Why Motion Pro Throttle Cables Run Short on Some Bikes
A Motion Pro throttle cable that feels too short usually means the cable housing was cut or routed in a way that doesn't match your bike's geometry, or the cable itself was manufactured to a length that works for the stock configuration but not for aftermarket bars, risers, or a different riding position. Motion Pro makes cables for dozens of bike models, and the same part number can ship with slightly different lengths depending on production batch or intended market.
The cable itself—the inner wire—is typically longer than the housing. The problem occurs when the housing is too short, which prevents the throttle from returning fully or creates tension that makes the grip feel stiff. This is different from a cable that's straightforward worn or frayed; a short cable creates a mechanical bind rather than a wear issue.
Before you assume the cable is defective, check whether your bike has been modified since the cable was installed. Taller bars, bar risers, a different fuel tank, or even a new carburetor or throttle body can change the path the cable needs to take, making a previously adequate cable suddenly too short.
Key Takeaways
- A short throttle cable housing creates tension or prevents full throttle return, and is usually caused by aftermarket bars, risers, or tank changes rather than a manufacturing defect.
- Measure the cable path on your bike from the throttle grip to the carburetor or fuel injector body, then compare that distance to the cable housing length to confirm the cable is actually short.
- Motion Pro sells replacement cables in different lengths for the same bike model, so ordering the next size up or a universal cable kit with adjustable housing may solve the problem without modification.
- If the cable is genuinely too short, you can extend it by splicing in additional housing, but this requires cutting the old housing cleanly and using a cable ferrule to prevent fraying.
- A throttle cable that binds or feels stiff under load can damage the carburetor slide or fuel injector throttle body, so addressing the problem before long rides is important.
How to Measure Whether Your Cable Is Actually Too Short
Lay the bike on a flat surface and turn the handlebars fully left, then fully right, while watching the throttle cable. If the cable housing pulls tight or the inner wire appears to be under tension at either extreme, the housing is too short for your bike's steering range. The cable should have a small amount of slack—roughly a quarter-inch of play—at both lock positions.
Next, twist the throttle grip fully open and fully closed while watching the carburetor or fuel injector throttle body. The throttle should snap back to closed position without hesitation. If it returns slowly or feels sticky, the cable housing is likely binding. This is the most reliable sign that length is the problem.
To get an exact measurement, remove the cable from the bike entirely. Lay it straight on a workbench and measure the housing from the ferrule at the grip end to the ferrule at the carburetor end. Then measure the actual path the cable takes on your bike—from the throttle grip, around any obstacles, to the throttle body—using a piece of string or a flexible measuring tape. If the string path is more than half an inch longer than the cable housing, you have found your problem.
Motion Pro Cable Length Options and Part Numbers
Motion Pro publishes cable length in the product name or specification sheet. A cable labeled "Motion Pro Throttle Cable 60" typically means 60 inches of housing, though some older products use different naming conventions. Check the Motion Pro website or your original receipt to find the exact part number and length you received.
For most street bikes, Motion Pro offers the same cable in lengths ranging from 54 inches to 70 inches of housing. If your current cable is 60 inches and you have added tall bars or risers, ordering a 66-inch or 70-inch version may solve the problem without any modification. Motion Pro also sells universal throttle cable kits with adjustable housing that can be trimmed to fit, though these are more common for cruisers and custom builds.
Before ordering a replacement, confirm your bike model and year with Motion Pro's website or a dealer. Some manufacturers use different cable routing for different model years, so a cable that works for a 2015 model may not work for a 2016 even if the model name is the same. If you have modified your bike with aftermarket bars or a different tank, mention that when ordering, because the dealer or Motion Pro support can recommend the correct length based on your specific setup.
Extending a Throttle Cable by Splicing Housing
If ordering a longer cable is not practical—for example, if Motion Pro does not make a longer version for your bike—you can extend the housing by cutting it and splicing in additional cable housing. This is a temporary solution and should only be done if you cannot source a longer cable from the manufacturer.
