Lightened Flywheel

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spanner boy
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Lightened Flywheel

Post by spanner boy »

I'm thinking of trying a lightened flywheel but I'm concerned about the effect on the durability of the bottom end. My question is how does this compare to the SP1? Is the flywheel similar but lighter, are the bearings similar dimensions and what about the crank train and compression ratios. I know the engine is significantly different but don't know the details?
tony.mon
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Re: Lightened Flywheel

Post by tony.mon »

Storm bottom end is very strong and copes without any issues with flywheel changes, increases in piston comp ratios and all manner of tuning up to quite extreme tuning levels..

The weakness at 140 bhp plus, if you can get there, is that the sa pivot on the rear of the gearbox can crack.
You won't cause any damage by fitting a light flywheel.
It's not falling off, it's an upgrade opportunity.
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fabiostar
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Re: Lightened Flywheel

Post by fabiostar »

the lightweight flywheel wont cause any harm, in fact your reducing the stresses on that side of the engine by removing a dirty great weight. iv done about 16 of them in the last year for folks with positive results :thumbup: :thumbup:
the older i get,the faster i was :lol:
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StormyRob
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Re: Lightened Flywheel

Post by StormyRob »

spanner boy wrote: Wed May 02, 2018 5:18 am I'm thinking of trying a lightened flywheel but I'm concerned about the effect on the durability of the bottom end. My question is how does this compare to the SP1? Is the flywheel similar but lighter, are the bearings similar dimensions and what about the crank train and compression ratios. I know the engine is significantly different but don't know the details?

I have another flywheel on the way. It, like the previous 4 or 5 will be for sale. You could buy it and keep your old one just incase you do not love the mod 😁
If you don't try you never know if you can do it.
spanner boy
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Re: Lightened Flywheel

Post by spanner boy »

How much do you take off?
spanner boy
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Re: Lightened Flywheel

Post by spanner boy »

Thanks guys how does it compare to an SP1?
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fabiostar
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Re: Lightened Flywheel

Post by fabiostar »

spanner boy wrote: Wed May 02, 2018 9:44 pm How much do you take off?
they all start off around 7.4 lbs give or take

well i kinda do 3 types. a light road skim. in around 6 lbs.
then a fast road/track in around 5.2 ish pounds
then a dont blame me if your clocks smash your face in weight. just over 4.5 lbs.

honestly the middle one for general use is the best.
the older i get,the faster i was :lol:
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E.Marquez
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Re: Lightened Flywheel

Post by E.Marquez »

spanner boy wrote: Wed May 02, 2018 9:44 pm How much do you take off?
A lot :lol:

At one time I was offering three levels, but after several years and a bunch of on bikes now, I really dont feel the needs for anything less than the lightest version.

All three versions have been used back to back by a first bike new rider, myself, and a rider/ racer with a pro license

All three of us (ok I'm biased..lol) chose my 4lb 7oz version (2012 grams)
No one had any stalling issues or concerns, no gear change issues and all clearly noticed the lighter flywheel effect.
We had 2 non riders doing the blind swaps... all three SH had 5 flywheel changes over the 6 hours of ride time. two us were giving back to back "no change" flywheel swaps to see if the "felt " difference was really felt or in our heads.... Both of us reported we felt no difference and assumed we had been giving a heavy to middle weight change and we just assumed the difference was too small to notice. Ride course was public road, though almost no traffic and it was a repetitive course, no stop lights, but 7 stop signs so starting out from a dead stop was part of the test ride.

Non of that is scientific, and it was just 5 blokes playing researcher. Likely a real R&D guy would point out all the mistakes and assumptions we made .. But, we did come away with some real results leading me to decide to only cut the one style now.
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spanner boy
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Re: Lightened Flywheel

Post by spanner boy »

Well done sounds like you've been enjoying yourself. Going to do a few more miles and then decide. Thanks for the help.
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fabiostar
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Re: Lightened Flywheel

Post by fabiostar »

E.Marquez wrote: Thu May 03, 2018 7:58 pm
spanner boy wrote: Wed May 02, 2018 9:44 pm How much do you take off?
A lot :lol:

At one time I was offering three levels, but after several years and a bunch of on bikes now, I really dont feel the needs for anything less than the lightest version.

