Balance factor scratch test tool

Hi, I had done 84% for Atlas , four of them, all were dynamically balanced , one at basset down with heavy Dunstall 10/1 pistons (GPM) and Johnson 360 (still on the bench!!), one with HC pistons (made from billet, by a friend),big valves, and 5S, balanced at Norvil (Les Emery) that one was perfect, one with Std engine balanced in Luxembourg via the French NOC, perfect too , slight buzz at 4000 but things getting better as breaking in was put in, last one Std Atlas perfect but tall gearing so not easy to go beyond 5000...........my last engine with JS stage one cam, Seeley frame (MK2), and JS pistons balanced dynamically at 70%
at Basset Down (still on the bench too), but not sure if wet or dry ........!will keep you inform, the last figure was upon JS advise.

Additional examples.

Race Bike : Featherbed Slime line with Commando Combat engine (cast iron barrel & est bike weight 380 lbs at 53% BF dry - that is how I purchased it. Shakes like hell, foul, beats you to death but runs like the wind if you have the endurance. I cannot recommend 53% in a Featherbed.

Race Bike: Norton Commando Mk3 sleeved down to 750cc @89mm stroke w/ 10:1 pistons and mild cam - & 53% BF dry (est bike wieight 380 lbs w/ cast iron barrel)- vibration as good as any street Commando used in anger

Race Bike: Herb Becker prepared Commando with big valve head, alloy barrel, (est bike weight 320 lbs) N480 cam, 12:1 pistons & 53% BF dry - smoother than any Commando I have ridden as well as many modern bikes - rediculously smooth - and fast!

Race Bike - Seeley Mk2 frame with ultra short stroke Commando - 75mm stroke, 12.6:1 pistons, big valves, N480 cam alloy barrel (bike weight 270 lbs) & 78% BF dry - reasonably smooth until around 9,000 rpm and then really starts to shake and feels like the motor wants to leave the frame behind (no need to rev that high so non issue).

I think you will find the motion orbitals involve are too fine for a crude laser pointer's diffused wide spot to resolve motion better than a pencil tip. Maybe with special lab optics or microchip laser but not anything off the shelf available. A fixing laser to the engine may hurt laser and its distant projection would be curde and magnified to make much sense of. Lasers good enough to aim a bullet or adjust telescope mirrors for atmosphere flicker but not resolve our 1/32-1/16" blurring that gets to our bone-joint proprioreceptors. Rub plate witness marks is best I have done.

HIghest reported BF in isolastic racer I've had reported to me twice was 93-94%, wet I assume, but no report of how it felt. I'm going to try 100% or over in Ms Peel to see if the mostly fo/aft orbitals has some affect through the isolastics on tire hook up I can detect and use. As Shrapnel Shredded says, if someone does find a magic BF for their particular self and bike construction, they are holding it close to heart and may not apply to anyone else.

I'll ping Geof Collins for his feedback on the offset crank BF if that term even applies the same way as 360's. His sales pitch though is selling more smoothness, which I can't understand yet in isolastic cases.

hobot said:

As Shrapnel Shredded says, if someone does find a magic BF for their particular self and bike construction, they are holding it close to heart and may not apply to anyone else.

Click to expand...

Ahh, bot hoe, I was being facetious. I have found racers (at least vintage racers) are usually the most willing to share information based on their qualified experience. Not like some factory secret is being guarded . The challenge is keeping it all in context, street vs. race, stock vs. light weight etc.

I don't keep secrets about my race bikes. If my comments help anyone to go faster I am happy, and in any case most of you guys won't be racing against me as much as I might love the thought. The simple fact is that if there was anyone here in Victoria who was persisting in bashing their head against the commando wall, I would do all I can to help them. I'd even let them ride my bike so they would have something to benchmark against. I have one burning ambition and it doesn't involve period 4 historic racing (up to 1972). I really want to get onto a race grid with 70s and 80s aircooled ducatis and guzzis, before I die. It would have to be a 'thunderbike class', and I'm pessimistic that our idiots would let that happen. I might have a strange outlook, but I know what it is like to REALLY race.

Bring your bike across the ditch and race amongst these guys and bike models. 2 classes to choose from.
I will have mine there next year
I will probably start in the Open Post Class and if all goes well, move into the Open Modified.
I know that one of the forum members races his BMW in the Post Classic class

Regards Mike
http://www.nzcmrr.com/index;jsessionid= ... C746F93565

Sharpnel, it may be just one big happy vintage family nowadays but it sure twern't in the era these were professional racers and some builders I quizzed a decade ago that kept records didn't give it up. Texas turned out to have the busiest shops doing this. The BSA research showed that low 60's wet BF was best for engine loads, so trick is how far above that is needed to protects pilot and frame? I and others half fast assume a more circular measured motion would even out vibes best in solid mounts [and maybe a bit sooner in iso's], but that may not be so to every rider or frame or sought for operation zone. Part of the ingenious isolastics solution to me, but for the handling that seems to bother others. So once the BF vibes tolerated - what else BF affects is my curiosity.

more leads on new age monitoring device to air our vibrations with others

http://www.extech.com/instruments/resou ... 880_UM.pdf

http://www.google.com/#hl=en&tbo=d&scli ... 31&bih=593

Oh man thanx for that wonderful crop circle image, I'm been on look out for one that matched Ms Peel's tapering size hole motif's and that's the best one yet. Hydro dipper opened in the woods as side line to stuffing head deer heads. If I or someone else does work up a neat vibration, oscillation gizmo that can be mounted on mid section of bars or on engine case, I'll put you on list in search of secrets of least pecking order harmonics. Oh yeah, I really do 'want' to believe.

Saucer scout ships helical stabilizer plasma tube are like ridding a cross between a rotary tripe cylinder and a 3 phase alternator build out of florescent tubes, ugh, sot when accelerated along with local space reference can't feel any thrill at all as time slows down with ya.


[video]http://www.youtube.com/watch?v=slJq5T6RvpA[/video]

Eventually we may even get predictive maintaince measures. Here's orbita
vibration measuring

[video]http://www.youtube.com/watch?v=VfN4-kMsa9U[/video]

Vibe Expert system as used to balance shafts in use.
[video]http://www.youtube.com/watch?v=KlWkfghG-iE[/video]


$500 dollar unit that looks workable for us
[video]http://www.youtube.com/watch?v=N789C0f2kDk[/video]

That is a very useful gadget.