Sticking cold start adjust - K-Bikes.com - Excellence in Motion
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post #1 of 20 (permalink) Old Feb 1st, 2013, 6:06 pm Thread Starter
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Sticking cold start adjust

My fast idle adjust is sticking. I sprayed some WD-40 on the lower pivot with no effect. Is there a return spring somewhere? There seems to be no easy way to access the cold start mechanism which is behind the throttle position switch. I can get the switch off but the switch mounting plate has two screws blocked by the fuel rail. I don't remember how to remove the injectors and there is a lot of dirt around them. Any advice on removing the mounting plate for the throttle switch?

Messing around has created another issue. Now the mc won't start. I think it is a fuel issue.I have fuel, have power, the starter cranks and the fuel pump is runnng. I suspect the fuel injectors are not firing. I did the following: removed the coil cover, disconnected the harness to the throttle position switch, removed the throttle position switch, disconnected one side of the crankcase breather hose, and removed a vacuum hose (?) from the rear injector. I put everything back. The vacuum line to the rear injector is very loose. I looked at one plug and it was dry. The fast idle light is working. Any advice on how to proceed here?
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post #2 of 20 (permalink) Old Feb 2nd, 2013, 6:39 am
PsyKotic Waterfowl
 
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Your post makes no sense.

Why would you disconnect the CCB hose?

Why would you want to take the mounting plate for the TPS off?

The vacuum hose connects to the rear THROTTLE BODY, not the fuel injector.

The "choke" can be adjusted via the locknut on the barrel of it where it connects to the TB assembly.

Did you correctly adjust the TPS when you put it back on?
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post #3 of 20 (permalink) Old Feb 2nd, 2013, 9:18 am
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Injectors just pull out of there. Remove the rail then pull them out.

Mind you if there is a lot of crud there, should be removed first less it falls into the engine. And then that "Crud" may have caused corrosion and the O-rings may be stuck in there. If you can't rotate the injectors a little by hand even when mounted and everything in place, I'd say they are stuck. Just a little or a lot.....can be both.

If the O-rings have failed,that would cause vacuum leaks and that may cause symptoms like you describe, high idle or takes a long time to go back down to normal. Same with all the rubber hoses controlling the fuel pressure regulator if the earlier models or the rubber bits sealing the throttle bodies for all of them, early and new.

If your bike has an O2 sensor, don't use sillycone products to free or reinstall any of the rubber parts that are fuel related.

Do you have a manual? I only have the early 100s and later 1200s here but both are pretty clear on the procedures to remove/install the fuel supply systems.

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Last edited by H96669; Feb 2nd, 2013 at 9:26 am.
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post #4 of 20 (permalink) Old Feb 2nd, 2013, 4:31 pm Thread Starter
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Quote:
Originally Posted by FlyingDuck
Your post makes no sense.
Hello to you also. The mc started and ran fine today at 23F. I suspect my issue was with the vacuum (?) line on the rear throttle body(?). That port is small and in a small space. I need to get a plumber's clamp or something on there.

Let me try again. The fast idle control on the left instrument cluster moves fine. With the fast idle off and the control in the off position, everything is fine. Moving the control pulls the cable and does whatever it does to increases the fuel mixture in that one throttle body/fuel injector combo. That is fine. The fast idle control of the instrument cluster can be moved back to the off position. At this point, it is no longer fine. The cable to the throttle body from the handlebar control does not retract. The fast idle remains. The only way to turn off the fast idle is to take a screwdriver to the end of the cable which is located behind the throttle position switch and push it to the off position. So, the problem is the cable is not retracting. That leaves four sources for the problem: the control on the cluster, the cable, the cable adjustment (wherever that is) and the lever on the throttle body. Right or wrong, my first guess is that it is the lever the cable is activating.

Quote:
Originally Posted by FlyingDuck
Why would you disconnect the CCB hose?
Because what is sticking appears to be the lever on the throttle body at the end of the cable. I cant see it because it is behind the throttle position sensor. Removing the rear screw holding the throttle position sensor is easier if you move the CCB hose out of the way.

Quote:
Originally Posted by FlyingDuck
Why would you want to take the mounting plate for the TPS off?
So that I can see how the cable attaches to the lever on the throttle body and whether that is the source of the problem.

Quote:
Originally Posted by FlyingDuck
The vacuum hose connects to the rear THROTTLE BODY, not the fuel injector.
OK, I admit I am an idiot when it comes to fuel injection. The throttle body/ injector unit is a magic black box to me. It does what it does. I dont really care as long as it does what it is suppose to. I will take some time in the future to sort that out.

Quote:
Originally Posted by FlyingDuck
The "choke" can be adjusted via the locknut on the barrel of it where it connects to the TB assembly.
I need to take a closer look at that. That might be the source of my problem. I will do that first. That will also tell me if the cable has stretched.

