BSA B50 -500 APG Build

[Frank06]

Looking good Tom, have a safe trip.

Frank

[Koncretekid]

Those look like 500 cc engine sized flywheels.  This might cure some of the vibe problem.

Bo,
Yes, these are original B50 flywheels.  I have lightened them to clean off the rust and clearance the inside for better oiling of the piston and had them re-balanced.  Still, the single can't be balanced well, so any balance factor chosen may not be the best for wide open high RPM applications.  But it's only for a few minutes at a time!
Tom

[DND]

Hi Tom

Just was thinking about those reverse rotation counterweight shafts , I wonder if one of those would help with the balance factor

Or maybe a weighted shaft with the weights held in place with urethane donuts for a type of harmonic balancer

Maybe the area under the carbs would work

G Don

[charlie101]

Basicly the balance shaft doesn't solve anything more than the vibrations transfered to the motorcycle frame. The vibration forces produced by the crankshaft is totally unaltered, but the balance shaft throws the engine case in opposite direction so the feel in the seat is smoothed.

[Koncretekid]

Good point, Charlie,
I believe the new big singles as well as the 360* inline twins use a balance shaft internally.  So now you have two unbalanced shafts running out of phase to make you think the motor doesn't vibrate.  The internal forces generated between these two shafts must be substantial enough to wreak havoc on the bearings and the cases. 

In any case, if I figure out a good way to mount an external shaft driven by the crankshaft, it will be driving something that enhances the performance way more than just balancing!  Food for thought for a future motor.
Tom

[Rex Schimmer]

Quoting Tom, "
In any case, if I figure out a good way to mount an external shaft driven by the crankshaft, it will be driving something that enhances the performance way more than just balancing!  Food for thought for a future motor.
Tom"

Are we talking "Super charger"?

Rex

[Koncretekid]

Rex,
What I know about superchargers you could print on the back of an envelop, but it is an interesting thought.  Rotrex makes some pretty interesting little chargers.  Driving the charger would be a challenge because the primary case shares oil with the motor, and the clutch rides on 25 tiny little rollers that start skidding pretty easily.  Would have to be a wet drive, or the cases would have to be custom made to allow the crankshaft to protrude thru the side far enough for a pulley, and then it would be cantilevered out pretty far.  I wonder how much hp that little transmission, originally designed for a Triumph Cub, would stand up to?  Or the rest of the motor, for that matter.  Maybe I should just go down a couple of sizes and slow down..........but not just yet.
Tom 

[wobblywalrus]

Tom, you can use a strong trans and clutch if you cut the engine free from the ones it has and use the engine like a unit construction motor.

[wobblywalrus]

"Pre-unit" i meant to say.

[tauruck]

Harley motors are being used on experimental planes. Check out the pulley system used on those. The prop doesn't run off the crank. There might be an idea you could expand on.

[Old Scrambler]

Tom, I have very little to add to the envelope................but did glean this from some drag-racer conversation. You could run the SC from the clutch, the tranny, or a jack-shaft on the chain. The latter would tend to slow the SC down and give you better control. Another discussion revealed the rider installed a switch on the shift-drum so his ELECTRIC SC would only run from 3rd gear and up.

I think your existing RAM-AIR system is a significant contributor to your speed.

[wobblywalrus]

Dennis, any specifics on the electric supercharger would be nice.

[Nortonist 592]

You might want to check the rules on electrically driven superchargers.  Both SCTA and BUB state a supercharger must be "mechanically or exhaust driven".   Some yer ago I got the idea of an electric blower but was told no as a blower must be engine driven.  I tried the argument that the alternator that charges the battery that drives the blower is engine driven.  That didn't fly.

[JimL]

Years ago I did a little work with the 24v Turbodyne, installed on some Celica Celebrity race cars that were planned for an event at Pikes Peak (would have been famous celeb drivers, not famous Hollywood celebs).

It took a lot of alternator to bring the dual BIG batteries back, and it was not certain to last long enough for the run.  The airflow spoolup was unusual, which gave us a little trouble with MAP sensors.  Driver misses an upshift with the throttle down (blower cranking full tilt) and suddenly the engine doesnt want all the air available.  It just squeezes the little silicone guts right into the narrow band MAP sensor, and you are walking back to the shop.

I distinctly remember testing at night (on industrial area streets), and it seemed like....about the time I was getting full boost, the alternator was so overwhelmed that I swore the headlight beams were sagging toward the ground in an arc!  Those Turbodynes could suck a lot of amps.  That was, basically, with an ambulance alternator adapted onto the 2.2l engine.....and couldnt keep up at 4.3 lbs of boost (and fading.)

On a side note, I was told those Turbodyne electrics were invented to provide cleaner emissions for inner city diesel delivery trucks, used only when starting up from a stop.  Sounded so odd, its probably true!?

Wound up involved again with the belt drive versions....which really hate vibration in the drive coupling system....lots of harmonics just waiting to be tickled, and we had a lot of broke bolts and bearings in the learning stages.

I better stop now, 'afore I get off onto the story of fitting ambulance alternators (Delco) onto 20R Toyota 4X4 for Rocky Mountain Rescue.  We were a couple years before the EFI....I had to invent a contraption to keep from stalling the engine at idle when you turned on emergency lights, radio, and siren!  No LEDs in those days.

Hmmmm....reminiscing tonight. . and I got to rambling.  This'll teach you to let old people on your forum!

[Seldom Seen Slim]

Minor hijack here:

"  This'll teach you to let old people on your forum!"

It's been a few years since I did it, but I once made a very unscientific survey of the ages of folks on this Forum.  I got about 30 responses, and - believe it or else - the median (half older, half younger) age of the folks was about 58 years.

So much for letting older folks on this Forum -- since it appears a bunch of us already qualify for the moniker.

End of hijack, old man.