KB Article #4 - Throttle Position Sensor
Senior Member
SuperSport
Joined: Jun 2010
Posts: 636
From: Baltimore, Maryland
I just did the TPS mod while I have things apart, so I'll add my experience
I meant to do it while I had the frame off, but I put the frame back on and "$%&# @##& I meant to do that with the frame off!!!"
My TPS ohm reading was way out at 1026. I don't have any lower throttle cruising problems or problems between 2k-3krpms, but I figure I will set it right and see what happens.
I tapped the shear bolts loose with a small screwdriver and a hammer then spun them out with my fingers. I started by bending the left tab to the left, and got the TPS reading down around 850. I couldn't get a good angle to bend the tab and was worried I would break it off, so I worked on the TPS housing also. Pushed the metal spacers out, and filed the holes longer and wider. I spread the spacers some so they would stay in the now larger holes and reassembled with two M5x10mm Hex Cap screws on the original washers. I still didn't have enough rotation so I had to do it again, but ended up getting the reading to 496.
I'll have to wait until the rest of the bike is together to see how it feels.
A picture of the tab after bending
Pictures of the holes after filing with the spacers reinstalled.
I meant to do it while I had the frame off, but I put the frame back on and "$%&# @##& I meant to do that with the frame off!!!"
My TPS ohm reading was way out at 1026. I don't have any lower throttle cruising problems or problems between 2k-3krpms, but I figure I will set it right and see what happens.
I tapped the shear bolts loose with a small screwdriver and a hammer then spun them out with my fingers. I started by bending the left tab to the left, and got the TPS reading down around 850. I couldn't get a good angle to bend the tab and was worried I would break it off, so I worked on the TPS housing also. Pushed the metal spacers out, and filed the holes longer and wider. I spread the spacers some so they would stay in the now larger holes and reassembled with two M5x10mm Hex Cap screws on the original washers. I still didn't have enough rotation so I had to do it again, but ended up getting the reading to 496.
I'll have to wait until the rest of the bike is together to see how it feels.
A picture of the tab after bending
Pictures of the holes after filing with the spacers reinstalled.
Snap, Tap or Nap!!!!
Back Marker
Joined: Feb 2012
Posts: 197
From: Melbourne, FL
Resurection of a old thread.
Just looked at mine and I have to presume the PO has already done this mod. There are normal philips head screws in place of the factory hardware. I havent checked the ohm's yet, but will tomorrow. Bike is really strong on the low end and mid.
Just looked at mine and I have to presume the PO has already done this mod. There are normal philips head screws in place of the factory hardware. I havent checked the ohm's yet, but will tomorrow. Bike is really strong on the low end and mid.
Last edited by 00SUPERHAWK; Feb 28, 2012 at 03:15 PM.
Senior Member
Superstock
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
Question
Well there was a service bulletin in '98 about them. At that time the holes in the carb stays were just a touch undersized and what happened was that under hard braking the rear carb would puke fuel into the front carb.
So the bike would run on one cylinder until the front cleaned itself out.
This condition was fixed in either '99 or '00 so it really isn't that big of an issue on the later bikes.
Though if the bike does run rough after hard braking, then you should pull them from the carb stay and reroute them.
So the bike would run on one cylinder until the front cleaned itself out.
This condition was fixed in either '99 or '00 so it really isn't that big of an issue on the later bikes.
Though if the bike does run rough after hard braking, then you should pull them from the carb stay and reroute them.
How does the fuel from the rear carb enter the throat of the front carb? Does it overflow from the three vents and run across the floor of the air box under gravity and into the throat of the front carb? That's the only way I can understand what may be happening.
Senior Member
Superstock
Joined: Oct 2011
Posts: 344
I tackled this yesterday, but could only get the TPS moved enough to get the reading down from 840 to 626...bike runs a bit better in the low-mid but still has an undesirable feeling when transitioning back onto the throttle after being on the brakes...which makes it sketchy sometimes at the track..
any suggestions ? I see bending the tab, and maybe grinding the holes larger on the tps itself so I can spin it more?
Also...I assume the resistance measurement is at WOT, yes? Because with the throttle closed its like 1500.
