Can anyone tell me if a KPH fireblade clock is acceptable for sva and if so whether you can calibrate it using a yellow box
Thanks mike

guess mounted correctly yea, ie:- no sticky out bits, i know people have put there own dial face's on to give correct speed readings, not sure bout "yellow box" never need'd one so don't know what they do do or don't do......

I've been told (on here i think) that the yellow box has to be switched to KPH mode to get correct mph on a BEC due to the large difference in gearing.

I may be talking complete w@nk, so this may be of no use to you.

A Yellowbox needs to be put in Mph/Kph conversion mode to bring the speed down to roughly the right range for a BEC. On standard blade MPH clocks, it will read around 180mph flat out in 6th, yet on the BEC, it needs to read about 120mph. The KPH/MPH conversion on the Yellowbox happens to give approximately the correct reduction ratio to bring it down near this figure, and the other adjustments on the box can be used to fine tune.
If you are running a KPH speedo to start with, then the conversion will still work, your speed will be roughly correct once the KPH/MPH conversion is turned on, but your speed will be correct in KPH, if you see what I mean!!
What might be easier is to get an overlay for the clocks to convert it to MPH, I know you can get them for a lot of bikes as some people import bikes from Japan etc, and convert them once they are here.

Chris

If your getting on overlay for the clocks why bother wasting your money on a yellow box.

Why dont you make your own overlay to convert the speed to suit your ratios.

I know the speedo wont go all the way round then but its cheeper and anyway the speedo is relatively unimportant, its the tacho that matters.

Thinking about it, if the KPH mode has to be turned on to get it roughly correct in MPH, then a KPH speedo will roughly show the speed in MPH with no conversion gizmo. As long as it doesn't read over, and it is not vastly out, then all you need to do is change the KPH marking on the speedo to MPH

Again, I may be talking complete w@nk, so this may be of no use to you.

[Edited on 28/2/03 by MK9R]

You are thinking in the wrong direction MK9R - a bike KPH speedo will go to say 300KPH max, so when at max speed in the BEC, it will be reading say 220KPH. If you were in Japan building a BEC, you could use an MPH speedo to give you approximately correct speed in KPH, but not t'other way round

carnut - true, you could get an overlay to just correct it without any Yellowbox, would be the cheap way to do it, but not sure if you'd be able to get a professional looking one done, or whether it would have to be a homebrew printout from your PC job.

cheers

Chris

[Edited on 28/2/03 by ChrisGamlin]

I am a tw@t!

Shame the BEC wouldn't really be doing 300mph

Not sure I'd want to be in any car with Cortina uprights and Mk2 Escort rear axle if it was doing 300mph!!