Studs, Mounts, and Chains: Why You Can't Keep Your Engine Mounted, and How to Fix It

In these days of motorized bike builds you may notice that while performance has gone up, part quality has taken a little bit of a decline. Whether it’s a Grubee engine or a Power King motor, some engine kit manufacturers have exchanged performance for quality. Thankfully there are some ways to make sure that your motorized bike stays mounted on your bike despite manufacturer flaws.

Studs

Photo: thegarage.jalopnik.com

Studs are some of the most frustrating parts of an engine kit because that’s usually where manufacturers will begin cutting corners. How many times have you tried to take off your clutch case cover only to strip the head of the stud because it’s torqued in there too much? Or walk out to your motor and see it on the ground because the motor mount studs snapped? There are two ways of going about fixing this issue:

1. The most common reason studs (especially motor mount and exhaust/intake studs) snap is because of pressure. When the engine vibrates while running it can loosen the nuts on your studs. When they’re loose, the pressure of the engine will bend those studs and they’ll eventually snap. To avoid this take a wrench to your studs after every other ride and give your studs a quick tightening.
   
2. If your studs are snapped off in the case you’ll first need an extraction drill bit to get the stud out of there (*Note: this drill bit will drill into the stud and, when the drill’s reversed, will remove the stud). Then remove the rest of the questionable studs and replace them with higher grade metal, like the studs we offer here.

Motor mounts

Not as complicated to snap but just as frustrating to fix is the motor mounts. These are what mount your engine to your bike frame, and if they’re broken you could be in a world of trouble.

Motor mounts usually break due to vibration coming from the motor. The metal from the mount is constantly rattling against the metal on your frame, and if the motor mounts are made of quality metal that vibration- coupled with any wear on that mount- will start to create cracks. Once those cracks get big enough that mount can snap, and when it does it’ll most likely take out your motor mount studs, too.

Aside from removing the broken motor mount (and possibly studs) and getting replacements, you can upgrade to a vibration motor mount. These are rubber motor mounts designed to absorb the vibration coming from the engine that damaged your motor mounts to being with.

The great thing about these mounts is that they’re direct replacements for your metal motor mounts, so there’s no need to fabricate them to fit. That is unless you have an over-sized or even oddly-shaped frame. Then you can cut into these and shape them. Just be careful, because while they come in hand, rubber does not last forever. When using these vibration motor mounts it’s best to check their condition about every 200 miles or so to make sure they’re holding up.

Chains

Photo: Youtube

415 Chains are usually built with low-grade metal, but we thought it’d be important to mention chains because we get lots of riders asking why their chain breaks so often.

The #1 cause of chains breaking is its tension. Whether it’s too much slack or not enough, chains are usually breaking left and right because the tension of the chain is off. Remember: depending on the type of build you have, you should only have .25” to .5” of slack on that chain. Any more slack than that and your chain will be too loose, which can get caught around the drive sprocket and/or rear sprocket, causing it to bind and snap when throttled. Too little slack and your chain will simply snap from wear when you give your engine some gas.

If you need to tighten the chain by taking links out start with the master link. Remove as many links as needed, then reassemble the master link to connect the chain again.

When a chain snaps, however, it’s best to use a half link to connect the chain again. Multiple master links around the chain may cause weak spots, which you don’t want. Instead, a half-link fills in where that stock link failed without having to mess with too many link components, like the pins and inner/outer links.