I Broke A Motorcycle Motor Mount Bolt.

On my ride back from a quick ride, I noticed my Boom Vader Gen 2 motorcycle was vibrating more than usual. I saw how much my feet felt uncomfortable after such a short ride. I usually ride my full bike throttle everywhere, but the bike’s vibrations were worse than usual. I’m sure if you are Boom Vader owner or any of the Grom Clones(TaoTao Hellcat, Icebear Fuerza, etc.), you know where this is heading. I broke a motorcycle motor mount bolt. 🙁

Right side of motorcycle, broken motor mount bolt sticking out.
Right side of motorcycle, broken motor mount bolt working itself free.

I didn’t buy into the Boom Vader motor mount bolts were a bad conspiracy.

I mentioned changing the engine mounting bolts on my update to-do list, but that was to increase the size for comfort. However, I didn’t heed the warning and broke a motorcycle motor mount bolt.

Broken stock Boom Vader Gen 2 125cc motorcycle motor mount bolt.
Broken stock motorcycle motor mount bolt.

I do not typically ignore warnings from other experienced motorcycle owners. I changed both stock chains from my TaoTao TBR7 and my Boom Vader Gen 2 motorcycles because I was warned the stock change is unsuitable for how we ride our Chinese Bikes.

I saw the photos of the damage done by broken Chonda motorcycle stock chains and knew with my performance upgrades of both bikes(TBR7 and Boom Vader). I was asking for trouble.

But I still ignored the warnings and broke a motorcycle motor mount bolt.

I saw photos of other Grom Clone owners showing their broken engine mounting bolts, but I didn’t pay attention. Why, you ask, since I tend to be a very cautious person that typically overthinks every decision?

Here’s why…

What Motorcycle Motor Bolt Recommendation?

When you go to the forums or the FB groups, the recommendation is to replace the Boom Vader’s engine bolts with Grade 5 or greater. 

I am familiar with bolts and fasteners like any DIY’er, so I know my way around the hardware stores. I checked Lowes(where I like to shop), and Home Depot, the highest level bolt you can buy off the shelf is in the Grade 8 range.

Now fasteners go higher, and one of the highest I could find online was 

Grade 12.9 bolts. Well, Guess What? 

The Boom Vader 125cc motorcycle came with engine mounting bolts with stamped heads saying Grade 12.9. Grade 12.9 is higher than the recommended Grade 5 upgrades, and Grade 12.9 is higher than almost all the bolts I could find in Lowes. So why would I change the motor mounting bolt?  

Broken motor mount bolt head with 12.9 stamp.
Noticed the 12.9? Notice the rust? Really Grade 12.9?

I spent my time and money on other Boom Vader upgrades. I was not replacing items on the bike that seemed ‘fixed’ from the factory.

Nonetheless, I broke a motorcycle motor mount bolt.

My Motor Mount Bolt Good News And Bad News.

The good news is I only broke one motor mount bolt. So I only noticed a slight discomfort with riding my Boom Vader motorcycle. I wasn’t treated to an opportunity to be pushing my bike home from multiple broken engine mounting bolts.

The bad news, unlike the Honda Grom motorcycles, Boom Vader motorcycles(like other Grom Clones) only come with two motor mount bolts. I only had one installed spare.

Boom Vader Engine Mount Bolt Failure Get Worse?

It could have!

The broken mount bolt was found on the right side of the motorcycle engine. The part that broke off was on the left side of the motorcycle, right in the area of the chain and front sprocket.

I suspect the threaded end of the motor mount bolt broke off, carrying away the nut and ultimately falling to the ground.  

The scary part:

If that nut, and threaded bolt end, bounced forward, it could have jammed up the front sprocket. 


If that nut, and threaded bolt end, got caught in the lower chain, it could have been carried rearward and jammed up the rear sprocket.

Imagine going 50mph, and the rear motorcycle tire locked up with no warning. I wear riding gear(boots, helmet, glove, and an armored motorcycle jacket), but I”m sure I would have gotten hurt badly.

Pretty sure no amount of regular armored riding gear will protect me if I cross into the opposite lane and am struck head-on.  

Am I Being Dramatic? Yes!!!!!

For a good reason. Change Your Boom Vader’s motor mount bolts.

How Could I Have I Been So Naive About The Bolts?

I talked about the Grade 12.9 stamped on the factory motor mount bolt, but I found this in Home Depot when I was looking for replacement bolts.

New motor mount bolt with same 12.9 head stamp.
New motor mount bolt with same 12.9 head stamp.

It might be hard to see, but the bolt is stamped on the head “YFS” “12.9.”

Rusty and Broken Stock Boom Vader motor mount bolt head stamp.
Broken Stock Boom Vader motor mount bolt head stamp.

Both bolts match and minus some damage to the stock motor mount bolt, and the letter changes from “F1” to “YFS”; they are almost twins.

Here is the kicker, look what Home Depot labeled the bolt as:

M8-1.25x120mm bolt from Home Depot.
Home Depot Packaging of possible replacement motor mount bolt.

It is labeled as “Plain Steel.”

I might be a new motorcyclist, but I’m sure this is enough information to confuse an experienced motorcyclist. So is this Home Depot Bolt Correct? Looks like the stock engine mount bolt that failed me. :/

What Next?

I was searching for a replacement option for the broken motor mount bolt and the still-installed bolt. Getting the right bolt might be a challenge and a lesson in becoming a better educated consumer.

Post Update, I replaced my Boom Vader’s engine mounted bolts with better bolts I bought from a big-box-hardware store:

Replaced Boom Vader Motor Mount Bolts!

Are You Going To Enlarge The Engine Mounts?

I talked about taking the time to enlarge the bike frame’s engine mounting holes from 8mm to 10mm, but for now, I will leave that to the future. I want to replace both bolts and return to riding my bike.

Post Update, I actually upgraded my motorcycle motor mount bolts:

Boom Vader Motor Mount Bolts Upgraded.

Your Feedback?

I was duped. Have you fallen for the grade stamp on your Grom Clone’s engine mounting bolts and regretted it?

What did you do? Modify the frame engine mount holes and upgrade the bolt sizes, or replace the motor mount bolts with better quality bolts?

Please leave feedback in the comment section below.

In the meantime, replace your Boom Vader’s motor mount bolts or any Grom Clone’s engine mounting bolts. Be safe.

Ride Safe, Ride Fun!

Click To See My Recommended

Boom Vader Gen 2 Upgrades

Picture of me, as a New Motorcyclist.
Just Me…Newly Licensed.

Hi I’m Tom, A New Motorcycle Rider and Blog Author.

I am a new rider(Pa Learners Permit at the end of 2020, and I received a Pa Motorcycle License in 2021 after passing a Motorcycle Safety Course).

I bought my first motorcycle, a TaoTao TBR7, at the beginning of 2021 and have been doing upgrades on that motorcycle since.

I added to my motorcycle collection by buying a Boom Vader Gen 2 in 2022, and that Grom-Clone motorcycle has been upgraded by me as well.

I continue to ride my Boom Vader Gen 2 motorcycle as well as my TaoTao TBR7 dual-sport bike.

Read more on my About Me page.

Fun Fact: I’ve only been on one group ride.

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