Backfire after CPS change

[Tonys]

My 2007 Yamaha attak did not start a day, checked the codes and bam ! Code 12 wich is crankshaft position sensor. Ordered it from rm stator and changed it. Fired up and ran well. About 3 miles later on the trail it starts to backfire a lot , but when I mean a lot I mean a lot , loosing revs and eventually not revving much so the clutch doesn’t engage anymore, I had to be WOP otherwise it would stalled. Towed it to the garage. Where do I start troubleshooting. I had to do some electric weld to put the new sensor and I put heat shrink as well. The weld seemed strong but I suspect that because it never did that before changing the sensor. Thanks in advance

 

[earthling]

Are you sure the stator is okay?

 

[Tonys]

Are you sure the stator is okay?

There was no burnt on the stator when I changed the cps and the battery was holding so I don’t think it is the problem. Here’s a pic of it. The weld in the cps wire isn’t my principal suspect anymore, I measured the resistance on the cps and it is the same as I measured when I got it.

 

[74Nitro]

Recheck your work. Did you secure the wire(s) properly inside and outside of the engine?
Also these are polarity sensitive, so try switching the wires.

 

[Stubbs]

Pickup coil gap is also critical, sometimes those RM Stator units need to be adjusted a little for good crank position sensing to the ECU.

 

[Tonys]

Pickup coil gap is also critical, sometimes those RM Stator units need to be adjusted a little for good crank position sensing to the ECU.

How do I adjust the gap. It is now throwing me code 12 again.

 

[Stubbs]

Double check the pickup Ohm reading is in spec with a DMM, if it is the pickup mounting holes may need to be slotted a little to reduce the pickup gap.

 

[74Nitro]

Double check the pickup Ohm reading is in spec with a DMM, if it is the pickup mounting holes may need to be slotted a little to reduce the pickup gap.

You're right about the gap, but a big gap won't cause a code imo.

 

[74Nitro]

How do I adjust the gap. It is now throwing me code 12 again.

Pull it apart again. I'd suspect you didn't fasten the wire properly and is damaged. Or your connections are faulty.

 

[Tonys]

Double check the pickup Ohm reading is in spec with a DMM, if it is the pickup mounting holes may need to be slotted a little to reduce the pickup gap.

Pull it apart again. I'd suspect you didn't fasten the wire properly and is damaged. Or your connections are faulty.

I’m currently doing that. The ohm reading was never in spec out of the box. It was around two hundred something. But the sled fired right after changing it and started doing the backfires/misfires 3 miles after. I currently have 213 ohm.

 

[Tonys]

I’m currently doing that. The ohm reading was never in spec out of the box. It was around two hundred something. But the sled fired right after changing it and started doing the backfires/misfires 3 miles after. I currently have 213 ohm.

Before changing it, the old cps was at 805 ohm

 

[Stubbs]

You're right about the gap, but a big gap won't cause a code imo.

You’re right, hadn’t thought about that long enough. A code 12 normally pops when that circuit has really high resistance or is completely open. Likely a damaged wiring/connection issue.

 

[74Nitro]

I’m currently doing that. The ohm reading was never in spec out of the box. It was around two hundred something. But the sled fired right after changing it and started doing the backfires/misfires 3 miles after. I currently have 213 ohm.

I think these are supposed to be 500ish ohm's.