Currently replacing TPS sensor, TBs are out. What else?

[Bixxer Bob]

Well,,,,, I didn't remove them to do mine.  But there again, I didn't have to change any shims either.  Where does it say to remove them?

[haroldo_psf]

I thought I had read in the sticky TB removal "how to" thread that it was necessary for valve adjustment/inspection, but now I went back there, and I think I was smoking something, because I can't find it!

So, the TBs don't need to come out I guess, which is good! Thanks

One more highjack real quick...

After I replaced my TPS, the bike is running so nicely that I get scared thinking about how bad it was before.

Is it possible for a bad TPS sensor to cause permanent damage to the engine? I mean, if the TPS is as bad as mine was, the engine must be constantly running with the wrong A/F ratio...That can't be good.

Has anyone experienced bad things from a TPS (I mean, a burnt valve or something)?

[walker]

maybe check your plugs, as they might get fouled, run hot, electrodes burned, etc .... but if those are fine, and the bike runs good, ride it till it dies! :)

I'm not sure why it says to remove the throttle bodies. I never did and did not have a problem. Maybe it's some easier way to remove the valve cover with the intake off? dunno.

[Bixxer Bob]

Is it possible for a bad TPS sensor to cause permanent damage to the engine? I mean, if the TPS is as bad as mine was, the engine must be constantly running with the wrong A/F ratio...That can't be good.

I can see what you're getting at H, but the bad TPS simply gives a dirty signal to the ECU so the ECU isn't sure which part of the map to use.  For example, if you watch a bad TPS on tuneboy, instead of using the correct value for engine load / throttle position it'll be jumping around - mine was leaping two values in either direction of where it should have been.  Although it gives a lumpy ride, the values are not so far out that the engine is going to be massively rich or lean so I don't think you have anything to worry about.  As the man says, just ride it.

One other point,,,,,  if it was that bad, it could be that you've inadvertently cured another common problem on 955i engines; that of the leaky TB gasket.  If the TB gasket is leaking you'll get enough air going by to upset low revs, but not enough to make any difference higher up the rev range.  Again, although the extra air makes for lumpy running, it's not so lean that it'll do any damage.  If it was that lean it wouldn't run at low revs at all.

[haroldo_psf]

Is it possible for a bad TPS sensor to cause permanent damage to the engine? I mean, if the TPS is as bad as mine was, the engine must be constantly running with the wrong A/F ratio...That can't be good.

I can see what you're getting at H, but the bad TPS simply gives a dirty signal to the ECU so the ECU isn't sure which part of the map to use.  For example, if you watch a bad TPS on tuneboy, instead of using the correct value for engine load / throttle position it'll be jumping around - mine was leaping two values in either direction of where it should have been.  Although it gives a lumpy ride, the values are not so far out that the engine is going to be massively rich or lean so I don't think you have anything to worry about.  As the man says, just ride it.

One other point,,,,,  if it was that bad, it could be that you've inadvertently cured another common problem on 955i engines; that of the leaky TB gasket.  If the TB gasket is leaking you'll get enough air going by to upset low revs, but not enough to make any difference higher up the rev range.  Again, although the extra air makes for lumpy running, it's not so lean that it'll do any damage.  If it was that lean it wouldn't run at low revs at all.

Bob,

 Those are good points. Thanks! About the leaky gasket...When I removed the TBs, there was no gasket per say...There was some remaining material that looked like a very thin redish film that was intermitently present along the mating surfaces... So, either whoever removed the TBs in the past did not put a gasket in there, or the gaskets tend to desintegrate over time? For those of you who have removed the TBs, how does the old gasket look like?

[Bixxer Bob]

The old TB gasket is normal greyish gasket material, about 0.5mm thick, there's no way it could just "disappear".  You didn't have one and I'd put money on that being the main source of your woes.