Ms Peel boring tough crank crying

Hey Ken, On the machining end of this project; How many holes are you drilling in the flywheel? Are you doing multiple holes in the fixturing pictured ? Are the locations and angles critical ? Have you done 1" tapped holes for any particular reason or just for their potential weight addition ? And how about the plugs ? What are they made out of ? Many questions, I know, but this is fascinating. I'm trying to get my head around the whole balance factor thing, as I'm into the bottom end of my '72 at the moment. I'm not sure if I should just grind the crank and re-assemble it or go further with balancing everything, Thanks and good luck.
Happy New Year All !!!

Dan a quick interrupt before Ken pings back as I may the most studied up on BF across the range of 360' cranks through the decades interviewing many famous to unknown extremists some dead for years now. Main issue is cast iron flywheel is a ticking time bomb if rev'd much into red line, where a Combat really kicks up its heel on 2S cam and head port size. Its safer/good to mill away cast iron flywheel and there are instructions available on how best to do it, but its still brittle fatigue dangerous. Isolastics can take up a wide range of BF, Norton apparently was wise in selecting mid 50's BF as gave least mass and cost to produce a smooth runner. Besides total mass the flywheel can be made smaller OD too. Higher BF = more horizontal vibes easier to handle by frame and pilot and visa versa. Main reason most add mass to counter wt's. is to rise BF so frame and pilot can handle it in solid mounts because they can get a ligher frame and better handling its seems than un-linked isolastic, unless at level of Doug McRae skill on race prepped real isolastic Cdo.

In Ms Peel's case its both a desire to have a bike that disappears out from under and to experiment with effects on tyre grip and power pulses, on and off tarmac. I think I'll like it better with more power unit vibration in line with tyre in sonic slippage zones - don't know yet. I can not stand to feel even valve train buzz the smoothest solid mount transmit. I am besides myself since finding out that a linked Combat can out zoom and plant more power than elites moderns when leaned much.

Both Jim Schmidt and me came to similar conclusions separately, to obtain a more circular orbital requires upping BF ~ 25-30% over factory into mid 70's %.
Ken will mill out to reach mid 50's BF then mass can be plugged back in to experiment w/o splitting cases. Jim Schmidt may be best authority on how to lighten a cast iron flywheel and consulted on Ms Peel's deal as his pistons/rods are what caused this new issue in poor long suffering Peel project.

Unfortunately my riding style wouldn't get much out of some of your technical mods, but I would be very keen to learn more about lightening the flywheel if that would be advantageous. Any info on that ?
Has anybody machined a flywheel from solid bar, like stainless or something ?

DanD said:

Unfortunately my riding style wouldn't get much out of some of your technical mods, but I would be very keen to learn more about lightening the flywheel if that would be advantageous. Any info on that ?
Has anybody machined a flywheel from solid bar, like stainless or something ?

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Quite a few people have made, and some still make, Commando flywheels from solid bar or plate, typically 4130 or 4340 alloy. The flywheel on Steve's crankshaft was made by Ron Fraturelli from steel plate with bolt-on counterweights. It's all welded together now as one piece, but it was originally bolted together. Steve Maney stll makes his flywheels from steel billets. I've known several individuals who have made them up fom steel plate for their own race bikes. It's not a complicated machining job. I believe Steve (hobot, not Maney) still has the drawings for his, in case he wants to have more made. I've included a picture of a crankshaft with a steel flywheel I had made back in '70s for my 750 race bike. It was made from a set of factory drawings, graciously supplied by Norton, and it's quite pretty, but no better than a simple flat one with bolt-on or welded counterweights. The two holes in the flywheel counterweight are to remove weight, which was then added back in with heavy metal slugs in the cheeks. The idea was to move some of the force from the counterweights closer to the main bearings. A bit of weight was also added to bring the balance factor up to 62%.



Even better is making a complete new crankshaft from better quality steel than Norton used. That's been done, and is still being done, by a variety of shops and individuals. I think one of the most interesting was the one Jim Comstock (comnoz) made from a VW diesel crankshaft. A new topic just for interesting Commando crankshafts would probably generate a lot of interest. Maybe later.