I didn't wanna grind the holes because they have that brass outer and after going through that it'll be plastic...probably doesn't matter but I'm not a mechanic at all and hesitate to mess with stuff like that.
any suggestions ? I see bending the tab, and maybe grinding the holes larger on the tps itself so I can spin it more?
Also...I assume the resistance measurement is at WOT, yes? Because with the throttle closed its like 1500.
I didn't wanna grind the holes because they have that brass outer and after going through that it'll be plastic...probably doesn't matter but I'm not a mechanic at all and hesitate to mess with stuff like that.
Former Superchicken Owner
SuperBike
Joined: Sep 2008
Posts: 1,607
From: Ft. Worth, TX
Well I set mine after I set the idle speed. It took a couple of times because of it changing with each idle speed adjustment.
So it was start the bike and set the idle speed.
Shut it down and adjust the TPS.
Restart and set idle speed.
Shut down and check TPS. If good you're done.
If you have to readjust the TPS repeat the steps of setting the idle and then checking the TPS.
Might be a little overkill but that is how I set mine.
So it was start the bike and set the idle speed.
Shut it down and adjust the TPS.
Restart and set idle speed.
Shut down and check TPS. If good you're done.
If you have to readjust the TPS repeat the steps of setting the idle and then checking the TPS.
Might be a little overkill but that is how I set mine.
Last edited by RWhisen; Mar 22, 2012 at 02:11 PM.
Senior Member
Superstock
Joined: Oct 2011
Posts: 344
Thanks, actually I had been taking the reading from the wrong pins...I re-adjusted it last night and got it to 496 ohms after it was all tightened back up...that + installing a new air filter made the bike run better than it ever has the entire time I've had it!
Would highly recommend this 'mod' to anyone with an SH.
Senior Member
Back Marker
Joined: Jul 2005
Posts: 156
From: Santa Cruz, CA
Thanks, actually I had been taking the reading from the wrong pins...I re-adjusted it last night and got it to 496 ohms after it was all tightened back up...that + installing a new air filter made the bike run better than it ever has the entire time I've had it!
Would highly recommend this 'mod' to anyone with an SH.
Would highly recommend this 'mod' to anyone with an SH.
Sure enough, that thing was way off, forgot to do a initial ohm reading, but when adjusted to the original grim line, it was at 860. I replaced the bolts by drilling out the old ones(I filed down those heads and center punched for a good drill bite), rotated her counterclockwise to a max reading of 620..., I lengthened the adjustment slots so I could achieve 500, it read perfect 500 upon initial placement, but I then took a final reading of 496. Put her all back together...Forgot to turn the petcock on as usual, had to undo the tank bolts again uggg, stupid. Started her up fired up on que. Not one hiccup, not one carb fart definitely running different than before.
Here's where thing get messed up....While center punching the bolts, I may have broke the choke cable insert on the rear carb, so now the spring is exposed. I suspect that may be the cause of.....Backfiring. I'm running great at idle, about 900rpm not a hiccup or anything(usually It would hiccup and die after a few seconds on warm up) So rear choke cable is not functioning properly at the moment, front is fine.
This backfiring is after I rev it to about 2.5-3 for a second, let off throttle and these minor backfires are popping out of rhythm, but definitely odd. I'm thinking I need to go back and do a cleaning job and check the jets and needles and such. Anyways, I'll get to that asap, maybe if I take it on a test ride it will go away...We'll see.
Member
Squid
Joined: May 2012
Posts: 95
I have to chime in and ask this. If you guys are adjusting the TPS at closed throttle, and the TPS affects timing, any adjustment will alter the idle speed due to the timing change. One would have to keep going back and forth until they get 500ohm@1200rpm. What would be ideal is a WOT ohm measurement. Has anyone done the back and forth adjustment? If so, can you take a WOT measurement? That way the TPS can be set proportionate to a fixed (WOT) throttle position. I'll get around to it eventually and post my results. Maybe it's not that critical.
On many cars, when adjusting the TPS, there's a jumper that bypasses the ignition advance. Then you set the idle, then you set the TPS.
On many cars, when adjusting the TPS, there's a jumper that bypasses the ignition advance. Then you set the idle, then you set the TPS.
