Angular sensor (gear position sensor)

[stevencovert]

OK, so my wife's 2008 GS 990 VTwin did the "I'm gonna stay in 2nd or 3rd gear and keep you there" thing, until the computer is off and resets. Then it would shift down by itself on the next start. Finally got an "E" on the dash. Ordered a new sensor. It is just a potentiometer in a plastic case that probably gets dirty. Go to replace it and find like a 1/4 of it is behind the front sprocket with maybe a 2mm gap! Oh Joy! Even if I could get the bolt out right under the sprocket, the sensor's case wouldn't slip off.

I've read the threads about checking for the red dust on the sprocket, and using locktite to replace the bolt, etc. but I didn't see a good recommendation on how to pull it off. It looks like I have to loosen the rear wheel to get slack on the belt. Then hope I can loosen the bolt. Is it normal counterclockwise? Then the trick of getting the belt lined up by jacking up the rear, dropping it to check tension, etc. I saw a video where a guy adjusted the belt position & tension, that should help afterwards.

I am half tempted to drill a tiny hole near the top and blast it with contact cleaner, go from R to 1st a few times and blow it out. If it was easy to pull I'd just hook it up to cordless drill and spin it for a minute. Probably clear off the spots where it stops of junk.

So anyone that has changed this guy, any advice is appreciated! This is the last problem before I can hand it over to the wife knowing it is 100% !!


Thanks!
Steve

[hypurone]

I am half tempted to drill a tiny hole near the top and blast it with contact cleaner, go from R to 1st a few times and blow it out. If it was easy to pull I'd just hook it up to cordless drill and spin it for a minute. Probably clear off the spots where it stops of junk.

Thanks!
Steve

It's worth a shot. My 2015 F3-S had it replaced under warranty (was having no probs but since they sent me something to come in and do it, wth) and it was all about moisture in the sensor. I have never used water to wash the byke with but the dealer may have and there was water in mine! So maybe getting it "dried out" might help things.... Instead of drilling a hole where more moisture could enter down the road, maybe just pull the cover back to gain whatever access you can and spray thru that gap? It wouldn't take much to get the spray tube that most cans have in there. You could then put something in there to hold the cover open a bit for it to air dry as well....

[Freddy]

Don't touch the wheel adjusters or axle bolt, simply jack the trike up until the rear wheel is just touching the ground, remove the lower shock absorber bolt, raise jack higher until belt can be slipped of rear pulley then front pulley - but firstly you need to loosen the drive pulley retaining bolt while the brakes are applies. After replacing the GPS retighten the pulley bolt to 110ft lb (which is a little higher than the revised spec) with a little Loctite on the thread. That bolt head should have a X marked on it if it was torqued higher as a result of service bulletin some year back. I wouldn't recommend trying to 'repair' the GPS, whether or not it's the cause of the trouble.

[stevencovert]

Don't touch the wheel adjusters or axle bolt, simply jack the trike up until the rear wheel is just touching the ground, remove the lower shock absorber bolt, raise jack higher until belt can be slipped of rear pulley then front pulley - but firstly you need to loosen the drive pulley retaining bolt while the brakes are applies. After replacing the GPS retighten the pulley bolt to 110ft lb (which is a little higher than the revised spec) with a little Loctite on the thread. That bolt head should have a X marked on it if it was torqued higher as a result of service bulletin some year back. I wouldn't recommend trying to 'repair' the GPS, whether or not it's the cause of the trouble.

Thanks Freddy. Bolt is shiny, no X. But does have 10.3 I think on it, pretty hardened. I would have never thought of the shock. Not so worried about alignment now.

EDIT: Well I am trying the jack trick, but that shock bolt is super tight! The sprocket bolt came off with LITTLE effort, was just holding the socket wrench in place grabbing a cheater and bloop! So that was worth it, that bolt had NO torques on it.

[Freddy]

Thanks Freddy. Bolt is shiny, no X. But does have 10.3 I think on it, pretty hardened. I would have never thought of the shock. Not so worried about alignment now.

EDIT: Well I am trying the jack trick, but that shock bolt is super tight! The sprocket bolt came off with LITTLE effort, was just holding the socket wrench in place grabbing a cheater and bloop! So that was worth it, that bolt had NO torques on it.

Yes there were a number of pulley/shaft failures because of that - happening all over again on the F3 now.

