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Discussion Starter · #1 ·
Been working on a FJR project bike, bought it off a mate recently.

His mechanic disabled the fast idle valve return spring to enable the bike to idle at normal RPM when warm.
There was a problem with fast idle, a separate circuit to the normal warm idle adjustment down by the side of the tank..

I was hoping reinstate the Cold/Fast idle !
So I had to strip out the air box to gain access to the throttle bodies.





I'm activating the plate that closes off the fast idle valves to enable warm/normal idle.
The little white plunger of the wax motor is not working.


The wax motor is fed from 2 small diameter coolant pipes, from pipe#1 on top if the cam cover, to the wax motor, then straight to the radiator.



Sorry, don't know who published the original picture.
Gives a bit better view of the throttle bodies, wax motor and the fast idle adjustment screw.

After stripping the front fairing plastics, gained access to the return feed pipe. Somewhat clogged .... totally !


Used a thin 14" probe to clean out the gunk from within the coolant pipes.



Some of the gunk !!!


Used a large fluids syringe to flush out the wax motor coolant circuit.


All up about 10 hours to strip & reinstall the bike bits, diagnose & fix the problem. A thousand + dollar problem !!!

Just goes to show to use distilled & not tap water.

The first owner of the bike may have fluffed up, my mate, the second owner knows FJR's extremely well; and he or his mechanic would have used the correct fluids.
 

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Top tip Ken many thanks for this one.

Make this a sticky?
 

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Good Morning, I seem to be having similar issues and it feels like ground hog day. FJR1300, behaving badly......

I recently completed my scheduled 80000km service, amongst the normal list of to do' I reset valve clearance's, spark plugs, synched the throttle bodies. Bike starts perfect every time when cold, after a short run up the idle speed slows down but instead of stabilizing at 1100 rpm, it continues to cut out. The bike will restart no problem but the throttle needs to be held slightly open to keep the bike running. Let it get cold and the same thing happens. I have started the bike and turned my fast idle under the carb screw up, reset my idle to 1500 cold and 1100 warm, bike runs no issues. Let the bike get cold, try and restart and the same issue all over again. I have rest the Fast Idle 3 times, I have advanced the butterfly screw on the carbs, no difference. Have no clue what the next steps are. Any sound advise would be appreciated. Many thanks.
 

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Cold to Fast Idle issue

Good Morning, I seem to be having issues and it feels like ground hog day. FJR1300, behaving badly......

I recently completed my scheduled 80000km service, amongst the normal list of to do' I reset valve clearance's, spark plugs, synched the throttle bodies. Bike starts perfect every time when cold, after a short run up the idle speed slows down but instead of stabilizing at 1100 rpm, it continues to cut out. The bike will restart no problem but the throttle needs to be held slightly open to keep the bike running. Let it get cold and the same thing happens. I have started the bike and turned my fast idle under the carb screw up, reset my idle to 1500 cold and 1100 warm, bike runs no issues. Let the bike get cold, try and restart and the same issue all over again. I have reset the Fast Idle 3 times, I have advanced the butterfly screw on the carbs, no difference.

Have no clue what the next steps are. Any sound advise would be appreciated. Many thanks.
 

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Discussion Starter · #5 · (Edited)
No it is not !
As stated, the dealer couldn't fix the cold idle, so he disconnected the cold idle circuit.

As stated in my post above, and several others, there are 2 separate idle circuits.
A cold / fast idle and the second, the warm / normal idle circuit.

There are TWO separate adjustments, the one on the RSH of the bike under the plastics for the normal / warm idle adjustment, the cold idle RPM adjustment is in the photograph, located underneath the throttle bodies.
The cold idle should only be adjusted ONLY when the bike is cold, likewise normal idle when hot, if not it can effect the RPM's of the "other"
Trying to adjust things too much can effect other bike systems, such as the FI, throttle body sync.

Having a bad TBS can effect the warm idle RPM.

Were any valve shims changed ?
One skipped tooth, 5 degrees, on the cam chain will cause exactly your fault.
Two skipped teeth, 10 degrees, will detonate the engine.

Having air in the coolant, not burping it correctly can effect both cold and fast idle.

Get back to me.
 

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Easier stuff first.... There is another possibility of slow idle issues, check these first as they are easier, based on the work you did.... all connectors connected, all vacuum hoses are connected not leaking, TBS caps on and not split/leaking, MAP sensor connected/intact/did not come apart (huge vacuum leak), and MAP sensor/vacuum hose not clogged (clean out with a pipe cleaner or similar). It is also time to unscrew (as you pull apart) the spark plug adapters off the wires, trim the wires 1/4" or so, spread the strands evenly and screw them back together... weaker spark at lower idle might be an issue if poorly connected. If all that fails to cure it, then dive into Ken's suggestion.
 
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Agree one tooth off on cam timing can cause an idle issue, depending on which way it is off. To test, go for a ride..... in third gear, if the bike noticeably does not develop horsepower like it normally does above 5000 rpm, i.e., does not put your eyes back in their sockets, slow to get to say 8000 rpm under load....... your timing is off.
 

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Awesome advise, many thanks. This may take me a few days between work and obligations, I am going to work off each item on the list and see if one by one I can isolate the issue. Yes all the shims had to be adjusted, and I made triple sure that the timing gear marks were aligned as per manual, so I don't believe it is the timing, its also runs well when cold and on start up. I will however take it for a quick ride and see, one never knows. Coolant also seems fin, filled up run the motor, waited for it to cool and settle, toped up the reservoir and run again till warm, added final top up and coolant level is now stable on the H mark of the reservoir. Any suggested ways to burb for just in case there is a lock in some pipe?

I will most certainly keep you posted, many thanks for your help, really appreciated.

Max
 

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Thanks Ray, as per my other note, I will add these items to my list certainly TPS keeps coming up, and maybe in assemble one of the vacuum pipes maybe not be well seated, I hopeful that between yours and Ken's suggestions I get to the bottom of this.

Rgds Max
 

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Excellent work Ken!

A mechanic with a diagnostician mindset. :surprise:
 

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One skipped tooth, 5 degrees, on the cam chain will cause exactly your fault.
^^THIS^^ One skipped tooth on the crankshaft sprocket when both camshaft sprockets are timed correctly will cause systoms [nearly] exact to the description. Please DAMHIK this.

Actively discussing the same thing in 2 different threads is a PITA for everyone. Threads merged.
 
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