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Machining a stock flywheel and gears

Started by Monsterlover, December 18, 2008, 07:38:36 AM

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Monsterlover

December 18, 2008, 07:38:36 AM
Any tips on cutting weight off the flywheel?  Im turning mine tomorrow and would love to hear any tips you all might have for me.

Im also pulling the gears I can get at with the left side cover off and putting holes in them to cut down on rotating mass.

Anyone ever do that?  Personally?  Ive seen pics, so i know it's been done. . .

[evil]
"The Vincent was like a bullet that went straight; the Ducati is like the magic bullet in Dallas that went sideways and hit JFK and the Governor of Texas at the same time."--HST    **"A man who works with his hands is a laborer.  A man who works with his hands and his brain is a craftsman.  A man who works with his hands, brains, and heart is an artist."  -Louis Nizer**

MotoCreations

#1
December 18, 2008, 09:01:57 AM
4-jaw chuck on the lathe and align it perfectly.  Never a problem with balance afterwards.  3-jaw chuck -- always a bit off.

Gears?  Use lots of lubricant and don't let them get too hot while machining.

Speeddog

#2
December 18, 2008, 10:38:04 AM
None of the gears on the left side of the motor, other than the cam drive gears, spin while the engine's running.
The ones that are easy to remove are starter gears.

You'll only save weight.
- - - - - Valley Desmo Service - - - - -
Reseda, CA
(951) 640-8908

~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

Monsterlover

#3
December 18, 2008, 10:50:42 AM
Good point.  Ill do the cam drive gear. . .

How about gears on the right side?

There's a really big one there, but im not sure how it comes off. . .

I doubt this machine will have a 4 jaw chuck, so Ill just indicate and shim as necessary.
"The Vincent was like a bullet that went straight; the Ducati is like the magic bullet in Dallas that went sideways and hit JFK and the Governor of Texas at the same time."--HST    **"A man who works with his hands is a laborer.  A man who works with his hands and his brain is a craftsman.  A man who works with his hands, brains, and heart is an artist."  -Louis Nizer**

Speeddog

#4
December 18, 2008, 11:32:07 AM Last Edit: December 18, 2008, 11:34:08 AM by Speeddog
Cam drive gear is small and runs at half of crank rpm, so the benefit is small.

Primary gear on the right hand side is large, and would be some benefit even though it runs at roughly half of crank speed.
I suspect it's going to be tough drilling/milling on that one.

It'd be a good plan to remove the right side cover anyway, just to look around and make sure all is OK, as you did have a bunch of crap on the drainplug magnet.
Watch out for the O-rings when replacing the cover.
- - - - - Valley Desmo Service - - - - -
Reseda, CA
(951) 640-8908

~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

TAftonomos

#5
December 18, 2008, 01:15:54 PM
I hope you have a LOT of good tooling to burn up.  Those gears are VERY hard indeed :) 

If you are interested in doing a few from a testa motor, please let me know  [thumbsup]

Capo

#6
December 18, 2008, 01:42:33 PM
Quote from: TAftonomos on December 18, 2008, 01:15:54 PM
I hope you have a LOT of good tooling to burn up.  Those gears are VERY hard indeed :) 

If you are interested in doing a few from a testa motor, please let me know  [thumbsup]

+1  Most machnine shops don't want to touch them.


Capo de tuti capi

Monsterlover

#7
December 18, 2008, 04:18:00 PM
I have the primary exposed. How does it come off?


Quote from: tSpeeddog on December 18, 2008, 11:32:07 AM
Cam drive gear is small and runs at half of crank rpm, so the benefit is small.

Primary gear on the right hand side is large, and would be some benefit even though it runs at roughly half of crank speed.
I suspect it's going to be tough drilling/milling on that one.

It'd be a good plan to remove the right side cover anyway, just to look around and make sure all is OK, as you did have a bunch of crap on the drainplug magnet.
Watch out for the O-rings when replacing the cover.
"The Vincent was like a bullet that went straight; the Ducati is like the magic bullet in Dallas that went sideways and hit JFK and the Governor of Texas at the same time."--HST    **"A man who works with his hands is a laborer.  A man who works with his hands and his brain is a craftsman.  A man who works with his hands, brains, and heart is an artist."  -Louis Nizer**

Speeddog

#8
December 18, 2008, 04:23:02 PM
Should just pull straight off.
- - - - - Valley Desmo Service - - - - -
Reseda, CA
(951) 640-8908

~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

ducpainter

#9
December 18, 2008, 04:26:06 PM
Quote from: Speeddog on December 18, 2008, 04:23:02 PM
Should just pull straight off.
Just?
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Speeddog

#10
December 18, 2008, 04:30:52 PM
Quote from: ducpainter on December 18, 2008, 04:26:06 PM
Just?