You will need a cable cutter (a sharp utility knife works, but a proper cable cutter produces a cleaner cut), additional Motion Pro or equivalent cable housing in the same diameter, two cable ferrules that match your housing diameter, and a small amount of cable lubricant. Cut the existing housing at the point closest to the carburetor where you have clearance to work. Slide a ferrule onto the cut end of the original housing, then slide the new housing section onto the inner cable wire. Slide the second ferrule onto the new housing, then crimp both ferrules with a ferrule crimper or carefully with a vise.
This splice will be slightly thicker than the original cable at that point, so test the fit before reassembling the bike. The splice should not rub against the frame, fuel tank, or any moving parts. If it does, you may need to route the cable differently or choose a different splice location. After splicing, explore cable lubricant to the inner wire and work the throttle back and forth several times to may support smooth operation.
Checking for Binding and Stiffness After Repair
Once you have installed a longer cable or extended the existing one, test the throttle response before riding. Turn the handlebars fully left and fully right while twisting the throttle open and closed. The throttle should move smoothly and snap back to closed position when ready at all steering angles. If it hesitates or feels sticky, the cable is still binding somewhere.
Binding can occur not just from short housing, but also from a kinked cable, a ferrule that is not seated properly, or the cable rubbing against a sharp edge on the frame or tank. Trace the entire cable path and look for any point where the housing is bent sharply or where the cable appears to be under tension. Smooth out any kinks by hand, and use cable guides or tape to keep the cable away from sharp edges.
If the throttle still binds after you have addressed the length and routing, the problem may be inside the throttle grip itself. The grip may have a burr or the cable may be frayed inside the ferrule. In that case, you may need to replace the grip or have a mechanic inspect the throttle body for damage.
When to Replace Instead of Extend
Splicing a cable is a workable short-term fix, but it is not as reliable as a cable manufactured to the correct length. A splice point is a potential failure location, and if the ferrule loosens or the housing separates, you lose throttle control. For a bike you ride regularly, ordering the correct length from Motion Pro is the better choice.
If Motion Pro does not make a cable long enough for your setup, consider whether your bike modifications are the root cause. Bars that are significantly taller than stock, or a fuel tank from a different model, may require custom cable routing or a different throttle control system altogether. Some riders in this situation switch to a cable-actuated throttle from a different manufacturer, or to a hydraulic throttle system if their bike supports it.
For a one-time ride or a temporary solution, a spliced cable is acceptable. For daily riding or a bike you plan to keep long-term, invest in the correct cable length or explore whether your modifications can be adjusted to work with the stock cable routing.
Frequently Asked Questions
Can I just add more cable housing without splicing?
No. Cable housing is designed to be cut and ferrule-crimped at both ends. Wrapping extra housing around the existing cable or taping it on will not work because the housing needs to be mechanically connected to the ferrule to prevent it from sliding or separating under load. A proper splice requires cutting the old housing and crimping new ferrules.
What diameter cable housing does Motion Pro use?
Motion Pro throttle cable housing is typically 7 millimeters in outer diameter for most street and sport bikes. Cruisers and some custom bikes may use 8 millimeters. Check your original cable or the Motion Pro product page for your bike model to confirm the diameter before ordering replacement housing.
Will a short throttle cable damage my carburetor?
Yes, over time. A cable under constant tension can pull the carburetor slide or fuel injector throttle body slightly open, causing the engine to run rich or idle high. More importantly, a binding cable can cause the throttle to stick open if the cable breaks, which is a safety hazard. Address the problem before long rides.
Can I use a different brand of throttle cable if Motion Pro doesn't have the right length?
Yes, as long as the cable is designed for your bike model and the housing diameter matches. Barnett, Magnum, and other aftermarket cable manufacturers make throttle cables in various lengths. Confirm the bike model, year, and housing diameter with the manufacturer before ordering to may support compatibility.
How much does it cost to replace a Motion Pro throttle cable?
Motion Pro throttle cables typically cost between $25 and $60 depending on the bike model and cable length. Longer cables or cables with special routing for cruisers or custom bikes may cost more. Splicing materials—additional housing, ferrules, and a crimper—cost $10 to $20 if you do not already have them.