Help KTM Issue dies when opening throttle and pinging (2000 KTM 300 EXC)

pablopic999

Member
Nov 4, 2024
1
0
Top end rebuilt (Millenium nikasil resurfaced and matched to piston), performed leak down test – broke it in per spec around the neighborhood over several months before taking it to the local trails one time to test out the bike. (I had another 300 which is what I rode then sold it to focus on this project.) Bike idled and ran well but still need to service suspension to make it my regular bike. Note that I added new reeds after the top end rebuild
The bike has a flywheel weight and I added a G2 throttle tamer to mellow out the bike for trails.
Rode the bike before adding the tamer and all went well. After I added the G2, I took it for a spin and noticed it revved higher than expected (I have installed a tamer before on another bike and had no issues). Pulled into driveway and noted very high idle and kill switch was not working. Noticed the coolant was starting to expel from overflow hose and shut off gas and stopped the bike. All within 2-3 minutes!
I figured I installed the tamer incorrectly, so re-installed it. Also ordered a cheap kill switch and installed it. I added coolant and started the bike to test the kill switch, and it worked, but not before attempting to give it throttle, where it died. At this point, I also noted a rattle versus the purr which I had prior to this fiasco.
Removed pipe to make sure I didn’t overheat and/or scour the piston, checked the plug – which was fouled and wet. Cleaned the spark plug and reinstalled after checking compression.
Any solution here? Going to check the exhaust packing as soon as possible.
Could I have “soaked the exhaust packing” in two minutes of high rev? Would that matter…
Stator? Crank bearing Fail? Air Leak? Please shoot over any ideas before I remove top end and start over
Thanks in advance for getting this far…
 
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