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Old 02-02-2014, 04:13 AM   #1
Skidmarkart OP
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Location: Durham NC, The Old Durty
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Sticky throttle. Where do I start?

So, I got myself a sweet GPZ1100e and have fixed most everything. On issue I am having can best be described as a sticky throttle. I do not know that this is actually the issue, per say, but that is the best way to describe it. Here's what happens...

1. Pull choke, switch to "run" (this turn on the new electric fuel pump), hit starter.
2. Bike starts easily.
3. Bike gets warm.
4. Slide choke back to normal position, and start to ride.
5. Throttle fails to drop back to idle between shifts.
6. When stopping, sometimes the idle is 3k-4k.
7. Adjust fuel screw on the carb bank back down to 1.2k rpm
8. Next stop, bike dies b/c fuel screw is turned down too low to maintain idle.

I have also noticed that often, when I release the throttle it rpms do no rapidly drop back to normal idle.

SO, any ideas? What gives?

Skidmarkart screwed with this post 02-02-2014 at 05:02 AM
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Old 02-02-2014, 05:39 AM   #2
headednw
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perhaps ?

post 23 on


http://www.kawasakimotorcycle.org/fo...njected-2.html
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Old 02-02-2014, 06:03 AM   #3
nx&ace
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Sounds like a vacuum leak.
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Old 02-02-2014, 09:56 AM   #4
Skidmarkart OP
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Well, I check with the bike off, and everything mechanical seems to be working normally.

I tested the grip for snapping back to resting position, and this seems normal.

Looked at the throttle rocker on the bottom of the carb bank. This seemed normal as well (snaps back into resting position quickly, with no restriction).

I turned off the fuel supply, but left the bike running (thinking this may be some kind of supply issue), but it seemed the same (still had the problem).

Got it warm (temp in the middle of the gauge), and she was happy running. Took her around the block. But died (I think this may have been because I had the supply off and she ran out what was in the line). BUT then she would not restart quickly. I had to adjust the supply screw to get her to hold idle. Moments later, she's idling at 3-4k again.

I am very confused. Even more than normal. Which is a lot.

Also, was going to try and oil the cable, but it seems damn near impossible to get into the top end.

I am thinking either vacuum leak, or an issue with the new fuel pump.

Skidmarkart screwed with this post 02-02-2014 at 10:07 AM
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Old 02-02-2014, 10:46 AM   #5
Motomantra
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Get it to idle as close to base as possible. Spray some contact/brake cleaner around the carb base. Does the idle flair up? Hmmm?
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Old 02-02-2014, 04:17 PM   #6
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Brake cleaner...bad for some plastics. And so do some electrical cleaners as I found out yesterday.

Don't spray the s...t around where it can get into electrical casings and assorted plastic bits around fueling systems.

And depending on their formulation, some of them products can be bad for the O2 sensor if so equipped.
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Old 02-02-2014, 05:41 PM   #7
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You should check the balance of the carbs as well, one carb opening sooner than the rest will cause a hanging idle as well.
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Old 02-02-2014, 05:47 PM   #8
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Old rubber carb adaptors are well known for splitting. It's difficult to see. Pull the plugs and see if one is running lean.
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Old 02-03-2014, 05:36 AM   #9
Skidmarkart OP
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Sigh...

Okay, so the carbs were just rebuilt and sync'd. My mechanic is really good at this, and has done 4 bikes for me, with no problems - so I do not think that is the issue.

I cannot find any evidence of a vacuum leak. I tried with WD40. Going to try again tonight, but it didn't seem to effect anything.

I am kind of down to the electric fuel pump.

Reason being, the bike will start just fine. You do not need to leave the choke on at all because the pumps seems to be feeding it fuel immediately. This all works fine... but, if you walk away within 3-5 minutes, the bike will either die, or is revving at 3k-4k. No reason. It just suddenly becomes unhappy with the fuel and air mix. You walk over, turn the supply screw up or down to compensate, restart the bike and it is happy again... for 3-5 minutes. Then the same thing.

