Yamaha TRX850 Enthusiasts Forum

ok so ive tried the wrapping the wire around the lead and to be frank its crap it jumps all over the shop on the rev counter so im now wanting to go directly to the coil however ive no idea which bit to attach the rev wire to so anyone care to help me out ?

umm. im not sure what your trying to do..

can you please tell us clearly what the problem is, how you can reproduce it, and what you are trying to do to fix it ?

Yeah mine does the same thing. Seems accurate when the revs are low but becomes erratic when revs get past 4000. Tried reducing the number of wraps but no better. Done that while it was running and got a good boot

Q-T The digital dash unit (TrailTech Vapor) Has the magnetic sensor for the speedo and a wire that wraps around a coil lead for the revs. You can program in how many pulses the bike produces but no settings seem to stop the tacho fluttering. Any ideas ?

oh ok... is it wrapped onto the positive side ?

If its flapping around, your loosing signal strength..

The lead that goes to the coil, it should be twisted up evenly, and fairly tightly.. so about 4-6 turns per inch.. Which will make the wire fairly twisted up. It helps with signal degredation.. Then wrap around the lead as needed.

Does that make sense to you ?

it also states you can connect it directly to the coil but there are 3 wires on the input side of the coil and i dont know which one to connect it to ?

mine was also a bit flappy ,so Ive just tired QTs idea Ive taken my signal for the rev counter from the ignition pickup i got some wire put one end in the vice 1 meter of wire put the other end in my cordless drill and twisted the wire like QT says re fitted the connections and now the rev counter is a lot smother but i only revved it to 5000 as its to gasley to go out but i will keep you informed when i get out on it ,,thanks QT ,,

There should be an orange wire to one coil, and a grey wire to the other coil. These are the +ve wires from the igniter unit.

so attach the wire to orange or the grey wire or both ?

what do the instructions say? I would think one only.

they show a coil with only one wire going into it and say connect it to that which i suspect is because its meant for a dirt bike really?

Then one only. As both coils will fire per rpm, you only need one signal.

PS don't blame me if you fry your igniter or coils or it won't run or anything at all.

no worrys it sez i cant kill the vapor by wireing it up wrong and im sure it wont make any diff to the coils

Had the same problem. Just stuck the red wire up the boot of the lead where it goes into the coil. A zip tie for good measure. Now good from 0-7000rpm

Sweeeet, thanks for the info guys. Sorted mine.

Kevtrx849 wrote:Sweeeet, thanks for the info guys. Sorted mine.

How? The LV Connection on the coil or my "stick the wire end up the lead boot trick?