Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater

Sun, 17 Aug 2014

Savage Beast: Tamed - How to Adjust the Throttle Position Sensor on a 2008 SV650

I followed through with the TPS adjustment procedure on my 2008 Suzuki SV650 today, and it certainly made a difference. This is your guide to doing the same thing.

First off, if you haven't already, go read the full write-up on sv650.org. I am only giving you the addendums to that excellent write-up. Do read through the whole thing.

There are three key and very important changes you need to know about, for any 2007 and onward SV650.

1. The Dealer Mode plug is in a different place.

2. There is no idle speed adjustment.

3. There are two TPS sensors now.

So, the procedure:

  1. Warm the bike up to normal operating temperature. On my 49-state bike, that seems to be about 170-175 °F. I recommend a short ride.

  2. Turn off the bike.

  3. Now comes the first difference: remove the main seat, and you'll find the Dealer Mode plug on the left side, toward the back. You can reach through from the passenger seat opening to grab it if you have a hard time getting both hands in there.

  4. Insert the Dealer Mode Tool (ie, length of wire) into the pin locations indicated in the sv650.org writeup.

  5. Turn the key on, and verify that you're in Dealer Mode. The temperature display will switch from its normal indication to -C00 (or something similar). If you see a number other than 00, you have a fault. Check with this list to see what the number means.

  6. With the motor still off, turn the throttle grip slowly until you see the little line move from the middle position to the top. If you had to move the throttle more than a couple of degrees, you'll be wanting to do the adjustment.

  7. Lift and prop the tank as described.

  8. Start the motor and slowly rotate the throttle until you see the line shift from the middle position to the top position. Note the RPM for future bragging rights (mine was at about 3200 RPM). The higher this number, the happier you will be with the change. Kill the motor for this next part, but leave the key on (it's hot enough already). If it switches around 1500 RPM, you're already done.

  9. Using your trusty T25 security Torx bit, which has been loaded into a shorty socket wrench using a 1/4" socket (don't drop it), unscrew the one and only screw on the rear TPS sensor -- it's only got one screw, and is a little thing compared to the big beastie just forward of it. It's also the only one with a T25 security Torx screw.

  10. Without touching the throttle grip, move the sensor body up and down until you see the the Dealer Mode display just barely shift to the upper line. It is slow to react. It takes about .2mm of movement. Be patient and gentle.

  11. Now, move the TPS body in the opposite direction by the thickness of a gnat's wing. Seriously, like .05mm. Almost nothing. The line should just barely drop down to the middle segment.

  12. This is more or less the right adjustment. Basically, you want the middle segment showing at idle, and the instant you're off idle, it should shift to the upper segment. For fun, start the motor and see where it shifts, but as long as it's in the middle at idle, and shifts to the upper line once you add a tiny bit of throttle, it's right.

  13. Tighten down the T25 screw, and test to make sure that you're still seeing the middle segment with no throttle, and it jumps to the top as soon as you add throttle (move the throttle very slowly). You may have to adjust and tighten several times to get it right.

That's it. Put everything back where you found it, and go try it out. The difference won't make you scream with delight, but you'll notice that suddenly the bike is a lot less twitchy at small throttle openings -- that is, in traffic, where it's the most annoying thing to have the bike surge forward at the slightest touch of throttle. It's still got that monster power you want, but you have to actually give it some gas to make that happen. Much nicer.

Note that Suzuki kindly included an automatic idle speed system on these bikes, and it may kick the idle up to 2000 RPM while you're adjusting the TPS. This is normal, and it will return to its normal and correct ~1200 RPM idle once you're done. There is no adjustment for idle speed available to us.

If you don't like the change, you now know how to change it back.

This will make your fuel mileage a little bit worse (it's adding more fuel at a smaller throttle opening now), but the difference in a calmer, more sane bike is worth it.

Posted at 20:09 permanent link category: /motorcycle


Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater