kx ignition on a kdx

[chicoman]

I was thinking of putting a complete kx ignition on my kdx, problem is my kdx carb doesn't have the therottle position sensor or pumper. My questions are:
how does the TPS effect the ignition map?
Do I need the TPS or can I just tape up the connections? How will not having the TPS effect performance?
And finally will the kx's ignition map cause my kdx to ping or run bad?
Thanks.

 

[adam728]

What are you looking to gain with the KX ignition? What other mods does your bike have?

I'm not sure how the TPS effects the ignition's mapping on KX's, but I would have to say, if it is designed to work with it I sure wouldn't take it off (refering to the TPS). Different engines call for different timing curves.

If anything, swap everything over, including the carb. It will take tons of tuning time, a dyno would be almost mandatory, and in the end it could be a great mod, an alright mod, or actually cost you power and ridability.

 

[chicoman]

My main goal is a lighter flywheel for a quicker rev and more snap. I already have the kx ignition so my plan is to just bolt it on and see how it feels.

 

[adam728]

Again, what other mods do you have? Lighter flywheel will hurt ridability, there are other changes you can make that will give much more snap, such as porting, a modified head, pipe, bored carb, reeds, proper jetting, etc.

 

[chicoman]

No mods yet, I'm only going to try one at a time and considering I already have the parts, I might as well try the free one first. If I don't like it I can always take it off. Im hoping the lighter flywheel will make ridability more like a KX.

 

[gurt]

I think that you will probably run into a dead end trying to swap the ignitions. Like adam728 said, I would try porting,pipe,reeds, etc. I doubt the kx and kdx have the same timing so you will probably end up with a backfiring monster at best if you do swap.

 

[chicoman]

Ya, you guys are probably right. Besides, nothing lines up, the stators are different diameters, and all mounting holes are in the most inconvient places. But the crankshaft tapers are the same, so I'm doing it anyway. I'l let you know how it goes.

 

[adam728]

Good luck.

Just a pipe and proper jetting will probably make a much bigger difference than changing the ignition. Like I said, even if it all lines up, I am sure the timing curves are quite a bit different, especially if it happens to be a 125 ignition.