Anyone making stronger motor covers yet? Cracked my stock one

[happyinmotion]

Front wheel kicked up a rock, cracked the right motor cover and bruised my big toe. The toe will fix itself; the cover won't. So, anyone making a stronger replacement cover yet?

The cover is just cast magnesium. It's thin and pretty exposed. I think I'm not the only one to break this part?

I'm more worried about protecting the housing behind than the cover. The cover is an $87 part; the housing means a new motor. You can see from my pics that there's some deformation in the motor housing. The mating surface where the gasket goes has some damage. I've filed it flat but is that flat enough? We'll see when the new parts arrive if I get a good seal or not. Either way, a stronger cover that projects ahead of the mating surface would protect the seal area from impact.

I'm also keen to protect the gears. The cover was pushed back into the gears, making a horrible noise when the bike was moving. The gears are steel so cut away the back side of the case, leaving lots of shavings in the transmission fluid. You can see the scraped area in the third pic. I think the gears are fine - I was only 15 km from the van so the gears didn't have to run in metal shavings for too long and the fluid leak was slow enough that there was still oil in there at the end of the ride. Still a longer ride or a faster leak wouldn't be good for the gears.

 

[Erwin P]

I know there are carbon covers for over this part.

 

[happyinmotion]

Any links to those?

Enduro Hog do a plastic stick-on cover. That'll stop scratches but not rocks.

Carbon Parts have done a forged carbon cover but they don't seem to sell them yet. I doubt that a thin cover is going to be stiff enough to help much in an impact like this.

Racetorx do a CNC'd replacement for the left motor cover but not the right side. I presume that's aluminium. That's the kind of thing I'm looking for.

 

[Theo]

Here is another one:
CMT Compositi | Right carbon crankcase protection for Stark Varg Stark Varg 2023 - 2024
They say it weighs 30 grams.
I'm not an expert on the subject but I personally wouldn't buy a carbon part for protection aginst impacts.

 

[happyinmotion]

Yeah, the stick-on carbon parts are mostly for looks. Fine if that's someone's thing, but that's not my thing. The bike's generally covered in so much mud that you can't tell what it looks like.

I just don't want it to break when I bang it on rocks.

 

[Erwin P]

I don't use them myself, but carbon bolt on parts have proven their use in enduro.
You see them a lot on 2 stroke exhaust and they prove to take quite the beating and less bent exhaust.

Carbons real weakness is getting twisted and bend, however when screwed to a solid object it won't so it will take a serious beating before giving in.

 

[happyinmotion]

Carbon exhausts are large curved parts with the impact in line with the radius of the curve. That's a geometry that helps it to be good and strong.

A carbon cover over this casting is going to help, sure, but this would be an impact on the thin edge of a stuck-on part. I don't see the current designs having much benefit and I haven't seen any testing or proof that they work.

Whereas a thick CNC'd piece of decent aluminium alloy is definitely going to be stronger than thin die-cast magnesium. It will be heavier, but I would rather have an extra 100 g of weight to stop me losing my transmission fluid if the cover cracks again.

 

[Theo]

Have you noticed this cover that they have used for the factory Stark? It's visible, for example, @0:23 and @0:32

 

[happyinmotion]

Well spotted.

Hard to tell from the video but that looks like a stuck-on plastic scratch cover.

 

[Erwin P]

A factory team doesn't care for scratch protection. Plastic, especially when a few mm's thick and and bit rubber'ish can absorb and distribute a lott of force.

 

[fsfs]

Front wheel kicked up a rock, cracked the right motor cover and bruised my big toe. The toe will fix itself; the cover won't. So, anyone making a stronger replacement cover yet?

The cover is just cast magnesium. It's thin and pretty exposed. I think I'm not the only one to break this part?