Ken

Ken

One of the hardest things for bolt on special flywheels is sourcing best bolts in off the shelf length and dia wise if using the same dia as 850 stock. Ken, others might expand on that nick pick detail.

Ron when on east coast in forefront of Commando development made 2 batches of flywheels. One standard OD and 4 lb lighter, the other 1/2" smaller OD 4.5 lb lighter. I had choice so picked the last of the fastest rev'r one. I had a shop measure and create a water jet file to cut one out anytime or material. Has two locating dowels, removable, three 3/8" allen bolts clamp em together. Here's another view laid on top hard copy basic graphic. The tricky part is aligning holes don't ya know.

DanD said:

Hey Ken, On the machining end of this project; How many holes are you drilling in the flywheel? Are you doing multiple holes in the fixturing pictured ? Are the locations and angles critical ? Have you done 1" tapped holes for any particular reason or just for their potential weight addition ? And how about the plugs ? What are they made out of ? Many questions, I know, but this is fascinating. I'm trying to get my head around the whole balance factor thing, as I'm into the bottom end of my '72 at the moment. I'm not sure if I should just grind the crank and re-assemble it or go further with balancing everything, Thanks and good luck.
Happy New Year All !!!

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Three holes. One in center and two others, each .875" offset from center. Center hole is just for weight removal, and will be bored to size required to fine-tune after finishing the other two holes. The holes on each side will be tapped for 1-14 plugs to a depth of 1.25". The calculations for weight removal to get down to the desired balance factor indicate that this choice will let us easily change the balance factor in the ranges Steve is interested in. Socket head set screws (steel) are readily available in that size. They can be machined to make plugs for changing the balance factor, if Steve chooses to experiment. If necessary to drastically increase balance weight, heavy metal slugs can be added to plugs, but I don't see that being likely.

Originally I had planned to just use one larger plug in the center of the flywheel, similar to the way Dave Nourish does his one-piece cranks, as shown below.



That's a much simpler way to modify the balance factor, and the calculations are also easier. Unfortunately, one of the high strength bolts that originally held the flywheel weights on goes right through the center area. Even though the crank is now fully welded, I still didn't want to drill all the way through the center of the bolt. Hence, two symmetrically located plugs. The crank was previously dynamically balanced, so if we change the static balance with precise enough drilling and machining, it should still be in balance dynamically. Anyhow, that's the plan.

As to whether you should worry about balancing your crankshaft, I don't think it's probably worth the cost for a street bike, unless you are changing piston and/or rod weights significantly. I've always had the cranks for my race bikes dynamically balanced, but that's because they spend a lot of time at high rpm.

Ken

Just an idea that MAY work to let you drill the crank.
I use this method when I need to mill a keyway into a hardened piece of steel stock.
Heat the area with a torch untill the work area is cherry red and let it cool slowley. (Heat the spot on the crank you want to drill not the whole crank)
Do the machine work, polish & fit.
Reheat untill cherry red, cover with Kasenit (From Brownells), quench in cold water.
re polish. ( on the crank just flood the hot spot).

Hobot, you started with a real good idea, BMW's use a similar idea, but they dont need to bastardise them with the electric glue gun, every bolt you have welded will be brittle, a better idea would be to machine the bottom of the center web flat, dovetail a step each end and bolt a counter weight that fit the corresponding dovetail, that way it has a mechanical lock holding it on. I have seen a BMW one come apart, but it had broached on a dowel pinand was bolted up with a air gap between it and the crank.

Thanks for the info. Very interesting. Lots of ways to do a Commando crank that I wasn't aware of. Looking at all that though, I don't think I need to get that into it. I just might have a go at reverse engineering a flywheel and machine one from solid bar. Just to do it. And yes, I agree Ken, that one you posted is VERY pretty !!

Ah shuck splat, Peel deal is welded up, bots just left in for their mass. Besides Peel will not have to rev to make good power so no having to resist jump rope as much and plenty meaty to take insane torque loads the rest of the drive train may not.

I wonder where are you going to race this bike? With a very light crank its not going to be that easy to ride in road racing, so I guess its going to get used on the drag strip?

