nitrosteve22

Replacing the clutch spring is pretty simple,and seems to be something all Redcat owners have done or will do as the factory spring doesnt hold up to well. Even if it breaks it can still be used again providing the break happened somewhere around the spot where the ends of the spring meet.

Symptoms of a broken spring are very obvious. If the vehicle can be started while suspended but not while the tires are on the ground,or if the vehicle wont stand still while at idle and the engine dies when brakes are applied its probably the clutch spring. Also,with the engine off,if the clutch bell spins with resistance and a metal on metal noise can be herd from inside the clutch bell,the spring has come loose. *Note* Having the idle on the engine set to high can also cause the clutch to engage. And having the idle set to low can also cause the engine to die when brakes are applied as it will close the air intake of the carburator to much,thus stalling the engine.

Ok lets get started. First you'll need to remove the four screws holding the engine to the chassis (pic 1),you'll also need to loosen the grub screw in the tip of the exhaust pipe (2.0mm) which secures the exhaust pipe to the chassis. With the engine out of the vehicle you'll need to remove the clutch bell (2.5mm) (pic 2). Pull the clutch bell off taking care not to lose any of the washers under the screw and the washer behind the clutch bell (and be sure you put them on exactly how they came off!). If you have a replacement clutch spring or if you've managed to reuse the old one this is the trickiest part,have the ends connected together and ready to go. I recommend using both thumbs for this but I needed a free hand to take the picture. Grasping the engine in your hands,slip the spring over the tip of the crank shaft and use your thumbs to roll the spring on and around the clutch shoes working from one point outwards,evenly in an upward motion as show in pic 3. Do it slowly and with caution as you dont want to overstretch the spring,it may take a couple of tries as these things require alot of force and can slip out from under your fingers.

If everything went well and the spring is secured in its little groove on the clutch shoes then your ready for assembly,pretty much in the same manor you took it all apart! For the last part once the engine is back together the gear mesh will need to be reset. One way this can be done,is to take a piece of notebook paper and run it between the clutch bell/gears and then snugging the engine/clutchbell up against the spur gears and bolting it down and removing the paper (blue locktite is recommended on engine screws as nitro vehicles have ALOT of vibration). If the gears are to close they will spin with resistance with a clickity feel,and if set to far apart the power from a nitro engine can easily chew the teeth right off a spur gear. Pic 4 shows how my gear mesh is set after assembly. Notice how there is a space between the teeth of the clutchbell and spur gears but the teeth still have a good amount of contact surface and still spin freely.

Well thats its,not a whole lot to it but stretching the spring over the shoes is the hardest part. The clutch shoes can also be removed if you've purchased the "clutch slice" assembly if you dont want to fuss with springs or if you wish to replace/upgrade. The large E-clip is the only thing securing the shoes to the flywheel and can be removed by using a narrow flathead screw driver. Stick the screw driver in between the E-clip and crank shaft and slowly turn the screwdriver,this will force the E-clip out but becarful cause these things can go flying off pretty easy!