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How To Cut A Motorcycle Chain To Length
To cut the motorcycle chain to the perfect length, you have to figure out how many knots you need. This depends on counting the pins on the old chain or checking the maintenance manual directly—don’t just take a ruler to measure the length, because the old chain will become longer if it runs for a long time.
Once the number of links is determined, lay the new chain flat on the table and mark the specific pin that needs to be removed. Here’s an extremely critical detail: you need to make sure that after truncation, the two ends of the chain must be “inner links” (the narrower part of the chain). Because the joint responsible for the connection is essentially an outer link, it must be buckled on the two inner links to connect the chain.
If you are dealing with the heavy-duty O-ring chain, first use an angle grinder to smooth the marked pin head until it is flush with the side plate. This step can save the life of your chain and prevent the thimble from collapsing under high pressure. Finally, accurately align the thimble of the chain cutting device with the center of the flattened pin shaft, and steadily rotate the handle to push the pin shaft out. In this way, you get a perfect chain that fully matches the tooth disc distance of your vehicle and the adjustment range of the rear rocker arm.
This video demonstrates how to shorten a motorcycle chain:
Step 1: Confirm The Number Of Links, Not The Physical Length
A chain that has traveled thousands of miles has what is called a “pitch elongation”. This is not that the metal is really stretched, but that the gap between the pin and the sleeve becomes larger after wear, resulting in the whole chain being longer in physical size than the new chain—even if their number of links is actually the same. If you foolishly cut the new chain according to the physical length of the old chain, your new chain will become too short to fit because of insufficient number of links.
To ensure foolproof:
- Number of pins: If you don’t plan to change the original gear ratio, honestly count the number of links on the old chain.
- Check the manual: turn over your motorcycle maintenance manual to see the number of chain links specified by the manufacturer (such as 112 or 120).
Step 2: Make Sure That Both Ends Are Left With “Inner Links”
Before you can use the knife, you have to understand the anatomy of the motorcycle chain.
Whether it is a snap-in or riveted standard joint, they play the role of the outer link. It consists of a chain plate and two pins. In order for the hinge to successfully connect the chain into a loop, both ends of the chain must be inner links.
- Inner Link: The narrow part of the chain, consisting of two inner link plates and rollers.
- Outer links: a wide chain plate wrapped outside.
When you make a mark to cut off the pin shaft, make sure that the inner link remains on that side of the chain. If you go down with a knife and leave an outer chain link at the end, the hinge can’t fit at all. At this time, you often cut the chain too short, and this new chain is basically useless.
Step 3: Grind The Pin Shaft Head Flat
Modern motorcycle chains, especially heavy O-ring, X-ring or Z-ring chains, have surprisingly high tensile strengths. When the factory is in production, the head of the pin shaft has been “swaged” or riveted to death, just to clasp the side plate.
Although many chain cutter on the market claim to be able to push these pins out directly, the hard top will bring great pressure to the thimble of the tool. This is also the number one reason for a broken chain-cutting thimble.
To operate safely and protect your eating guy:
- Secure the chain.
- Take an angle grinder and point it at the riveting pin head you marked.
- Grind off that mushroom head thoroughly until the metal face is flush with the side panel.
After grinding off this part of the material, the resistance required to push the pin through the sleeve will be greatly reduced, and the operation will be much easier.
Step 4: Use The Chain Cutting Machine
After the pin shaft head is worn off, the last step is to use the chain cutting device to completely separate the chain links.
- Align: Put the chain into the tool. The most important thing in this step is to make the thimble of the tool accurately align with the center of the pin shaft you just polished. If it is off, the thimble of the tool will not only bend, but may also collapse directly.
- Pressurize: Start turning the handle. Because you have worn off the riveting head, just apply moderate and steady pressure and the pin should begin to slide out.
- Separation: Continue to rotate until the pin is completely pushed out of the other side of the chain.
Once the pin falls off, the chain will naturally separate. At this time, you should have just left the correct number of links in your hand, and both ends are open inner links, which can be installed at any time.
Author: Alex Turner
“Hi, I’m a certified motorcycle mechanic with over 17 years of garage experience. I specialize in drivetrain maintenance and DIY repair guides. I hope to help riders save money and stay safe by mastering essential skills—like correctly counting links and cutting chains—so you can get back on the road with confidence.”