This the intake leak - high idle problem.

[Redman]

GK just started doing this the other day.
When engine warm, and come to a stop with clutch pulled in, engine idles at about its regular 800-1000, then in a couple seconds starts increasseing and in a few seconds is up to 2000 and after a few more seconds is at 2500 and stays there. If blip the throttle it incerase but comes back to 2000-2500. Doesnt seem to have much power at that 2000-2500 because if just let out clutch a little bit the rpms drop right away.

So, my main question is:
THis sound like the intake leak problem I have seen talked about here?
So should suspet the intake boots, the intake o-ring, right.
Ah, and maybe about the petcock.
Right?


Other info:

I did replace the intake boot o-rings about 3 years ago (getting out those screws was quite a memerable experience). Was the kit from Robert Bar with the stainless steel allen head bolts. I have had the GK for almost 5 years now, and dont think I have replaced the intake boots.

This evening I tried the WD-40 spray test/trick.
Started the bike, let it idle till it wamrned up and started running higher rpms (1500-1600 or so). Used the straw on the WD-40 to spray it where the boot meets the head and where the carb inserts into the boot. Didnt notice any immeadiate idle speed change. One time it did decrease for a bit, but that was a few seconds after done spraying and could not get it to repeat. SO dont know what to think of that.

Did use a good light to observe (where could see) and I didnt see any wd40 getting sucked in. BUt on #4 I thought is did see it seem that I could see the wd40 pulse in and out where carb inserts into the boot.

The clamps all seem to have been tightened in the past to where they cant be tightened any more. DOnt know if rubber deformend of if the clamps stretched out.

.

 

[Steve]

Sounds like it's time for new boots, size 34.

At only three years old, the o-rings are probably OK, but they are cheap.

.

 

[BassCliff]

Hi Dave,

You might want to check to see if one of your carb diaphragms has developed a tear or pinhole. Have you checked the airbox and the airbox boots too?


Thank you for your indulgence,

BassCliff

 

[bwringer]

FWIW, I've never had any luck with the WD-40 or water trick. Air leaks big enough to make the bike run like poo can still be too small to slurp in enough WD-40 or water.

Also, the o-rings around the air screws on the carbs can cause similar issues.

And change the airbox boots while you're in there. Might as well.

 

[Nessism]

Where are the pilot screws set? If they are too lean the idle can hang.

 

[Redman]

Sounds like it's time for new boots, size 34.

At only three years old, the o-rings are probably OK, but they are cheap.

.

Hello Steve,
Got boots on order. Decided to order from BB. With the 10% AMA discount, and with shipping $9 instead of $16, it was only a couple bucks more than the lower price places. ANd BB says ship in a few days. SOme other places were listing 14 - 16 days (I suspect maybe they order from thier supplier only once a week).

And am getting a set of orings from Robert Barr. Man, that guys does us a good service.

Hi Dave,

You might want to check to see if one of your carb diaphragms has developed a tear or pinhole. Have you checked the airbox and the airbox boots too?


Thank you for your indulgence,

BassCliff

Hi Cliff,
I know that the carb diaphram can sometimes have a problem, but that would just start/run poorly. DOnt know if would cause this particular type of idle-run-up problem. (I just now made up that name.) Are you saying that you know a carb diaphram problem will cause this particular symptom? or just that the carb diaphram is a general carb problem that can occure. When I have corbs off, I can check that also.

Went through air box sealing a couple years ago, that seemed to improve the higher rpm power.

FWIW, I've never had any luck with the WD-40 or water trick. Air leaks big enough to make the bike run like poo can still be too small to slurp in enough WD-40 or water.

Also, the o-rings around the air screws on the carbs can cause similar issues.

And change the airbox boots while you're in there. Might as well.

Thanks Brian,

So, I did notice something going on with the WD40 test, but didnt notice anything like sswwooop sucking it in or anything. SO your words of wisdome is that a small enough leak will cause noticable symptoms but not really detectable with the wd40 test. Okay, Thanks.

Replaced air screw o-rings this January with help of some great GSRers, including this fine fellow (and your shim kit).

.



.

 

[Redman]

Where are the pilot screws set? If they are too lean the idle can hang.

Had been running good all summer, then just started this problem.
Don't know if it can be called "idle hang".
When comming to a stop (with load on engine) the idle is where it has always been, and then when sitting there with clutch pulled in, after a second or two the idle starts to increase, and slowly inceases to about 2500 in about 6 or 8 seconds. But, yah, after the idle runns up, if rev the throttle, the rpms do decrease like expect, but only decrease to the 2500, so in that sense, suppose that could be called hanging up.

To answer your question, I can not quote specific settings, but the Pilot screws were set by these fine gentelmen back in January, (shown here doing the syncing) using the no-more-rpm-increase method.

 

[tkent02]

I can not quote specific settings, but the Pilot screws set by these fine gentelmen back in January

Perhaps one of them should have set all four screws?

 

[Redman]

WHat I may try, while waiting for parts to arrive, is to try a trick that I think I invented for use on a lawn mower I had. And that is, to push in some grease inbetween the carb and the intake boot. THis made enough of a seal to prove that was the problem, and served as a temperary repair.

Anybody ever try that?

.

 

[Redman]

Perhaps one of them should have set all four screws?

Tom, You saying that someone has a screw loose? Did you meet Joe on Western States Rally?

.

 

[twr1776]

Originally Posted by tkent02 Perhaps one of them should have set all four screws?

