Curvy lightened Flywheel assembly

[millemille]

Suzuki chose to fit the SV650 with a heavy flywheel assembly; made of the flywheel itself and the starter sprag bearing housing.

The Curvy has a very, very heavy flywheel. The Pointy slightly less heavy, but still not light.

Suzuki did this to make the bike novice friendly because the rotating flywheel assembly has massive inertia; so the bike is difficult to stall, easy to launch from a stand and reduces engine braking.

But this has several drawbacks;

It give the crank a very hard time, particularly at high rpm, because every time each cyclinder fires the crank is trying to accelerate but the inertia of the flywheel assembly resists this and is trying to twist the crank. This can lead to...

http://imagizer.imageshack.us/v2/640x480q90/913/9rUiCm.jpg (https://imageshack.com/i/pd9rUiCmj)

It blunts the performance and character of the engine because the heavy flywheel assembly is slow to accelerate and slow to decelerate.

It slows the bikes ability to change angle of lean (roll) because you're trying to effectively move the axis of rotation of very heavy gyroscope.

It makes it easier to lock the back wheel of down shifts if you're a bit clumsy with the clutch and revs.

I couldn't find anyone in the UK who sold off the shelf lightened flywheels or would lighten the flywheel on a one-off basis who I trusted to know what they were doing and didn't want an extortionate amount of money to do so.

So together with 2 other engineers we have designed, FEA'd, machined and tested, over several thousand miles, a lightened flywheel assembly for the both the curvy and pointy SV650.

We machine down the Sprag housing on a 3 axis Hass CNC mill using bespoke jigs...

http://imagizer.imageshack.us/v2/640x480q90/540/xslwQl.jpg (https://imageshack.com/i/f0xslwQlj)

After machining...

http://imagizer.imageshack.us/v2/640x480q90/538/2U2zQG.jpg (https://imageshack.com/i/ey2U2zQGj)

That's a saving of between 1/2 and 3/4 of a lb, depending on whether it's a Curvy or Pointy.

There are pictures of lighter sprag housings on the net, but we weren't convinced that going any lighter was a good idea. We've kept the circumference that ensures the sprag housing is accurately located on the flywheel locating studs...

http://imagizer.imageshack.us/v2/640x480q90/913/pRT0V8.jpg (https://imageshack.com/i/pdpRT0V8j)

...and we've kept the 6 bolts, rather than reducing to 3, to ensure balance is maintained.

We also machine down the flywheel itself, again using bespoke fixtures.

Here's a lightened curvy complte flywheel assembly...

http://imagizer.imageshack.us/v2/640x480q90/673/nmow7E.jpg (https://imageshack.com/i/ipnmow7Ej)

A total weight saving of 1.27 lb, which is massive when you're talking about rotating engine components.

Here's a lightened pointy complete flywheel assembly....

http://imagizer.imageshack.us/v2/640x480q90/537/HPcdcd.jpg (https://imageshack.com/i/exHPcdcdj)

A total weight saving of 3/4 lb, again a significant weight saving.

We've also done a flywheel with 3 magnets (for TD's or racing if you want to keep a charging system) that weighs ~1,100 grams and a total loss flywheel with no magnets that weighs ~950 grams.

We check the balance after machining, and if neccesary rebalance to with 1 gram, which is better than what Suzuki let them leave the factory at.

The bike is significantly improved with the fitment of a lighter flywheel assembly - faster accelerating, reduced engine vibration, quicker/easier to lean, smoother down changes...all in all it releases the true v-twin character of the engine. There's still enough weight there to not make the bike any more difficult to pull away.

Having thoroughly tested and validated the design we're happy to start selling them and are confident enough that the benefits are immediately obvious we'll offer a money back warranty if you're not immediately happy.

£145 to lighten your flywheel, with a 7 to 10 day turnaround (normally quicker than that).

We can also offer titanium bolts to replace the 6 steel bolts holding the assembly together, these save another 36 grams and cost £40 a set.

Please PM me if you're interested - this has been cleared with Admin.

