Frequently Asked Questions – 3D Motorsport Engineering
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    1. When will I know if the clutch discs need to be replaced?

    The friction disc facings are made of very hard and wear resistant ceramic brass material. As a result, the wear life is exceptionally long. The vast majority of enthusiasts may never have to replace the discs. However, if the disc thickness drops below .093" thick, the disc should be replaced. 


    2. Is the 3D Manual Clutch safe for my young son or daughter?

    As long as your son or daughter knows how to ride or drive with a centrifugal clutch, the 3D manual clutch is perfectly safe. In fact, the 3D manual clutch will allow them to learn proper clutch technique that will carry over to other disciplines such as dirtbike riding and driving vehicles with manual transmissions.


    3. How wide is the 3D manual clutch relative to the PTO shaft of the engine?

    The length will be longer than almost all PTO shafts. Most shafts are approximately 2.375" long. The 3D Manual Clutch is approximately 3.125" long. For additional dimensions, please see the '3D Manual Clutch Basic Dimensions' webpage located in technical info.


    4. Will the 3D Manual Clutch work on any engine with a 3/4" straight PTO shaft?

    Yes, the 3D Manual Clutch is a universal bolt on unit designed for use on an utility engine that has a 3/4" keyed PTO shaft. This includes Briggs & Stratton, Honda, Tecumseh, Honda Clone, Predator, etc. It will also work on electric motors and engines using a shaft adapter.


    5. Can the 3D Manual Clutch be used in wet/muddy/dusty conditions?

    Yes, the 3D Manual Clutch uses sealed bearings to exclude dirt/moisture and retain lubrication. However, the clutch should be disassembled and cleaned periodically for optimal performance and service life. The bearings are sealed and greased for life- if you believe that the bearings have been damaged or contaminated, we can supply you with the appropriate replacement items.


    6. Does 3D Motorsport and Engineering plan to offer a 1.0" version of the manual clutch?

    Yes! We are working on the designs currently and will be in the prototyping/testing phase in the near future. Stay tuned.


    7. Do I have to use the clutch guard that comes with the 3D Manual Clutch or can I use my own?

    The clutch guard that comes with the clutch serves three main purposes. The first and most important is to keep the rider away from the rotating components of the clutch assembly. The second is that the clutch guard serves as a mounting point for the anti-rotation bracket and clutch cable housing. So to answer the question, a custom clutch guard could be made to work as long as it serves these three purposes. 


    8. How do I disassemble and reassemble the 3D Manual Clutch? 

    Detailed instructions can be found on the "Assembly & Disassembly" webpage which can be found in technical info. 


     9. Does the 3D Manual Clutch allow for gear shifts?

    By itself, the 3D Manual Clutch will not give your bike or kart gears to shift through. However, the manual clutch enables you to add a transmission of your choice to your bike or kart. 


    10. Will the clutch perform better with the governor removed from my engine?

    Absolutely. You will get the most performance out of your engine if the engine is able to rev beyond its peak torque RPM. While most engines are governed to 3600 RPM, their peak torque is typically between 4000-4500 RPM. Additionally, higher engine RPM stores more energy in the flywheel which can be used to accelerate the mini bike or kart at a faster rate. 

    3D Motorsport and Engineering strongly recommends that a billet aluminum flywheel and connecting rod be installed prior to removing the governor. Stock flywheels and connecting rods are not designed to withstand RPM beyond 3600 RPM.


    12. Does the 3D Manual Clutch make wheelies easier on a mini bike?

    Definitely. One of our test bikes is a DB30 with a predator 212. Using 12-70 gearing, we can easily initiate a wheelie at nearly 15 MPH by pulling the clutch lever in, increasing engine RPM, and releasing the clutch. The front wheel comes up with relative ease. The reason behind this is because the 3D Manual Clutch allows the energy stored in the flywheel to be instantaneously released once the clutch lever is released. This cause a spike in rear wheel torque that causes the front end to lift off the ground.

    For trail riding, the 3D Manual Clutch provides a significant advantage because it allows the rider to loft the front wheel over obstacles.


    13. Are any special tools required to assemble and disassemble the 3D manual clutch?

    The only special tool required is a quality set of external retaining ring pliers (if you don't have any, we sell them in the product page under 'tools'). Other than that, you will need a 5/64 allen wrench, a 5/32 allen wrench, 7/16 box wrench, and 9/16 box wrench. 


    14. Can the 3D Manual Clutch be used for industrial applications, or other applications not related to mini bikes and go karts?

    Absolutely! The clutch is extremely versatile and we have had customers install them in tractors, machine tools, and even super-mileage vehicles. Give us a call at 1-(888)-934-7458 and one of our engineers can discuss your application in further detail.


     15. Is it normal for the clutch to make noise when it is disengaged (lever pulled in)?

    Yes. Like all dry running disc clutches, the 3D manual clutch will produce a slight amount of noise that is very similar to the noise that Ducati Sport Bike clutches make. When the clutch is disengaged, the friction disc outer tangs are able to rattle against the slots in the clutch basket which results in a rattling noise. The noise is completely normal.


    16. I'm trying to decide between a multidisc centrifugal racing clutch and the 3D Manual Clutch. Why is the 3D Manual Clutch better?

    The modern centrifugal racing clutches are superbly designed and manufactured. They are completely adjustable in terms of the RPM they start engaging at which means that they can be tuned to engage at or near the RPM that peak torque is created. They can do this very consistently. However, no matter how well these centrifugal clutches are designed, they will never be able to convert the rotating energy of the flywheel and engine components into rear wheel torque and extra acceleration. It takes more skill to operate a manual clutch but, when mastered, will smoke a centrifugal clutch out of the gate every single time.

    Centrifugal race clutches are only good for one thing: racing. They can be easily damaged or destroyed when in use for anything less that aggressive riding. The 3D manual clutch works equally as well on a 3hp mini bike as it does on a 15 horsepower race kart.

    Lastly, as centrifugal clutches wear, the engagement speed changes. It takes pretty consistent adjustment and fine tuning to keep a centrifugal clutch engaging at ideal RPM. When the RPM can no longer be achieved through tuning, the clutch requires a lengthy and expensive rebuild that requires precision machining of many of the internal components. The 3D manual clutch on the other hand will engage at exactly the RPM you want it to no matter how worn out it gets. 


     17. What is the refund policy?

    All products that 3D Motorsport and Engineering sells are 100% refundable if there is an issue with the product(s) received. For example, if parts are damaged or missing, that particular item is eligible for a full refund after the product is shipped back to us.


    18. How much does the 3D Manual Clutch weigh?

    The clutch itself (i.e the part that mounts to the shaft of the engine) weighs 3.1 pounds. The better figure to look at it is the weight of the rotating components that make up the clutch.  The rotating components weigh 2.25 pounds. The clutch guard and associated fasteners will add an additional 1.4 pounds.