Just a minor clarification. I'm pretty sure CVT refers to Continuously Variable Transmission.how a constant velocity transmission works.
Hi qaz, you ask the question. Chatman is about right in what he is saying. The heavier the weights the more this may stress the engine. It depends how heavy you go and what sort of riding you do as to whether this is a problem. You'll find the burgman 400 engine a bit different to what you are used to. Ok so why does it stress the engine? All the Burgman 400's are short stroke engines. As you may know, this means they have low piston speed inspite of high rpm. That's compared to a long or longer stroke motor. This makes it a lowly stressed engine even when cruising at high rpm. It's happy and will last and last! This means the engine is designed to rev to be efficient, develop it's power, and importantly, to last a long time. For example, one of my customers put 21g slider weights in his 2008 400 and it laboured in the sort of riding he did. It felt like the bike was overgeared and it wasn't developing the power it needed. Sure it cut the revs down, but too much for most of his riding. He was revving at just under the 6000rpm mark at actual 70mph (indicated 75). This was making his engine labour. It was like riding in too higher gear. He was using more fuel not less. Headwind slowed him unless he wound the throttle wide open. Not good. All this was causing his engine stress. Short stroke high revving engines don't like low revs under load as it increases compressive wear factors on the engine bearings and piston/rings etc. It can have a significant effect on engine wear, increasing it exponentially. How much it may affect a particular engine depends on how it's ridden ie: country roads mostly or highway work at speed. Also whether the bike is used two up or solo and the weight of the rider too. You prolly know all that though. So choose your weights carefully. Others on here have tried 21g plus and found them to be unsuitable, overgearing in effect the bike for normal cruising. But others have found the sweet spot weight for them and the way they ride. Good luck with what you want to do and let us all know how you are getting on with it. You may have to experiment a bit to find what you are looking for.Chatman- The " constant velocity" remark started among my friends who all ride as a ribbing to me because of the sound the scooters make which is a constant drone under acceleration. I have heard it so much, that now I refer to it as such, but I do know the correct name for CVT. You have to admit, they do make a constant droning sound.
The statement was made that if a person changes the roller weights much heavier than factory that it would stress the engine and I wanted to know how?
This is just about the only post in this thread that displays intimate knowledge of how the CVT (Continuously Variable Transmission) drive in our scooters, most scooters, and most snowmobiles works.Just a minor clarification. I'm pretty sure CVT refers to Continuously Variable Transmission.
But to the original topic...
You basically have three potential variables in play. The engine rpm, the weight of the rollers/sliders and the torque load on the driven plates. All three interact to deliver the end result. Increase rpm attempts to drive the variator plates together. Counteracting this is the spring force in the driven plate assembly and the effect of torque causing relative rotation of the driven plates to each other. This relative rotation of the two driven plates in reaction to the instantaneous torque demand adds to the spring force to attempt to keep the driven plates apart. Increasing your roller/slider weights in effect adds a scale factor to the rpm contribution so things tend to start transitioning at lower rpms. At the operational endpoints things will be pretty much the same, e.g. initial rpm vs speed and cruising rpm vs cruising speed will not change much for a given system, either sliders or rollers. The weight of the rollers really comes into play with how the scooter behaves during acceleration and in the middle speeds.
Not excruciatingly correct, but reasonably good for imagining how stuff works.