I'm more worried about protecting the housing behind than the cover. The cover is an $87 part; the housing means a new motor. You can see from my pics that there's some deformation in the motor housing. The mating surface where the gasket goes has some damage. I've filed it flat but is that flat enough? We'll see when the new parts arrive if I get a good seal or not. Either way, a stronger cover that projects ahead of the mating surface would protect the seal area from impact.

I'm also keen to protect the gears. The cover was pushed back into the gears, making a horrible noise when the bike was moving. The gears are steel so cut away the back side of the case, leaving lots of shavings in the transmission fluid. You can see the scraped area in the third pic. I think the gears are fine - I was only 15 km from the van so the gears didn't have to run in metal shavings for too long and the fluid leak was slow enough that there was still oil in there at the end of the ride. Still a longer ride or a faster leak wouldn't be good for the gears.

View attachment 11969

View attachment 11970

View attachment 11971

Ouch,

To me the damaged cover seems to be the secondary concern. The damage on the main housing is more worrying.

 

[happyinmotion]

To me the damaged cover seems to be the secondary concern. The damage on the main housing is more worrying.

Definitely. The cover is an easy replacement. The housing isn't.

If the cover had a lip that projected forward then that would do a reasonable job of protecting the gasket from impacts.

If the cover had an overlap that wrapped around the housing then that would be even better as it would protect the housing.

 

[Erwin P]

Not so sure about that lip or overlap.

A lip is more exposure and change to grip onto whatever.

The overlap is a good way to transfer force that otherwise would only hit the cover onto the motor and thus cracking it.

A plastic/rubber protector of roughly 5mm over the cover has a better change of absorbing impact, especially from hard objects like rocks.

Creating a hard metal protection is kind of stupid, imagine your helmet to be made out of metal...

Edit: For the time being glueing a cut open Ultra-Heavy-Duty inner tube (they are up to 7mm thick on the market) to the cover and over the first part of the motor might be as impact resistant as it gets.

 

[happyinmotion]

What we want is something more impact resistant than the current design.

Thicker stronger metal is going to be more impact resistant. More resiliant materials like rubber or HDPE are also going to be more impact resistant. Move coverage over the gasket line or motor housing is going to provide more protection than the current exposed design.

There should be a variety of ways to achieve this but currently there's not a lot of options being made.

 

[Ross Shafer]

well done!

 

[happyinmotion]

As expected, Racetorx are now on to it with a CNC'd aluminium replacement for the right side motor cover.


Looks beefy, costs HOLY CRAP two hundred and twenty quid.

Err, I think I'm just going to try to not hit rocks.

 

[Upinsmoke57]

I say not worth the money. It might take a tip over better than the stock pot metal but if you're riding in rocks the probability of hitting something head on is high! I made a simple plate out of 1/8" abs with 1/4" felt behind it that guides rocks over and around the case. So far I have put my bike through the test and it has worked very well. Feel free to copy

 

[Aleksandar13]

As expected, Racetorx are now on to it with a CNC'd aluminium replacement for the right side motor cover.
View attachment 12608

Looks beefy, costs HOLY CRAP two hundred and twenty quid.

Err, I think I'm just going to try to not hit rocks.

Rather good loo but very steep the price

 

[happyinmotion]

Rather good loo but very steep the price

I was talking about this component with a company that CNCs bike parts. They do the design in NZ and the manufacture in China, so pretty competitive on cost. For the complex shape, two-sided setup, and low numbers, they were thinking this part would be about that price to manufacture and sell.

So it may be a fair price, but it's still ouch.

 

[Aleksandar13]

I was talking about this component with a company that CNCs bike parts. They do the design in NZ and the manufacture in China, so pretty competitive on cost. For the complex shape, two-sided setup, and low numbers, they were thinking this part would be about that price to manufacture and sell.

So it may be a fair price, but it's still ouch.

You might be right. Maybe a rubarized plastic one on top of the stock one is a good start... 4 mm thick or something which costs a bit less than half .. Also all that beautifull cnc machined aluminium will get scratched so quickly it's not even funny .