KTM launched the Adventure 390 in the first quarter of 2020 and the bike stands out against the other bikes manufactured by this company in the Indian market. It was predominantly made to compete against the ever so popular RE Himalayan, also known as the mini Tiger and the Kawasaki Versys 300.
Being an adventure bike, it falls in the dual sports segment, which means it is designed for both on-road and off-road use. In simpler words, the KTM Adventure 390 is a tourer bike with off-road capabilities. Even though KTM in India is known for the Duke and RC bikes which are predominantly race bikes, the company is globally known for its Rally machines. KTM has dominated the Dakar Rally since 2001 and only lost the title this year to Team Honda. Using all this in mind, they released the KTM Adventure 390 which is the smaller version of the Adventure 790 available globally.
However, this adventure bike suffers from a poor low-end and the owners soon noticed this. The throttle needs to be pushed hard in order to make sufficient progress and even after this, the performance is nowhere close to bikes such as the Himalayan. The issue was slightly resolved when KTM realized that the fuel pipe provided by one of their vendors for the bike was defective and was bending at two places causes less fuel to go to the engine. Although this did reduce stalling and the owners saw an improvement in the overall power delivery, the bike still felt lacking. The Adventure 390 engine uses the same engine and gearbox combo as seen in the Duke 390, but required a stronger punch for it to be an ideal off-roader.
To deal with this, Mr. Parth Menon planned a KTM Adventure 390 Sprocket modification, replacing the stock 15T front sprocket with 14T sprocket after studying the potential effects of doing so. For those who are not aware, sprockets are the gears that turn the chain connecting them to make the bike move. The front sprocket which connects to the gearing rotated the chain which in turn rotates the rear sprocket connected to the wheel.
Lowering the teeth in the front sprocket meant that each rotation gets over faster, which in turn resulted in more revolutions per minute (rpm). If the rpm is higher, we get more power.
Similarly, increasing the teeth in the rear also means we are increasing the amount of torque applied through the rear wheel. Increased torque helps the wheel spin easier and faster thus improving the overall acceleration.
Read Also: KTM 390 Adventure Fuel Economy Test [VIDEO]
Both these methods can be used to increase the low-end power but increasing the teeth overall means more surface area for the chain to run over which is better for the longevity of the chain and the gears.
But changing the front sprocket is easy and only takes a couple of minutes. The front sprocket is also cheap for just Rs 195 at the KTM service center (ask for Duke 250 front sprocket). Changing the rear sprocket is a complex procedure as it involves taking out the wheel, removing the bolts, and replacing the current sprocket with the new sprocket. The rear sprocket was sourced from Sparrowteck and costs Rs 3100.
As per what Mr. Parth shares, the 14T front sprocket helped them get a better low-end grunt from the engine. The bike felt more stable, planted, and less stuttering was observed. The bike was moving on its own without any throttle at 9 kmph on 1st gear. On the downside though, the engine was spinning at the higher rpm which caused more noise and heat. The overall top speed in 2nd gear also dropped from 24 kmph to 16 kmph on the setup which used 14T sprocket and similarly, the top speed in the 3rd gear dropped to 28 kmph as against 34 kmph which was achieved on 15T sprocket.
If on paper calculations are considered, one tooth difference in front is equivalent of 2.3 teeth difference at the rear. So by replacing the 15T sprocket with 14T, he achieved an increase in the low end 6.7% and high end reduced by 6.7%. This is a big change on paper but in real life, but in real life, Mr. Parth only noticed a difference of about 4kmph at top speeds. But the fun top end of the 15T front sprocket was taken away for the fun at the low end by the 14T.
To make the bike more balanced, Parth will be soon replacing the 45T sprocket with a 47T sprocket, which too will be sourced from Sparrowteck. He believes that the 15T-47T combo will cause a variation of 4.3% which should feel much more stable than the 14T-45T setup and will have a more low end than that 15T-45T. In addition to this, the bike also features some additional accessories such as headlight grille and aux lamp which are very useful in day to day conditions.
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Check Out Parth's YouTube video for more information on KTM Adventure 390 Sprocket Modification, Fuel Pipe, and more at -
https://www.youtube.com/watch?v=eyoheX7A0Jk
While Parth awaits his order to be delivered, a likeminded biking enthusiast, Karan( SilentBiker_kv) received the 47T sprocket from Race Customs and has installed on his bike. Here is how the sprocket looks like:
His review and video of him doing a wheelie can be seen here -
https://www.youtube.com/watch?v=4b81j8beJlk
Here's a quick video of an off-road test done with the new sprocket