I'm assuming he means the driven gear behind the clutch basket.

If he means the drive gear on the crank, well.... that requires a hella stout puller, preferably the OE Ducati unit, and a beefy impact driver.
Helmet and flak jacket optional.  ;D

If he does mean the crank gear, that's not worth drilling, it ain't that big.
- - - - - Valley Desmo Service - - - - -
Reseda, CA
(951) 640-8908

~~~ "We've rearranged the deck chairs, refilled the champagne glasses, and the band sounds great. This is fine." - Alberto Puig ~~~

ducpainter

#11
December 18, 2008, 05:00:29 PM
Quote from: Speeddog on December 18, 2008, 04:30:52 PM
I'm assuming he means the driven gear behind the clutch basket.

If he means the drive gear on the crank, well.... that requires a hella stout puller, preferably the OE Ducati unit, and a beefy impact driver.
Helmet and flak jacket optional.  ;D

If he does mean the crank gear, that's not worth drilling, it ain't that big.

Ya never know with ML.   ;D
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Monsterlover

#12
December 18, 2008, 08:37:44 PM
2 seconds after I posted that I put more ass into it and it pulled off. I figure I might as well port that clutch basket while I'm at it ;D

I also set aside the cam drive gear off the left side.

For the record I doubt a drill would even touch these gears. They're likely heat treated to 60rc or more. Generally you need at least 30 points more on the hardness scale to cut something. I can tell you that no hss or hssco drill is in the 90's.

Carbide on the other hand definitely is

Years ago I put an lsd diff from an integra type r into an 88 prelude. I had to bore the ring gear to fit. That wasn't a big deal. I also had to machine a new bolt circle. I tried a cobalt drill and it died instantly. I ended up endmilling all the holes.

It worked ;). The car was much improved!

As for the flywheel... I'm going to turn off every last free gram of material from it [evil]

I thought I read somewhere about running no fw at all but I don't see how that can be done. If someone knows let me know cause I wanna do that!!!
"The Vincent was like a bullet that went straight; the Ducati is like the magic bullet in Dallas that went sideways and hit JFK and the Governor of Texas at the same time."--HST    **"A man who works with his hands is a laborer.  A man who works with his hands and his brain is a craftsman.  A man who works with his hands, brains, and heart is an artist."  -Louis Nizer**

Ducnial

#13
December 19, 2008, 06:21:06 PM
The primary objective of lightening the fly wheel is to reduce inertia of the rotating mass. For a flywheel or gear Inertia = Mass x Radius^2 x 0.5  Here you can the the inertia varies by the product of the mass and radius squared. In other words reducing the diameter of a rotating mass will reduce its inertia much more (squared) than simply reducing its thickness by the same percentage.  On that same thought lightening the flywheel or gears by drilling holes in it, especially near the center will have very little impact on inertia, but it will be lighter.  Because these type changes (engine) only effect acceleration by reducing rotating inertia it has diminishing returns as compared to the rest of the bike.  Remember inertia is inertia, regardless if its going in a straight path or rotating.  Substantial reductions in total mass e.g. bike weight will have a bigger bang for the buck after you've picked the low hanging fruit like the fly wheel.  Wheels are also a big candidate for inertia reduction because they have a big R and are a substantial fraction of bike weight, you get two bangs for your buck, reduced rotating inertia and reduced straight path inertia.

2c

Monsterlover

#14
December 21, 2008, 05:10:42 PM
It's done.

I weighed it before I started (postal scale) and it was about 4.5 pounds.

2 pounds now ;D

I reduced the OD big time, cut the rear face down by .200, and cut a big chamfer on the back side/od to get just that last little bit.

I did not get a chance to work on the gears, but Im going to.

The box I used to carry parts in weight a *ton*  (Primary, flywheel and the gear behind it, cam drive gear) Discounting that it's rotating mass that I'm reducing, the static weight reduction should also be in the neighborhood of pounds.  How can this be bad?

[evil]

I love cutting metal :D
"The Vincent was like a bullet that went straight; the Ducati is like the magic bullet in Dallas that went sideways and hit JFK and the Governor of Texas at the same time."--HST    **"A man who works with his hands is a laborer.  A man who works with his hands and his brain is a craftsman.  A man who works with his hands, brains, and heart is an artist."  -Louis Nizer**
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