Throttle Position Sensor and Shop Manual Error

Anyone here ever tried to adjust the throttle position sensor on a 2nd gen (or even just check the closed throttle measurement)? I think I found another significant error in the shop manual, but I would like to compare notes with others who may have already gone there.

Page 6-13 of my shop manual describes how to calculate the proper maximum resistance of the sensor in the throttle fully closed position (typically around 700 ohms), then they instruct you to measure this resistance between the yellow and blue wires. Well, the resistance between the yellow and blue wires is HIGH in the fully closed position and goes down as you open the throttle. You get the correct low resistance with the throttle fully closed when measured between the yellow and BLACK wires.

Just for the record, the TPS on my 05 was reading a bit high in the fully closed position, and it could not be adjusted down within specs - close, but not quite low enough (calculation showed it should have been between 629 - 726 ohms. It started at 778 ohms and I could not get it below 752 ohms). I have not researched this circuit yet to know how this should affect the bike. I'll let y'all know more when I figure it out.

Goose

I think we would all be a mess without Goose's adept mechanical ability!

I saw that method of testing in the manual a couple of weeks ago when I was checking my bike trying to find my problem. I never did check the resistance. When I where it said that it was not adjustable and would need replacing if bad, I decided to just focus on the other things first. Next time I get a chance, I'll see what mine reads.

Wow, you really have too much time on your hands. Do you peruse through the shop manuals just looking for errors? Wanna know another one? Pick up a V Max shop manual and look up what the firing order is. Why is it different than our engine, and how can it possibly be different when the cams interchange? I've heard tell that some 1st gen manuals have this wrong too.

What the TPS does is adjust the spark timing based on engine load. Under constant cruise the spark should advance for better gas mileage. Under WOT is should be retarded to avoid detonation. Exactly where the shift occurs is not real critical, as long as all spark advance is gone under WOT. I've never checked mine with a VOM. I have checked it with the status LED on the D3K. As long as the status of the LED changes at about half throttle, it's good. If you don't have a D3K, get one. The TPS is adjustable, but it takes special bits to loosen the screws. Vise grips will loosen them also, and then regular screws can be put in. Unless you're having detonation problems at part throttle, you will never see or feel any difference in the bike's operation by playing with this thing.

Where did you find the info that it is adjustable, unless I missed it, the service manual just says that it must be replace if it's out of spec.

I don't know what the manual has to say about it. I don't read the manual for much more than bolt torque specs. I look at the thing and I see that the mounting holes are slotted for position adjustment. Then they used security screws to keep folks from playing with it. They set it at the factory and probably don't intend for it to ever be adjusted again. Once it's set up the first time, it normally won't ever need it.

The screws are simply tamper-resistant Torx T20 screws (with the post in the middle). The manual says you have to lift the carb assembly up to get to them. This is mostly true, but if you just use a Torx bit without the screwdriver attached, you can get the bit in the screw head and then turn it with a 1/4" open end wrench without removing anything except the fuel tank. The measurement and adjustment procedure is in the Carb section, starting on page 6-11. The sensor itself cannot be adjusted if the total resistance is out of range, but the sensor rotates a bit in the mounted position to enable you to set the correct resistance with the throttle fully closed. You will need a digital ohm meter to reasonably make this calculation and adjustment; although, a high quality analog meter should work if that is all you have.

Goose

My 06 RSV had a TPS that was not in spec either. I had to take the TPS out, remove the metal oblong inserts and file them to obtain a better reading. I set the TPS on the high side and the bike does have more mid range power. My low end is still poor. If you look in the owner’s manual under specs, you will find a statement in the timing area that at 3500 RPM you should be at 45 deg. BTDC. (off the top of my head). The oil flies out of the timing hole above idle so I am going to try and make a plexiglass plug to fit the hole and check the statement. HMMMMMMM!!! ???? Does the TPS and Speed sensor set up the timing curve???????