Slacker
Superstock
Superstock
Joined: Jun 2005
Posts: 489
From: San Antonio, TX
500ohm@1200rpm. What would be ideal is a WOT ohm measurement. Has anyone done the back and forth adjustment? If so, can you take a WOT measurement? That way the TPS can be set proportionate to a fixed (WOT) throttle position. I'll get around to it eventually and post my results. Maybe it's not that critical.
I recall a post years ago where one forum member did MULTIPLES of dyno runs adjusting ONLY the TPS and claimed that 650 was the setting that produced the best power. Not sure if I remember correctly though.
Last edited by BeerHunter; May 23, 2012 at 10:30 PM.
Banned
MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
It may not be critical, but I did in fact do something like this 2 weeks ago. Had a similar thought as you about adjusting the WOT reading to the highest value that that sensor is capable of. I am not sure of the exact numbers, but I believe WOT is right near 4600 ohms and that put my closed throttle reading somewhere between 600-650 ohms with an idle speed of 1200. I have yet to ride it thoroughly since the left fork seal blew and the bike is sitting in the workshop waiting for me to feel like fixing it.
I recall a post years ago where one forum member did MULTIPLES of dyno runs adjusting ONLY the TPS and claimed that 650 was the setting that produced the best power. Not sure if I remember correctly though.
I recall a post years ago where one forum member did MULTIPLES of dyno runs adjusting ONLY the TPS and claimed that 650 was the setting that produced the best power. Not sure if I remember correctly though.
Banned
MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
Junior Member
Squid
Joined: May 2012
Posts: 14
what caused that round mark on the slide(22-23)?
I'm trying a trick to get the front slide to open slower as per 8541Hawk's suggestion. There's a recent thread on carb setup that he started- It's explained in there
You're supposed to pull those rubber lines out of the holes between the carbs for a reason I can't recall offhand (i think it's because they look too orderly all tucked away like that. haha). may cause a stumble i think and you wouldn't want to stumble would ya? what would your friends think?haha
You're the second person to tell me no to do that. They're out now! The holes just looked like a perfect hose storage
why did you drill out the tps holes when you did such a great job slotting the rivets? I would have left the metal inserts in there and reused the rivets, but no big deal though.
My TPS was so far off that just bending the tab wasn't enough (no joke, 1190 ohms). I drilled the holes to allow the sensor to be rotated, creating what ended up being 499 ohms. I ended up putting the metal inserts back in after I drilled the slot out
did you remember to insert a fitting and rubber tubing into the bottom of the front carb for the quick carb sync which you will need to do shortly?
Nope- didn't even know this trick. I think I've seen pics of your $5 homemade one (was that you?). I'll go search for that thread later today
did you put a #48 pilot in? If you didn't, 8541Hawk is gonna punish you boy. haha
No local shops had them in stock, ordered a set from hollisterhonda. Pretty much everything is direct from 8541's advice- even the parts venue!
just food for thought in case you may have missed something you didn't know about. great pics
You're gettin close to launching that rocket huh!
It's been a long time coming. Parts are at paint, electrical only has a few more hickups... ohhh man my buddy just got a little Monster and I can't wait to show him the awesomeness of a Honda twin
I'm trying a trick to get the front slide to open slower as per 8541Hawk's suggestion. There's a recent thread on carb setup that he started- It's explained in there
You're supposed to pull those rubber lines out of the holes between the carbs for a reason I can't recall offhand (i think it's because they look too orderly all tucked away like that. haha). may cause a stumble i think and you wouldn't want to stumble would ya? what would your friends think?haha
You're the second person to tell me no to do that. They're out now! The holes just looked like a perfect hose storage
why did you drill out the tps holes when you did such a great job slotting the rivets? I would have left the metal inserts in there and reused the rivets, but no big deal though.
My TPS was so far off that just bending the tab wasn't enough (no joke, 1190 ohms). I drilled the holes to allow the sensor to be rotated, creating what ended up being 499 ohms. I ended up putting the metal inserts back in after I drilled the slot out
did you remember to insert a fitting and rubber tubing into the bottom of the front carb for the quick carb sync which you will need to do shortly?
Nope- didn't even know this trick. I think I've seen pics of your $5 homemade one (was that you?). I'll go search for that thread later today
did you put a #48 pilot in? If you didn't, 8541Hawk is gonna punish you boy. haha
No local shops had them in stock, ordered a set from hollisterhonda. Pretty much everything is direct from 8541's advice- even the parts venue!
just food for thought in case you may have missed something you didn't know about. great pics
You're gettin close to launching that rocket huh!
