All
Do you have the bolt and washer upgrade? The stock washer can deform when tightened.
I lapped my rotor to the crank with valve grinding compound and then used the thicker washer and have not had the rotor come loose before
heat rotor to 220-250F in an oven for at least 20 minutes. clean crank taper and then put rotor on crank (with oven mitts or thick gloves.. move fast). zip down with air gun. use thick washer as stated, 3-6mm thick minimally. let cool down will shrink on taper. i never, ever get slipping out of the 4 bikes i have them on currently.
Mine slipped a couple times after I did my first installation, then I got my crank rebuilt (they cleaned up the taper). I reinstalled it with upgraded bolt/washer kit and it's been dead nuts since. Thousands of miles and 2 years since the last adjustment.
Torque the crank/rotor bolt to 15ft/lbs.
You need a key way slot done by a competent machinist to address this "defect". The Vape rotors are ok for low revving 4strojes. Yamaha had a reason to have all of their 2stroke rotors with a keyway slot....
that's a common belief.. but also technically very incorrect. the keyway is for alignment on assembly, not holding it. the crank is tapered specifically to hold it tighter than even a keyed straight shaft. an interference taper fit is far stronger than a straight one with a single key, as long as its torqued correctly and the tapers are in good shape. fwiw, the factory race ignitions didn't have keyways either.
it would have been WAY cheaper to machine a straight shaft than a tapered one, it was done exactly for this reason.
the primary side is straight because it side loads under accel/decel, and would not work w a taper. the ign side however has zero side load so a taper is fine.
if you don't believe me, look up a morse taper on machine tools.
Quote from: RD350NL on March 09, 2025, 02:58:56 PMAll
Unfortunately I burnt a hole in my pistons (+ crank damage) because the vape ignition didnt maintain its timing. This is already the second time the flywheel moves on the crank during operation causing the timing to be way off.
Last time it happened I was close to home so could drive it back but now I was further away from home and despite driving slowly the temperatures became too high. Yes, I should not have driven it back in hindsight but I thought it was a carb issue as I couldnt believe the timing would be off again (torqued the bolt really well).
Is this a familiar issue with these ignitions? How can I prevent this from happening in the future?
Much appreciated.
I had one fall apart while riding at my first meet at the gap.
Economy Cycles warrantied it.
The second one slipped timing and I seized my motor.
I was not the one to install it, but I feel the issue with the slipped timing was not correctly tightening the bolt.
when it was re-done, it was heated as directed by Mark, and torqued while being held by a homemade "holder" and red lock tight was used. no more issues.
good luck. great system.