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To do this, you need to find the book you are interested in and click on the “Buy” button. The price of the book is indicated on the button.
For convenience, the price on the website for residents of Russia, Belarus and Kazakhstan is presented in rubles.
For residents of Ukraine in hryvnias, and for all other countries - dollars.
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Payment via Yandex Cashier
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This payment method is optimal for residents of Russia, Kazakhstan and Belarus.
Official website of the Yandex Kassa payment system https://kassa.yandex.ru
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The price in the Portmone payment system is converted into dollars at the exchange rate of the Central Bank of the country where you are located.
If you have a bank card in a currency other than the dollar, then the money will be debited from the card at the rate of the Central Bank of your country at the time of the purchase.
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Official website of the Portmone payment system https://www.portmone.com
Payment via PayPal
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Official website of the PayPal payment system https://www.paypal.com
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Official website of the WebMoney payment system https://www.webmoney.ru/
When is it necessary to change the transmission oil on a scooter?
Due to the fact that the scooter gearbox endures enormous loads, it must be maintained regularly.
After all, after a certain mileage, the transmission oil becomes saturated with various metal particles, and a sediment also forms in it. All this leads to a deterioration in its physical condition and properties, which means that it will no longer provide the necessary protection, and the part will fail in the near future. In principle, the frequency of replacement, as well as the class of oil, is indicated by the manufacturer, and it is these recommendations that should be followed. However, if we take an average, the frequency of this event should be about three thousand kilometers. What about running in equipment, then this operation should be carried out a little more often. The first time - after three hundred kilometers, the second - after a thousand, the third - after the mark has passed 2000 km, and then every 3000 km or once a year if the equipment is not used very often.
Downloading a book
After successfully completing the payment (by any method) and returning to the KrutilVertel store from the payment system website, you will be taken to the successful payment page:
On this page you need to indicate your e-mail, where access to download the book will be sent.
If you are already registered on our website, then simply follow the link to your personal account.
The book you purchased will be in your personal account, from where you can always download it.
Please note that after making the payment, you need to return back from the payment system website to the KrutilVertel website.
If for some reason you did not return back to the site and closed the payment system tab with a message about the successful completion of the payment, please let us know - we will send you a letter indicating access to download the book.
Scooter gearbox
The job of a scooter gearbox is to transmit rotation from the driven pulley of the variator to the rear wheel. The first gear ratio goes straight through the CVT. The CVT reaches its final ratio (the belt in front goes to the outer radius) by rotating the driven pulley about 5 times per crankshaft rotation (at 10,000 engine rpm, so 50,000 pulley rotations). Presumably, if the wheel were sitting on a driven pulley, then the wheel would have to make 5 full rotations with each ignition (corresponding to the rotation of the crankshaft). The result would be such a long ratio that the motor would not be able to pull. Thus, the importance of the gearbox becomes obvious: by transmitting torque from the driven pulley to the rear wheel, it reduces the rotation speed. How many times? On different scooter models, this number may differ slightly, but it is always close to 12, for example on the Yamaha Aerox, to be precise, 12.28, and on the Chinese Baotian Tanco 50 about 11.3. This means that for one revolution of the rear wheel there are 12.28 and 11.3 revolutions of the driven pulley, respectively.
The gearbox gears are located in a closed container at the rear of the scooter housing. The container is filled with oil, so the oil must be drained before opening the lid.
The scooter gearbox mechanism is divided into PRIMARY (gears 1 and 2) and SECONDARY (gears 3 and 4) gears. Primary or secondary gears always consist of two gears - large and small. By dividing the number of teeth on the drive gear by the number of teeth on the driven gear, we obtain the gear ratio. For example, the small and large primary gears (1 and 2) of the Yamaha Aerox have 13 and 52 teeth, respectively. It is clear that the drive in this case is the small gear, so the gear ratio will be equal to 13/52, or 1:4 if we divide the numerator and denominator by 13. For us, this means that for every four revolutions of the drive (small) gear there is only one slave revolution (large). Knowing the sizes of the secondary gears (3 and 4) of the same Yamaha Aerox - 14 and 43 and acting in a similar way, we obtain a ratio of 1: 3.07. Now all that remains is to multiply the resulting ratios 1:4 and 1:3.07 to get the final ratio of the Aerox gearbox 1:12.28 - it was mentioned at the very beginning.
