1st gear is the jerkiest gear on most motorcycles since the gear engages differently than the rest of the ratios in your gearbox.
Engaging the first gear from neutral will cause vibrations not noticeable in other gears; riding in first gear gives you less control than any of the higher gear ratios simply due to the difference in how the gears are constructed.
That said, if your motorcycle is shaking in 1st gear to the point that it’s uncontrollable, stalling out, or feels dangerous, it may indicate one of the following problems—to help you troubleshoot, we’ve listed the most common reasons a motorcycle jerks in first gear.
1. Clutch Cable Needs Adjustment
If your motorcycle’s clutch cable is either higher or looser than the spec outlined in your make and year model’s owner’s manual, you may find your bike jerks in 1st gear.
- Your motorcycle clutch cable needs to have a specific amount of slack in reserve to move the clutch back and forth between engagement and disengagement.
- Whether from overtightening it or a drastic temperature change, a clutch cable that doesn’t have enough free play can’t travel the full range required.
If your clutch cable is too tight, the absence of the required free play can drag your clutch plates upon releasing your clutch lever and engaging your first gear. The limited cable movement restricts the clutch plates and causes your motorcycle to jerk in first gear.
Adversely, a clutch cable that’s too loose can cause some of the same shifting problems that cause motorcycles to vibrate in 1st gear as an overtly tight cable can.
- A clutch cable with excessive slack isn’t tight enough to provide the force needed to engage the first gear fully.
- Too much free play causes the clutch to slip when engaging first gear, and your motorcycle may shake aggressively at first.
- The owner’s guide for your make and year model moto likely contains directions for clutch cable adjustments with a specified or spec measurement.
- The standard recommendation for roadside clutch cable adjustments is to set it between 2mm and 3mm.
- If the 2-3mm adjustment is enough to stop your motorcycle from jerking in 1st gear, we suggest looking up the spec clutch measurement and modifying the cable tension as soon as you get home.
2. Clutch Cable Passed Due for Lubrication or Replacement
A worn, dry, or dirty clutch cable with insufficient lubrication can cause a motorcycle to jerk in 1st gear.
Regular clutch cable inspection and lubrication are part of the routine ownership maintenance outlined in your owner’s manual.
Your clutch cable needs to be examined for wear, damage, poor adjustment, and lack of lubrication, and needs to be serviced accordingly.
Furthermore, all clutch cables wear out eventually, and once they do, they don’t hold the tension between service intervals. You’ll find yourself constantly adjusting your clutch cable to keep it from rough movements when shifting into 1st, especially during long rides or in drastic changes in weather or temperature.
Routine inspections also catch cable wear early, not only before it causes rough 1st gear engagement but also before the cable snaps, leaving you stranded or worse, causing a collision.
For more on this, please read our article on how to fix a faulty motorcycle clutch.
3. Low Oil Level
If you run your motorcycle with less oil than the spec suggests, your engine and transmission parts can overheat, leading to your bike jerking while shifting into 1st gear.
Motorcycle engines are dynamic systems of metal parts rapidly rubbing against one another and generating heat inside a small compartment.
The oil keeps the machinery lubricated and the metal cool so it doesn’t glaze, seize, or expand and cause damage.
- Running your engine with low oil causes cylinders, valves, and pistons to overheat and wear early.
- The main engine oil supply keeps the transmission on many motorcycles cool and lubricates it.
- Therefore, low oil levels also put your motorcycle clutch plates and gearbox components at risk of overheating due to increased friction.
The increased friction and elevated heat levels inside the gearbox caused by a lack of oil can cause your motorcycle to shudder intensely when in 1st gear.
- A motorcycle’s engine oil needs to fill to the specified level.
- The spec oil fill level differs from moto to moto.
- Your motorcycle should be checked and topped off before and after every long ride, especially when traveling and riding long distances.
Read this article to learn the 8 symptoms of low motorcycle oil.
4. Neglecting to Change Your Engine Oil; Using the Wrong Oil
Your motorcycle might jerk in 1st gear if you use a different type or grade of oil. It also results from running contaminated or expired oil through your bike or failing to service it per the manufacturer’s advised intervals.
There are multiple types of engine oil moto manufacturers suggest based on several factors.
Three of the most common types of oil used on a motorcycle are mineral, semi-synthetic and full synthetic.
- Using the wrong type of oil can cause gearbox and engine damage, including grinding, accelerated friction, and heat wear on your clutch and gears.
