TPS Adjustment: Was 840 - Now 590 Can't get to 500 - No Way!

[Tempest]

You've already got the pipes off as you've removed the tank and carbs. Remove the tap take it apart and clean it out, pop it in the ultrasonic bath once the diaphragm is removed. The fuel filter sits inside the tank where the tap goes, you'll see it when the tap comes off. once you've got the tap back together put a small pipe on the small hole at the rear and suck/blow, you'll hear and feel it work the diaphragm, you'll know it's ok then. Once back on the tank and with some fuel in it there should be no leak, turn the tap to on position there should still be no leak.

Thanks.... Great advice, very much appreciated.

Well, as for "Tank off" kinda cheating at the moment

Due to the "Look at all those pipes!" I turned the tap off (before I knew it was not just a normal tap) and disconnected the two pipes that can from it to the carb, and was able to rotate the tank then 180 degrees carefully, and position the tank where the seat goes, without pulling off the other pipes (my theory is/was the least I disturb the better)

So the tank is still connected via at least 2 pipes (from memory either side of the tank) still don't know what they are!

I'll see about removing the tap this evening, and hopefully a good clean will make all good. I saw some people were making their own rubber gasket/washer as their one had issues. hopefully I don't have to worry about that, just be gentle.

Will get some "normal" fuel for "washing out purposes" on the way home also.
Hope the filter will come out good. the small Ultrasonic Tank I've borrowed from work! is great at making dirt just fall away from things

[VTR-Paul]

I'm going though the same thing at the moment -> getting a long stood bike on the go.

I measured my TPS and it came up at 900. A curious number, exactly 900. I wonder why the factory aimed for these numbers at build. Emissions maybe, but then why would spec sheets say 500 +/- 100. I can only guess to get through emissions homologation.

For those wanting to adjust their TPS, the screws are security-torx, with the small peg in the middle of the screw head.

[Tempest]

I'm going though the same thing at the moment -> getting a long stood bike on the go.

I measured my TPS and it came up at 900. A curious number, exactly 900. I wonder why the factory aimed for these numbers at build. Emissions maybe, but then why would spec sheets say 500 +/- 100. I can only guess to get through emissions homologation.

For those wanting to adjust their TPS, the screws are security-torx, with the small peg in the middle of the screw head.

Welcome to my, "getting bike back up and running club!"

I modified a couple of stainless steel socket head screws (reduced shank down in the area is passes thru the TPS unit) which allows the unit to move an extra 1mm.
I also slightly bent down the metal prongs the plastic bit fits into with some long nose pliers.

After doing both these mods, even with the idle stop screw opened back up a bit (guessing at the moment) I can now get just below 500 on the multimeter, so I'm pretty sure I should be able to hit around the magic? 500 number when all up and running again.

From comments here, I does not sound THAT critical. My bike WAS running ok in the past and the TPS was around the 840 mark, before I started messing, so I don't know... but hey, there are people here on these forums that know way way way more about firestorms than me, so I bow to their greater knowledge and understanding, and if people here say 500 is a good number to aim for, then that's what I will do

(may try and get carbs back on tonight, but I need to rid up a temp fuel supply as my fuel tap is knackerd!)
but at least carbs are super super clean

I need to get the plugs out also to check them over, and replace if they look bad (they may be great) but until you get them out, you don't know.
Just don't have a nice long reach 18mm box spanner at the moment, (don't have ANY 18mm box spanner, come to that:( )

[VTRDark]

Don't loose the little spring inside the diaphragm tap. And the 500ohms is not from the forums but Honda. Have a look in the workshop manual.

(:-})

[VTR-Paul]

Hi Tempest,

Yep, we're on the same 'journey'.

My TPS, at full normal tilt, got down to 550. With a tiny bend of the carb spindle arm I got down to 508 and left it at that.

Vroom vroom.

Paul

[Tempest]

Just something I want to check...............

The small pipe that attaches to the back of the fuel tap (coming from near a carb) and makes the Diaphragm move in the fuel tap that starts the fuel running into the carbs/engine.

I presume that it creates a vacuum (Sucks) to make this happen, and when it stops sucking the diaphragm closes and stops the fuel.
Am I right? It's nothing to stop, suck to open.

I can't imagine it would blow (put pressure down the pipe) as that would risk the pipe blowing off the fuel tap connector.

Am I right, or have I got it the wrong way round?

[VTR-Paul]

Hi tempest

Yes, it's vacuum.

The natural state of an engine is to want to rev its tits off. We stop this (control this progressively) with the twist grip. This is why it's called a throttle, as it strangles the motor to a varying degree.

