Engine swap now engine backfire

[wvdealz]

Thanks for all the advice

 

[SabrToothSqrl]

psstt: https://www.youtube.com/watch?v=J3YNK32HAws

 

[Minnetonka4me]

psstt: https://www.youtube.com/watch?v=J3YNK32HAws

Your very last sentence....boom. I just dont like seeing mis-information posted for someone else to come across and take as correct. The 98 is different than the 99 and up. But...as this thread shows...people can swap stuff from another parts ski, hell people swap vins from time to time too. You never really know whats been done to a 20 year old machine.

 

[Sportster-2001-951C-Stock]

Yeah, the 99 flywheel had 2 long magnets and the 2000 had one long and 3 short magnets.

This is interesting and helpful to have the detail, thanks!

 

[SabrToothSqrl]

This is interesting and helpful to have the detail, thanks!

That is not correct.

98 has 2 long strips and is a single coil.
99-02 is 3 small and one long. Dual coil.

 

[Sportster-2001-951C-Stock]

That is not correct.

98 has 2 long strips and is a single coil.
99-02 is 3 small and one long. Dual coil.

There must be some sort of exception and that's okay with me b/c factories sometimes do that at production run changes. I have a clear understanding thanks to the OP just explained it all:

Summary (it is what it is!):
0) Donor ski ran fine
1) Donor ski has 2 separate coils
2) Donor ski had 2 long magnets on wheel
3) Donor engine would not run using target ski electronics
4)Target ski has two separate coils.
5) Swapping flywheel to 4 magnet type resolved the problem.
6) Whatever you want it to be floats ur boat.

To me, mystery is resolved and now I know the difference between the flywheels thus what to look for in case this comes up again. Also important, OP has his ski running (win-win, soup for all!).

 

[SabrToothSqrl]

I'm glad it works, just want to be factual.

The donor ski was a 1998 XP in the above scenario.

I believe issue is the term 'coil'. As I haven't opened a 1998 ebox, which has a connector on top (vs only on sides of the 1999-02) it may contain two coils, however the plugs on that one would both fire at the same time.

So it would be correct that it's 'dual coil' however it's still wasting a spark, as it's triggering both plugs every time, which is the only option when you only have 2 points of reference on the magneto. you can't tell the computer anything other than when to spark, so you can't tell it which one to spark, so you spark both.

I'd have to see inside a 98 e-box to confirm.

I should have worded it like this: 951 carb engine:

97.5 to 98 has two long tabs on the magneto, and uses a wasted spark system

99-02 uses 1 long and 3 small, and does not use a wasted spark system

also the 00 or 01 adds a TPS as well, I don't think the 98 has that...
something else to consider for the swap. i think it either does or doesn't show 5v below 90% throttle, then the opposite above. 3 wires, black, white, purple, but it's been a while since I looked at one.

ohh and the 01 added a rubber gasket between the exhaust manifold and pipe to seal better. it uses a newer manifold. those are the ones I run.

 

[jburke-007]

Sounds like timing is off

 

[Sportster-2001-951C-Stock]

Yep, I believe you're correct the 00 was first year of throttle position switch (TPS). Not sure if the flywheel magnets were rearranged for that or if just the MPEM but sounds like just MPEM assuming carbed '99-on use same flywheel.

Wasted spark ignition strategy would only need two magnets but cylinder specific would need additional magnets to identify #1 compression stroke.