[stevencovert]

So, after all that work to get the sprocket off and replace the sensor, the Spyder acted weird again. The old GPS sensor rattled when I shook it, and the shaft wobbled in the hole so it was definitely toast. Was made be Nin-something. The new one was marked as "Rotax." I backed down the drive a few feet, then went into first and went forward a couple time without issue. Went out on the road and I swear it was a gear off, engine was lagging hard. I know I got the sensor in right, can't fit unless it's lined up. No errors. Shut it off, waited a few then back on and it was better. Went on a short ride around town was great until I got on it a bit then it stuck in 2nd. Did the wait and start then it was OK. The sensor was new sealed in a bag, stamped 2009. Got home no problem.

I checked the usual things and did see the oil was bit high, about 1/4" above the full. Maybe that's it. I'll drain a bit. Maybe getting on the throttle is doing something. If it ever gets warm out, I'll see if it still gets stuck in gear. I can't imagine anything else other than the sensor.

[hypurone]

So, after all that work to get the sprocket off and replace the sensor, the Spyder acted weird again. The old GPS sensor rattled when I shook it, and the shaft wobbled in the hole so it was definitely toast. Was made be Nin-something. The new one was marked as "Rotax." I backed down the drive a few feet, then went into first and went forward a couple time without issue. Went out on the road and I swear it was a gear off, engine was lagging hard. I know I got the sensor in right, can't fit unless it's lined up. No errors. Shut it off, waited a few then back on and it was better. Went on a short ride around town was great until I got on it a bit then it stuck in 2nd. Did the wait and start then it was OK. The sensor was new sealed in a bag, stamped 2009. Got home no problem.

I checked the usual things and did see the oil was bit high, about 1/4" above the full. Maybe that's it. I'll drain a bit. Maybe getting on the throttle is doing something. If it ever gets warm out, I'll see if it still gets stuck in gear. I can't imagine anything else other than the sensor.

Mine had to be calibrated via the BUDS according to the service manager, so maybe yours is simply "relearning"....

[Freddy]

No mention of the above in service manual for RS/GS but the transmission must be in neutral. What I would try with the ignition off and trans in neutral is unplugging the GPS connector, then replugging the connector to ensure that at next key-on, the signal sent from the GPS really is neutral.

Good luck with it Steve.

[stevencovert]

Just attaching a note here for future searches on gear position sensor. I jacked up the bike very slowly until the rear shock bolt came off easily, then jacked on up quit a bit. Belt was sagging, easy to get off. Pulled off the front pulley (took a lot of wiggling). Replaced the sensor. Replaced bolt to 110 ft-lbs with locktite. Bike ran like crap, then started to clear up a bit. Broke out the service manual.

It says after replacing the TPS (Throttle position sensor) or the GBPS (gearbox position sensor) you have the connect to BUDS to reset the values. This is called "Closed Throttle and Gear Position Sensor Reset" (page 311 of the 2008 - 2011 Service Manual; in the Electronic Fuel Injection Chapter). It says to put bike in Neutral, roll the throttle a couple times to settle it out, and click a button. I'm sure a dealer will be like "OK done that'll be $300!!".

When changing the gearbox sensor, the voltage read while in Neutral will change a little. The computer calculates what gear the bike is in based on this starting point. The computer keeps adjusting the Neutral position as the sensor gets grimy. If too far off it throws that "E" on the dash. A new sensor reading is off now, and the computer struggles to adjust (I'm guessing), so maybe that is why after a few runs the bike shifts decently but not perfect yet. So I'm scheduling an inspection & this to be done, hoping to hover over the technician so he can't put down three hours' labor

[Freddy]

snip>

It says after replacing the TPS (Throttle position sensor) or the GBPS (gearbox position sensor) you have the connect to BUDS to reset the values. This is called "Closed Throttle and Gear Position Sensor Reset" (page 311 of the 2008 - 2011 Service Manual; in the Electronic Fuel Injection Chapter). It says to put bike in Neutral, roll the throttle a couple times to settle it out, and click a button. I'm sure a dealer will be like "OK done that'll be $300!!". <snip

Good find Steve. No such mention in the 'remove & replace' section of the SM where I looked. I replaced my GBPS some years back without issue.