[maviczap]

Cool sounds like a winter swap over will be on my to do list.

[Davemurphy007]

Definitely interested in getting a set of these fitted!

Are any other parts required to fit these? What's the process to change one of these and what sort of time do you reckon to change them? Are you looking at a ride-in, ride-out service or would you need the bike for a couple of days!

[millemille]

Definitely interested in getting a set of these fitted!

Are any other parts required to fit these? What's the process to change one of these and what sort of time do you reckon to change them? Are you looking at a ride-in, ride-out service or would you need the bike for a couple of days!

Clean engine, drain the oil, remove the generator cover, undo the alternator bolt, remove old flywheel, fit new flywheel, torque up alternator bolt, fit generator cover with new gasket, fit drain plug with new washer, fill oil (either reusing old or with new).

Parts needed are sump plug washer and generator cover gasket.

You'll need a flywheel holding tool and a torque wrench capable of 120NM.

If nothing seizes or breaks it's a ride in/ride out service taking about 30 minutes.

[Davemurphy007]

I'd be bringing it to you to do. Do you have stock of the genny cover gasket and the sump washer or would I need to provide these (along with some new oil and a filter I reckon, I'm not a fan of re-using engine oil).

[millemille]

I'd be bringing it to you to do. Do you have stock of the genny cover gasket and the sump washer or would I need to provide these (along with some new oil and a filter I reckon, I'm not a fan of re-using engine oil).

Gasket and sump plug washer are included in the £30 fitment charge.

I can source oil and filter if needed, at retail prices, or you can bring your own.

[Davemurphy007]

Excellent stuff. Give me a couple of weeks to get back in the country and I will get in touch to arrange fitting :-D

[Nicky S]

I like this post :)

Would you ever think of just selling them with out having the oem one sent to you ??


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[millemille]

I like this post :)

Would you ever think of just selling them with out having the oem one sent to you ??


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Yes.

£145 + whatever it costs to replenish the float with a 2nd hand one.

I'm going to put a post in the wanted section for more flywheels due to the interest we've had....

[Nicky S]

Ok cool what are the prices from Suzuki ??? Or will we all have to get loans ??


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[millemille]

Ok cool what are the prices from Suzuki ??? Or will we all have to get loans ??


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:D

No, 2nd hand is fine as long they're in good condition.

I've bought a few over the last week or so and have paid between £35 and £70 for them.

[maviczap]

Might just post mine to you, once I've taken it off to install the off set woodruff key I've had hanging about to fit. Kill two birds with one stone then.

Plus pull my finger out & install the pointy cams I've also got to install

[millemille]

Might just post mine to you, once I've taken it off to install the off set woodruff key I've had hanging about to fit. Kill two birds with one stone then.

Plus pull my finger out & install the pointy cams I've also got to install

Just done exactly that work on one of my SV engines!

[millemille]

Thanks to everyone who's bought a flywheel or made an enquiry...

All of the ones ordered have been despatched and more are being machined and assembled.

Here's a sprag housing being machined earlier tonight on the Haas CNC mill...

http://imagizer.imageshack.us/v2/640x480q90/540/xslwQl.jpg (https://imageshack.com/i/f0xslwQlj)

[millemille]

Titanium bolts - £40 a set.

OEM steel bolts...

http://imagizer.imageshack.us/v2/640x480q90/537/TEuHuL.jpg (https://imageshack.com/i/exTEuHuLj)

Titanium bolts....

http://imagizer.imageshack.us/v2/640x480q90/537/CWzxwG.jpg (https://imageshack.com/i/exCWzxwGj)

[millemille]

We've now got Pointy flywheels as well.

Original post updated.

[toshy595]

Hi, very interesting thread, can you please text me a tel no so we can discuss a drop of & fit as discussed in previous thread? 07772623226 Cheers Regards Andy oh btw K4 Sv650s


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[tadekk]

I am very interested, I will be eagerly looking for some testimonials from happy pointy riders!