The lower the gear ratio, the longer the transmission. For example (for primary gear), 1:4.2 - short gear; 1:3.15 - medium gear; 1:2.73 - long pass; 1:2.11 - very long pass.
It makes absolutely no difference which gear - primary or secondary - is used to change the final ratio of the gearbox. On scooters prepared for competitions based on High-End piston engines, sometimes even both gears are replaced.
Why lengthen the transmission?
It's one thing to have more power, and another thing to implement it. On a standard scooter motor, there is no need to lengthen the gear: the manufacturer has selected a gear ratio that allows optimal use of the motor power. However, when tuning the power unit, peak power sometimes increases two to three times. This cannot be done without intervention in the transmission.
The fact is that all internal combustion engines operate only within a certain speed range. Above this range, the engine's power—torque—decreases very quickly. Moreover, at such a speed that the power quickly drops (which is actually determined by the product of torque and revolutions). This is especially true for tuning engines (red curve in the diagram).
As you can see, at 10,000 rpm the tuning motor develops 7 hp, and already at 11,000 rpm - only 2. If the gear on the tuning motor is left standard, then an increase in maximum speed will be achieved only due to an increase in maximum speed. At the same time, the main advantage - an increase in torque due to an increase in volume - remains unrealized, since this is only possible with the help of upgrading the transmission.
For those who are not very familiar with the relationship between power, torque and engine speed, the following example should help in understanding. A car with a manual transmission will never accelerate to maximum speed in first gear, since the engine will not spin above a certain speed. In first gear, excess torque is spent on traction properties: You can drive up a very steep hill with a packed car, or you can drive down a hill without passengers and luggage, but the speed will be the same. Longer gearing limits your ability to push uphill, but on flat roads you can go much faster.
So, the need to lengthen the transmission when tuning the power unit becomes obvious. But it is not entirely true that the longer the gear is selected, the faster the scooter will go, or other similar statements. If you use an excessively long gear, the engine will not have enough torque to reach maximum speed. In this case, they say that the engine cannot handle the long transmission. Now it becomes clear why lengthening the gear on a standard engine is pointless. In short, the transmission length must match the capabilities of the engine.
How much to extend?
The Sport 70cc piston, combined with a properly tuned 17.5 mm carburetor, has enough torque to lengthen the gear by 12-20%. On Racing class piston engines there is a little more. Please note that the longer the gear, the correspondingly less acceleration dynamics, since the torque on the rear wheel decreases during acceleration. Many manufacturers give ready-made attitude recommendations, however, as practice shows, they do not always meet the requirements of a particular owner, so you should be more careful when choosing an attitude. To understand by what percentage the transmission will be lengthened, you need to calculate the ratio of the standard and tuning transmission. Let's look again at the Aerox example: its native secondary transmission has a ratio of 1:3.07. Top Performances offers a 16/41 tooth ratio secondary gear for this motor, which equates to a 1:2.56 ratio. Now we divide the gear ratio of the tuning gear by the ratio of the standard one, subtract the result from unity and multiply by 100%. We get the transmission elongation as a percentage.
So: (1 - (2.56/3.07)) x 100% = 16.62%.
Straight or oblique gear teeth?
Most manufacturers prefer straight ones; they transfer force better and result in less significant heating due to a smaller friction area. However, helical gears are much quieter.
Problems when paying with bank cards
Sometimes difficulties may arise when paying with Visa/MasterCard bank cards. The most common of them:
- There is a restriction on the card for paying for online purchases
- A plastic card is not intended for making payments online.
- The plastic card is not activated for making payments online.
- There are not enough funds on the plastic card.
In order to solve these problems, you need to call or write to the technical support of the bank where you are served. Bank specialists will help you resolve them and make payments.
That's basically it. The entire process of paying for a book in PDF format on car repair on our website takes 1-2 minutes.
If you still have any questions, you can ask them using the feedback form, or write us an email at [email protected]
How to extend the life of a gearbox
You can avoid all of the above problems with a scooter gearbox. to change the transmission oil at least every two seasons . Fill only with high-quality oil recommended by the manufacturer. Such a simple procedure will increase the service life of the scooter gearbox several times. However, it's usually much worse. Many people don’t even remember about this unit during the operation of the scooter, paying attention to it only during a breakdown.
