newb here saying hi and question about high revs

rs · May 10, 2011, 02:04:35 PM

Hello everybody,

First let me give some basic info on myself. Been riding for 5 yrs. Learned on a 250 ninja. Just picked up a GS500 and wanted to start working on my bike.

Bike is 1998 GS500. First owner had it from '98 to '02 and put maybe 2000 mi on it. 2nd owner was my friend who had it from '02 til last month when I bought it from him. Total mileage on it now is 5,500.

OK. More about the bike. Only basic oil change and chain maintenance performed by previous owners. Always stored in a garage with stabil in the tank.

When I first got it, had trouble starting (then I read about the infamous cold start on this thing), and once I got it started and warmed, the revs would stay at 6K even in neutral.

I have since cleaned the carb, which didn't really need it cause there was virtually nothing in the float bowl. Replaced the float bowl gasket, plugs, and the battery.

That had a positive effect by easy start now,(start with a choke and I'm good to go in 5 min), and once I start out riding, with choke off, the GS hovers at 1200 rpm or so. However, once I really get going, the rpms go back up to 4k. If I shift at 6k-7k, everything is good. If I shift lower than 4k, the rpms jump up to 4k-5k when i squeeze the clutch and then settle back once gear is engaged. Stopping at a red light in neutral, the rpms again hover at 4k-5k. Any thoughts would be appreciated. And please keep in mind I'm a learning newbie at this. Thanks again.

Fry · May 10, 2011, 03:13:35 PM

Welcome....You'll quickly find out this is a great site, some really talented, funny, creative people, riders and wrenchers, great community.

For some reason your problem sounds like a clutch issue or something or another, like it's sticking or somethings not engaging?

Wait a bit, someone with the exact culprit of your problem, and the simple quick way to fix it, with videos, full high res picture albums documenting the repair, part#'s, pricing, and national availability of NOS and Aftermarket inventories, without fail.

Good luck, and welcome/

jacob_ns · May 10, 2011, 03:59:09 PM

This might sound crazy but did you adjust your idle speed screw?

rs · May 10, 2011, 04:40:19 PM

tried to mess with the idle speed screw prior to any of the things i mentioned. at that point, it had no effect. well, it would shoot it up to 8k. and then when i would adjust it back down, it would settle down at 4k again. after the plugs, battery and carb clean, i closed the screw all the way and then adjusted it to where it finally settled down to 1200 rpm at idle so i haven't touched the idle screw since. the only problem is, i can't remember if that final adjustment was done after a proper warm up. i doubt it. but i can say that the bike was on the highway for a good 20 minutes, left alone to cool down for 20 min, the aforementtioned work was done, and then started again and idle was adjusted. does that help?

moosehead28 · May 10, 2011, 04:43:56 PM

You can only really set the idle after the bike is good and hot, start it up and take it for a 30 min ride, then set the idle between 1200 and 1500.

It may not hold idle as quick on a cold start, but it will be set correctly

moosehead28 · May 10, 2011, 04:47:21 PM

You could also check for air leaks, as a lean condition will cause high idle

check your air filter, and all clamps connecting air box to carbs and from carbs to intake

rs · May 10, 2011, 04:49:56 PM

ok, thanks. but what do i do if i get it warmed up, try to set the idle lower, and it just doesn't adjust lower? that's the problem i had before i did the work previously mentioned. oh, and right now, if i'm not mistaken, i believe, i left the idle screw approx 3 turns out from completely closed position. oh, and thank you for your replies thus far. i also must apologize if i don't respond to your suggestions quickly. from this point on, my time is owned by my children.

moosehead28 · May 10, 2011, 04:56:04 PM

Turn the idle screw out all the way and start it, if it is backed out all the way and it still idles high I would check for air leaks around the carb boots, or even check the throttle cable isnt bound up

Fry · May 10, 2011, 05:01:43 PM

Quote from: moosehead28 on May 10, 2011, 04:56:04 PM
Turn the idle screw out all the way and start it, if it is backed out all the way and it still idles high I would check for air leaks around the carb boots, or even check the throttle cable isnt bound up

I retract my initial suggestion, and 2nd the notion of an air leak....

rs · May 10, 2011, 06:30:46 PM

ok. first thing tomorrow i'll check air leaks from the 2 points where the air box connects to the carbs. is there another point from which air can leak? also, if i turn the idle screw all the way out, will it in fact come out? and finally, with the idle screw all the way out, do i start it with choke or without?

