2 right hand flywheels

[Laurie]

Hey Folks
I'm having a 74 cu Knuckle engine gone through as its been sitting for a while and have found out that it has 2 right hand flywheels, So if I have this right it'll mean that it revs up a bit quicker but will lose torque? as I weigh about 105Kgs I reckon i'll need all the low down grunt I can get, so my question is how much difference will it make torque wise? and will it effect the smoothness/ running of the engine around town and or on the highway? as I'm not building a hotrod, now I have a 74" set of Pan flywheels I could swap but are they the same as Knuckle wheels?
Thanks in advance

Laurie

[Jerry Wieland]

Laurie. You are correct in your assessment and you might notice it if you have ridden stock bikes in the past but if you are not hotrodding it won't matter. Pre 1955 panhead flywheels will slip right in your knucklehead. Jerry

[kitabel]

The heavier wheels store more inertia, but deliver the same foot-lbs. Easier to ride in traffic
1st gear accel will slightly improve with 2 X R, slightly rougher low speed operation, more prone to stall/chain snatch

[T. Cotten]

Hey Folks
I'm having a 74 cu Knuckle engine gone through as its been sitting for a while and have found out that it has 2 right hand flywheels, So if I have this right it'll mean that it revs up a bit quicker but will lose torque? as I weigh about 105Kgs I reckon i'll need all the low down grunt I can get, so my question is how much difference will it make torque wise? and will it effect the smoothness/ running of the engine around town and or on the highway? as I'm not building a hotrod, now I have a 74" set of Pan flywheels I could swap but are they the same as Knuckle wheels?
Thanks in advance

Laurie

Your instincts are correct, Laurie!

Herbert Wagner's "Revolutionary Machines" recounts how they learned the hard way more flymass was needed for more payload, and thus the fat left wheel became the bloodline.

(I wished for depleted uranium.)

"Smoothness/ running" depends almost entirely upon the truing of the crank, assuming everything else is in order. (Balancing is a second-order concern, as most real rider-comfort vibe concerns originate in the chassis.)

....Cotten

[Rubone]

Big Twins were the only H-D s with a heavy crank, 45s, Ks, Sportsters, all had equal size flywheels. It was common in the earlier times to try shaving left wheels to match rights for a performance upgrade. Make your bike as light as possible, and no need for mass!

[Laurie]

Big Twins were the only H-D s with a heavy crank, 45s, Ks, Sportsters, all had equal size flywheels. It was common in the earlier times to try shaving left wheels to match rights for a performance upgrade. Make your bike as light as possible, and no need for mass!

So Robbie is there a noticable difference in performance? could the gearbox ratios be changed to say a longer first to work with quicker revving?

[bobphd]

About 20 years ago I put a stock stroke S And S flywheel assembly with the thin left wheel in my 47 fl. I rode it for 1 year and maybe 5000 miles with this and did not like it as the vibration was more than I was used to and the overall feel of the motor was not to my liking. I did not notice any quicker revving or performance but I am a touring rider not a hot rodder. I purchased and installed a Truett and Osborne full weight torque monster flywheel assembly. To me the difference was night and day as it was much smoother and overall performance for my riding style was much better. The difference may have been in the trueing or balancing as they were done by S and S and Truett and Osborne as I did not have my own truing stand or balancing equipment at the time. I have put many thousands of miles on this bike including a 8200 mile 3 week ride to Alaska and back this summer so that is my real world experience and opinion on flywheel weight.
Bob

[kitabel]

From a stop, slipping the clutch to get underway, heavy wheels need less "management" (throttle & clutch control), but once the clutch is fully engaged (and all stored energy has been fed into the primary chain) the lighter wheels are faster in low gear.
Which is more important?
Your choice.