It's been a long time coming. Parts are at paint, electrical only has a few more hickups... ohhh man my buddy just got a little Monster and I can't wait to show him the awesomeness of a Honda twin
Edit* Sorry, answered in following comment by 8541
Last edited by strokeburger; Jul 15, 2012 at 09:10 PM. Reason: LOL, answered in following comment by 8541
The Pirate Sportbiker
Squid
Joined: Mar 2012
Posts: 55
From: Wisconsin
Not sure which tab y'all are bending, but I removed the two metal collars lining the mounting holes on the sensor. I was able to insert a very small flat blade screwdriver between the collar and the plastic and carefully bend it inward. One of 'em needed a slight bit of persuasion with a small needlenose pliers, the other literally fell out once it was "crushed." Recommended setting is 500-ohms? I managed to get mine set to 501.
Senior Member
MotoGP
Joined: Aug 2006
Posts: 2,934
From: altoona, pa
http://i743.photobucket.com/albums/x...g/DSC03948.jpg
the 2 metal tabs are located inside as you can see in the pic, not the inserts that protect the plastic slots from cracking. but whatever works. Hell I'm so dumb i had it turned all the way in the opposite direction to who knows how many ohms and rode it like that for a year without knowing it.
Do you notice any diff in low end performance? If you get in there again you can probably do like 490 if i recall.
the 2 metal tabs are located inside as you can see in the pic, not the inserts that protect the plastic slots from cracking. but whatever works. Hell I'm so dumb i had it turned all the way in the opposite direction to who knows how many ohms and rode it like that for a year without knowing it.
Do you notice any diff in low end performance? If you get in there again you can probably do like 490 if i recall.
The Pirate Sportbiker
Squid
Joined: Mar 2012
Posts: 55
From: Wisconsin
Yes, those are the tabs I *thought* everyone was talking about, but it made more sense to remove the collars on the TPS itself, so that's what I did. 490? I thought 500 was ideal? I managed to set mine to 501. 501 > 490
I noticed the bike idles more smoothly, runs better overall and I can't even remember the last time it farted on me! I'm waiting another few months (until it snows) to do a full "tune" on the carbs...
I noticed the bike idles more smoothly, runs better overall and I can't even remember the last time it farted on me! I'm waiting another few months (until it snows) to do a full "tune" on the carbs...
Senior Member
MotoGP
Joined: Jul 2010
Posts: 3,871
From: Phoenix, AZ
I've just removed the collars as well. Not sure if I'd worry about cracking with a standard screw rather than the factory "crushed" head. But I could be wrong . And anywhere in the 490-510 range I doubt you'll notice much of a difference. IMO setting it as close to Honda recommended spec (500) is best, although way back in some thread I remember someone really being pleased with 450 ohms. As Mike would say, ymmv, haha!
. And anywhere in the 490-510 range I doubt you'll notice much of a difference. IMO setting it as close to Honda recommended spec (500) is best, although way back in some thread I remember someone really being pleased with 450 ohms. As Mike would say, ymmv, haha!
Senior Member
Back Marker
Joined: Nov 2012
Posts: 211
From: Henderson, NV
Just completed this update to my Hawk. Initial reading was .822, drilled out the heads of the screws, replaced them with ss buttonhead allen screws, cranked the tps over and read .647 on my multimeter, removed the tps, removed the bushings in the slotted holes and filed them both longer, replaced the bushings, bolted it back up and they read .501 on the multi, snugged the bolts down and final reading is at .500, exactly. Thanks to everyone, who contributed their input, for the information to accomplish this task with such relative ease. Now I just have to wait to replace the stator so that I can give it a test drive to feel what the difference is going to be.
Last edited by Aquasnake; Dec 21, 2012 at 10:14 PM.
Junior Member
Squid
Joined: Feb 2013
Posts: 14
From: Melbourne. Fl. 32904. Exit 180 off I 95
Ditto on what Aquasnake said. Mine was at 916 and jetted but felt too weak to me. Now feels more like a Honda v twin...smooth and torquey. Thanks everyone for their info. Cleaned the plugs and filter while in there as the bike is new to me.
