Rev counters.....

[fossie]

Both my pop up rev counters lie, Both are ok up to say 4000-6000rpm.

However this last trip I suspect it was not just lying but telling fables, all the way back home 10-12000 rpm! Now the fact the engine is still ticking over at the end of the journey tends to have me believe electrical glitch.

Olde worlde ones like 650 s are more reliable because they are cable into worm drive, however later bikes are pulse from coil driven. Can these be sorted?

For myself at the momentI will replace the gash one with another one .........which will lie I suspect.

[Uncle Bob]

Looking at the circuit for 750SE the feed comes from the low tension of the coil that does 2 and 3 and is B/Y = Black with yellow tracer. As that also comes out of the Ignitor box not sure where it splits. I would just check that wire back and make sure any connectors are clean - same with the ground that comes out (B/W) and power that goes in (O/G). The manual also says check continuity between B/W and O/G at the 9 pin connector (manual says O/G(reen tracer) on circuit but just O on the continuity page so not 100% sure one is correct but it will have orange...).

You'd have to be unlicky to have 2 with the same issue, but you never know.

If still iffy on both I guess you are looking at a component failure on the circuit board. I know my 1100 reads a little strange at 5-6k (ish). Years ago I did see an article on the web from someone in the states that said a resistor starts to fail - I remember it was a green one but cannot find the article anymore - JohnR was (is?) going to take a picture of he circuit board of the 1100 tacho to see if it reminds me.

If it's dead(ish) anyway and the curcuit has soldered on compoments (not surface mount or sealed over) I could possibly try to diagnose it, just need a 12V supply and signal generator I think I know someone with an oscilloscope!

Rob

[fossie]

I intend to swap the rev counter with another in a few weeks( 12 hour days and booked weekends)
So if you wanted to have a dig about I 'll send it down .

I mention this issue as it very common on pop ups and other Kats I believe.

I have swapped a few on other peoples bikes in the past all the same fine up to 3000 then a mystery tour!

Could be a corrosion issue at ignitor as it onthe side quite exposed but I wil still change this anyway as the bulbs need oing in the clocks.

[Uncle Bob]

Swap it over and send me the old one so then there is no pressure my end to get sorted as you need it back to fit! As all it's doing to counting pulses and converting that to analogue I wouldn't think a duff connection would be the issue personally but always handy to check the easy bits first.

I did want to look at mine (1100) really but as it works (more or less) I did't want to take mine apart and risk breaking it, hence i thought a dead one would be handy but given prices that isn't going to happen soon. that's when I hoped JohnR would send me an image of the circuit board so I could at least see if it tallied with what I remembered.

Let me know when you have swapped it.

Rob

[callyboy]

I have a bashed up speedo if anyone wants one for tinkering/spares.

Pete

[Uncle Bob]

So long as the rev counter would work and circuit board not broken then I can take a look. Not sure what is in there until I start looking. It would be handy to see if I can get it working on the bench as then I will know if I can fix Fossie's or anyone else's or publish a guide. I'm happy to try if you're happy to send to me. If so I can PM you my address. When I'm finished with it I can send back (the pieces!)

Rob

[callyboy]

Welcome to keep it Rob. Will grab a pic for you.

Pete

[callyboy]

its rough.....

[Uncle Bob]

Happier with rough as I'd hate to work on someone's perfect spare! I don't know how easy it is to get to the parts I need to test.. I'll PM you my address.

Cheers

Rob

[callyboy]

ok mate.

Pete