[millemille]

Hi, very interesting thread, can you please text me a tel no so we can discuss a drop of & fit as discussed in previous thread? 07772623226 Cheers Regards Andy oh btw K4 Sv650s


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No problem, I'll give you a shout over the next couple of days....

[CLARKYsv]

I live on Canvey. Fitting service would take how long? Do I have to drop the bike off or can it be done while I wait etc? :)

[millemille]

I live on Canvey. Fitting service would take how long? Do I have to drop the bike off or can it be done while I wait etc? :)

If all goes well fitment takes about 45 mins.

Yeah, you can stand there and watch if you like....

Mike

[CLARKYsv]

Once the bike has been Mot'd I shall be down to you for the Full Padoodle.

Then its the Cam swap for me and et voila... bike done haha :)

[jambo]

et voila... bike done haha :)

A bike is never really finished though is it? ;)

Jambo

[CLARKYsv]

A bike is never really finished though is it? ;)

Jambo

With a GSXR front end
Pointy Nose
Vapor clocks
Gsxr1000 tail
Dual pipes
Zx10r shock
Gsxr 600 rear wheel

..... I don't want to do much more... time to ride the baby haha :D

[Davemurphy007]

Looking forward to getting mine fitted in the morning, will report back on how it feels.

[Bibio]

might be interested in one of these over the winter.

if you have access to a mill have you thought about making radial brake legs/brackets. the bracket would bolt onto the original fork leg lugs but allow you to use radial brakes. i think a lot of people would be very interested in that.

[millemille]

might be interested in one of these over the winter.

if you have access to a mill have you thought about making radial brake legs/brackets. the bracket would bolt onto the original fork leg lugs but allow you to use radial brakes. i think a lot of people would be very interested in that.

That's an interesting idea, thanks, and we'll have a think about it...

[millemille]

I won't put words into Dave's mouth, but I think he's quite happy with his new flywheel.....

http://imagizer.imageshack.us/v2/640x480q90/907/N7Cy3C.jpg (https://imageshack.com/i/p7N7Cy3Cj)

[millemille]

Thanks very much to everyone who's bought one of the flywheels, hopefully all of you who've got one fitted are happy with the performance and handling improvements....

We're changing slightly how we deal with the flywheel orders from now on.

Of the 8 flywheels we've received in exchange for lightened ones, 2 of them are not fit for further use. Obviously the customers weren't to know that and supplied them in good faith so we'll bear the cost, but we can't afford to carry on with that attrition rate.

We also thought that all flywheels were interchangable, within the same model type, as the part numbers are all the same. However this isn't the case - there appears to be an occasional bike where the flywheel and crank are matched due to tolerance build up of the tapers and you can't fit another flywheel. Many thanks to toshy595 for his patience and understanding whilst we sort this out on his bike.

So from now on, rather than supplying flywheel assemblies on an exchange basis, we will machine your own flywheel and return it you. We can turn round a loose flywheel in 7-10 days absolute max, normally quicker. If you want it fitted we can machine it whilst you wait if you bring your bike to our unit in Basildon.

[toshy595]

No worries, as an engineer too, I empathise with your project completely, as much as I wanted to be embracing the performance upgrade, patience is a virtue. & I believe to marry the same parts lightened, to be a much more efficient & reliable way forward in your venture. Will liaise next week to arrange the upgrade👍


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[millemille]

We recently sold a lightened flywheel assembly to a customer by the name of Lawrence in Manchester who has a pointy SV650.

His flywheel had Ti bolts and was 0.81lb lighter than standard.

Here's some of his feedback...

"It definitely turns much more nicely now..."

"With regards the acceleration, it feels perkier all round, when the revs get above about 8500 it feels much freer revving. The most obvious thing is still donking it down through the cogs quickly, the revs just surge up with no problems at all, the back end doesn't even think about locking up, it's really good."

Also bear in mind that the pointy flywheel is a fair but lighter than the curvy flywheel to start off with. A curvy flywheel can be made 1.27lb lighter than stock, so the improvement in "feel" will be more pronounced on a curvy.

