I replaced the Throttle Position Sensor for £12.59 and got rid of low speed glitches!

[Renegade Hippy]

I have had my Raptor 1000 from new in 2003 and so I have a distant memory of what the low speed fueling was like. It used to be good. It used to be able to pootle along reasonably happily at 30 mph in 4th gear, at a steady 2000rpm or thereabouts and pull away smoothly from that RPM.
That all changed after a few years of neglect and it developed what is well documented on here by others and I have seen called the low speed stumbles or the 3K glitch.

The fault meant that I rarely rode my Raptor. I hated it. It was horrible and almost unsafe going round small roundabouts in 2nd gear. I had played with resetting the TPS and I had modified the throttle twist to make the 1st part of the cable pull non linear and slower (Thanks to Nickst4 for that tip). Nothing made the bike bearable.

By about 2015 the bike had been off the road for years and I had thought the problem was probably water in the fuel or an injector misfiring due to being gummed up. But I just put it away and shut the garage door on it.

Fast forward to 2023 and I was determined to find the source of the issue. These bikes are getting old now and this issue seems to have affected many.

I have spent a good few weeks going through every aspect of the fuel delivery and injection system and it has been a frustrating and steep learning curve!
I have had the tank off and the pump and filter out. I bought a cheap fuel injector tester and a fuel pressure gauge off Amazon. I have had the fuel rail off and cleaned everything with carb cleaner (though I have to say nothing was really dirty). The injectors were absolutely fine. I checked the pressure regulator during prime and with the engine running. Nothing seemed wrong and nothing I did fixed the problem.

Eventually I decided to drill a hole in the case of the TPS and flood it with contact cleaner (See other forums and YouTube for people who have tried this too). Cleaning it didn't fix the problem but it DID change the behaviour in subtle ways. I knew that I was probably onto something but loathe to swap the TPS for a used part off ebay. New ones were very expensive and I wasn't 100% confident it would fix the issue.

The Throttle Position Sensor basically works like a volume control on an old school analog radio. It is 5K ohm linear potentiometer.
I was able to see that the resistance wasn't changing predictably using my multimeter by mounting the TPS in a vice and carefully rotating it using a screwdriver. At some points the resistance would jump from about 1.5K to infinity and then recover to 1.53K as I continued the rotation.
I actually think that leaving the bike in the garage over multiple winters, the wiper contact had become stuck to the track at some point and then subsequent twisting of the throttle had damaged it by lifting a bit of the carbon track up and amost leaving a hole in the track causing an open circuit at that point of rotation. If you've ever had a favourite old radio in the garage or kitchen you will know that the volume control can get all scratchy when it's left in damp and not being used.

I did a LOT of internet research and figured that all early fuel injected Suzukis between the TL1000 and mid 2000s probably have a 5K Ohm TPS and I decided to take a punt on an item on Amazon. I bought a Chinese copy of the part for £12.59 shipped from China that was listed for a GSXR-750. The Raptor is FIXED and it is good as new now. Result!

I would say that anybody with a Raptor 1000 that is still running with the orginal TPS will get the same results as me and that for £12.59 it is a no brainer to swap it, even if the problem is minor and not as bad as mine was.

The listing on Amazon is for a SHYEKYO TPS Sensor Replacement, Throttle Position Sensor ABS Metal Quick Response Long Durability 13550 13D60 Wearproof for Motorcycle I have also seen a similar part on ebay but Amazon was a little cheaper. It took nine days to arrive and I was able to watch it's journey step by step with the tracking info.

You will still need to setup the TPS position very very carefully. It is absolutely critical that the ECU is getting the right voltage to know where it should be on the fuel map. (check the manual and elsewhere on this forum for the procedure)

Photo of the box I received from China attached

[nickst4]

Brilliant fix: well done!

Despite the modest change of the throttle ramp, I still wish I could get a more-progressive power delivery, even though it doesn't glitch at all. Has your new TPS made any difference there, do you think?

Nick

[Renegade Hippy]

Brilliant fix: well done!

Despite the modest change of the throttle ramp, I still wish I could get a more-progressive power delivery, even though it doesn't glitch at all. Has your new TPS made any difference there, do you think?

Nick

No the power delivery is still as brutal as ever! However I do think your ramp mod has made it a tad easier to roll on from zero.
I think it's hard to say that your TPS is working properly just because you don't feel a glitch. The ECU is a pretty basic computer and to some extent will probably blur and mask some position errors.
If you think about my scratchy volume control anaolgy, a slightly bad TPS won't be sending a wholly reliable reference to the ECU and I figure that is a bad thing. The TPS will wear most where the wiper spends most of it's time and that is at zero when the bike is just parked. Each twist from zero will be going over the same part of the track over and over.

I read on a V-Strom forum that a mechanic in the US said swapping the TPS should almost be considered a service item and at the price I paid I think I am about to order another!

[andybaggies]

Top top post - some fantastic info in there.

I actually think that leaving the bike in the garage over multiple winters, the wiper contact had become stuck to the track at some point and then subsequent twisting of the throttle had damaged it by lifting a bit of the carbon track up and amost leaving a hole in the track causing an open circuit at that point of rotation.

That's an interesting point because I've never had any issue with the 'glitch' but then I have used the bike pretty much on a daily basis even throughout the winter.

Btw how much was Suzuki prepared to stiff you for an OEM TPS? And it wouldn't surprise me to find it's the same factory in China that sells them on Amazon and also makes them for Suzuki.

[andybaggies]

Just checked on Fowler's parts and the OEM TPS is over £100

See part 32 in https://www.fowlersparts.co.uk/parts/52 ... ting-parts

[Renegade Hippy]

Btw how much was Suzuki prepared to stiff you for an OEM TPS? And it wouldn't surprise me to find it's the same factory in China that sells them on Amazon and also makes them for Suzuki.

As you have found, OEM part is over £100! Whilst the replacement looks and measures exactly like the original I am not sure it is exactly the same part as the original has 'Mikuni Corp Made in Japan' in the moulding.
Photo of my original (complete with hole drilled by me to flood it with contact cleaner) attached.

I should add that I have since read on a US forum for some othe bike (I don't recall which) that buying cheap is prone to further issues down the line and the poster had horror stories of people replacing their TPS with cheap Chinese parts off Amazon. This may or may not be true. I can only report that the quality of mine feels and looks the same as the original and that is working great right now.

[andybaggies]

In a similar vein to my recent post on a replacement reg/rec from a Japanese company called TourMax I see they also do the TPS at a slightly cheaper cost to OE and the one your looking for is TPS-110.

I notice in all the adverts they don't show the underside of it and therefore the makers label. I understand from a motorcyle shop I go to that TourMax is a big company from whihc they purchase a good deal of their spares stock.

https://www.ebay.co.uk/sch/i.html?_from ... 0&_sacat=0