Answer to cvt start clutch failures for the 4g city. Clutch principles law a body of law and concepts which have been established by olav aaen which is the framework of modern cvt systems. Many tuners feel that this is the holy grail for clutch tuning. Primary and secondary clutch movements have basically stayed the same over many years. Clutching part 1cvt clutching theory polaris rzr forum. We have been servicing cvt clutches for polaris, canam, and kawasaki. Venom products team performance clutching product categories.
Spring rates and helix angles should be selected to satisfy these criteria first. Cvt clutch tuning basics part 3 making the adjustments. Here are some general clutching rules you should play by. Cvt cvt allows for the operation at the lowest possible speed and highest possible load, partially avoiding the low efficiency region of the engine map. Epi has been the industry leader in cvt clutch tuning for over 20 years and weve made it our goal to educate enthusiasts like yourself about the importance of recalibrating your clutches when you add bigger tires or more power to your machine. Venom products team performance clutching showing 110 of 27 results. Buy olav aaens clutch tuning handbook updated 99 by aaen, olav isbn. How is the process of tuning a cvt done and what are the. Numerous and frequentlyupdated resource results are available from this search. I think many folks will tell you that olav aaens clutch tuning handbook is pretty much the bible on that subject. Various transmissions were purchased with the specific task of disassembling then to gather the needed resources photos, diagrams, etc to develop this cvt series. A continuously variable transmission cvt transfers power through a range of speedtorque ratios from engine input to output, continuously without interruption. Cpc clutch tuning handbook cutlers performance center. Understanding the fundamentals i have made mention a number of times to a book by olav aaen entitled clutch tuning handbook currently updated 2009.
Choose your spring by part number or rate in the drop down when adding your cart. There are two options for clutch optimization a a scientific method, or b a not so scientific. But, like any transmission, cvts do break down occasionally, and diagnosing some of the problems that crop up is not always a piece. Aaen performance, carb tuning handbook, atv, snowmobile. However, unlike the cvts other cousin, the automotive automatic transmission, the cvt is designed very ingenuously, to continuously vary the transmission gear ratio to do one thing only, hold the. Placed 4th in baja socal acceleration largely due to proper tuning. Team engineering has design and application engineers who are solely dedicated to the development and implementation of cvt technologies. According to an analysis by kelley blue book, today one out of every four new cars sold in the u. This book, continuously variable transmission systems cvt of which theres also a companion dvd by the same title, was a long time in the making.
The dashed line represents the rise and fall of engine speed as each. The secondary clutch is mounted to the input shaft of the transmission, transaxle, or the like. Is your utv having clutch issues or you are not sure what the problem is. The primary clutch uses arms and a spring inside it while the secondary uses a helix and spring. High performance tuning tips for your cvt clutch dirt. The cvtech trailbloc clutch itself is an amazing clutch that allows you to have a oneway bearing, that is a smaller diameter than the factory clutches oneway bearing, which allows the belt to ride lower in the primary, and higher in the secondary giving you a lower starting gear ratio thus giving you more low end. Honda actually has a patent on the use of a viscous coupling clutch on their cvt gearbox, which they called multimatic, back when it was launched in the mid1990s on the. These are the 4 basic tuning parts of the snowmobile cvt clutch arms, primary spring, secondary spring and helix. Using a shim to lengthen the bushing to allow belt to ride all the way down has best. Default sorting sort by popularity sort by average rating sort by latest sort by price. Zen and the art of cvt tuning hey all, been reading and learning on this forum for a couple of years now and wanted to share some advanced clutch tuning info i have not seen on here before. Atvutv action cvt clutch cvt clutch install howto polaris rzr xp1k sport utv utv.
Reliable information about the coronavirus covid19 is available from the world health organization current situation, international travel. By considering a vehicles weight, engine type and power, top speed desired, engagement rpm, and other factors, these experts can select or design the best clutch for nearly any. If you want to know how your clutch works, this book will save you valuable time and money. This needs to be in your models peak powerband for best results. Everyday low prices and free delivery on eligible orders. Modeling of a continuously variable transmission and clutching of. Spring rates and helix angles should be selected to satisfy these. However, if highperformance is what youre aiming for you might want to pass on on what cvt has to offer. Ideal clutch tuning dear ralph september 27, 1995 0. Olav aaen clutch tuning handbook manuals and guides in pdfolav aaen clutch tuning handbook full version 4100 dls 3565 kbs. Automotive continuously variable transmissions cvt. In general, shes got slow acceleration and struggles on hills. So, how does the average joe do it the reality of the matter is that most guys will replace this.
