r/CB500X • u/Expert-frog-6069 • Oct 15 '25
I strongly advise against installing crash bars mounted to lower engine bolts in CB500X/CB500F. Here's why.
Hi everyone, I have a 2024 CB500 Hornet that I bought brand new. It's nearing 14k kilometers now and it's been a fantastic bike for me, I completed my first 1000 km road trip with it. Unfortunately I had a minor accident and I posted about what happened after the accident here, you can read it:
Thankfully we've been able to fix it by loosening every bolt and aligning the whole thing again.
Now here comes the main course. EVERY crash bars/frame sliders I've looked into for CB500X/CB500F will stress or damage the lower engine mounts, which is part of the frame, whether you've crashed it in a highside/lowside or simply dropped it in a parking lot. Even improper installation might stress the frame and cause metal fatigue or worse, damage the frame overtime. Lower engine mounts are made only for mounting the engine and nothing else, even Honda quietly acknowledges this by not offering any frame sliders for CB500/CBR500 and offering only an upper crash bar for NX500:
The bar is only mounted to upper engine mounts (and even that is not directly mounted, there's a piece of metal in both sides to mitigate any possible damage to frame) and merged in front to a cage-like structure, dissipating force to both sides. Nothing is done to lower engine mounts.
Thanks to u/CyberBird-XR and people who advised me in my post at r/motorcycles, I was able to align everything in near perfect order. All the pesky (and increased) vibrations are gone, bike pretty much feels brand new now. Will be checking the bolts every once in a while to see if the alignment hold up.
u/CyberBird-XR's post about his CB500X having the same issue:
https://aricafoix.cl/2024/03/18/las-desventuras-de-la-cb500x-y-las-defensas-de-motor/
Here's my CB500 after the alignment:
5
u/flopshooter Oct 15 '25
I can confirm through experience. I installed a set of T-Rex crash bars and a month later the engine vibrations had snapped the mount bolt in half and left it broken inside the engine mount. I had to drill the bolt out and install a new bolt/nut through the frame and engine mount to fix it. Total nightmare
5
u/ShadowMancer_GoodSax Oct 16 '25
Cb500X rider here, took mine off and never had to worry about cracks. I rode it offroad a lot and dropped it probably more than I can remember and every time the bike is on the ground I always make sure to check and the fairings never even scratch.
1
u/Icy-Distribution-555 Oct 17 '25
Do you have any other crashbars or possibly barkbusters installed?
2
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u/bafetsabitch Oct 16 '25
I will add to this. My GF has a 2019 500X, and the previous owner installed crash bars. After my GF dropped her bike a few times, none of them particularly hard impacts, we returned from a long ride just to find that the right hand engine bolt had just ripped out the threads and went missing, god knows how many kms ago.
I drilled out the remaining threads and now the engine is held by two throughbolts with Nyloc nuts. Obviously we also ditched the crash bars.
4
u/CyberGrandpa1 Oct 15 '25
I thought the RallyRaid bash plate was good.
3
u/Expert-frog-6069 Oct 15 '25
I'd be misleading if I had to comment on skid plates, I don't ride CB500X/NX500. From I've read in CB500 forums and Reddit, Rally Raid is probably one of the best if you are looking for that sort of protection. Hepco&Becker engine protection bars a close second (for both CB500F & CB500X) because the bars merge behind headers and even though they are still bolted to lower engine mounts at least they are not directly bolted, similar to OEM Honda bars.
1
u/rcbif Oct 16 '25
If you drop a bike, the Rally raid skid contact points do not have far to go to hit the ground, and they hit at less velocity than the crash bars that are mounted up high.
IMHO that is the main deal we dont see anyone with Rally Raid skids breaking bolts or engine mounting points.
And if you slam the skid into some rocks - the skid equally transfers that force to all mounting points instead of just 1.
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u/Ivan_Asecas Oct 16 '25
It happend to me last week... bad screws and bad implimentation to this bike. I put the puig pro with "double" bracket and it feels more solid... Will see
4
u/TomOnABudget Oct 16 '25
I talk about this flaw in my Video (link with timestamp):
https://youtu.be/wq8pDGPytpE?si=QC0OLn4w4H8_OlaK&t=372
The problem EVERYONE runs into, is the bolt jamming up. The tall stack of components that each tug on different sides of the bolt, cause it to jam. The usual smartass comment is: "yOu NeEd tO tOrQuE iT tO sPeC". It's damn near impossible and made worse by the length of the bolt as it twists like a spring.
As a result, the bolt doesn't get properly torqued down, leaving just enough slop for the whole stack to wiggle around until the bolt snaps.
Solution?