[squirrel_hunter]

Well I thought I'd post something up in case any one was considering this. While I can't give any feedback on the flywheel once installed I can show a couple of pictures I took and comment on the great service I got from millemille.

I sent a spare flywheel I had off and in about a week I got a modified one back for use on a road bike. So I thought I'd take a couple of pictures side by side with another spare to see where the mass is removed from.

http://i153.photobucket.com/albums/s216/squirrel_hunters_photos/Spannering/DSC_0850_zpszzxaon3x.jpg

http://i153.photobucket.com/albums/s216/squirrel_hunters_photos/Spannering/DSC_0848_zpsa7ienbhr.jpg

Modified is on the right.

While I was doing this comparison I noticed that there were no longer the timing marks on the wheel so contacted millemille. He said that while the timing marks are not the most accurate and that the cam lobe position can be used for getting the right position for the valve clearances, I wasn't the first person to ask. Thus he was putting the marks back on in the later batches and if I wanted I could have them added to mine. So as I need all the help I can get I sent mine back to have the marks put on. Which was also quite useful as I also asked for the TI bolts.

About a week later the flywheel came back with the bolts and marks on it. So I decided to compare the weight on my not 100% accurate cheapo scales.

http://i153.photobucket.com/albums/s216/squirrel_hunters_photos/Spannering/DSC_0883_zpsauphlwol.jpg

http://i153.photobucket.com/albums/s216/squirrel_hunters_photos/Spannering/DSC_0892_zpsrughs2by.jpg

Quite a weight saving.

So while I cant comment on the results yet the service was beyond fault and I'm very happy with the flywheel I have. Have to wait a bit before its used in anger. Just thought I'd post this up in case anyone was wanting to hear first hand from a customer if they were thinking of getting one.

[maviczap]

Yep, its on my to do list. Cam swap first, then this, and the stepped timing key at the same time.

[millemille]

Thanks for the kind words @squirrel_hunter, we aim to please.....

If anyone is interested I've got a few 3 magnet flywheels for race bike use, both curvy and pointy, which can be had for a 10% discount if on exchange or for £175 (steel bolts) if bought outright.

[curlylee]

How much for a pointy with titanium bolts outright posted cheers lee

[millemille]

How much for a pointy with titanium bolts outright posted cheers lee

6 or 3 magnet?

[curlylee]

3 for track bike

[millemille]

3 for track bike

I've got one 3 magnet pointy flywheel left that I can do with Ti bolts for £210 posted.

[millemille]

Just a quick one...

Anyone posting flywheels in for lightening; PLEASE, PLEASE, PLEASE pack your flywheel with loads of bubble wrap and other shock absorbing packing. A customer has sent in a flywheel with no protective packing, just in a box, and it's got destroyed in the post. Flywheels are not designed to survive sharp impacts and the magnets will come off/shatter/split, rendering your flywheel fit for scrap only.

[CLARKYsv]

Do you take credit card? :P Looking at getting this done soon. :)

[millemille]

Do you take credit card? :P Looking at getting this done soon. :)

I don't take credit cards directly, but obviously you can use your credit card with Paypal.....

[Nicky S]

Millemille are you still doing this ??

[CLARKYsv]

Want to book mine in :-)

[millemille]

Want to book mine in :-)

Drop me a PM and we can plan it in

[CLARKYsv]

PM'd my good man :) Pm'd :)

[SheepShagger]

Want this done for my build, i have pm'd you Mike.

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[Zim]

How big a job is this whipping out of the flywheel then popping it back in? Is this "careful beginner level" stuff?

[SheepShagger]

It should be pretty novice friendly, just make sure you have a torque wrench capable of the required setting when you reinstall. While you're doing this its a good time to install the 4 degree advancing woodruff key for a few extra ponies :)

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[SheepShagger]

Anyone got contact details for Mike?

[SheepShagger]

Again, anyone got contact details for Mike? really want this done as aoon as the bottom end is stripped.

