Variator back plate breakage

[redonkulousruntsracing]

I switched to a complete Malossi Overange set up this season and have had issues with the back plates on the variators cracking. I've seen this many times with other racers and different motor combos. Has any one figured out how to prevent this or has a fix been made for this. I dont like the thought of one of these coming apart at 14k rpm!! For now, I will keep a couple spares, but would like to find a cure for the problem.

[selbygirl]

we never had problems with ours but i would clean the variator after every pratce and moto so that every thing moved properly, and the sprng and belt and rollers would last longer

[#404's Dad]

Originally posted by redonkulousruntsracing
I switched to a complete Malossi Overange set up this season and have had issues with the back plates on the variators cracking. I've seen this many times with other racers and different motor combos. Has any one figured out how to prevent this or has a fix been made for this. I dont like the thought of one of these coming apart at 14k rpm!! For now, I will keep a couple spares, but would like to find a cure for the problem.

First I've ever heard of this, Got pics and Details on the Setup?

[Logan #34's Dad]

This is pretty common. I went through a few Malossi back plates and I know Voiles did as well. I think its caused by overtightning the nut and basically crushing the plate. Locktite the nut and ease up a little.
I eventually had success with the smaller 19.2v Craftsman impact gun. Guys with limp wrists like Corey won't have this issue..:blah: :devil:

[#404's Dad]

Originally posted by Logan #34's Dad
This is pretty common. I went through a few Malossi back plates and I know Voiles did as well. I think its caused by overtightning the nut and basically crushing the plate. Locktite the nut and ease up a little.
I eventually had success with the smaller 19.2v Craftsman impact gun. Guys with limp wrists like Corey won't have this issue..:blah: :devil:

LMAO, too funny Rocky.

So its user error then I guess?

I've not seen one have any issues at all in years but I use common sense when tightening the clutches as well, a few blurps with a 12v Dewalt or a 18v Makita both 3/8 and all has been well for us and our riders.

Maybe y'all just got a bad batch of them =)~

[Logan #34's Dad]

I couldn't resist.
Anyhow, I think when we r impacting them on it puts all the pressure at the rear spacer which pushes the back plate inward and cracking it. Do that over and over and it won't take long before it's junk.
Ever shake Doug Voiles's hand? He's a strong one....

[#404's Dad]

Hmm, so maybe a larger diameter spacer behind it to spread the force would help you guys possibly?

[redonkulousruntsracing]

Yup, one whack of the 12v impact and its tight, the same way Ive done it for 6 years, SO NO USER ERROR. The only ones I have seen break are the Malossi Overange ones. Must be something with how the variator works. We are using scooter parts on things they werent designed for. I cant remember the last time I heard a Vespa spinning 14K tearing ars up the street!!
Maybe a thicker rear spacer would help. They always break right in the corners of the hard bends that give it its shape. The crack starts at the outer edge and works its way towards the center hole.

[mini racer #39]

make to remove the metal ring were the starter gear rides or use to ride it is hiting and when you tighten the face plate nut it is transfering pressure to the back plate or to short of spacer will also let it hit

[RCR_531]

I have seen this happen to Deal and Beebe's this year. Someone else had it happen too but I can't remeber who it was.

[mmsoup]

Broke three in the last couple years

[Hetrick Racing]

The cause is usually because of the spacer not sitting true or square to the crank or plate when it is tightened.
I can also agree with Rock that over-tightening will break them, but the ones I have seen have been a spacer issue.
One I had this year the crank was not machined properly, but only one.

[#404's Dad]

Originally posted by Hetrick Racing
The cause is usually because of the spacer not sitting true or square to the crank or plate when it is tightened.
I can also agree with Rock that over-tightening will break them, but the ones I have seen have been a spacer issue.
One I had this year the crank was not machined properly, but only one.

Kinda what I have been thinking, that its not the Variator's fault, something else has to be wrong like Too Tight, Crank Out of Balance, Wrong Spacer behind it or soemthing.

I went out and looked at all 9 of our personal used ones from this season and see absolutely no issue with any of them other than the faces being worn and my kid is no slouch and our chit isn't slow so they are being abused and also we have ran these on customer bikes for years and never seen this issue, somewhere somebody is doing something wrong like one of the above mentioned suspected causes.

Some good pictures of the Backing Plate and the Inside of the Variator would be nice to see along with any spacers being used if you want others to help get to the bottom of this.

[FISH ON!]

Broke three this year as well. All three had cracks that started on the outside edge. That makes me wanna say the spacer is not the most likely culprit in my case........but stress cracks are not the easiest to figure out. That last one we cracked might of had 70 or 80 min run time on it.

Anybody see a trend on it happening more on a large spline versus small spline? Large spline spacers are thinner and have even less contact force distribution. 2 or our 3 failures were on large spline stage 6 cranks.

[nastynotchback1]

Todd your pm box is full.

I just discover we have a cracked one also and i ran 2 all last year on the stage 6 with no problems.Go to this 90cc and it is broken.