Hypothetically- M900 mods.

[Goofle]

If I was to try and get the best from an early M900, what could the improvements be?
So far - reworked front and rear suspension (Maxton and Wilbur).
Keihin FCRs. (An ongoing idea, currently awaiting new seals)
Tyres - Sat on Diablo Rossos at present, Supercorsas (medium) waiting to be refitted post mot)
The criteria are... actually, no. I’m not making any!
I know it’ll never keep up or outhandle with a Triumph Speed Triple - but how could it get closest??

Just a ‘for fun’ thread, really, I’m not saying I’ll go out and do any. I know that the whole magic of the bike isn’t Bhp!

[Goofle]

Oh, not a turbo as one on eBay is sporting either!

[Nasher]

Decent Battery.
Rebuilt fuel pump.
Ignitech Ignition module

[slob]

monobloc front calipers/radial master cylinder
carbon or magnesium wheels

depending on your base motor
cylinder head work/cams/big valves
bigger pistons
lighter flywheel

[Flip]

As far as suspension goes I can only speak from my experiences for both the transformation of the bike afterwards and the customer service (initially and later for service work) I received from both companies I chose to use:

Maxton GP20 Fork conversion
Nitron NTR R1 rear shock

Then probably one of the best real world tuning exercises ever done to a 2v motor:

http://www.sigmaperformance.com/torquemonster.html

[mickj]

Originally Posted by slob

monobloc front calipers/radial master cylinder
carbon or magnesium wheels

depending on your base motor
cylinder head work/cams/big valves
bigger pistons
lighter flywheel

Why a lighter flywheel, I thought it would make the engine more peaky?

[Goofle]

Mmmmm, Interesting ideas...

[slob]

Originally Posted by mjgt

Why a lighter flywheel, I thought it would make the engine more peaky?

indeed, it’ll pick up revs faster, at the expense of some smoothness. you definitely would building a race/track motor.

probably look a twin plugging the heads too, since this is a theoretical exercise

[Darkness]

Originally Posted by slob

indeed, it’ll pick up revs faster, at the expense of some smoothness. you definitely would building a race/track motor.

Isn't the weight reduction insignificant unless you are in neutral or have the clutch released?

The weight of the back wheel and tyre are more likely to affect pickup whilst riding?

[slob]

every part counts

i was surprised, running in a big bore motor with lightened flywheel, how fast it revved as i aimed to take it to 6k rpm and had trouble stopping the tacho needle at the desired point.

lighter wheels will almost certainly give you the most ‘bang for your buck’, but the suspension is equally important, since no amount of power or brakes is any good if the tyres aren’t in contact with the tarmac

[Dukedesmo]

My Monster started as a project with just a frame and an engine and I did most of the above, including, big-bore, hi-comp, gasflowed heads, split-single Keihin FCR41 carbs, Ignitech, Ohlins, Radial calipers, light flywheel/clutch, Spaghetti headers, termis etc. and whilst it did get a 'tad' out of control spend-wise, it turned out good.

The light flywheel, combined with the (chokeless) Keihins does make it a bit stall-prone when it's cold but once warmed up it picks up speed instantly on the throttle and pulls strongly throughout the rev range meaning that it makes more torque up to 6,000 rpm than my (also tuned) 916, despite having 30hp less at the top end.

It is a bit 'lumpy' at anything under 2,500rpm but still manageable in traffic and certainly has lots of 'character'.

[Darkness]

Physics dictates that rotational inertia impedes acceleration, which is why a lighter flywheel is considered to be a performance mod.

Less rotating mass = more acceleration, if all else is equal.

I was hoping someone had done the maths on costs and comparative effects of losing 1Kg from the flywheel, rear sprocket, and back wheel & tyre?

Weight reduction of the sprocket, wheel and tyre also has the benefit of reducing unsprung weight making the suspension’s job easier too.

[utopia]

Originally Posted by Darkness

Physics dictates that rotational inertia impedes acceleration, which is why a lighter flywheel is considered to be a performance mod.

Less rotating mass = more acceleration, if all else is equal.

Yes, one of the effects which I wasn't really expecting from fitting my carbon wheels was the improvement in acceleration of the bike.
It stands to reason I guess but I hadn't expected the effect to be large enough to notice.
In fact, I've ended up dropping another tooth off the rear sprocket as a result of the improved straight line performance.

[Luddite]

Originally Posted by Darkness

I was hoping someone had done the maths on costs and comparative effects of losing 1Kg from the flywheel, rear sprocket, and back wheel & tyre?

There's a very simplified calculation ('force = mass x acceleration') in the Ducati Up North article on lightened flywheels http://www.ducati-upnorth.com/tech/flywheel.php which also touches on the benefits of lighter road wheels.

Here's an extract:

"When you remove weight from the flywheel (and to a lesser degree, from the clutch) the effect on the engine’s ability to more quickly spin-up is indistinguishable from increasing your engine’s torque (and consequently horsepower) output.

But only in neutral. In any other gear, there’s little benefit at all.

Obviously, your bike’s ability to accelerate faster through the gears is enhanced by reducing the overall weight of the bike as well as the inertia of rotating components. The crankshaft, pistons and connecting rods, transmission gears, drive chain and sprockets, wheels and tires, clutch and flywheel are all candidates.

However, the overall weight of the bike and rider completely overwhelms any reduction of rotational inertia produced by a lighter flywheel. A kilogram lighter flywheel on a 300 kilogram bike-plus-rider will accelerate only 0.3% faster. F=ma.

Of course every 0.3% helps a racebike. When you reduce weight you’ll get faster acceleration, and faster lap times - IF - you can modulate your wheel spin driving out of corners. Factory racebikes make so much power, for example, that transmitting the power to the road effectively becomes the limiting factor - so heavier flywheels actually become a benefit. Fear the high-side."

[Darkness]

Thanks Luddite. Yes, I’ve read that post previously but it doesn’t really answer my question.
The 0.3% improvement mentioned is solely due to the reduction in mass, a three hundredth of the weight of bike and rider. It completely ignores rotational effects.

https://en.m.wikipedia.org/wiki/Newton's_laws_of_motion

It should be possible for me to get my remaining brain cells to quantify the change, I was just hoping someone had already done it!