Installation of All Balls Tapper Roller Bearings
After having changed the stock wheels to ultra lightweight Brembo Marchesini (detailed in previous posts) it became necessary to upgrade the suspension to account for the reduced un-sprung weight.
After considering all the options available to us, we came up with a detailed game plan for making the required changes. Considering the deficit of height difference (detailed in the post for wheel change) created by using Metzelers, we decided that the front suspension assembly needs to be attended to first in order to address this deficit.
Considering all the pros and cons we have decided to change the complete internals of the fork and convert the stock damper type fork to cartridge one. The forks will have custom made springs and dampening rates, which take into account the reduced un-sprung weight, my weight, riding style, etc.
However, before we start working on the forks it was necessary to address the weakest link in the whole front assembly i.e. bearings for steering cone set. We decided to install tapper roller bearings in lieu of the stock ball bearings. There is nothing wrong with my stock steering cone set. It is working just fine. However, the steering cone set is another part where the bean-counting accountants have made their presence felt. While ball bearing type cone set is a cheaper option, which gets the work done, it is not the best of solutions.
In the ball bearing solution the loads are applied radially to the balls and race cup thus creating highly concentrated load spots on the balls. While this works just fine under most conditions, they tend to fail early compared to other solutions. Most of you will have replaced the cone set of your bikes within a couple of years of buying your bike. I suspect many of you may have done this within months of getting your bikes.
The problem with the ball bearing application is that while the radial loads are taken care of by the bearings, they combine with axial loads that create flex and twisting loads on the ball and race cups.
Typical Ball Bearing. Note the contact area between the balls and the races.
Example of thrust type ball bearing used in stock steering cone set.
Cutaway of tapper roller bearing. Note the enhanced load area vis-a-vis the ball bearing above.
Therefore, considering the above factors we thought it prudent to improve and strengthen the weakest link in the front assembly.
The other problem that most of us face after replacing the steering cone set is the fact that it never feels like the original fitting. This due to the fact that during production, the chassis is completely bare and the races of the cone set are installed with jigs and fixtures with the correct amount of recommended force. However, when installation is done at the service center no jigs or fixtures are used. Many a times I have seen races being hammered into the chassis. Without fail this gives me a near heart attack to see such abuse being done to something so crucial. Whenever, I speak to so called service engineers, I get a blank look and a standard reply, “This is how it is always done!” Bearing installation is a science and not a hatchet job. Check any of the ball bearing manufactures website and you will find elaborate instructions on how their bearings should be fitted. I shared my concerns with Vikram of Motozone. He assured me that the mounting of the bearings will be done with proper jigs and fixtures and correct amount of force will be applied at all times during installation. Even if he did not have right fixture, he would make one before starting the work. He also showed me the special hydraulic press that he had for such applications.
Thus started the hunt of tapper roller bearings. We started looking for bearings from reputed manufactures like SKF, Timken, NMB, etc. However, it seemed that none of these manufactures had the bearings with the required dimensions. After a fruitless search, we came upon a small company called All Balls Bearings in the U.S. that specially manufactures bearings for conversions like the Ninja 300. Therefore, a set of tapper roller bearings were ordered from All Balls Bearings.
The All Balls Bearings packing.
Contents of the packing. 2 sets of bearings and dust covers.
The bearings, races and dust covers.
The lower bearing being mounted on to the steering stem and lower triple clamp. Note the hydraulic press used to ensure that even pressure is applied across the race collar while mounting the bearing.
Measurements were carried out at various points of the installation to ensure that the mounting of the bearing is within specified parameters.
The outer race of the lower bearing being mounted into the steering stem with the hydraulic press.
Measurements being taken of the installed outer race.
Similarly the upper bearing outer race after installation.
Installation of the bearings completed. The complete installation took 8 hours!
Another interesting thing that was found was the misalignment of the forks. Kawasaki recommends that the forks be 10 millimetres above the upper triple clamp i.e. the distance from the top of the fork to the top surface of the top triple clamp should be 10 mm. Much to our surprise we found that the left fork was 9 mm whereas the right one was 10 mm. That is a huge difference. This was corrected before completing the final assembly.
Once again I would like to thank Vikram and Vijay of Motozone for taking so much of trouble to do the job right.






Comment