All three versions have been used back to back by a first bike new rider, myself, and a rider/ racer with a pro license

All three of us (ok I'm biased..lol) chose my 4lb 7oz version (2012 grams)
No one had any stalling issues or concerns, no gear change issues and all clearly noticed the lighter flywheel effect.
We had 2 non riders doing the blind swaps... all three SH had 5 flywheel changes over the 6 hours of ride time. two us were giving back to back "no change" flywheel swaps to see if the "felt " difference was really felt or in our heads.... Both of us reported we felt no difference and assumed we had been giving a heavy to middle weight change and we just assumed the difference was too small to notice. Ride course was public road, though almost no traffic and it was a repetitive course, no stop lights, but 7 stop signs so starting out from a dead stop was part of the test ride.

Non of that is scientific, and it was just 5 blokes playing researcher. Likely a real R&D guy would point out all the mistakes and assumptions we made .. But, we did come away with some real results leading me to decide to only cut the one style now.
pretty much sums it, go home or go large, or small in this case :thumbup:
the older i get,the faster i was :lol:
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E.Marquez
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Re: Lightened Flywheel

Post by E.Marquez »

fabiostar wrote: Fri May 04, 2018 10:20 am pretty much sums it, go home or go large, or small in this case :thumbup:
Working on a new flywheel for my bike right now... Needed an oil change to go with the new radiators, new micro bearing shift star and selector lever..so figured why not a new lighter flywheel as well. Trying for sub 4lb 7 oz (2013 grams for you blokes...lol)
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8541Hawk
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Re: Lightened Flywheel

Post by 8541Hawk »

Well once again I guess I get to be the contrarian and say it might not be the best, for all riding styles, to just take all you can off the flywheel.

Sure you get quick acceleration but are there any downsides? I'm not saying you will have engine issues, enough miles have been done with them to feel confident that reliability is a non-issue

Instead its a rideablitiy thing. I do have pics of different race bikes with interchangeable flywheels, different weights for different tracks
or race teams are known to adjust flywheel weight for rider style and where the bike is going to be run. Though in our case we only get to pick one.


Also, taking a clue from what Roger has done (his flywheels for the VTR are much heavier than the ones out now) and one might wonder if the lightest flywheel around is actually the best.

I know I am coming from my own experience and also the locations that I ride. I have a few sections that are a bit faster than some folks get to ride.
To give an idea to can youtube "Upper Big Tujunga Canyon Road" or "9 mile" and you can see one section of my local ride.
It is what we call a "National Forrest" which means there are no side roads or cross traffic. The main limiter to the speed carried is that 96mph is go to jail and have your bike impounded.
Then to counter the fast bits we also have "Little Tujunga" on which you will never get out of 2nd. So the bike needs to do super tight and twisty and also top end runs.

This last weekend while on Upper Big Tujunga I was chasing down a pack of GSXRs and was turning between 7-9K in 3rd and 4th.
In this situation, I believe a ultra light flywheel would actually slow you down as, again IMHO, you would not be able to get back to the throttle as early or as hard as you can with a slightly heavier flywheel.
I can also say that with my only slightly lightened flywheel, these bikes rev really quick once you get past 7K with a handful of throttle :angel:

Though I do also like the stock 1\4 turn throttle for the same reason.

With all that, run whatever you want but always remember that nothing is "free" there is always a trade off.

Gain power, lose mileage
Gain traction, lose tire life

Lighter flywheel....
Gain acceleration, lose ??

I mean you have to loose something..... :thumbup:
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Stephan
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Re: Lightened Flywheel

Post by Stephan »

Dont want to start argue as it is down to personal taste, but i am on the same boat. Rogers cut and 1/4 throttle for me.
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fabiostar
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Re: Lightened Flywheel

Post by fabiostar »

im lucky in that i have two bikes i can ride back to back... the yellow one suits the mid weight flywheel. the same as roger done.. its what that bike is used for, bit of touring, work days, general faffing about..

the lighter one i run in the other bike is more suited to what that bikes used for... riding like a tw@ on a sunday morning.. :clap: :clap: :clap:
the older i get,the faster i was :lol:
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VTRDark
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Re: Lightened Flywheel

Post by VTRDark »

Are you saying that you have gone lighter than the mori spec in the mori engine then :confused I too question why did mori stop at where they did. I'd love to know the reason why and there must be one. Is it down to ridability or is there some other reason. Maybe that is at the point where going any furthur does not equate to beneficial gains accept the seat of the pnats.
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