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[millemille]

Sorry for the delay in replying.

I'm afraid we're no longer doing the flywheels or any work dealing directly with the general public. I'm moving out of the South East and up to the Peak District but the machine shop is staying in Essex with my business partners.

They don't want to deal directly with the general public, which is what I do for them, and concentrate on supplying race teams/racers/companies and it's not practical to carry on doing flywheels through me as I'll be 150 miles away.

Sorry and all that....

[SheepShagger]

Superb :(.

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[Blapper]

That's a shame millemille, best of luck to you.

[millemille]

Due to demand I'm doing a batch of flywheels early in the new year (it works when we can do a batch, it's one offs that don't) so if anyone is interested please let me know...

[maviczap]

Yep, put me down. Do you want our ones to machine, or exchange ones you've got to machine?

[millemille]

Yep, put me down. Do you want our ones to machine, or exchange ones you've got to machine?

Yours to machine. About a 2 week turnaround if you can get it to me for the 1st week of the new year.

[maviczap]

Yep, no problem, although i need to get a flywheel removal tool, although correct me if I'm wrong, but it just needs a bolt of the correct size?

[millemille]

You'll need an M20 x 1.5 bolt and either a decent impact gun or a flywheel holding tool.

[maviczap]

Cheers, ill get it sorted next week. Once its off ill pm you for your address

[maviczap]

Many thanks to Mike for doing this service, refitted my lightened flywheel tonight. Haven't fire it up yet, as I need to fill the engine with oil.

[SheepShagger]

FFS, i missed this, typical.

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[millemille]

FFS, i missed this, typical.

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I did PM you before xmas about the batch I was doing and whether you wanted in....

Anything more than a batch of 5 is worth my while doing, so if you want yours doing you can either wait until 4 more need doing or you can see if you can round any more up yourself.

[DomP]

On a pointy what extra bhp can be expected and how much does it alter the characteristics of the engine?

[millemille]

On a pointy what extra bhp can be expected and how much does it alter the characteristics of the engine?

Ok, a lightened flywheel doesn't - despite what some may tell you - result in any increase in power from the engine.You aren't improving gas flow through the engine or increasing the engine's capacity or reducing the drag of a part that runs in oil.

What the lightened flywheel does is reduce the rotational inertia - the engine's resistance to change in rpm - and gyroscopic inertia - the resistance of the flywheel to changes in angle of lean when spinning.

So the engine revs up and down more quickly - improving the throttle response and making engine braking/downshifting smoother and less likely to upset the back end/lock the back wheel.

The bike is quicker/easier to steer and lean. Imagine you're holding a spinning bicycle wheel by each end of the axle between your hands. Now imagine trying to twist the wheel, the gyroscopic inertia of the spinning wheel resists you trying to twist the wheel. Well the flywheel spins at engine rpm and we take between 300 and 800g from a flywheel (depending on model, number of magnets, steel or ti bolts etc) - so imagine how much easier it would be twist a bike wheel spinning at 10,000rpm if it were that much lighter...

It also gives the crank a much easier time; the inertia of the flywheel fights the crank trying to accelerate every time each cylinder fires. Now Suzuki very cleverly put an oilway (a hole) in the end of the crank shaft close to the keyway (slot) also in the end of the crankshaft and the SV crank has a reputation if fitted to a bike that is ridden hard for cracking between the oilway and keyway and failing catastrophically.....

http://imagizer.imageshack.us/v2/640x480q90/913/9rUiCm.jpg

[DomP]

Thanks for the detailed reply, now I feel like I need it doing having seen that crank.

[millemille]

Thanks for the detailed reply, now I feel like I need it doing having seen that crank.

I'll do another batch if there's enough interest. If Sheepshagger wants his and you want yours then there's 3 more, minimum, needed which shouldn't be too much bother to get together...

[DomP]

Was it £125 all in using my flywheel?

[millemille]

Was it £125 all in using my flywheel?

£145 now, sorry should have updated the original post.

[SheepShagger]

Count me in if more people want it done.

