A completely-gutted MT125 pipe should be an absolute low-mid
beast, with much-improved top end as well. If your MT pipe is louder than it was but has only a weak mid-top powerband, you may have removed the spark arrestor section (rear of the pipe, ahead of the tailpipe) but not the center baffle (middle of the pipe, above the center frame mount ahead of the toolbox). Sorry, I should have gone into more detail but I didn't think you would actually do it
as it's a fair amount of work, but the payoff is big as well. If there are two round welds on the back of the MT pipe about 11.5" - 12" ahead of the body/tailpipe weld seam, the center baffle is still in place (and killing power everywhere). It's also important the clean-out plate below the '361' stamped on the pipe side is installed & sealed; I welded a plate over the hole. The MT pipe tucks in great, especially with the heat shield removed and a few small tweaks to the mounts. If you decide to go with the snail pipe that should be OK, but the modified MT pipe will have more power over a wider range if it's working right.
The CR125M ignition installation is two parts: replace the MR stator/cable/flywheel with the CR ones (pretty easy), then replace the MR coil with the CR CDI box and coil (not as easy). Below is a composite photo of how I did it:
http://i399.photobucket.com/albums/pp74 ... 1754-1.jpgHere's another thread that has CR-ignition info - if you search "cr125m ignition" you should find more:
viewtopic.php?f=21&t=3771&hilit=cr125m+ignition&sid=ad03385ea218af4377af4eb6b9236a3e#p13002I don't think I'd try the XL ignition swap, even if it has CDI and lighting. A four-stroke motor needs more ignition advance with increasing rpm, while 2-strokes need the reverse.
Ray