Throttle Position Sensor

[benny hedges]

ok, before i put the bike back together i thought i'd check the tps.
honda recommend setting it around 500 ohms at rest.
taking a reading from the top & middle pins, i was quite surprised to find mine set at 969 ohms

i shocked the shearbolts loose with the end of a screwy and turned it anticlockwise as far as it would go but could only get it as low as 580 ohms.
(my fluke meter is calibrated btw)
so i removed the sensor and with it disconnected the lowest possible reading (without altering the plastic stop) is 433.4 ohms

this is close enough to mik.str's magical 430 ohms figure - it makes sense to set the position at rest to 430 ohms seeing as that is the starting position of the potentiometer.

but it was impossible to set that without opening up the slots in the sensor mounting plate.
i cut them right to the end with a dremel cut-off disc


then replaced the metal inserts as to get the right setting the screws will be right on the edge of the mounting plate, and filled in the old slot with epoxy resin (araldite)


then trimmed off the excess and it's ready to fit with new m5 caphead screws


on the bike it now reads 436 ohms

ive read different views on doing this but seeing as most of them were from americans i'll disregard them all & bow to the knowledge of mik & the great mr ditchfield.
the icm controls ignition advance according to input from the tps, temp sensor & pulse generator so it's pretty obvious that if this setting is wrong then the ignition advance will be wrong and the bike will lose power.

from reports ive seen, they are more or less set at random from the factory, ranging anywhere from 500, 700 & in my case over 900ohms.

this could possibly explain why some bikes wheelie like crazy from take-off whereas some are a bit more placid.

i'll edit this when i have tested it on the road (in a few days)

[benny hedges]

thought bollox to it. 430 ohms..... so i dremelled the stop away half a mil & got it spot on to 430

[tony.mon]

When I did mine a while back I, too, ran out of adjustment, but found it easier to slightly bend the tangs inside to get them in the middle of the adjustment range of the slots as they were as standard.

Fiddly job, though.

Mine was out at around 900, too. But sad to say I didn't notice any difference when reset.

[Opel]

Adjusted mine today and have noticed a marked improvement overall, however I appreciate that this judgement is subjective, but I believe that I know my own—recently serviced— Storm!

This mod was investigated in an attempt to reduce the ‘cough and die’ annoyance that has always plagued my VTR at tick-over. It’s perhaps too early to tell whether that goal has been achieved, but the (perceived) improvements gained have warranted the effort involved.

The value was measured at 873 (calibrated Fluke also) reduced down to 493. Fortunately for me, I have a set of security bits so there wasn’t any issues encountered removing the TPS. I elongated the ‘slots’ as shown previously but stuck to the factory guideline of 500 +- 10, when setting up.

Incidentally, for those wishing to follow the complete guide to this procedure located elsewhere, I found that there was no need to do more than undo the front of the tank and to raise it on the rear bolt to access all (necessary) areas…so to speak.

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