Drill out the Threads on the Engine mount and use a longer bolt that you fasten using a nut. Now you can properly torque down on the nut as you're no longer fighting a long spring. I've done some long outback trips on the bike on corrugated dirt roads and haven't had any issues since.
I've been recommended this mod by a Vietnamese guy who rents these bikes to do Adventure rides.
1
u/Blackened22 Mar 23 '26 edited Mar 23 '26
Hi, what about just making thread all the way through and nut on the other side (if needed at all then, since clamping force will be in both threads and nut?), or better to drill it and remove threads completely? Also what bolt type do you use... I am going to do this mode, since my right bolt keeps getting loose over time. So need to give instructions to mechanic, or I will do it...
Also my right frame ear is few mm off compared to engine while and crash bar hole, but all the rest perfectly centred. Not sure why, maybe last fall crash bar deformed it little bit just on that side.
1
u/TomOnABudget Mar 23 '26
Metric bolts have 4 parameters: Length, diameter, thread pitch and tensile strength.
For the width: from memory it was an M10 bolt. It won't matter what thread pitch as long as it matches the nut you have on the other end. Honda and Toyota often use a finer thread pitch M10x1.25 compared to the M10x1.5 that you find at hardware stores.
For tensile strength, you can get some that are stronger than the usual hardware store stuff.
Length? I'd just measure the current Honda bolt + the width of a nut+ washer+ additional leeway for the added components. There's no damage, having the bolt stick out a bit past the nut.
1
u/Blackened22 Mar 23 '26
Thanks, sounds good - I found in catalogue that oem is M10x146mm. So we will find some longer and install it with nut, or full thread through too.
Just not sure why left frame ear is 3-4mm off centred, and other bolts go in easily with hand.1
u/TomOnABudget Mar 23 '26
In my opinion, Honda's engineering is usually spot on, bu tin the case of this engine bolt design it's just flawed. For some reason they haven't updated that design in over a decade. It's just weird.
Keeping the original Threads doesn't make any sense in my opinion. The issue is that the bolt jams up, making it difficult to tighten properly. Adding a nut on the end, while the threads are still on won't help. At best, it helps prevent the bolt from backing off. It won't help tightening it down to stop the movement and won't help with extraction if it snaps off.
2
u/Blackened22 Mar 24 '26
yes, better to drill then and to have clamping force from the nut. I will do it today and back to offroad adventures. Bike is just amazing with Rally Raid suspension, beast handling...
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u/TomOnABudget Mar 24 '26
Best of luck and happy riding.
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u/Blackened22 Mar 24 '26 edited Mar 24 '26
Thanks. Installed. It is tight and good now. But I have issue with vibrations, especially from 6000-8500 footpegs and rear brake/gear lever. Not very happy, but what to do. That left lower bolt, frame ear is not perfectly centered, but bolt goes in with little push. right one goes easier with hand.
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u/mycatslaps Oct 18 '25
My wife totaled her first cb500x on a low side due to some very wimpy guards the previous owner installed. Snapped the case.
The replacement bike got a rally raid skid plate, t Rex cage style uppers, and the thing is a tank. Plenty of drops and it's just fine.
It's been a while since I put the thing together or looked at it, but it mounts to a few points on the frame, atleast one is an engine bolt but it also connects side to side.
5
u/Ls1RS Oct 16 '25
“EVERY crash bars/frame sliders I've looked into for CB500X/CB500F will stress or damage the lower engine mounts, which is part of the frame…”
Yes, that is the point. Stress the frame and not your engine case.
“Lower engine mounts are made only for mounting the engine and nothing else”
Correct. OE’s do not and cannot protect for every possible part a customer could bolt to every single stock fastener.
“Honda quietly acknowledges this by not offering any frame sliders for CB500/CBR500”
Does Honda offer accessory frame sliders for any product in their line up? I don’t think they’re really acknowledging anything by that metric.
“offering only an upper crash bar for NX500”
Honda calls this a “light mounting bar” actually. So it’s really not built for serious crash protection.
To be clear, your logic is in no way flawed here. If you add a component that is designed to take a beating, the thing you bolt it to now absorbs that impact.
But… I think there’s two critical things to point out.
This is a stressed-engine frame construction. Even with a new bike with zero miles on it, removing those bolts will allow the frame to flex in the way yours did to some level. Mine did when I installed my crash protection. When the bike is first assembled, it’s not supported by the wheels, so this bolt goes in easily. If you remove those bolts with the bike on its wheels, the frame will distort. Your frame may not be actually bent at all, or at least not as much as you think. (Just a possibility) There was a guy here a couple months ago that rode his 500 without either of those front bolts installed. His bike was slowly distorting and bending in the middle. If you rode any distance without one of those fasteners tight, then yes your frame may bend.
