... some new stuff!! A service to lighten your primary gears. You send us your gears - £70 cost includes return post to a UK address (Individual gear £35). We can also modify your flywheel if it does not have the ignition trigger on the outer rim. We now manufacture Aluminium intake trumpets for both the injected and carb 2v bikes - £75 for a pair (includes post to a UK address)
We are on a mission to remove 10kg from a customers engine (for racing next year) - these primary gears are part of the stratergy along with the flywheel, aluminium clutch basket/plates and aluminium cam pulleys. There are others but much less relavent to a 'standard' bike. In addition the loss of rotational inertia helps increase acceleration of the engine (and therefore bike) and the feel of engine breaking. Some will say that removing this weight makes the engines prone to stalling but this is not my experience. The trumpets I like the look of when fitted and they improve the air flow in to the engine.
We make them at 50mm long so you can shorten them if required for your bike. Longer is possible as are ones for 4v. Not done yet as we're not building a 4v engine at the moment.
And there are people telling me Dd bikes don't accelerate better with lighten flywheel and components so cant be cheating ;-) Interesting post tho, as I'm keen to understand the benefit of lightening stuff like primary gears. Does it make a noticeable difference or is it one of those things that you get benefit by doing all of the changes but one or two really isn't worthwhile?
As with all things it's a deminishing return thing. Start with removing weight from the heavy components and carry on to the light components. Crank - not the easiest to lighten without causing the balance issues. Flywheel - easy to lighten if the ignition triger is not on the rim. Clutch - easy to lighten if there is no aluminium basket and plates already fitted. Primary gears - easy to lighten once the crank gear is removed. care is needed with how much material is removed.
How do you guarantee that you maintain harmonic balance given that you are removing metal of a given weight against inertia of the crank? Surely once metal is removed from this area crankshaft balance must come into play? Great idea but being as all inertia is in the same plane then are there problems?
Its difficult to guarantee maintaining harmonic balance when the balance has a habbit of being poor out of the factory. Just about every engine we build gets the crank rebalanced as an assembly including primary gear, flywheel and the piston/conrod set.
