Casatronic flywheel weight

[GT Guy]

I've just fitted a Casatronic kit to my RB20. All went well and fired up ok. Lights all working and strobed to 24 degrees. The 2 kg flywheel has been out of stock so Dean at Rimini kindly had a heavier one machined down to 2kg. This bike ran with an AF light flywheel before but I was always having issues with stators and mismatched components. Unfortunately the heavier weight has killed the performance. I'm really shocked how it has affected it. It takes much longer to pick up any get into the power band. Has anyone machined one down to make it lighter or know of any issues with doing it? A bit drastic maybe but it's just not the same bike

Cheers

Guy

[dscscotty]

yes they can be machined down further to lighten, AF Ducati type flywheels weigh around 1.4kg,

[GT Guy]

Thanks. That's the sort of weight I'll aim for

[bluebob]

is there a reason you think the problem is the flywheel rather than the new ignition system?i have never used a lightened flywheel,but the change in performance you describe seems a bit drastic to be just the flywheel.hopefully someone in the know will be along shortly to point you in the right direction.when you strobe it does it retard like you expect it to.

[GT Guy]

It regards some 9-10 degrees as it should. I did try a 2kg flywheel previously and it had a similar effect. I thought I'd try again with this one just in case it was a timing issue before. This suggests that it's down to weight. I'm having it machined next week by friend who does the Avanti kits. I'll report what happens

[Warkton Tornado No.1]

I agree entirely with the desire to have a lighter flywheel with a tuned motor.

There’s no doubt in my mind(!) that the lessened inertia makes for much crisper pick up & the lighter mass is more forgiving when changing down through the gears.

Of course it’s a case of ‘horses for courses’, but even with a J125 flywheel on a points ignition, even I can obtain a steady tickover...

[Wack]

A word of warning is don't follow the taper of the flywheel as it gets thin towards the front. The last one I did ended up at around 115 mm diameter on the bottom and altered the angle to take more off the lower part of the taper.

[GT Guy]

The Casatronic flywheel is lightened by machining from the outer to the inner as you are suggesting. I would expect material to be removed from the outer face/edge when it gets done

[bluebob]

GT guy,hope you get sorted and be interesting to hear how you get on.I have just reread your original post .as I said before I am not clued up on the subject of lightened flywheels but the way I read your post is this.due to problems you buy a new casa ignition kit.you want a lightened flywheel ( for the reasons WT mentions).you fit the new kit,and you say the lack of performance is shocking.what I don't get is why such a dramatic change,and if the flywheel on its own can improve performance to such an extent why do we all not use them.if we were talking the difference between a standard flywheel and a very light flywheel then I guess you would expect a noticeable difference,but between a 2kg flywheel and an even lighter one is it going to ruin the performance of your engine?be good to here from some rb owners.

[Warkton Tornado No.1]

GT guy,hope you get sorted and be interesting to hear how you get on.I have just reread your original post .as I said before I am not clued up on the subject of lightened flywheels but the way I read your post is this.due to problems you buy a new casa ignition kit.you want a lightened flywheel ( for the reasons WT mentions).you fit the new kit,and you say the lack of performance is shocking.what I don't get is why such a dramatic change,and if the flywheel on its own can improve performance to such an extent why do we all not use them.if we were talking the difference between a standard flywheel and a very light flywheel then I guess you would expect a noticeable difference,but between a 2kg flywheel and an even lighter one is it going to ruin the performance of your engine?be good to here from some rb owners.

I hope GT Guy doesn't mind my attempt @ explanation :

When I said ‘horses for courses’ I meant that a light flywheel will tend to suit an engine that has been tuned for its power to be generally in the upper range which is so often a compromise that the owner is willing to make. The consequences are that full use must be made of the gearbox to keep the engine ‘on song’ which doesn’t suit all riders. However, there is no doubt that such an engine can be exhilarating, even if to make rapid progress on twisty roads there is a lot more gear changing required. Lambrettas fitted with race rotors will have very little ‘flywheel effect’ weighing, as they do, about 330 grams, but riders adapt to them quickly, as the performance is addictive...

On the other hand, a full weight flywheel will tend to suit standard states of tune, or engines that have been torque tuned to make their power within the lower range. Again, an engine modified in such a manner that is ‘grunty’ can be a joy to ride, particularly if covering some distances as many rally goers would probably confirm. An engine fitted with a heavier flywheel should be a lot more difficult to stall & might feel perceptively smoother.

Ultimately, the flywheel mass will not affect the actual flat out speed of either type of engine, or the difference would be negligible.

The flywheel mass will only have any bearing upon the way the engine behaves in the manner that it gets there. I'm fairly certain that is what GT Guy is trying to re-create by reducing the weight of the Casatronic flywheel.

[Fast n Furious]

By reducing the weight of the flywheel we are actually looking to reduce the inertia effect, and that depends where on the flywheel material is removed as to the amount inertia reduction you get.
Very often, machined down flywheels lose their balance characteristics because the area where the balance holes used to be are now gone. Re-balancing after machining down is highly recommended for a more comfortable ride with longer life from the engine.
Ideally, we could do with dual or even variable mass flywheels to get the best of both worlds!

[martin1310]

V/tronic fly wheel can be supplied @ 1.3kg no need to have it turn-down jobs all ready done

[GT Guy]

Thanks again for your replies chaps. WT your explanation is spot on. The previous flywheel weighed 1320 g fins removed. This would be my target weight but as F n F says where the material is removed will have the affect on inertia. In my case I'm pretty sure that the diameter of the flywheel will be reduced thus reducing inertia so could I aim for a slightly heavier weight but still gain the same improvement? I was able to achieve a decent tickover with the previous flywheel, perhaps because it was still the full diameter. If I lighten to 1320 g i guess I might achieve a better pickup than before given the reduction in diameter/ inertia. There are no balancing holes in this flywheel so presumably by taking the material away on a lathe it should remain balanced.

[mcbrid]

Any news on this project GT Guy?