Dave, the intake boots did look a bit aged but seemed to be OK when we worked on it, the sync guage did not give different readings after blipping the throttle. As far as your specific settings we shimmed the needles one position (washer method) and your airscrews were at 3 turns out and then adjusted slightly using the high idle method. Diaphrams looked OK as I recall, I think the new boots and o-rings will take care of it.

Today 03:40 PM Redman Tom, You saying that someone has a screw loose? Did you meet Joe on Western States Rally?

Dave, I think all three of those mugs have screws loose. Just my opinion though. :-\\\

Roadtrip?

 

[BassCliff]

Hi Dave,

I just wanted to say, I love the look on Joe's face. It's like he's adjusting the carbs using telekinesis!

Great picture! Tell Tim and Greg I said "Hi".


Thank you for your indulgence,

BassCliff

 

[Redman]

***
And now about 2- 3 weeks later
***

Did recieve new o-rings from RobertBarr (Man, that guy does us a good service.)

Did recieve boots from BB in about 10 days, but only two of the four. Got the other two 5 days later.

When I took off carbs and boots, I noticed that that one airbox boot had a small part of the lip folded over back into itself, like could happen when installing the box onto the carbs. Would have been that way since January, but only had symptoms crop up here in August. But wonder if that was my problem, dont know if that little bit of a problem with airbox boot could cause the symptoms I described. But... anyway....
Was able to straighten that out that boot lip.

Here is me with puzzled look.

Puzzled because The way I remembered the intake boots came off, did not seem like the way they should go back on.
And Suzuki manaul just said the "R" ones go on right and the "L" ones go on left, but didnt make any comment of give any clue at to which way, could get them up-side-down.
But I got that figured out.

Got new intake boots and new o-rings installed, and carbs back on, and air box back on - and airbox boots on straight and all the way.

Started up and ran seemily well. But seemed that I had to keep adjusting the choke. Went for a ride and after it warmed up the idle stayed high (didnt run up like it did before, just stayed high). So I adjusted the idle (knob under carbs) and seemed fine.
Today I started it from cold and seemed to start and runn okay, and I didnt have to play with choke so much, and after it warmed up idle was still fine.

So, I hereby declare it fixed.

I dont think problem was that air box boot, but maybe it was (and I didnt need a hundred dollars worth of new intake boots).

But, now I have new intake boots, with clamps just snug to where they will not move around and still have some threads exposed on the screws.

Exisiting intake boots were not hard, not cracked, but clamps were clamped down as far as the screws could go (bottomed out). O-rings only about 3 years old, were still round and plyable.

Thanks guys, for your comments.

.

 

[tkent02]

***
And now about 2- 3 weeks later
***

Did recieve new o-rings from RobertBarr (Man, that guy does us a good service.)

Did recieve boots from BB in about 10 days, but only two of the four. Got the other two 5 days later.

When I took off carbs and boots I noticed that that one airbox boot had a small part of the lip folded over back into itself, like could happen when installing the box onto the carbs. Would have been that way since January, but only had symptoms crop up here in August. But wonder if that was my problem, dont know if that little bit of a problem with airbox boot could cause the sym,ptoms I described. But... anyway....
Was able to straighten that out that boot lip.

Here is me with puzzled look. The way I remeber the intake boots came off, didnt seem like the way they should go back on.

But I got that figured out.
Got new intake boots and new o-rings installed, and carbs back on, and air box back on - and airbox boots on straight and all the way.

.... more later .....

So how does it run?

 

[TheCafeKid]

Looks like you have the problem sorted or on it's way, but I was going to suggest inspecting your boots motor side. If they're old enough, the rubber will rot and break away from the metal backing flange, which can create an intake leak there. You may not even be able to see it without pulling the boot and prying on the rubber a bit to see if it pulls away from the flange. My 1000G did this very same thing almost over night. Rose and I took it out for dinner one night, ran fine. Came back out to leave and it was sucking air so bad you could hear it. It ran like crap and I limped it home and pulled it down and found the boots were literally falling apart. Replaced em and bob was my mothers brother...

 

[Redman]

So how does it run?

Hi Tom,

Is now running back like it did before this problem (idle running up and poor power at that rpm) started. So that problem taken care of.

I added further description, apparently after you saw it before I completed the posting. Wife came home and somehow thought I should pay some attention to her.

Looks like you have the problem sorted or on it's way, but I was going to suggest inspecting your boots motor side. If they're old enough, the rubber will rot and break away from the metal backing flange, which can create an intake leak there. You may not even be able to see it without pulling the boot and prying on the rubber a bit to see if it pulls away from the flange. .
....
....

Hi Josh,

Intake boots seemed plyable.
I just now went out and looked at the ones I took off. No, could not pull rubber away from metal parts.

I, too, Have seen others that were hard and and cracked and metal parts exposed and rusty.

Ew, you are getting a bike from the current decade.

.

 

[bwringer]

A couple of other things to check:

1) Air filter sealing -- make sure there's a good foam seal between the air filter and the airbox. Sometimes this is a problem if the foam seal folds up when you install the air filter.

2) Airbox halves -- if you have the type of airbox that is made from two plastic halves bolted together, make sure they're sealed.

3) Airbox/carb boots -- you mentioned one had folded up a bit. Check these again. These can cause all sorts of issues, and problems can be very hard to see.


Also, do you know what the idle mixture screws were set at? How many turns out?

You usually need to go a little richer than you get with the "best idle" or Colortune. The final tweaks should always be made by test-riding. You could try turning these out another 1/4 to 1/2 turn to see what happens. I think this might be the main problem, assuming the air filter/airbox check out.