Rev counter stopped

[Max4music]

Hello all

After successfully trashing by racebike at Gooseneck at cadwell Ive completely rebuilt the bike into new frame. All appears fine (it fires up, runs, temp gauge works), except the rev counter does not work. Ive changed the rev counter and nothing and checked for power coming to the rev counter and it appears there is nothing getting to it.

Just to put you in the picture, its got a stripped down race loom and in the crash I destroyed the kill/start button. Ive rewired a new one one and (after a few attempts at getting it right) it works fine, Ive found a wee resistor (it look like) wired in just before the black CDI which looks a little worse for wear. Could this be it? Whats does it do? What do I need to do?

I'm guessing, If I used the bike without it working it might not have a working rev limiter and therefore I could easily pop the engine by over revving.

Please help

[zimm]

rev limiter is internal to the ignition, so no worries there ..

assuming your loom is a stock one that's been stripped out and which works with the stock clocks (rather than a custom jobby, or wired for an aftermarket tacho which can take the feed from various places/pins) the tacho takes its signal from the feed to the coil for #1 and #4 (the black wire) .. if its getting voltage across the other two connections @ the clock try splicing in a feed from the coil and see what happens

[Max4music]

Hi Zimm, thanks for the response

Yes, its just the standard loom thats was stripped back by the previous owner. I'm not too hot on electrics so bear with me. So the tacho is takes its power from the 1 & 4 coil so if the bike runs ok, power is at the coils ok. So which two connections do I need to see if there is a voltage across? I'm a bit lost at this point, sorry.

[zimm]

there's three connections on the back of the tacho, the black wire is the signal feed, which is spliced off the feed to the coil for #1 and #4

there should be 12v across the other two connections on the tacho, one being live, the other being an earth..

if there isnt, then its a loom/fuse/something problem ..

if there is, then its possibly the signal thats not getting through on the black wire.. so add in a new signal wire from the coil to the clock and see if that works

[Max4music]

Thats great

My bike is kept over at my folks so I'll give that a go tomorrow and get back to you

Thanks

Max

[Max4music]

Well Ive tried those options and there is current between the other two connections (y/b and br). The temp gauge has these as well and is working, so could I ust tap off from these?

Man, I sure do hate electrics.....

[kawaman]

If you do have +12v between the brown and black/yellow wires going to the tacho, the problem should rather comes from the black wire coming from the #1/4 coil.
Try to put a wire from coil to tacho just to try, then if it works checks for black wire continuity or add a brand new wire to the loom...

[Max4music]

Cheers for all the replies. All valid and all tried. In the end Ive found a few faults and ended up making a new loom from scratch only to find the tacho still didnt work. Tried on another bike and fine. Turned out it was actually corrosion on the screws connecting the wires as randomly it started working. A good lesson on how to spend many many hours rebuilding the whole electrical system to find it was the corroding screws. Jeeeeze! Still I got a nice new lightweight loom now