You're going to need a specific honda grom clutch tool if you plan on doing anything more than just adjusting your cable tension on your favorite mini-bike. If you've ever pulled the right-side engine cover off a Grom, you probably realized pretty quickly that a standard socket set isn't going to get you very far. Honda decided to use a very particular "castle" or "crown" nut to hold the centrifugal oil filter and the clutch hub in place, and trying to remove them without the right gear is a recipe for a bad afternoon.
I've seen plenty of people try to get around this by using a flathead screwdriver and a hammer to "tap" the nut loose. Please, don't do that. You'll end up marring the nut, getting metal shavings in your engine, and potentially bending the input shaft if you're really unlucky. For about fifteen bucks, you can get the actual tool and save yourself a massive headache.
What Exactly Is This Tool?
When people talk about a honda grom clutch tool, they're almost always referring to a double-sided deep socket with four teeth on each end. One side is typically 20mm and the other is 24mm. It's a simple piece of machined steel, but it's designed to fit perfectly into the notches of the specialty nuts Honda uses on the Grom, Monkey, and several other small-displacement bikes.
The reason you need two sizes is that the Grom uses one size for the centrifugal oil filter (the "oil spinner") and another for the actual clutch center nut. Since you have to remove the oil spinner just to see the clutch, you're basically forced to deal with both. It's one of those "while you're in there" situations that requires you to be prepared before you even drain the oil.
Cleaning the Oil Spinner
One of the most common reasons to buy a honda grom clutch tool isn't even to fix the clutch itself; it's for routine maintenance. Unlike most modern bikes that have a spin-on or drop-in paper oil filter, the older Groms (the OG and the SF models) rely on a centrifugal filter. This is basically a heavy spinning drum that flings heavy particles—like bits of clutch material or metal shavings—against the outer wall, trapping them there.
Honda suggests cleaning this out every 8,000 miles or so, but most owners who care about their bikes do it way more often. To get the cover off that spinner, you'll need a JIS screwdriver (don't use a standard Phillips, you'll strip the screws!), and once that's off, you're staring right at that 24mm castle nut. Without the tool, you aren't getting that drum off to properly clean the gunk out of the corners. If you've never done this, prepare yourself—the stuff that builds up in there looks like gray, metallic clay, and it's oddly satisfying to scrape out.
Swapping Out Those Weak Clutch Springs
If you've added an intake, exhaust, or a cam to your Grom, you've probably noticed the clutch starting to slip. The stock Honda clutch springs are notoriously soft. They're designed for comfort and an easy lever pull, not for holding power. Most riders find that as soon as they start riding a bit more aggressively or add a few horsepower, the engine starts revving faster than the bike is moving.
This is where the honda grom clutch tool becomes your best friend. To install stiffer aftermarket springs, you have to pull the pressure plate, and to really do the job right—or if you're upgrading to a 6-plate clutch pack—you have to pull the whole hub.
When you're swapping those springs, it's also a great time to check the friction plates for any signs of burning or glazing. If you've been riding with a slipping clutch for a while, they might be toast. Having the tool on hand means you can tear the whole assembly down in minutes, swap the parts, and get back on the road instead of staring at a half-disassembled bike on a rear stand while you wait for a package to arrive.
The 2022+ Grom and the Five-Speed Gearbox
It's worth noting that things changed slightly with the third-generation Grom (the one with the five-speed transmission and the funky body panels). Honda finally listened to the masses and added a traditional paper oil filter that you can access from the outside of the case. This is a huge win for maintenance, but it doesn't mean the honda grom clutch tool is obsolete.
Even though you don't have to pull the side cover just to change your oil anymore, the internal architecture still uses those specialty nuts for the clutch assembly itself. If you plan on doing a big bore kit or just want to beef up the clutch to handle some wheelie abuse, you're still going to need that four-pronged socket. The "crown nut" design is a staple for Honda's small engines because it's secure and space-efficient, so that tool will likely stay relevant for years to come.
Tips for a Successful Tear-Down
Before you go sticking your honda grom clutch tool on an impact wrench and blasting away, there are a few things to keep in mind. First off, you're going to need a way to keep the engine from spinning while you loosen the nut. Some people put the bike in gear and hold the rear brake, but that puts a lot of stress on the transmission. A better way is to use a clutch holding tool or even the "penny trick" (jamming a copper penny between the gear teeth), though a dedicated holder is much safer for the aluminum components.
Don't Forget the Gasket
Every time you pull that right-side crankcase cover, you should really replace the gasket. Sometimes you get lucky and it stays in one piece, but usually, it tears. If you're ordering your honda grom clutch tool, go ahead and throw a side cover gasket into your cart too. It's cheap insurance against oil leaks.
Watch for the Washer
Behind that castle nut on the clutch hub, there's a washer labeled "OUTSIDE." It's slightly conical (a Belleville washer). When you're putting things back together, make sure that the side marked "OUTSIDE" is actually facing you. If you put it on backward, the clutch won't engage or disengage properly, and you'll have to take the whole thing apart again. Trust me, it's an easy mistake to make when you're in a rush to get back out and ride.
Is It Worth Buying the Expensive Version?
You'll see a wide range of prices for a honda grom clutch tool. You can find unbranded ones for under ten dollars, and then you'll see name-brand versions from tool companies or motorcycle specialty shops for thirty or forty.
Honestly? For most DIY riders, the mid-range ones are perfectly fine. This isn't a tool you're going to be using every single day like a 10mm wrench. It's a specialty item that comes out once or twice a year. As long as it's made of hardened steel and the teeth are cut cleanly, it'll do the job. Just make sure it's a 1/2-inch or 3/8-inch drive that matches your ratchet or impact gun.
Final Thoughts on the Job
The Grom is one of the most user-friendly bikes to learn mechanics on. Everything is small, accessible, and generally logical. However, trying to work around the lack of a honda grom clutch tool is one of the few ways you can actually make the job miserable.
Whether you're just cleaning out the oil spinner to keep the crank bearings happy or you're installing a high-performance clutch to help with those second-gear wheelies, having the right socket is the difference between a 30-minute job and a stripped-nut nightmare. It's a small investment that pays for itself the very first time you use it. Plus, once your buddies find out you have one, you'll probably be the most popular person in the local Grom squad. Just make sure they bring the snacks while you help them fix their slipping clutches!