Get this book if you plan on messing with your cvt. How a cvt works ingenuity and engineering to create. High quality array of cvt clutch at a range of prices. Automotive continuously variable transmissions cvt by.
The positive effect continuously variable transmissions cvts have on engines is what makes them such a favorite with a number of automobile manufacturers. The secondary clutch will always be bolted to the transmission input, as it is the last part of the cvt system. In modern cvt systems such as those used in recreational vehicles, the secondary clutch has two functions. In other words the space between the two plates on the bushing the belt rides must be all the way open and all the way closed for best performance. It is also called the driven clutch because it is driven forward by the belt. Primary clutch drive clutch front clutch off the motor. True cvt clutching theory indicates that the main purpose of the secondary driven clutch is to provide just enough belt tension to prevent. I was thinking bbk but i was told to look at cvt and clutch before shelling out on a bbk. The up shift from the primary clutch must always exceed that of the secondary clutch or the cvt clutch system will stop shifting out. A continuously variable transmission cvt offers a continuum of gear ratios between desired limits, which consequently enhances the fuel economy and dynamic performance of a. There are several methods and recommended processes for ideal clutch tuning. A dualclutch gearbox is an automatic, and it isnt even the best one. Various transmissions were purchased with the specific task of disassembling then to gather the needed resources photos, diagrams, etc to develop.
Cvt, if that was his name, invented a marvelously simple and effective way of transmitting power to the ground without the need for manual shifting, manual. Their testimony is more than likely to be true based on hisher experience, knowledge, training and appearance of honesty and. As an engineer in my day job, i really like a hard challenge. Cvt clutch tuning test run on maxii bigfoot26 tires, 40 horse kohler. Our popular clutch tuning handbook has been revised for the ninth time, bringing you the latest in clutching technology. Their testimony is more than likely to be true based on hisher experience, knowledge. Peak rpm the rpm the machine sits and holds most of the time at wot. When tuning your cvt its where your belt rides between the plates of the fixed drive and ramp plate of variator. Olav aaen clutch tuning handbook full version 32 lundpubdia.
If youre looking for an energyefficient and convenient transmission system then the answer may be yes. Belt or chain driven, a cvt offers a continuous range of effective gear ratios, rather than a fixed number found in. True cvt clutching theory indicates that the main purpose of the secondary driven clutch is to provide just enough belt tension to prevent slippage, and good backshifting characteristics the torque sensing aspect. What is the procedure to do a cvt tuning for a baja buggy. Powersports cvt clutch kits free shipping on orders over. The belt in most cvt systems is a heavy duty vbelt which. Cvt largest cvt manufacturer, continuously variable. So i have a 2017 taotao racer 50 and i was advised to look into cvt and clutch tuning to improve acceleration and hill climbing, the two problems that i have with this bike. Cvt clutch tuning basics part 2 understanding the fundamentals. I can truly say after 34 years of working on cvts and doing as much research as i can in my.
A continuously variable transmission cvt is a light weight, gear reduction system that utilizes. I talked earlier about belt stretch and belt slippage being forms of efficiency loss. Section 1 cvt clutching theory how it works jump to latest follow 1 1 of 1 posts. Featuring cvt clutch available for purchasing right now online.
The answer will be of better insight to people who have basic information about cvt transmission and its working. Clutch rebuilding looking to upgrade your clutches for better performance and shifting. The primary clutch will always be directly bolted to the crankshaft, as it is the first piece of the cvt system. In the tuning firstly you have to adjust your belt tens. Any questions for proper tuning of a ddp clutch can be handled by calling their knowledgeable staff at 763 2284345. C program files stc ilqa 0666 root images headerlogo. Oclcs webjunction has pulled together information and resources to assist library staff as they consider how to handle. It helps explain what youre doing and will likely save you a lot of time out testing. Pdf performance optimization of continuously variable. Special chapters on clutch theory, testing and flyweight machining. Come by utv service and i will test drive it with you. Venom products team performance clutching archives. Up shift force in the primary and the secondary are built in losses in the cvt clutch design.
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