With the engine wanting to pull like crazy, there is low pressure created in the intake. We tap off this to pull a diaphragm in the fuel tap and switch it to on.

HTH, and sorry if I'm doing a granny sucking eggs thing.

Paul

[Tempest]

Hi tempest

Yes, it's vacuum.

The natural state of an engine is to want to rev its tits off. We stop this (control this progressively) with the twist grip. This is why it's called a throttle, as it strangles the motor to a varying degree.

With the engine wanting to pull like crazy, there is low pressure created in the intake. We tap off this to pull a diaphragm in the fuel tap and switch it to on.

HTH, and sorry if I'm doing a granny sucking eggs thing.

Paul

No no no.... Love the explanation.

I'd much much rather too much info and basic, plain English speaking info than a few tech comments from an "expert" who just assumes everyone else will know (find that a lot on many subjects)

Keep it clear, basic, and simple and I'm more than happy

Must say, despite bike sitting 2? years, after cleaning the carbs (and I checked and cleaned the plugs) etc..... It's actually running lovely and smooth now, from a temp, jury rigged fuel supply.
Amazing actually how doing this has made all my problems vanish in one hit

[Tempest]

One thing I have found.....

It's dam bloody hard (verging on impossible) to get multimeter probes onto the top two metal prongs in the TPS sensor, when it's all back and mounted on the bike.
Can't see sod all.
Fiddling with fingers and probes, poking them blindly into the black plastic surround hoping you will eventually just get lucky and the pins will touch and you will get a resistance reading.

Now someone clever can tell me the trick!

I have run the bike, got the tickover to 1100 ish, so I'm good, just struggling to get a reading. if I had a scrap plug I could cut the wires and probe those and easy job.

Any tricks ?

[popkat]

Pull them off again and set it.

Or just leave it, it's closer than it was before

[Tempest]

Pull them off again and set it.

Or just leave it, it's closer than it was before

Pull what off?

I don't suppose you are mad enough to think I'm going to remove the airbox an carbs and all pipework again are you!!!

Errrr, nope!

I can, after a little cursing and fiddling, just about find the prongs by luck.

It's just luck!

I know the exact amount if obviously not THAT important, but as I've replaced the screws that hold it on, with stainless allen bolts, it's easy to loosen and tighten it in situ now

No rush, can't do anything yet much without petrol tap and just ordered new oil filter (not that old one should be dirty, just that, bikes been sitting, and everyone here SHOUTS change the oil, etc etc

[popkat]

Pull them off again and set it.

Or just leave it, it's closer than it was before

Pull what off?

I don't suppose you are mad enough to think I'm going to remove the airbox an carbs and all pipework again are you!!!

It takes minutes to pull the carbs off, lid off then 10 screws out, 2 loosened and pull them up a bit for easy access, you've got the skills now


One other thing, you have made double sure you've got the front cam cover breather properly on the air box, yes ?


.

[bazzashadow]

I thought I read somewhere that you very slightly elongate the holes in the tps to get the 500 needed

[MacV2]

I thought I read somewhere that you very slightly elongate the holes in the tps to get the 500 needed

Yes that is correct...Obviouslt Mr Tempest didn't read that bit...

[Tempest]

Ha Ha...

If you think I'm pulling all that off again to make finding the terminals a little easy for something that in reality is not going to make any difference anyway you've got another think coming!

And yes, I got the front hoses onto the front underside of the lower half of the airbox, and recall thinking at the time..... What idiot designed this! No room for hand, but too short to put on without it in place.
Actually, getting the pipe on (both pipes) was not so hard, getting the little sprung metal ring, up into position with almost no hand access was the sweary bit

I kinda developed a technique after a while, one hand round the back, the other finger tips thru the frame, and a torch to check, but yes, got there in the end, all super clean and snug fitted.

As for elongating the TPS holes, well, they are metal lined, but I guess, I could of slipped the metal out, removed plastic on one side and refitted the metal, however, as I'm a toolmaker with some nice machines, I was able to find some nice stainless steel socket screws and reduce the dia of the screw just at the point it passes thru the TPS plastic/metal, to give a further 1mm of travel. I also bend down the metal tangs about 1mm also which gave a little more also.

Basically I can easy get down to the 460 mark now with the bike ticking over. I just need to spend some time getting it as near to 500 as possible, though I know it can't make much difference, as I thought the bike was fine before and before it was around 840! So it's not exactly something that seems uber critical.

Can someone explain a little more about it, what it's doing, what difference it makes, how important it is etc etc?