Junior Member
Squid
Joined: Aug 2011
Posts: 25
I just did the TPS mod while I have things apart, so I'll add my experience
I meant to do it while I had the frame off, but I put the frame back on and "$%&# @##& I meant to do that with the frame off!!!"
My TPS ohm reading was way out at 1026. I don't have any lower throttle cruising problems or problems between 2k-3krpms, but I figure I will set it right and see what happens.
I tapped the shear bolts loose with a small screwdriver and a hammer then spun them out with my fingers. I started by bending the left tab to the left, and got the TPS reading down around 850. I couldn't get a good angle to bend the tab and was worried I would break it off, so I worked on the TPS housing also. Pushed the metal spacers out, and filed the holes longer and wider. I spread the spacers some so they would stay in the now larger holes and reassembled with two M5x10mm Hex Cap screws on the original washers. I still didn't have enough rotation so I had to do it again, but ended up getting the reading to 496.
I'll have to wait until the rest of the bike is together to see how it feels.
A picture of the tab after bending
Attachment 12439
Pictures of the holes after filing with the spacers reinstalled.
Attachment 12437Attachment 12438
I meant to do it while I had the frame off, but I put the frame back on and "$%&# @##& I meant to do that with the frame off!!!"
My TPS ohm reading was way out at 1026. I don't have any lower throttle cruising problems or problems between 2k-3krpms, but I figure I will set it right and see what happens.
I tapped the shear bolts loose with a small screwdriver and a hammer then spun them out with my fingers. I started by bending the left tab to the left, and got the TPS reading down around 850. I couldn't get a good angle to bend the tab and was worried I would break it off, so I worked on the TPS housing also. Pushed the metal spacers out, and filed the holes longer and wider. I spread the spacers some so they would stay in the now larger holes and reassembled with two M5x10mm Hex Cap screws on the original washers. I still didn't have enough rotation so I had to do it again, but ended up getting the reading to 496.
I'll have to wait until the rest of the bike is together to see how it feels.
A picture of the tab after bending
Attachment 12439
Pictures of the holes after filing with the spacers reinstalled.
Attachment 12437Attachment 12438
At last have found out what tab to bend with a picture
. Just to confirm the tab you bend is the left hand one as you look at it? This is a bit odd as that would allow rotation of the TPS in a clockwise direction unless I am mistaken. To rotate it counterclockwise would mean the right hand tab would need to be bent. Please can someone confirm with a picture & an arrow pointing to the correct tab to bend. This would be most helpful.Thanks
Member
Squid
Joined: Apr 2013
Posts: 42
From: Canberra ACT Australia
top two not bottom two tabs
Just did this mod today and was having a world of trouble getting any kind of meaningful reading across the tabs when it came time to tune in that magic 490-510ohms.
Going off the Haynes bible i put the multimeter across the bottom two posts on the TPS and came back with 4.89 to 6.78 ohms?!?! Humm, somethings not right here..
Now i cant know who to thank for the post but somewhere here it was mentioned to check across the top two..
Bingo! gold! Ohms up in the hundred..
So now after completing a PAIR removal and general oil, air, filter as well as plug replacement the thing feels all but new.
Can report the throttle feels a lot softer on initial opening but, and, i dont know if others can shed some light on this, a slight buzzy feeling across the rev range. Not harsh just not Honda smooth.
Can this be smoothed out by adjusting around that magic 490-510 range?
Going off the Haynes bible i put the multimeter across the bottom two posts on the TPS and came back with 4.89 to 6.78 ohms?!?! Humm, somethings not right here..
Now i cant know who to thank for the post but somewhere here it was mentioned to check across the top two..
Bingo! gold! Ohms up in the hundred..
So now after completing a PAIR removal and general oil, air, filter as well as plug replacement the thing feels all but new.
Can report the throttle feels a lot softer on initial opening but, and, i dont know if others can shed some light on this, a slight buzzy feeling across the rev range. Not harsh just not Honda smooth.
Can this be smoothed out by adjusting around that magic 490-510 range?
Junior Member
Squid
Joined: Jul 2013
Posts: 3
From: Palm Bay, FL
Who wants the rear seat cowl shipped and how much?
