Fast idle wax unit question

Discussion in '6th Generation 2002-2013' started by jswisc, Jun 10, 2015.

  1. jswisc

    jswisc New Member

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    My 08 doesn't high idle when cold lately. Had the bike for a year. It has 8k on it now. High idle worked fine till about a month ago. Still starts and after 30 seconds or so idle is around 1250 and runs fine. Hot starts no issue. I've searched and read plenty of threads on this unit and I have several question;
    1. This is a non electrical unit as far as I can see. Works similar to a thermostat. When cold, is the cold condition of the unit contracted, with the linkage pulled open? I've removed my airbox and looked over the unit. Shaft is extended. I can manually work the linkage and it seems to operate fine. The shaft going into the unit does not move. If it were electrical, upon turning the key the solenoid would be energized, pull the shaft in, the linkage would then engage all 4 starter circuits. So I assume once shut off, as the unit cools, the shaft is slowly contracted so when the key is next turned, the start circuit would be ready to go, like a carb with an automatic choke.
    2. Any reason why I couldn't hook up my own choke type mechanism hooked up to the wax linkage and operate the circuit manually. I've ridden several Ducatis with FI and they have a lever on the left grip that acts like a choke on older bikes. I assume this lever is operating some type of FI start circuit.
     
  2. OZ VFR

    OZ VFR Member

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    Or just fix it.
    There must be a reason it has stopped working.
    The wax unit on my 01 is still working fine.
    It might just need a clean and lube.
    When was the last time the starter valves were adjusted?
    The unit works on coolant temperature and is mechanical, no electronics at all.
     
  3. jswisc

    jswisc New Member

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    I've read lots of threads on this problem. Some have lubed and had some success, others not. Some have replaced the unit and still had the low idle. Some balanced the starter valves and it made no difference. Before I do anything I want to know exactly how the unit SHOULD function. When the bike is cold, what is the status of this unit? Does it contract when cold? To function, the shaft on the unit must contract into the unit which in turn pulls the linkage to all four circuits. On a functioning unit, how does it accomplish that?
     
  4. Terry Smith

    Terry Smith Member

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    I've got a '99 VFR, which has FI but no wax unit, but as you queried it does indeed have a manual fast idle lever on the left bar. The other end of the cable pulls on a plate that lifts all starter valves together. On the 6th gen there is a linkage that connects from the starter valve link plate on one cylinder bank across to the bank on the other side, so all valves open together.

    I think you need to view the wax unit shaft when cold, and then again when hot, and see whether it is expanding or contracting as it should.
     
  5. jswisc

    jswisc New Member

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    No movement on the shaft. Had the airbox off both hot and cold. This started to happen the past few weeks. Weather has been pretty warm and it's kept in a garage, not heated, but warmer than outside. Then in a heated garage at work. Curious if it's just too warm out? Anyway, if anyone out there can tell me , when the bike is cold, should the valves be all closed or open? Bike runs like a top and I hate to start dicking with it unless I confirm I actaully have a problem.
     
  6. jswisc

    jswisc New Member

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    Bump. Anybody, when the bike is cold, is the wax unit shaft in or out? Is the linkage engaged when cold or is there some other system on the bike engage it once the starter is touched?
     
  7. Mark919

    Mark919 New Member

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    The shaft is 'in' when cold and 'out' when warm. So it pulls when cold and relieves the pull as it warms up. It's all mechanical.
    If cold is like 70 degrees F I don't think it does much.
     
  8. jswisc

    jswisc New Member

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    I'm guessing the fast idle is suppose to work any time the bike is "cold". By that I mean not warmed up to temp. My unit is fully extended when cold. Must be bound up. Guess I'll have to order a new one.
     
  9. Terry Smith

    Terry Smith Member

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    Yeah, mechanically these will be similar to a thermostat, and they also tend to fail in the open/hot position.


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  10. jswisc

    jswisc New Member

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    Yeah, that's what it looks like. The shaft is fully out and the linkage needing to be pulled has no pressure on it. I can pull it on and off. Looks like a new unit or fab a mechanical solution. I've read they can be replaced without removing the throttle body. Anybody have any hints for replacing the unit?
     
  11. Terry Smith

    Terry Smith Member

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    From the service manual it looks like there are two screws that hold the unit to the throttle body, but they're mounted from underneath so I can't see that you could get to them. I've had the TBs off my 5th gen and it's not too hard to do.


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  12. Terry Smith

    Terry Smith Member

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    There's a good write up for this, search "thermostat replacement - 6th gen vfr800 vtec".

    Have you got a copy of the service manual?


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  13. jswisc

    jswisc New Member

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    Yes I do. Looked at the setup with the airbox off and it looks like if you moved the vacuum lines to remove the in/out radiator hoses the only issue is the 2 bolts/screws holding the unit on. Figure out how to get them off and you're good. If not, the t/body has to be removed.
     
  14. Motographer

    Motographer New Member

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    Any updates on replacing it without taking the TBs all the way off? Mine appears to have failed as well and I'd like to replace it with as little hassle as possible.
     
  15. jswisc

    jswisc New Member

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    Haven't done anything yet. Honestly, I've been trying to locate just the right "on/off" mechanism to make it manual. Seems these units fail with some regularity and it would be simple to convert it. Very simple operation and the unit is a little over complicated just to make it hands free in my opinion. I'm going to take the airbox off one more time and if I can come up with some way to remove w/o disturbing the throttle bodies I'll probably just replace. If not, maybe a "replace your fast idle unit kit" will be born!
     
  16. ricky

    ricky New Member

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    You can buy the parts lever, cable and the part that goes on the TB assembly from the 1998 to 1999 VFR to convert it to manual. It's all bolt on. I just did this during my engine swap.

    Taking the TB off isn't that hard btw. Just go step by step and remember all the connectors, wiring, cable and hose routing.
     
  17. jswisc

    jswisc New Member

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    Thanks Ricky. That was one of the options I was going to look into. Ducatis still do it that way on some of their late model bikes. I just hate going through the hassle of replacing it and have it fail in a year or two again.
     
  18. Terry Smith

    Terry Smith Member

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    If you do go manual, you'll also need the handlebar parts like the LHS switch gear and fast idle lever.
     
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