Motorcycle gear not shifting smoothly is one of the common problems associated with bike gears. The main reasons for gear shifting issues include problems in the clutch cable, engine oil, chain and sprockets, and the gear shift lever itself.
Each of these reasons responsible for motorcycle gear not shifting smoothly are described in detail below.
#1. Not Enough Slack in the Clutch Cable
One major reason why your motorcycle gear shifting is not smooth is because of improper slack in the clutch cables. If your clutch plates are dragging and they are not fully releasing whenever you are pulling the clutch lever, then there is little to no doubt that it is your clutch cable that is causing the gear problems.
The reason why clutch cables with not enough slack can cause problems is because when the slack is too tight, i.e., lower slack than the required specifications, pulling the clutch wire completely will not be enough to fully release the clutch plates.
So, it is very important to adjust the clutch by giving it a proper slack. Ensure that the wire has some free play to operate and at the same time, the slack should not be too much.
A simple thumb rule is to maintain the clutch slack at about 2mm to 3mm. However, if your auto-manufacturer has provided specific slack measurements in the manual then go for the prescribed specifications.
If you do not have any company specifications, try adjusting for 2mm to 3mm. Check whether the motorcycle works fine, if you feel it is still too tight or loosened, adjust accordingly.
#2. Too Much Slack in the Clutch Cable
The same problem occurs when the clutch cable has too much slack. This is opposite of the above case where there isn’t much slack in the cable.
If the slack is too high, i.e., higher than the required specifications, the clutch can slip even when you have fully released the lever.
Again, you need to adjust the clutch cable by giving it the sufficient slack but not too much. Maintain the slack according the manufacturer recommendations mentioned in the user manual.
If there are no recommended specifications, try adjusting for 2mm to 3mm. Check whether the motorcycle works fine, if you feel it is still too tight or loosened, adjust accordingly.
#3. Low Engine Oil Levels
Low engine oil levels in the motorcycle is another reason why your motorcycle gear is not shifting smoothly.
The effects of low engine oil also include – engine overheating, wear and tear, and carbon deposits. This can result in damaging clutch plates, cylinder lining, piston and even engine valves.
That’s why the engine oil needs to be changed frequently to avoid low engine oil levels. The frequency of oil change depends on the make of the motorcycle, the type of oil you use, how old the motorcycle is, what condition the motorcycle and engine is in, how you use your motorcycle – for short rides, long rides etc.
As a general rule of thumb, the recommended frequency of oil change for the distance traveled based on the type of oil you are using. For mineral oil, it is advised to change oil every 2000 miles, the same is 5000 miles for semi-synthetic oil and 8000 miles for synthetic oil.
#4. Poor Oil Quality
Another engine oil problem that can cause problems in smooth gear shifting is when you have a poor and deteriorated quality of oil in the motorcycle.
Even if you have used a good quality oil, the oil degrades overtime. The engine oil in your motorcycle is not meant to last forever. Over the course of time, the quality of the oil degrades because of its usage.
The degradation of quality will hamper its performance. This, in turn, hampers the engine performance. That’s why, it is important for us to change the engine oil regularly.
While choosing the oil, along with selecting the type – mineral, semi-synthetic and synthetic; you also need to select the right viscosity grade oil, suitable additives – detergents, corrosion inhibitors, anti-wear etc.
So, select the right oil quality depending on the condition of the motorcycle, type of engine, and even your preference and budget.
#5. Warped Clutch Plates
If you have recently traveled for a long distance in your motorcycle, then there is a chance that the clutch was overheated due to riding the bike under full power for long periods.
Warped clutch plates can be because of these reasons – no free play in the clutch lever; clutch plate not adjusted properly; shifting gears without pulling in the clutch; releasing the clutch lever suddenly; and careless riding with improper clutch usage.
Whenever you are driving with a warped or burnt clutch plates, you will feel that the gear is not shifting smoothly and the pickup has dropped.
In warped clutch plates, there will be lots of rubs and friction between the clutch plates resulting in their damage. That’s why warped clutch plates need to be addressed as early as possible in a motorcycle.
For warped clutch plates issue, you need to visit your mechanic to fix the clutch plates. Even misalignment in clutch plates need to readjusted again.
#6. Loosened Chain
Another major reason why the gear shifting is not smooth in your motorcycle can be because of loosened chain.
A loosened chain can be seen both in an old chain due to rust and also in new chain. It is not a must factor that only old chains will become loose.
That’s why, one needs to clean the chain and sprockets with a maintenance spray frequently, especially after a long ride where you have run the motorcycle over muddy roads.
It is also essential to lubricate the chain regularly. The thumb rule is to lubricate for every 5000 miles you drive.
The major symptoms of a loose chain include chain teeth skipping over the sprockets, uneven transmission of power to the wheel leading to jerky wheel movements, chain lash and the chain slapping the swindle arm, and in the final case, chain coming off the sprocket.
So, check the chain whenever the gear shifting in your motorcycle is not smooth. The chain might be loosened and is causing the shifting problems.
#7. Chain Sprockets are Worn-Out
Another reason why smooth shifting of gears is not happening might be because of worn-out chain sprockets in your motorcycle.
If the chain sprocket is damaged, the gear transmission may not take place smoothly and as a result, the gear shifting will be difficult and the gear can even get stuck.
However, checking chain drive components are easy since chain can be inspected visually.
The objective here is to determine whether you need to replace the existing chain with a new chain and sprockets or not.
You can use gloves for checking if you want. Pull the chain away from the rear end of the sprocket on your rear wheel. If you have a worn-out chain, you will see about half a tooth of the sprocket. A good conditioned chain will wrap around the sprocket tightly and will not be easy to pull away.
In addition, you need to look for rust and other damages. Spin the rear wheel to see whether the chain maintains the same tension throughout. Examine the entire length of the chain to check for any signs of damage or worn-outness.
You also need to look for the sprocket during the entire course. If any teeth is chipped away or damaged, you have to replace them.
Now, if it is confirmed that the chain is worn-out and you have to replace it with a new one, then it is better to go to the mechanic for replacement.
However, if you decide to replace it by yourself, make sure you know the make of your motorcycle and organize the components you remove in an orderly fashion.
#8. Seized Transmission
Sometimes, it is the seized transmission gear that is causing issues in gear shifting or even gear being stuck.
The seized transmission gear can be because of a foreign object stuck between the gears, bent shift shafts, or incorrect assembly of the transmission gears.
The transmission problems result in you not being able to change or shift the gears easily. There will be a strong resistance while shifting from one gear to the other.
If this is the case you are facing and suspect one of the above problems is the issue, then you need to immediately take your motorcycle to your mechanic.
Any transmission gear problem can prove to be lethal to the gear system. The issue might run deeper than a simple gear shifting problem. If you let it rot, you might end up paying a higher repair cost for a damaged transmission system.
#9. Faulty Gear Shift Lever
The least obvious reasons are sometimes the most plausible causes. A faulty gear shifting lever can also be the reason why your motorcycle gear is not shifting smoothly.
So, it is better to check and inspect the gear shift lever for any issues that might be causing problems in gear changing. Check whether the lever has become loose or any problems associated with smooth gear shifting.
Which of these reasons turned out to be the cause when you faced the problem of your motorcycle gear not shifting smoothly? Comment below.