Hi All, Can anyone point me in the correct direction for some information please.

Trying to find out the MPH per 1000rpm in top gear for a yr 2000 UK spec F4.

Alternatively - what rpm should it be doing in 6th at 70mph ?

Cheers

 

Not sure about uk spec, but mine does 4000 rpms at 50 mph and around 4800rpm at 60 mph with stock gearing.

 

I have no idea. Can you find out using Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator ?
I wouldn't think that the US spec would be different from the UK.

 

sccbr600 - thanks - that means that the gearing is around 12.5mph per 1000rpm in top.

So 70 divide by 12.5 = 5600

kilgoretrout - thanks - nice site.

It says that at 70 mph the F4 should be doing 5500

So 12.73mph per 1000rpm in top.

Both agree within 100rpm so looks good to me.

SO - Any idea why a speedo on an F4 would read low ?


Bike rides very well - pulls cleanly and reaches red line so I belive the tachometer.
Sprockets are the standard 16F and 45R
Rear wheel has a 180/55R17 on it.

However at 7000 rpm in top it is only showing 60mph.

 

UPDATE.

Had a good dig around the bike and found some slightly corroded connectors.

Will be cleaning the connectors in next couple of days.

Whils I was checking the connectors I noticed a box that is not on the wiring diagram.

The box is in the line fron the speed sensor on the gearbox to the wiring loom.

It is all black with no markinga on it - honda male and female plugs on each end so the loom plugs in to it.

Has anyone else got this small black box fitted or is it possible that a speedo healer has been fitted at some point ?

 

Given that your gearing is OEM 16/45 w/ 180/55 tire it *should* read correctly. My F4 has OEM setup & is dead-on w/ speedo.

 

Has anyone else got a box like this plugged in to the speed sensor wiring ?

What is it for ? - it's not showwing in the wiring diagram.

 

Are there any markings of any kind on it?

 

Nothing at all

All wires are black - the only way you know which way to connect it is the male/female plugs are directional.

 

UPDATE - pulled all connectors apart and cleaned those that needed it.

Put ACF50 on all the connectors before plugging them back together.

left the unknown black box out of the loom

Speedo vs RPM in each gear now matches what the book says it should so all sorted.

To confirm - I Plugged the black box in again and speedo reads low.
I assume it is some kind of speedo healer but it must be pre-set because there is no way to calibrate it on the bike.