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VTEC 2002 choke problems


RADU

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Hi guys,

 

I have a problem with choke on my VFR 800 VTEC 2002. When the engine is cold and also outside is not quite warm (like autumn or spring), the choke does not go on when i start the engine. 

I turn the ignition on, start the engine and it struggles to run , at low rpm, strong vibrations etc. After one minute or so when the engine starts to heat, the rpms increse a bit, the choke suddenly comes in (sometimes it does not at all), but that is too late; it runs for a while, then it gets off (normal behaviour, as the engine in that point gets hot enough to run normally).

How can i repair this? What part is responsable for this? Can i change that part? Can i take a second hand one and install it? What code does that part have? Is it a simple operation or it requires calibration and more advanced stuff?

 

Thanks.

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Being fuel injected there is no choke as such.  It sounds like you wax unit is playing up or the linkages from it to the sync valves need lubricating. You will need to lift the tank and remove the air filter box to gain access to these items.

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Thanks Marooncobra. I now read about it and i think i understand what you are saying. Some quetions about it:

-are the terms "choke" and "fast idle speed" meaning the same thing in this context?

-if linkages are stuck,some wd40 on them would be enough?

-is there a way to check if the wax unit (which i read it does not have any wax at all) is not working properly? I mean a simple way, not taking it of and dismantling it.

-if i find out the wax unit is malfunctioning, how can i change it? Is it a simple operation, or a complicated one which presumes calibration etc? I am asking this because i know the wax unit has a nut painted with white, at the end of its  piston where the linkages are and a mechanic told me that is complicated stuff which needs calibration-very hard to do (the nut and wax unit i mean).

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Radu

 

If you remove the air box and leave the fuel tank connected in the up position you will still be able to start the bike, as you would for a valve synch, and see if the wax unit is moving as the bike gets warm. WD40 will free the linkages up if they are gummed up and if you need to replace the wax unit you will need to remove the throttle bodies as it is screwed onto an area you can only get to from underneath. If you go down this route I would suggest, whilst you have the throttle bodies off, you replace the thermostat and the hoses in the V at the same time. Although it isn’t difficult it does put a lot of people off when they see the complexity of the throttle body.

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Thanks marooncobra,

 

I will investigate as you say. Thermostat was changed last year because it got completelly stuck.

Again i may ask, in case of wax unit change, does the procedure involve calibration of any components or is it just unscrew things, change parts and screw back?

Reffering here mostly to the nut part at de end of the wax unit's piston.

 

Thx again

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It is pretty much the following:

 

  • Lift fuel tank up
  • remove vacuum pipe leading to flapper valve
  • remove top of air box
  • remove filter
  • remove velocity stacks
  • unclip all electrical sensors and vacuum hoses clipped to bottom and side of the air box and remove the box
  • disconnect throttle cables from throttle bodies
  • unclip the idle adjustment knob from right hand side (near clutch cover)
  • unscrew the 4 clips holding the throttle bodies to the intake rubbers
  • lift up throttle bodies moving the idle adjustment knob through the maze of pipes in the V
  • remove both coolant hoses that feed the wax unit
  • unscrew the wax unit
  • fit new wax unit. Honda state not to touch screw painted white on end of it
  • reassemble and if you have the vacuum gauges conduct a valve synch

let us know how you get on

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Big thanks again marooncobra. It will take a while(at least one week) until i will start the tshooting, but will definetely get back with feedback.

Thanks a lot for the detailed steps. It is what i was looking for.

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