Carb issues V's TPS issues

[Varastorm]

I have been chasing the perfect carb jetting since fitting the Ducati stack mod & after a dyno run that led me to believe it was running rich throughout the rev range.

It was running spot on at the dyno & was quite happy, but once home the plan was to go down the road of a leaner mixture throughout. Leaner mains, needle & pilot to hopefully get closer, or break the 100bhp barrier with std Varadero cams.

In order to achieve this I decreased the mains to #175 rear & #172 front & fitted Dyno jet needles to enable a lower needle height.

I tried both #45 & #48 pilot jets, & every pilot screw setting in 1/4 turn increments from 3/4 out to 3 1/2 out. During this process I started to get a 3000rpm stutter which I presumed was due to me playing around with the pilot end of the fuelling.

I was starting to run out of ideas trying to remove the stutter problem & so I went back to the original dyno carb setup but noticed the stutter was still there.

To try to get to the bottom of this little riddle, the plan was to balance the carbs & check the TPS. The carbs where spot on but the TPS was way out, 200 ohm's

It had been a while since I had set it or checked the setting, since it had been running so well I thought there was no need

Since I had used Cybercarl's Mcct thread, brilliant BTW . I went back to the Cyborg links to use Carls method for the TPS setting, this was a head scratcher though.

Carl states you use the top pair on connections to get a reading.

You need to measure the Resistance from the top two contacts as you face it. You do this with your Multimeter set to Ohms within a 2000 ohm range.

I couldn't get it to read 500 ohm's, no matter how much I tried.

If I held the TPS so it read 500 ohm's on the carb frame there wasn't enough TPS movement to allow the butterflies to reach full throttle

The throttle only opened around half before the TPS hit it's stop.

I ended up using the Haynes/Honda Manual method & using the bottom two wires & finally got it to read 500 ohm's

I still had to remove the steel inserts & file the holes a lot to get it to read correctly.

I knew something was up using the top two wires, as there was no way I could get it to read 500 ohm's & use the two slotted holes to bolt it on, slotting the holes or bending tabs wouldn't help either. It was way out.

I have set the TPS before, but can't remember any problems like this, perhaps I did it wrong last time

I can now say that the stutter has completely disappeared It looks as if it was the TPS, not the jetting

I just can't help wondering why this happened half way through a jetting experiment

It runs spot on again now, if a little rich again Looks as if the carbs are coming off again & back to the leaner settings again

So a big warning, if you have or are experiencing a problem @ 3000rpm.

CHECK your TPS

[tony.mon]

When fitting the tps, the little tang needs to be carefully inserted between the two locating prongs. Sounds like you fitted it above them, and it will then read completely wrong and foul the tps body, meaning that you can;t open the throttle fully.

[Varastorm]

When fitting the tps, the little tang needs to be carefully inserted between the two locating prongs. Sounds like you fitted it above them, and it will then read completely wrong and foul the tps body, meaning that you can;t open the throttle fully.

I tried it all ways Tony & they were all in the correct slot/way. All together including tea breaks 6 hrs & 2 TPS's trying to get to the bottom of the problem.

Here's quick vid of the carbs after the TPS was set to 500 ohm's, no sync adjustment was needed after 2000 miles

[youtube][/youtube]

[sirch345]

An interesting thread Phil, I must admit I have not checked my TPS for ages,

Chris.

[kev64]

I was trying to connect my test leads onto the bottom two TPS connectors today but broke the spade connector
on my lead and couldn't get a correct reading (sorry not much help really, but will try again when I get the chance)

[MacV2]

I stole an Idea from Lloydie...Got an old TPS plug off a damaged loom put some plugs on it that fit into me meter.

Disconnect the plug off the TPS, fit the adapted plug read the reading...Simples.

[Varastorm]

I stole an Idea from Lloydie...Got an old TPS plug off a damaged loom put some plugs on it that fit into me meter.Disconnect the plug off the TPS, fit the adapted plug read the reading...Simples.

Which wires did you use Mac? Top two (Carl)? Or bottom two (Honda + Haynes)?

[MacV2]

I stole an Idea from Lloydie...Got an old TPS plug off a damaged loom put some plugs on it that fit into me meter.Disconnect the plug off the TPS, fit the adapted plug read the reading...Simples.

Which wires did you use Mac? Top two (Carl)? Or bottom two (Honda + Haynes)?

Now your asking...

I asked lloydie & he said....IIRC green to black & the other colour to red...

Be buggered If I can remember exactly but I'll look in to it & check for you but it will be later on as I'm off to work shortly...

[VTRDark]

I'm a bit confused. Red/Yellow and Yellow/Black wires IIRC are the top two connectors and then there's the green/Black. I think there are two different tests. the one in the Honda manual (bottom two contacts) is for checking the resistance with an open and closed throttle whereas measuring from the top two I think may be for a static reading. I haven't got a Haynes to hand so can't check that right now. But it's the top two contacts or top and middle as they say coincidently over the pond.

Take 2 pieces of wire and 2 spade connectors or any such other contrivance as your fertile imagination can come up with and connect the ohm meter to the TPS. Measure the resistance between the top and middle pins. Resist the temptation to use the old mechanics trick of pushing a dressmakers pin into the wires as this leaves a place for invisible corrosion and may cause a failure at some time in the future. It should be 500 ohms +- 10 Ohms.

http://www.superhawkforum.com/forums/kn ... nsor-9876/

I have always taken the reading from the top two with no problems but am willing to have a play when I get home. Oo er that sounds so wrong. play with my TPS that is. One does have to be careful that your meter prongs don't touch each other and short the connection which is easily done. If this happens you will get no reading at all. The Lloydie Mac trick is a good way to get around that problem.

(:-})

[MacV2]

Right the way they were connected as per Lloydie's instructions...

Black meter cable to green/black wire.

Red meter cable to red/yellow wire.

As the plug is cut from the loom leave a few inches of wire from the block, connect these as above to the meter cables, plug into the meter & the plug the connector in to the TPS...