her ticking over in the mornings - even now in the Summer - it doesn't take much but it needs a little.

Glad you got your problem sorted out Chandler - i guess cables can seize even if your riding everyday (or night in your case) if they don't get used every now and again

vii

[bmxr123]

Just my two cents:

My buddy rides a bone stock gz250. I pulled the spark plug only to see WHITE...EVERYWHEREEEEE!! indicating LEAN/HOT conditions. Suzuki has their heads so far up the EPA's &%$ that they forgot what put them on the map. That bike was STARVING for fuel, and CHUGGING at wide open throttle. Just drill out that little air/fuel screw cap and put that beast 2 turns out! Your GZ, along with your manhood, will thank you.

In all seriousness an idle drop should be performed, but even if you have no idea what you are doing, 2 turns out on that screw is better than the 3/4 of a turn it came from the factory with!!!!!! what the?!!....arrgh...


It shouldn't be that infuriating when working with a GZ, but the Cam overlap/EPA settings they released these 4-cylinder carbureted(And crappy F.I. mapping!) sport bikes with is stupid..They post 35-40 MPG but AT WHAT RPM??!! They feel like my mother's Fiat 500 until about 7000 RPM upon which you are reminded that you are sitting on a bike built for racing. The danger discovered in a bike that triples its horsepower in a split second should have taken precedent to the potential improvements in MPG to please the EPA. Reminds me of the first 911 turbos that were killing people left and right!

[Yountz]

Yes, could be. Also could be stuck or tight throttle cables, which sometimes only happens when the bars are turned to the extreme. Might try rotating the throttle grip to the slow direction and pointing the front wheel straight ahead.

OTOH, it could be a brain cramp too. Try it with the choke lever in the OTHER position. :biggrin:

Just as a refresher: GZ owners, for the choke, which way is OFF......????

Wow... I did a lot of work today. I adjusted the valves and cleaned the carb out on a gz250 I just bought . The choke cable was stuck before, and I freed it up. I would of never though it went towards the front because of the choke sign. I was really panicking. Thank you