[Jdr00ejr]

Where did this land? Needing to replace the GBPS on my wife's 2011 RT. A few questions based on what I'm reading:

1) Manual says to discard and replace the Front Sprocket Screw - do you guys trash them and buy new? If so do you have a part number?
2) What kind of Locktite did you use? Blue, Red?
3) Do I really needs to take it to a dealer for a BUDS reset? :-(

[Freddy]

Get a new bolt, it comes with thread locker on it. The other answers are above.

[youngers]

wondering how the cycle is doing now ? did you get it too the service guys , and reset the g/p/s sensor ?

[youngers]

this gear position dealiee do thing { gear postion sensor } , I wondered , there is a spring in the housing , and the sensor pushes against it ? how much is the sensor ? and would it be cost effective to just replace the spring ( the thinking seems to be , the spring is loosing its push back value --- getting weak , I may have to investigate this a bit further !

[stevencovert]

this gear position dealiee do thing { gear postion sensor } , I wondered , there is a spring in the housing , and the sensor pushes against it ? how much is the sensor ? and would it be cost effective to just replace the spring ( the thinking seems to be , the spring is loosing its push back value --- getting weak , I may have to investigate this a bit further !

The shaft coming out of the engine has a flat on it. This flat lines up with the sensor. No springs. As the Spyder changes gear the rotation of the shaft changes. This changes the feedback voltage to the computer. I don't know HOW, but over time the plastic wears out and the rotating part gets sloppy. This gives wrong feedback.

As it gets worse, the computer tries to keep up, but eventually throws the "E" error on the LCD screen. When a new sensor goes in, the feedbacks the computer is expecting are all way wrong and the bike runs TERRIBLE. I think I was 2nd when it said 1st. Right after the dealer cleared the sensor and the computer learned the new setpoints (a few minutes up and down the road shifting gears) it ran great and shifted great.

In my case I still get a weird problem with the bike going in limp mode (I guess, it doesn't say anything on screen). It gets limited to 2500 RPM. So now I am changing the throttle position sensor. Both these sensors get reset with the BUDS software, I wish I had just replaced both sensors and been done. The gearbox sensor was around $140 and the throttle was maybe $110 or so. I'd swap them both out if you can, they WILL eventually fail. I have 27K miles on my 2008 GS.

I did NOT replace the bolt, I have one on order. Only put about 20 miles on it with re-used bolt. I used red locktite, as you do want to be able to service the bike at a later date.


Steve

[Jdr00ejr]

The shaft coming out of the engine has a flat on it. This flat lines up with the sensor. No springs. As the Spyder changes gear the rotation of the shaft changes. This changes the feedback voltage to the computer. I don't know HOW, but over time the plastic wears out and the rotating part gets sloppy. This gives wrong feedback.

As it gets worse, the computer tries to keep up, but eventually throws the "E" error on the LCD screen. When a new sensor goes in, the feedbacks the computer is expecting are all way wrong and the bike runs TERRIBLE. I think I was 2nd when it said 1st. Right after the dealer cleared the sensor and the computer learned the new setpoints (a few minutes up and down the road shifting gears) it ran great and shifted great.

In my case I still get a weird problem with the bike going in limp mode (I guess, it doesn't say anything on screen). It gets limited to 2500 RPM. So now I am changing the throttle position sensor. Both these sensors get reset with the BUDS software, I wish I had just replaced both sensors and been done. The gearbox sensor was around $140 and the throttle was maybe $110 or so. I'd swap them both out if you can, they WILL eventually fail. I have 27K miles on my 2008 GS.

I did NOT replace the bolt, I have one on order. Only put about 20 miles on it with re-used bolt. I used red locktite, as you do want to be able to service the bike at a later date.


Steve

Thank you! I bought the sensor but haven't started to replace it yet. With Spyderfest coming up - not sure if we can get it into the dealer before we leave to do the reset. I'm guessing the reset is very quick, but don't know their availability.

I'm hoping the removing the shock trick allows me to take the front pulley off and back on without changing the belt tension. We will see.

I thought the red locktite was the permanent must use heat stuff?

[stevencovert]

Thank you! I bought the sensor but haven't started to replace it yet. With Spyderfest coming up - not sure if we can get it into the dealer before we leave to do the reset. I'm guessing the reset is very quick, but don't know their availability.

I'm hoping the removing the shock trick allows me to take the front pulley off and back on without changing the belt tension. We will see.

I thought the red locktite was the permanent must use heat stuff?

Yes you are correct!! I meant to say BLUE!! Torque to 110lbs per service bulletin many years ago.