I am thinking of bypassing the pump, and just letting the vacuum pull the gas out (the way the bike originally supplied gas). If the problem persist, then I have a vacuum issue, right?
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Old 02-03-2014, 08:25 AM   #10
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I'm not sure where you are going with the fuel pump, all it does is supply fuel to the carbs, the carbs control the fuel metering to the engine. The problem (if it's not an air leak) is in the carbs.

If your mechanic just rebuilt the carbs then the mechanic needs to have a look at it, there is a good chance he has not got it right.
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Old 02-03-2014, 09:37 AM   #11
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Well, I hosed down the boot with WD-40 per someone's rec above. This really didn't seem to do much besides cover everything in WD-40. The RPMs didn't really change at all. Admittedly, I probably need to take a couple try at this, but I didn't seem to get anything with that one.

If the pump is forcing gas into the carbs, or not supplying enough gas for the carbs to feed, wouldn't it cause the same problem? I know they regulate the flow, but if they are starved or drowned they can really serve that purpose.

Just thought that bypassing the pump might be an easy way to get a fix on where the issue is. The carb bank on this thing is a b#$%h to get off.
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Old 02-03-2014, 12:15 PM   #12
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Quote:
Originally Posted by Skidmarkart View Post
If the pump is forcing gas into the carbs, or not supplying enough gas for the carbs to feed, wouldn't it cause the same problem? I know they regulate the flow, but if they are starved or drowned they can really serve that purpose.

Just thought that bypassing the pump might be an easy way to get a fix on where the issue is. The carb bank on this thing is a b#$%h to get off.
If the pump is forcing gas in then it will run richer but to do that the float valves must be stuffed so it's still a carb problem.
If it's running out of fuel it will run lean for a while so you may have a point there, ride it and see if it stops / runs out of fuel?

If it's simple to eliminate the fuel pump then do that but you may be better off testing it for flow (into a bucket?) so you know it is working correctly. That way you are sure it's not the fuel pump and must be something else.
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Old 02-03-2014, 01:39 PM   #13
baldman1
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You didn't mention this but is it the early GPz1100 like 1982 , 83, 84? If so take a look at your mechanical advance mechanism which is under the right engine cover. It sits behind the ignition pickup coils, on these older bikes the advance mechanism can get gummed up over the years and stick. The idle will hang up as because it is constantly in the advance mode. Take it apart, clean it up and apply a very light oil like 3 in 1 oil on the advancer. Also make sure the advance springs are not loose and worn out.
Another problem could be the throttle cables. If the return cable si to tight it will cause a high idle also. To check, loosen the return cable so there is a lot of slack in it and check the idle again.
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Old 02-03-2014, 05:45 PM   #14
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It may be possible that the increased pressure from your new fuel pump may be overcoming your needles and seats, therefore dumping excessive fuel into the engine. You said this bike never used a pump from factory correct?

Pull your carbs, leave the fuel lines connected, secure the carbs in the same position they would be when still on the engine and turn on the fuel pump. Check to see if fuel is pumping right through the carbs.
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Old 02-04-2014, 05:32 AM   #15
Skidmarkart OP
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Yes, sorry this is a 1996. NOT the FI models of the 1980's (though those are totally awesome).

I am gonna take it back to my mechanic. I am fairly certain it is a fuel pump issue.

He can probably track it down faster and fix it better than I.

I wish he read/posted here. He's a very good mechanic, has great rates, and usually does quality work. BUT, he could definitely use some tips from places like ADV from time to time.

He was shocked when I rebuilt the carb on my DR650 (I am not the most mechanically inclined). When he asked how, I sent him the tutorial "BST-40 Bible".

Oh, and no worries on the WD-40. I wasn't complaining, just saying it didn't change the idle. It actually made the engine look quite nice
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