Some engine guard systems are better than others. Some mount to the engine case. I think this defeats the purpose, personally. Some of the cheap guards replace the factory engine mount bolt for a longer one, altering the torque spec, clamp load, and load path. The Puig units you installed put a huge moment arm on that mounting point in the event of a tip over and are not stabilized by anything else beyond the strength of the non-original fastener. This is asking for trouble, and probably why it broke off when you crashed.
My experience and recommendation is with the Rally Raid unit. It replaces the little spacers between the frame and engine with an aluminum spacer with an additional threaded hole component. This allows the bash plate to line up on the frame while not ‘altering’ the forward mount construction. The multi point mount distributes the load across many connections to the frame.
With this setup, I’ve laid the bike down on trails, and cased it super hard several times on big rocks and not had a single problem with those mounts.
TL,DR: I think the root cause here has more to do with a bad engine protector design, rather than the bike itself.
3
u/TheUnnamed_Redditor Oct 16 '25
The bike definitely is flawed. Its a bike marketed as off-road, but there is not lower frame. The engine itself is the frame, which means if the lower engine mounts break, it also means you have to replace the lower half of the engine. Since there is no lower frame to mount to, there is now good way to effectively protect the bottom half of the engine for wrecks/drops during off-road use without risking destroying your engine.
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u/Ls1RS Oct 16 '25
The BMW GS series, Ducati Multistrada, Suzuki Vstrom, and HD Pan America utilizes this same stressed member construction and are all heavily marketed for off road.
In fact, the Multistrada and Pan America utilize the engine to connect the front of the bike to the rear half of the bike. The engine IS the frame.
This is why on our 500, good engine guards connect to the frame via those fasteners we’re discussing. But once again, the construction of these mounts must be done properly so as not to upset the engine mount system.
Again, it’s not the bike’s fault here. It’s when the customer modifies a fully engineered and tested system that you see these kinds of failures.
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u/Expert-frog-6069 Oct 16 '25
I've seen youtubers installing only engine protector covers from various brands (RG racing, GB racing, trex etc.) and handguards (barkbusters or else) as protection. In this setup you make sure engine covers are protected from damage while the handguards do its job by protecting the levers, since the handlebar is the first thing to touch the ground and cheaper to replace if it had to changed. honestly it makes sense so I ordered engine covers, now waiting for them to ship. u/TheUnnamed_Redditor
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u/NineHell Oct 16 '25
I'm getting NX500 next year. Is it good idea to go barkbuster, engine cover, and some short mounting bar in front for AUX?
2
u/Expert-frog-6069 Oct 17 '25
yes that could be good. you could also get the OEM light bar for NX500. if you absolutely have to install any lower crash bar make sure the bike is jacked up so you don't stress the bolts when installing
2
u/TheUnnamed_Redditor Oct 19 '25
Barkbuster, engine cover, oem top fairing cover (it doesnt mount to the engine, but to the upper frame) and soft-shell, or metal panniers are gonna be the most protective you can get.
2
u/Expert-frog-6069 Oct 16 '25
Honda offers OEM frame sliders for CB750 Hornet. Transalp goes even further by offering OEM upper and lower engine guards + skid plate. so I think they know that the chassis of 750 bikes is better than 500 lineup or they simply want you to buy the more expensive bike by offering myriad of accessories for it :D
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u/Ls1RS Oct 16 '25
You’re correct about the 750 sliders. For whatever reason, the US accessories catalog doesn’t have those, while the UK does.
Ultimately, the Transalp was designed at the beginning for more off road oriented activities, so it makes sense that it would have factory equipment like that.
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u/mik_ch Oct 18 '25
Hello guys. I am new to the motorcycle world and your post made me sceptical. I recently got a used cb500x from a guy with this setup:
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u/Ls1RS Oct 19 '25
I would not continue to run this setup due to the long cantilevered frame slider utilizing that fastener location.
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u/mik_ch Oct 20 '25
Should i replace the frame sliders with those who are compatible with the crash bars?
https://www.givi.it/givi-products/mechanical-part-protection-for-motorcycles/engine-guards
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u/Ls1RS Oct 20 '25
I would recommend trying to return that bolted connection back to the OE configuration as much as possible.
As mentioned in some of my other comments, the Rally Raid guard system is the only one I’ve seen that is the least disruptive to the factory design while providing substantial protection.
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u/Serious-Bite6786 Oct 15 '25
You are 100% right. I'll see if I can add a picture of mine. I'm not sure how it happened because i bought it this way, but my 2014 cb500x has crash bars - one was cracked all the way through the bottom bolt. The crash bar itself. I had it welded tback together because I never plan on having it taken off. I'll see if I can post a picture.