Fry · May 10, 2011, 06:32:51 PM

I would suspect that the actual carb to engine boots have cracks or a dry rotted gasket/oring....On 2 strokes this is a common area for air leaks.

rs · May 10, 2011, 06:37:53 PM

thanks. i'll check tomorrow. am i doing any damage by riding with rpms this high or running lean? also, on a slighty different note: the runoff tube that runs from the middle of the fuel tank, does that run straight down and to the side or is it supposed to bend immediately and then run toward the rear of the bike, up on top of the air box?

kman · May 10, 2011, 06:39:47 PM

how is the throttle cable play? is it too tight or something? It sounds like an air leak or something stopping your throttle from closing all the way besides the idle stop screw if you can't get the idle all the way down. Might not be the problem but probably worth a check.

Fry · May 10, 2011, 06:42:44 PM

Quote from: rs on May 10, 2011, 06:37:53 PM
thanks. i'll check tomorrow. am i doing any damage by riding with rpms this high or running lean? also, on a slighty different note: the runoff tube that runs from the middle of the fuel tank, does that run straight down and to the side or is it supposed to bend immediately and then run toward the rear of the bike, up on top of the air box?

Well, if you have a leak after the Carbs., you are introducing un metered air/O2 into the system and thus you will be running lean.

NO idea on your line placement?

Fry · May 10, 2011, 06:47:07 PM

Speaking of Carb Cleaner (Another Thread) if you have some handy, start your bike up let it idle and spray a bit of carb cleaner at the carb to engine rubber boot, if the revs increase you found your problem.

Paulcet · May 10, 2011, 06:49:36 PM

If it is a leak, it won't hurt for a short time. It's usually only big enough to cause lean conditions at idle. And it is important to adjust idle with a fully warmed up engine. If I were you I would ride for 20 minutes or so, pull into a parking lot and put it in neutral. Try to set idle down to 1200-1500. If it won't go that low, check for binding throttle or choke cables - turn the handlebars lock-to-lock and see if the idle speed changes. Then check for leaks when you get home.

Quote from: rs on May 10, 2011, 04:49:56 PM
oh, and right now, if i'm not mistaken, i believe, i left the idle screw approx 3 turns out from completely closed position.

If you were turning the right screw, that isn't the correct procedure.

Is this the screw you were turning?

Oh, and the line placement: It goes down and over to the right, just in front of your brake lever.

rs · May 10, 2011, 07:54:23 PM

To Fry:

is the boot you're referring to, those 2 spots where the airbox meets the carbs with the large circular clamps? if so, does it matter what kind of carb cleaner i use? i believe i read on some other post to use petroleum based carb cleaner. is there a substitute i can use to spray there?

To Paulcet:

yes that is the screw i've been turning. so the correct procedure you refer to would be to unscrew it all the way and then start turning in? and thanks for the line placement.

i'm about to hit the sack, so i will check back with you all tomorrow. again, all this help is much appreciated!

mister · May 10, 2011, 08:01:27 PM

Quote from: rs on May 10, 2011, 07:54:23 PM

is the boot you're referring to, those 2 spots where the airbox meets the carbs with the large circular clamps? if so, does it matter what kind of carb cleaner i use? i believe i read on some other post to use petroleum based carb cleaner. is there a substitute i can use to spray there?

If air comes in from the air cleaner side, it is as if it had come from the air cleaner. The side that is unmetered is the engine side. That is the side you need to spray - and WD40 will do to let you know if you have a air leak.

Make sense?

Michael

rs · May 11, 2011, 12:41:31 PM

ok so rode to work and tried the idle screw. no help. had it all the way out and all the way back in again, opening/closing at 1/2 turn intervals and allowing a min for adjustment. lowest it got was 4k. hovered at 5k. highest was 7k.

unfortunately realized as i got to work that i didn't have wd40 with me. besides, i'm not familiar with where to spray it. if it's not the boot of the air box, where is the engine side that i need spray? what am i looking for?

also, when i got to work, i had 1 back fire just at the very end of the engine cutting off and a small wisp of white smoke drift up from the front of the engine. is this related?

moosehead28 · May 11, 2011, 12:53:36 PM

Spray around the boots between the carb and the engine, they are the ones above the idle screw in the pic posted above

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newb here saying hi and question about high revs