Grrrr HPI ignition failed me

[1976RD400C]

Catastrophic HPI ignition failure wipes out my new top end. I freshened up my bike with new Wossner pistons. Ran good for the first 100 miles. I noticed it was a bit cack-cack-cacky on the pilot jet so when I got home, I turned the air screws out 1/2 turn and thought next time out we will see how that goes. A few days later off I go and notice something is not right, it's either lean or it is misfiring at lower rpms. I adjust the air screws back to where they were. Try again, something still is not right, it's misfiring at low rpm. Come home and pull the plugs and they are darker than usual. Hmmm, what's up with this thing. While the plugs were out, I checked compression. It should be 140 and the left side is 120. Pulled the left side and the piston is worn and the rings are shot. WTH? I just meticulously rebuilt this thing, checked the timing with a light, all was good. It was running ok just an occasional misfire. Then I pulled the ignition cover, grey dust everywhere. Pulled the rotor and said, oh my. My HPI self-destructed, threw my timing off, and fried my new pistons. The ignition is 8 years old, I emailed HPI and they said send pictures. Waiting to hear back. Kinda pissed $350 top end got ruined. 

[SoCal250]

  Oh man that sucks!

[m in sc]

the rotor Insert came loose? holy shit that's a new one

[RD350NL]

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?

[1976RD400C]

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?

The dark magnet ring that is in the rotor didn't stay put and began to move out. Then it ground away on the plate that holds the coils making a deep trench. Then the timing was off and the pistons got too hot. I'm surprised the only symptom was it started to misfire at low rpm.

[1976RD400C]

HPI says too old to warranty, just buy a new one. Seems like 8 years of heat and the glue didn't hold. I'm afraid to try to green Loctite it back in, plus it must be damaged from rubbing so much. Shit happens to the tune of $450 once in a while. 

[m in sc]

if it's any consolation, I had a 1st gem mzb magnet come loose once before they potted them all in together. luckily didn't cause any damage.

[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?

[RDryan]

HPI says too old to warranty, just buy a new one. Seems like 8 years of heat and the glue didn't hold. I'm afraid to try to green Loctite it back in, plus it must be damaged from rubbing so much. Shit happens to the tune of $450 once in a while. 

Ahh that sucks what a bummer. Yeah sometimes things get expensive quick. Hope you're able to sort it out.

[m in sc]

it's not theory. it's a fact. install dry it's a tapered interference fit. look up 'Morse taper' for more info.

fwiw, that's def an outlier. I've had my hpi on my bike for almost eight years,  and been running vapes/mzbs since 2007. the only issue I ever had, I mentioned. 

[1976RD400C]

Here's why it started to misfire. New pistons and rotor will be here Friday.

[gargantua350]

You think this is a problem that will occur on all of them eventually?  I don't know what kind of bonding they are using.  I am assuming it is pressed in and epoxied and over time it starts to separate. I wonder if some holes in the ignition cover would help to cool it down some?  Had mine for 4 years and no issues.

[1976RD400C]

You think this is a problem that will occur on all of them eventually?  I don't know what kind of bonding they are using.  I am assuming it is pressed in and epoxied and over time it starts to separate. I wonder if some holes in the ignition cover would help to cool it down some?  Had mine for 4 years and no issues.

I think it was just a fluke. I used 2 screwdrivers and pried a little bit and the magnet came right out. Willey at HPI said it is just "glued" in there. It doesn't seem like much of a press fit. I wouldn't worry about it. Maybe check timing once in a while and if you see any dust when you look inside the cover, panic.

[85RZwade]

That's what I wasn't thinking; just make it part of the maintenance schedule

[RD350NL]

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.