Grrrr HPI ignition failed me

[RDryan]

That really sucks man. Bless yourself only a piston is shot. Couple of months ago the flywheel of my vape ignition moved on the crank resulting in catastrophic engine failure (pistons, cylinders, complete crank). It felt like some dirt was blocking the main jet during operation, if I had only known..

Curious to understand the root cause of the damage you are facing. Looks like the rotor came loose from the crank?

How long did you have that set up installed? Curious I have the Vape on my RD. I got mine from HVC Cycles and opted for the machined keyway service although in theory that is not what holds the rotor secure to the crank but rather the taper. Can you recall if you used any kind of sealant as well to hold rotor onto the crank?

It happened within 100miles after install. The root cause was that I used a regular simple bolt with a simple washer, which did not provide sufficient pressure to the rotor to stay in position. Even though I used thread locker.

Resolution: Used a heavy duty bolt with a thick washer and torqued it to ~25nm. Its on it for over 750 miles now without any issue. No thread locker used.

Yeah I wanna say while I can relate technically I can't as the rotor has always had a happy marriage with the taper fit on her crank.

I did get lucky though and got tipped off to do this heavy washer kit whilst chasing jetting issues.https://www.economycycle.com/product/mzb-cdi-electronic-igntion-for-yamaha-rd250350400r5ds6ds7-street-version-hardware-upgrade/#

Is this what you got?

[RD350NL]

No I just sourced something locally

[RDryan]

No I just sourced something locally

Yeah that makes sense. I wanna say the kit is expensive especially if you needed just the kit and gotta pay for shipping but since I'm no expert I appreciate the knowledge that put it together. Actually I added another lock washer to that kit just because it seemed to make sense. Also I have a Vito's crank and a keyway was machined into the rotor to properly clock/locate it at 2 mm BTDC. Although my understanding is it's just for locating purposes and it's the taper that's really holding the rotor in place I like to think that the keyway helps. And I figure that it's possible the taper of the Vito's crank may have a better mating to the Vape rotor rather than stock. It's just funny how some parts work better with others and the opposite being true as well. Just slight differences in dimensions can make a big difference in how parts fit and work.   

[m in sc]

double washer can fail, it will fold. . use a thicker one. I make my own out of stainless, 3mm thick but mcmaster sells them (thick washers). also the one john sells w the kit is def good enough. ... ask how I know about the double washer not working. lol. you're going for the clamping force. as a general rule of thumb: square keys are load bearing, half moon ones are locating.

[RD350NL]

Dont use double washers, they will deform. Use one thick one.

[1976RD400C]

Color change on the new rotor.

[RDryan]

double washer can fail, it will fold. . use a thicker one. I make my own out of stainless, 3mm thick but mcmaster sells them (thick washers). also the one john sells w the kit is def good enough. ... ask how I know about the double washer not working. lol. you're going for the clamping force. as a general rule of thumb: square keys are load bearing, half moon ones are locating.

Dont use double washers, they will deform. Use one thick one.

Roger that and it totally makes sense. Good explanation...I think I will check out that rotor bolt as well as the stator plate bolts before the next ride just to make sure everything is torqued and well in the case of the rotor bolt proper hardware is used. I guess I figured adding the lock washer to the thick washer would help keep the bolt from loosening but in that regard all I need is the liquid thread lock. I did scribe Marks just to see if things stayed put a year ago when I was chasing a wiring short.

[1976RD400C]

I use a heat gun to warm the rotor up to just above too hot to touch right before installing.

[quocle603]

Sorry to hear man. I had my HPI fail on me. I think it ran too hot and the magnets did not like that. Got a new one and it was the wrong one and got a replacement and waiting to see if it blows up or not. I do love my hpi system though