- The different moto oil types come in various viscosity grades, often including additives and anti-corrosion agents.
- These may be ideal for specific bikes but cause gear-changing problems on others.
Furthermore, the various oil grades and materials expire after different periods. The oil change intervals outlined in your owner’s manual aren’t accurate unless you use the exact type of oil specified in the manual.
And finally, oil that’s been contaminated by rust, moisture, dirt, fuel, or coolant can cause severe shifting problems, including rough vibrations in 1st gear.
5. Worn Clutch Plates
Your clutch plates rub against other components, grabbing and releasing as part of everyday use. Eventually, the friction wears down your containers enough to cause warping, which can cause your bike to jerk in 1st gear.
The following poor riding habits can accelerate the wear on your clutch plates:
- A skimpy or rushed clutch plate adjustment.
- Quickly or aggressively popping the clutch lever out from your hand when releasing your clutch.
- Running improper, low, or contaminated oil through your transmission.
- Shifting without completely drawing in your clutch lever.
- Overtightening your clutch cable.
- Powershifting; changing gears without disengaging your clutch.
Proper riding technique is critical to the longevity of your motorcycle’s performance, reliability, and smooth shifting capabilities.
Failing to adhere to the riding and upkeep habits outlined in your moto manual leads to micro-damage on your clutch that not only adds up over time until your clutch finally fails but also causes rough shifting and jerking in first gear.
A damaged clutch causes more noticeable jerking in 1st gear in the others because of the unique cut of the lowest gear.
- If you catch the problem early on, adjust your cable and plates before the friction burns the metal sufficiently to cause warping.
- Once the clutch plates become warped, they are beyond repair and cause friction damage to the other components they come in contact with.
6. Motorcycle Chain Needs Adjustment
A motorcycle chain drive that’s too loose, too tight, lacks lubrication, is contaminated by debris, or is worn from everyday use can cause your motorcycle to jerk in 1st gear.
- A chain can become too loose to function efficiently if it dries out and rusts due to a lack of regular chain care or unsuitable storage.
- That said, even a well-cared-for motorcycle chain eventually wears out from the stress of constant motion while in contact with the sprockets and gears.
- Once worn, the metal on the chain expands, stretches, and doesn’t hold its tension, even with proper lubrication and cleaning.
We suggest troubleshooting your motorcycle chain if your motorcycle jerks in first gear, mainly if your bike exhibits the following symptoms:
- Chain teeth are bouncing over sprockets.
- Irregular power transfer to the wheels, causing jerky movement and shaking while riding.
- Chain slipping, often accompanied by a metallic slapping sound of a loose chain.
- The motorcycle chain jumps off the sprocket.
We cover this topic more comprehensively in this article about 7 symptoms a motorcycle chain is too loose.
7. Broken or Worn Chain Sprockets
A worn, chipped, cracked, or filed-down chain sprocket leads to missed shifts and jerking in first gear. If left unchecked, a faulty sprocket can jam your motorcycle transmission, so it’s stuck in 1st gear.
The chain sprocket is essential to the gear engagement.
Once they break or wear down, you’ll notice an apparent dip in how smooth your clutch and shifting action is, most noticeably in 1st gear.
One of the most common causes of worn chain sprockets is a poorly lubricated or loose chain, slapping around and skipping over the sprocket unevenly.
A chain tightened unevenly on one side can damage or warp sprockets, and the friction caused by insufficient chain grease overheats the sprocket during use.
If you recently replaced a worn chain or suspect the current chain is worn, inspect your chain sprocket too. Putting a brand new chain on a damaged sprocket causes uneven wear to the new chain, the same way a bad chain wears out a sprocket.
If the piece to the chain-sprocket-puzzle is damaged, you not only risk wearing the other, but you’ll experience an increase in jerking while shifting and riding in first gear.
8. External Debris Causing Gearbox Interference
Whether bent shifting shafts cause it, flawed gearbox assembly or a foreign object lodged between gears, the first sign of a jammed transmission gear is an increase in jerking while shifting into 1st gear.
- Your motorcycle’s gearbox comprises numerous components operating in harmony as a united process.
- If a gear seizes or gets jammed for any reason, it triggers failures elsewhere in the transmission system, including with gear engagement.
As we mentioned earlier, due to the unique design of the first gear compared to the cut of the higher ratios, jerking is most noticeable in 1st gear and maybe the sign you need to catch a gearbox problem before it causes more damage.
Please also read our article about reasons motorcycle won’t shift up into 1st gear.