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Light Flywheels Again.

Started by koko64, June 28, 2016, 06:24:34 PM

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Monsterlover

#60
February 05, 2018, 07:04:13 PM
High risk, high reward!
"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**

GK

#61
February 06, 2018, 01:39:19 AM
Harsh mistress - not for me, but I do see the attraction! 😉😉
2001 Ducati  Monster 900S ie
JE high comp pistons, bit of porting, open airbox with DP filter, PC3 with custom map, CCW matched injectors, Termignoni cf slip ons, 14:39 gearing.

Gone but not forgotten!
Honda VFR800i, Honda CBR600F3, Honda CBX750, Norton Commando 750S, Suzuki GS750, Yamaha XT250, Kawasaki Z250, Kawasaki KX80, Honda XL250, Suzuki TC100.

koko64

#62
February 06, 2018, 02:27:28 PM Last Edit: February 07, 2018, 08:38:51 AM by koko64
Edit: My comments here are in relation to rough and snatchy low speed operation. From previous experience I think a very light weight flywheel could be a pita at times with FCR's and the stock Kokusan ignition. I believe the CV carbs and tunable Ignitech will mitigate much of the downside. I have tuned a hi comp 944 Supersport with light alloy flywheel, FCR 39's, hot cams and Ignitech to be much smoother than a stock M900/900SS. Careful carb and ignition tuning made all the difference.
2015 Scrambler 800

Speeddog

#63
February 06, 2018, 04:23:15 PM
The light flywheel hi-comp FCR'd 900SS I did was not a happy camper with retarded pickups and standard boxes.
Really ratty idle.

Regular pickup timing and Ignitech made a *huge* improvement.
- - - - - 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 ~~~

koko64

#64
February 07, 2018, 03:16:04 AM
Kamna have a range of flywheels including carb models in light and extra light versions.
2015 Scrambler 800

Frank C

#65
February 07, 2018, 07:36:44 AM
The biggest improvement in idle with mine was switching over from the vacuum fuel pump to an electric one.  The change was so pronounced, that one of my neighbors came walking over asking what I did to make it sound so different. 

This on a 97 with a Nichols flywheel, aluminum clutch, FCR's, ie heads and cams, FBF header, dyna coils, and the stock ignition boxes. 

koko64

#66
February 07, 2018, 09:33:18 AM
That's interesting. I haven't noticed a difference in idle quality between a carbed 900SS and a carbed M900. I have even switched an early 900SS to a Monster vacuum pump to save a few Watts for it's LiFePo4 battery and didn't pick up a difference in idle quality.  Do you think the vacuum pulse pump causes an erratic idle due to the fuel pulsing into the float bowl at those low revs? Or was it just a bad vacuum pump? I have never compared them side by side for idle quality. I will ask the owner if he has noticed a difference.
2015 Scrambler 800

Frank C

#67
February 07, 2018, 10:14:12 AM
I'm assuming it was the pulses due to the vacuum pump, since there is no regulator between the pump and the carb inlet.  The Airtex electric pump is rated for the correct flow rate and pressure for FCR's.   

Have had the bike since 2001.  Idle did not change when a vacuum pump started to fail.  Just would notice that the fuel was transferring from the tank to the crank case :(

Speeddog

#68
February 07, 2018, 10:21:53 AM
Which Airtex pump did you get?
- - - - - 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 ~~~

Frank C

#69
February 07, 2018, 11:13:55 AM
E8016S
30 GPH, 2.5 -4.5 PSI
Currently $35 on Amazon.

I have it mounted under the seat, where the emissions stuff use to be.  From what I read, these pumps like to push vs pull.  I also have heat shield between it and the header just in case. 

Speeddog

#70
February 07, 2018, 11:35:08 AM
Cool, thx, good info.

If you were getting raw gas into the crankcase, either a leaky diaphragm inside the vacuum pump, or a stuck float on the FCR's, which they're rather infamous for.
- - - - - 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 ~~~

Frank C

#71
February 07, 2018, 12:08:49 PM
It was the diaphragm in the vacuum pump.
The sticky FCR float usually resulted in fuel pissing out the side of the bowl.  And always the left carb.  So I stopped storing the monster on its side stand.

But one time, while touring around the Gaspe, both floats got stuck.  The seats and the jets were full of this white, sugar like substance.  I'm assuming it was the additives in Canadian fuel not getting along with low delivery pressure. 

Solved that problem by picking up a ST4s.

ducpainter

#72
February 07, 2018, 01:16:17 PM
Quote from: Frank C on February 07, 2018, 11:13:55 AM
E8016S
30 GPH, 2.5 -4.5 PSI
Currently $35 on Amazon.

I have it mounted under the seat, where the emissions stuff use to be.  From what I read, these pumps like to push vs pull.  I also have heat shield between it and the header just in case. 
All pumps push better than pull.
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    is even more amazing than yours."
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    Ask a mother who gave birth to a stillborn.
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koko64

#73
February 07, 2018, 01:59:22 PM
Quote from: Frank C on February 07, 2018, 12:08:49 PM
It was the diaphragm in the vacuum pump.
The sticky FCR float usually resulted in fuel pissing out the side of the bowl.  And always the left carb.  So I stopped storing the monster on its side stand.

But one time, while touring around the Gaspe, both floats got stuck.  The seats and the jets were full of this white, sugar like substance.  I'm assuming it was the additives in Canadian fuel not getting along with low delivery pressure. 

Solved that problem by picking up a ST4s.

Yep. What cleans injectors at 45 psi clags carbs at 3 psi
2015 Scrambler 800

koko64

#74
February 17, 2018, 05:57:11 PM
Got a Kaemna superlight "evo" flywheel on its way and some spare JE pistons. This one's staying.

The "evo" version flywheel is under 300gms and has one purpose only..
2015 Scrambler 800
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