Junior Member
Squid
Joined: Jul 2013
Posts: 12
From: Portage la Prairie, Manitoba
Just did this mod today and to me it seems smoother at low rpm/around the neighbourhood type of riding. Im a new rider and definitely not very smooth yet but for the life of me couldn't seem to make a nice shift from first to second without a jerky jumpy response from the bike. Now? Nice and smooth!
I think getting the hoses undone from the air box actually took more time than removing the TPS. I drilled the shear bolts with a 1/8" bit and used a Snap-On screw extractor. Bolts came out without a hitch. I had to bend the tab on the throttle shaft as instructed in the write up and that was that. Set it to 501 Ohms and slapped it all back together. Works like a charm!
Thanks for the instruction!
I think getting the hoses undone from the air box actually took more time than removing the TPS. I drilled the shear bolts with a 1/8" bit and used a Snap-On screw extractor. Bolts came out without a hitch. I had to bend the tab on the throttle shaft as instructed in the write up and that was that. Set it to 501 Ohms and slapped it all back together. Works like a charm!
Thanks for the instruction!
European Member
Back Marker
Joined: Mar 2013
Posts: 194
From: Netherlands
I did this mod today aswell,
really easy because i have a firestorm or a euro superhawk so i have torx with pins instead of headless bolts on the tps,
without bending the tabs i got straight away 420 (good number
)
so i set it at that because it was stock around 700.
grtz
really easy because i have a firestorm or a euro superhawk so i have torx with pins instead of headless bolts on the tps,
without bending the tabs i got straight away 420 (good number
)so i set it at that because it was stock around 700.
grtz
Senior Member
Superstock
Joined: Mar 2015
Posts: 409
From: Central CA
I was able to set my TPS to 500ohms last night.
I tested the resistance while slowly rotating the throttle. The readings do not seem to flow smoothly when the throttle is increased.
Measuring from the top 2 terminals, the resistance seems to jump when above 800 or so. It jumped to 1.2 K then increased steadily again.
Can anyone tell me the ohm range of this TPS?
I tested the resistance while slowly rotating the throttle. The readings do not seem to flow smoothly when the throttle is increased.
Measuring from the top 2 terminals, the resistance seems to jump when above 800 or so. It jumped to 1.2 K then increased steadily again.
Can anyone tell me the ohm range of this TPS?
Last edited by Hangfly; Mar 20, 2015 at 01:48 PM. Reason: sp
Senior Member
Superstock
Joined: Mar 2015
Posts: 409
From: Central CA
Since I had an extra TPS with a broken shaft (not by me 
) I decided to open it up.
I used a shop sander to take the top plastic lid off.
I expected wear on the poteniometer and wiper arm. But this one looks nice inside. Not sure of the mileage on this part since I received it as an extra when I recently purchased the bike.
The bottom photo shows the moving part on the left which is connected to the shaft which extends out the back.
) I decided to open it up. I used a shop sander to take the top plastic lid off.
I expected wear on the poteniometer and wiper arm. But this one looks nice inside. Not sure of the mileage on this part since I received it as an extra when I recently purchased the bike.
The bottom photo shows the moving part on the left which is connected to the shaft which extends out the back.
Last edited by Hangfly; Mar 20, 2015 at 12:48 PM. Reason: grammar
Senior Member
Superstock
Joined: Jul 2018
Posts: 277
From: Champaign, IL
Thanks!
While I see this thread has not has a response for almost 4 years, I found it very useful. My new--to-me '99 with 7k had 900 ohms with a Factory Stage 1 and Two Brother's cans.
Can't wait to see how much this may help that low end stumble. And...I get to install some very good looking brass Valve Starter ferrules....crap.
Can't wait to see how much this may help that low end stumble. And...I get to install some very good looking brass Valve Starter ferrules....crap.
Moderator
MotoGP
Joined: Jul 2007
Posts: 5,219
From: Gettysburg, Pa
While I see this thread has not has a response for almost 4 years, I found it very useful. My new--to-me '99 with 7k had 900 ohms with a Factory Stage 1 and Two Brother's cans.
Can't wait to see how much this may help that low end stumble. And...I get to install some very good looking brass Valve Starter ferrules....crap.
Can't wait to see how much this may help that low end stumble. And...I get to install some very good looking brass Valve Starter ferrules....crap.
