How to replace your crank shaft position sensor

[haroldo_psf]

I going to do this tonight, and it seems pretty straight forward. I will post pictures and description while I'm at it.

The only part that I'm wondering about is when I need to adjust the sensor gap to the crankshaft alignment mark.

If I have the bike in gear on the centerstand, is it a good idea to spin the engine by spinning the rear wheel? Or should I use a nut on the crank bolt? I'm afraid to knock it loose, even though I will only spin it clockwise. I will not need to remove the tank to do this, so the spark plugs will be in, and I will be fighting compression...

How do you guys do this during your valve adjust, do you just use the rear wheel or the crank nut?

Also, from this picture, I can't see how the gap can be adjusted once the sensor is screwed in there, but I guess I'll find out tonight when I get into it.

[jwray76]

Not on my Tiger since I haven't actually taken delivery of it yet, but on other bikes I usually turn it over by putting the bike in high gear and spinning the rear wheel. Gonna be tough to get it to stop were you want with the plugs in though. I am guessing with the right wrench that the plugs can come out with the tank in place. Just guessing though since I haven't worked on a tiger yet.

[John Stenhouse]

Plugs out with the tank on.....................no way no how. Wait til yours arrives then have a look, packaged too tight for anything to get in there.

[jwray76]

^well I guess I shall find out then.

[haroldo_psf]

Ok, mission accomplished!

Here is the step by step, and a few key points to be aware.

1) Warm up the engine and drain the oil.

2) Remove Clutch cover. I don't know if some of my clutch cover screws have been replaced or not, but they were of slightly different length, and the service manual makes no mention of this. So I made a drawing of the clutch cover gasket on a piece of paper and laid the screws in their proper place.

[haroldo_psf]

3) I disconnected the sensor plug before actually popping the clutch cover off, so dirt wouldn't fall in there. I used a small flat screw driver to ply the securing metal clip up and pull it off.

[haroldo_psf]

4) Again, before pulling the cover off, give all the slack to the clutch cable, and slide the bead off the retaining bracket to disconnect it from the clutch cover.

[haroldo_psf]

5) Pop the clutch cover out. My old gasket pealed right off. If yours doesn't, clean both surfaces well before reassembly.

6) Remove the retaining crankshaft sensor bracket.

7) Pop the old crankshaft sensor grommet off the notch on the crankcase. Clean it well.

[haroldo_psf]

8) Transfer the new sensor onto the retaining bracket. DO NOT try to hold the retaining bracket while unscrewing the old sensor out. I did this, and to my horror, I bent the screw tabs on the retaining bracket. I freaked out mementarily thinking I would have to order a new one and wait. The service manual has very tight specs for the sensor placement (0.2mm to 1mm gap to the crankshaft teeth), so a slight bend on this bracket can mean disaster if thing make contact, or if they are not properly aligned. I then took a deep breath, straightened the bracket out as best as I could, and plowed ahead. Use an open end hex wrench to hold the bracket while you unscrew the torx with another wrench. It's awkward and it's hard to get it out, but it will come loose.

[haroldo_psf]

9) Put a bead of sensor safe high temp RTV sealant around the new sensor grommet and pop it into the grove. Screw the retaining bracket with the new sensor in, but don't tighten it all the way. Tighten it enough to keep it in place when you move it in order to achieve the proper gap.

You will need to shim the gap. The manual specifies 0.2mm to 1mm gap between the sensor and the teeth. The adjustment is very coarse, and you can spend some time sliding it back and forth. Have patiance. I achieved a gap of 0.4mm and stopped there.

[haroldo_psf]

10) I coated both surfaces with a thin layer of sensor safe high tem RTV (copper). This also helps hold the gasket in place before replacing the cover.

[haroldo_psf]

11) Put all the screws back on and tighten them across each other. The service manual specifies 9N.m (7ft-lbs). DON'T DO WHAT I DID. I used a cheap Harbor Freight torque wrench and in my excitement, I set it to 10FT-lbs... I snapped the head of one screw. The head is still there, although I know it's snapped. It is not leaking, so I will leave it there until next time that cover comes off then I'll replace it.
I also almost forgot a rag I put in there to cover the "death hole", or the hole that goes to the crank. I didn't want to drop a screw in there and have to drop the oil pan down... I actually started to assemble the cover then remember the rag was still there! HOLY CRAP! thank god I remembered it before firing it up!

12) Reconnect the clutch cable, reconnect the sensor, and you are done!

Observation: The service manual instructs you to disconnect the battery. I didn't, but you should. It also tells you to measure the gap specifically on the T1 marked tooth. I didn't, but you should.

CONCLUSION: IT FIXED MY CONFUSED IDLING!!!!!! Before it was lumpy, idling between 900 and 1000 rpm, sounded like it was missing a fire every now and then, and there was some knocking sounds. It is now idling at 1200, smooth as butter, no knocking, no confusion, no missing a beat! I LOVE IT!!!!!!!

[iansoady]

Sounds good.

One thing I've never understood is how the crankshaft sensor knows which stroke the engine is on so it can tell the right coil to fire (as there are two engine revolutions for each power stroke). The only way I can imagine is if the ECU detects the variation in engine speed due to each cylinder coming up to compression but this seems a bit hit-and-miss.

Anybody know?

[Mustang]

Sounds good.

One thing I've never understood is how the crankshaft sensor knows which stroke the engine is on so it can tell the right coil to fire (as there are two engine revolutions for each power stroke). The only way I can imagine is if the ECU detects the variation in engine speed due to each cylinder coming up to compression but this seems a bit hit-and-miss.

Anybody know?

it fires twice .once when it needs to and again on the exhaust stroke when it is not needed

[iansoady]

Ah. The old lost spark like the Boyer on my Commando. Thanks Mustang.