TPS adjustment out on an SV1000 - Symptoms?

[Mark_h]

Anyone got any idea of the symptoms of the TPS being out of adjustment on a K3 SV1000?

Trying to adjust out the residual lumpiness low down. Balancing the TBs makes by far the largest difference was wondering if TPS adjustment could help or best left well alone given the rest of the bike is running rather well.

[DJ123]

I would check it 1st, then adjust if it is definitely necessary. If it is a touch out I would leave it, any thing more I would tweak it. Mine was easy enough to do, if a bit fiddly.

[Sid Squid]

Snatchy throttle transitions, particularly from idle/low revs. Depending on which way it's off it can cause unstable idle.
Set the balance at as low a speed as is stable, then set the idle, then set the TPS, then check idle is still on target if necessary readjust that then check TPS indicator moves from centre to top as close to engine speed lifting off idle as is possible. It's fiddly, but worth spending time to get right, and when it is right the throttle transition will be creamy smooth.

[Mark_h]

Snatchy throttle transitions, particularly from idle/low revs. Depending on which way it's off it can cause unstable idle.
Set the balance at as low a speed as is stable, then set the idle, then set the TPS, then check idle is still on target if necessary readjust that then check TPS indicator moves from centre to top as close to engine speed lifting off idle as is possible. It's fiddly, but worth spending time to get right, and when it is right the throttle transition will be creamy smooth.

Sounds sensible. Last time around I just set the balance when it was about 2.5k so it was smoother at the point it was lumpy but looks like I was just fixing around the problem rather than fixing the cause.

If you mark-up the TPS before you start messing can it all be put back in the right place or is it one of those jobs that once you start you have to carry on?

Any peculiarities with it being a K3 as everything else seems to be slightly different on a K3.

I also get an occasional cut-out when dropping back to tick-over when it's half-warm. Fine when it's cold and fine when it's fully warm but occasional problem 100 yards from home when it's reading about 40 degrees. Is there some sort of half-choke setting somewhere that needs messing with or is that likely to be a symptom of balancing?

[Sid Squid]

Balance:
Needs to be set at as small a throttle opening as is practical, which is when any imbalance will be a larger fraction of the total flow - the larger the throttle opening the smaller a fraction of the total any difference will be, in extremis; when the throttle is wide you wouldn't even be able to measure a small difference.

Marks:
The setting is very fine - I doubt you'd be able to mark it finely enough to make a realistic point to return to. I can't stress this enough; an imperceptible movement of the sensor can make a sizeable difference to the setting.

Peculiarities:
The K3 is the same as all the other similarly equipped FI SVs.

Cutting out:
The STV sets the fast idle, and that's known to drop out a bit as the cam and adjuster screw can wear a tiny bit, and this also is an area where very fine adjustments make sizeable differences. But rather than chase after a problem that may not exist, make sure all the service basics are right first; clearances, plugs, filter and a careful setup.

Last note; make sure the engine is properly hot before your final balance/idle/TPS settings, and bear in mind that the final exact idle setting can change after you're ridden it a bit and it's all settled in, and if you readjust the idle it moves the TPS setting a teeny weeny bit - which can sometimes be enough to tip it over the edge to not quite perfect again.

[Mark_h]

Cheers Sir Squid. Just been getting access to everything in prep for checking valves at the weekend. One of the head cover bolts isn't coming off yet so will soak in GT-85 and try a better hex socket on it in the morning.

Finally managed to track down the TPS plug. Looks like the loom has been twisted at some point, probably when the alarm was fitted, so it was between the loom and the tail plastics so tricky to get at and couldn't see it at all until I unbolted the tail plastics and flexed it all away.

Did however also find missing tyre pressure gauge, roll of masking tape and the screwdriver that is the perfect size for setting the rear suspension while I was furtling about in the plastic cavities looking for the illusive plug.

EDIT. few hours of GT85 + 18" length of 15mm copper pipe on the alan key and head cover bolt #8 is off! I'll not remove the covers and disturb the seals until I know we're definitely going to play with them on Saturday.