Rev Counter | Not working

[Gregmeister]

Hi All,

I've recently purchased a VFR400 NC24 - Its rev counter isn't working, I'm not to sure where to start looking, although - Probably should start with a multimeter will be my best option, but don't know what voltages or Ohms I need to record,

Any common issues experienced? Any other bits a pieces i should be aware of to make life easier?

Thanks in advance.

[Gregmeister]

I checked the Tacho unit its self and all seems well, no issues and really clean - I'm thinking its the pickup - Must be dirty or damaged - Anyone know how to check?

Thanks

[Neosophist]

I checked the Tacho unit its self and all seems well, no issues and really clean - I'm thinking its the pickup - Must be dirty or damaged - Anyone know how to check?

Thanks

How exactly did you check it?

The input signla is fed from the ignition box, if the pickups were not working the bike wouldnt run.

Make sure it has 12 volts going to it then do a reistance checked between the taco end of the wire and the feed from the igntiion box and look for a brake in connection

[spikenipple]

Sorry for hi-jacking a little, but do these bikes rev freely without clocks fitted? I finally got my NC21 running on the weekend but it wouldn't rev over what sounded like 5-6k. There was a mention in the NC30 carb megathread about the CDI cutting ignition if it doesn't 'see' the clocks.

[Neosophist]

nc21 is different it shoukd rev fine, but when wsrm

[spikenipple]

It won't run when it's warm

Sounds like I need to recondition the carbs. That megathread is an absolute godsend!

Thanks for your help!

[Neosophist]

It won't run when it's warm

Sounds like I need to recondition the carbs. That megathread is an absolute godsend!

Thanks for your help!

Yes carbs sound messed up.

Strip and clean.

Dont forget float heights, importatn, 6.8mm height. Pilot screws 2 turns, dont do any drilling with the throttle slides, thats for NC30 carbs.

Balance em by eye with a drill-bit before puutting back on the bike and vaccum balance after.

110 / 112 jets maybe or 112/115 I forget, i think 110,112.. eitheway, bigger jets and emulsion tubes with the most holes go in the rear carbs, people often mix them up.

make sure no extra shims other than the stock under the needles.

should run nice after that.

[spikenipple]

Thanks for your help Neo!

I think I have NC24 carbs fitted; they are fitted with rubber trumpets and appear to have similar settings to what you've posted in the carb megathread.

All pilot screws are set to 2 turns out
All pilot jets are #35
All main jets are #115
I haven't yet had the needles out, so will check those once I've cleaned all of the jets and put the bottoms back together.

At what height do I check the floats? Stationary (resting) position when upside down?
I guess I'm measuring the height of the highest part of the larger float to the float bowl mating face?

[Neosophist]

Thanks for your help Neo!

I think I have NC24 carbs fitted; they are fitted with rubber trumpets and appear to have similar settings to what you've posted in the carb megathread.

All pilot screws are set to 2 turns out
All pilot jets are #35
All main jets are #115
I haven't yet had the needles out, so will check those once I've cleaned all of the jets and put the bottoms back together.

At what height do I check the floats? Stationary (resting) position when upside down?
I guess I'm measuring the height of the highest part of the larger float to the float bowl mating face?

They are nc24 carbs then,no trouble to use them.

Float height is measure from here to here (see pic)



It is important to not let the weight of the float compress the springy pin on the float needle as this will give you a false reading, best way to do this is to tilt the carb 30 degrees



6.8mm is what your aiming for on these carbs.

Not everyone has a proper adjustable float height tool as they don't work on enoguh carbs so its easy enough to make an accurate fixed tool using an old plastic credit card / membership card etc.



You want to cut it so each edge rests on the carb bowl where the float gasket would sit and the hole part to be 6.8mm deep.

[spikenipple]

You are a fountain of knowledge, thanks again