Quote:
Originally Posted by FlyingDuck
Did you correctly adjust the TPS when you put it back on?
I was worried about that. How do you adjust that? The only thing I see to do is to twist the sensor using the slots for the screws. And how do you know when you have it right?

Thanks for the help.
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post #5 of 20 (permalink) Old Feb 2nd, 2013, 4:42 pm Thread Starter
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Quote:
Originally Posted by H96669
Injectors just pull out of there. Remove the rail then pull them out.

Mind you if there is a lot of crud there, should be removed first less it falls into the engine. And then that "Crud" may have caused corrosion and the O-rings may be stuck in there. If you can't rotate the injectors a little by hand even when mounted and everything in place, I'd say they are stuck. Just a little or a lot.....can be both.
I suspect mine are stuck. I really dont want to force them out. That means more self-inflicted damage to repair.

Quote:
Originally Posted by H96669
If the O-rings have failed,that would cause vacuum leaks and that may cause symptoms like you describe, high idle or takes a long time to go back down to normal. Same with all the rubber hoses controlling the fuel pressure regulator if the earlier models or the rubber bits sealing the throttle bodies for all of them, early and new.
Definitely a cable related issue.



Quote:
Originally Posted by H96669
Do you have a manual? I only have the early 100s and later 1200s here but both are pretty clear on the procedures to remove/install the fuel supply systems.
I have the Clymer

I may just pull the cable and forget about the handlebar control. If I am correctly understanding how the fast idle works, I should be able to duplicate it using the throttle and a throttle lock.

Thanks for the help.
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post #6 of 20 (permalink) Old Feb 3rd, 2013, 10:45 am
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A good set of Vacuum gauges may help a lot if you need to diagnose vacuum leaks. That is before they drive you crazy trying to find exactly where they are without dismantling.

There is also a procedure to balance them throttle bodies with such gauges but obviously can't work if there are leaks.

Also, the fuel pressure regulator on them works with vacuum,any leaks and that can affect fuel delivery. May leak cold and as the engine warms up things expand and the leaks disappear.....drives you crazy. Been there....!

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post #7 of 20 (permalink) Old Feb 3rd, 2013, 11:40 am
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What model K?

On a K75/K100, the TPS should be adjusted so that you can hear a slight click right when the throttle comes off idle. You need to do this with the engine turned off to hear the click. However, if the "choke" (throttle advance) is stuck somehow then you need to fix that first.
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post #8 of 20 (permalink) Old Feb 3rd, 2013, 3:35 pm Thread Starter
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Quote:
Originally Posted by H96669
A good set of Vacuum gauges ma help a lot if you need to diagnose vacuum leaks. That is before they drive you crazy trying to find exactly where they are without dismantling.
How does that work? I just bought the Motion Pro SyncPro, a 4 port nonmercury vacuum gauge. I plan to learn how to sync my throttle bodies. I know the K100 is way overdue. Anyone have a guide to using a vacuum gauge to trace leaks?

Quote:
Originally Posted by H96669
There is also a procedure to balance them throttle bodies with such gauges but obviously can't work if there are leaks.
Luckily, I have a friend with a K75 who understands the syncing process. So, the learning curve there is not very steep.

Quote:
Originally Posted by H96669
Also, the fuel pressure regulator on them works with vacuum,any leaks and that can affect fuel delivery. May leak cold and as the engine warms up things expand and the leaks disappear.....drives you crazy. Been there....!
My K75 had that problem. Had a very unpleasant ride to Roswell out of silver country in the snow due to that. Ran fine above 50F; ran horribly around 32F. Never did find that leak. So far the K100 has been good. Only leak issue has been the CCB hose.

Once we get a stretch of 50 degree weather here, I plan to sync the TBs.
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post #9 of 20 (permalink) Old Feb 3rd, 2013, 5:55 pm
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If you have a vacuum leak then you won't be able to sync the TBs.

Another way to diagnose leaky boots below the TBs is to spray some starter fluid down there when the bike is idling. If the idle goes up......
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post #10 of 20 (permalink) Old Feb 3rd, 2013, 7:21 pm
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Plug them gauges in you'll see. Different bike maybe but sure was getting an erratical reading on one cylinder. Even if they differ they should be pretty stable at idle. No quick oscillations of the needles. And then sync so they are even.

Handy things them gauges, may even tell you how good your valves are.Long even deflections of the needle at each stroke aren't good news if there aren't any vacuum leaks. We used to time car engines back then with just that a single vacuum gauge, within a degree or so of the specs.

Benelli 50cc at 14
Yamaha RD 200 at 16
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Honda CB 750 F at 18
Honda V45 Sabre at 24
BMW K100RS at 27
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