Yamaha TRX850 Enthusiasts Forum

Hello all,

I fitted my ignitech (ta Coxy ) to my bike. Whilst setting up the TPS and the mapping I noticed that the TPS never settles back to the same voltage. WOT is 4100mV every time, +/-20mV. The idle position is hit and miss. I know the butterflies are coming back to their stop as I can clearly hear the mechanical stop being clicked against (and the revs returns to 1050).

So, in detail, if I quickly flick the throttle shut I get 740mV +/-10mV every time. If I return the throttle at a normal pace the idle voltage is 1000mV =/- 100mV. Once in this state no further tugging of the throttle cables yield a lower voltage. Once in this '1000mV' condition re-opening the throttle doesn't increase the voltage until it gets past its real 1000mV position - then it tracks linearly once again.

Is it a proven weak spot where the TPS slot wears or the shaft lug wears or something of the like to create some slop? I've tried using the search but I'm probably not using the right combo of words.

Cheers,
Glen.

Interesting - the TDM850 had a TPS recall due to an ineffective seal on the spindle allowing dirt to scratch the TPS track. I don't know if it also affected the TRX

Hmmm. With this second hand bike came a cardboard box with a spare pair of carbs. It's not impossible that a previous owner has fitted an old TDM TPS.