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[Nicky S]

I'm in :)

Is the naked and s fly wheel the same ??


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[millemille]

I'm in :)

Is the naked and s fly wheel the same ??


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All carbed flywheels are the same, all injected flywheels are the same (allowing for manufacturing tolerances).

[Eulaca]

Thanks for sorting my flywheel, it looks good. I'll try and get it all back together this weekend.

[millemille]

Thanks for sorting my flywheel, it looks good. I'll try and get it all back together this weekend.

No problem, hope you're pleased with the improvement when you ride it.

[maviczap]

Filled mine with oil & fired it up last night, no nasty noises from my mechanical hamfistedness, just need to get it MOT'd for a test ride & also fit the pointy cams I've had for ages

[robertw95]

Hi mike im coming round to fitting the flywheel back in my engine after its had its full rebuild. I have still to re fit flywheel and cylinder heads. I had a look at the body and can still see the timing marks but no letter f or r is there a way to determine this? Im pretty sure one mark should be 180 degrees from the other for the rear cylinder is this correct? Thanks

[N1xxl]

Hi Rob, we will be fitting Ks on Sunday 5pm if you want to pop over, I have a spare original you can take and mark yours from this if need be.

[N1xxl]

We have had four lightened flywheels from Millemille for our SV race bikes. We are going testing in Spain in just over a month so should have some feedback then. Thanks for the excellent service Mike.

[millemille]

Hi mike im coming round to fitting the flywheel back in my engine after its had its full rebuild. I have still to re fit flywheel and cylinder heads. I had a look at the body and can still see the timing marks but no letter f or r is there a way to determine this? Im pretty sure one mark should be 180 degrees from the other for the rear cylinder is this correct? Thanks

Just align one of the marks and see which piston is at the top of the barrel.

As the meerkat says, simples!

[millemille]

We have had four lightened flywheels from Millemille for our SV race bikes. We are going testing in Spain in just over a month so should have some feedback then. Thanks for the excellent service Mike.

No worries my friend.

We'll be really interested to hear your views on the improvements.

[I.Porter]

Hello all,
I machined all the flywheels and sprags for millemille when he was still offering this service. I have continued to do the machining on a one off basis when he directs forum members over to me. If you need an SV650 flywheel and sprag clutch ring machining just fire me a message.

Current pricing is £100 for the flywheel and £100 for the sprag ring + £10 UPS delivery (carb or injection version)
Spec is as described in the above thread.

Please note: I am not willing to take on the risk of removing the magnets.

Turn round time will depend on the work load I have on at the time, but less than 2 weeks would be normal. I'm sure you will appreciate that this type of work has to fit in around the regular commercial work load.

my website is https://www.iporterltd.co.uk/
facebook https://www.facebook.com/IPorterLtd
instagram https://www.instagram.com/iporterltd

I use Haas and Doosan CNC's.

I hope this is of some help.

[gadget]

Sounds like a total 'no brainer' will definitely be up for this mod at some point in the new year. Much prefer the option of a 'ride in-ride out service. 👍

[I.Porter]

Hello all,
I machined all the flywheels and sprags for millemille when he was still offering this service. I have continued to do the machining on a one off basis when he directs forum members over to me. If you need an SV650 flywheel and sprag clutch ring machining just fire me a message.

Current pricing is £100 for the flywheel and £100 for the sprag ring + £10 UPS delivery (carb or injection version)
Spec is as described in the above thread.

Please note: I am not willing to take on the risk of removing the magnets.

Turn round time will depend on the work load I have on at the time, but less than 2 weeks would be normal. I'm sure you will appreciate that this type of work has to fit in around the regular commercial work load.

my website is https://www.iporterltd.co.uk/
facebook https://www.facebook.com/IPorterLtd
instagram https://www.instagram.com/iporterltd

I use Haas and Doosan CNC's.

I hope this is of some help.

I should have made it clear that this is only a machining service.
No ride in ride out or fitting offered.

No one in their right mind would pay what I would charge for that!