Carbon, in the world of light wt crank shafts Peel is just mediocre = guesstimating maybe 23-24 lb compared to stock ~28 lb or lightest available ~18 lb billet jobs.

No one else but Bob Patton can understand the Real Amazing Feature of Ms Peel, can be held in palm of hand and nothing to do with engine power or light mass of anything THE Rump Rod = rear isolastic linkage = helms joint down low and far from rear isolastic. Period end of story, throw in the old towel and wrap it UP! Peel don't need the front or top links but for the extra comfort level they provide as don't eliminate handling upsets just raise the crazy antics threshold a bit higher is all, enough to make it almost human impossible to save.

So Yes in a way Peel's crank and such is for drag racing in the opens but my crank BF ponder is traction and traceability on loose wet leaf severe slopes or total dry electrostatic repelling Gravel on severe slopes [both in turns of course] or tarmac leans hooking up a sideways wheelie to sharpen up decreasing radius for Peel's level of orgasms. Also for turning longer sweepers into a faceted series of short full WOT straights. So far I've not bee able to slide a unicycle.

What I seek in straight line sprints picture Peel running up on a SR100 of Duci 1198 in my normal commute rates- that excites them to nail it and they double take as Peel's nose drops 3-4" and zips out head on more torque per mass w/o wheelie worry leaping forward and no need to leave 4th.

You just can't imagine the spikes of emotion and mental incomprehension of both me and surprised super bikes Ms Peel could just leap ahead of going into turns by just mere Combat power on about same crank shaft specs. None of the others can use much power going into turns. But 100 hp and above bikes could out pull her in the opens so seek to solve that weakness. With all 3 links set loose and same with both isolastics only the quantum level of molecular electron clouds of contact adhesion get through to pilot from sacrum to brain stem faster than sluggish brain can react but sit back in awe recording it : ) Traction is only analog up to limit of max grip ~10% slippage then it becomes digital on/off. Things can happen so fast only way to change angle in time is trip out by power or hi side jerk up.

So will Peel retain her past electric rheostat like throttle reaction to tire grip and spin? Peel needs a fast acting throttle but not for get go drags but for instant shut down at just right instant. Will the crank mass and blower slow down too fast or not slow down fast enough on maxed out lean angles? When past Peel let her hair out in turns, let off of power gave the most spikes in forward acceleration G's like a sling shot as chassis un-twists right at least point of traction where everyone else and their donkey is tippy toeing the most.

I already know what its like to have Norton P!! that floated front level in all gears, fun as can be but boring/relaxing compared to having front floating in forward G's leaned sideways Plus the side load G's thrown on top of that! THE Gravel taught me to get all slips slides and crashing done before the least traction sharpest part, so I do that part as if in full crash recover behavior which I am, by letting off all loads of fork and rear thrust or bike angle.

[ P!! with light crank had 9K tach mark and was wonderful easy to lug at idle in 4th through deep dry sand where delicate response prevented spin outs.]

In this state the only effective control is the rear thrust, rear tire angle and rear tire spring back, so only pilot effort is just R wrist action, as butt so smashed back down towards rear patch its one with chassis and suspension.
If front has any effective contact its just dolly wheelied to have no effect on rear tire angle and thrust or spring off. Boy howdy will front dolly wheel when not paying it much attention but to follow its flings so it does not twitch throttle out of delicate control. Rear brake and throttle at these points can only change rear angle not speed. Front fork should be free to flip sides like a boat in a tack but Oh My does Cdo chassis wrap up during the transition.

Its- getting into through and out of these phase transitions that isolastics, thin steel sway bar frame, rod links, engine rpm-harmonics-traction pulses, fork freedom with hi freq stiffness above tire hysteria all come together to either pass through the loads or store them up for later predicable-wonderful orgasmic release, -that the BF means so very much to me. Peel can twist up and load rear tire multiple times her actual mass, which smashes down patch into taking Insane Spikes in grip/torque. [watch crash video to see how harsh fast a bike can react beyond human power and speed reflex] ahhhh so.

When I cut power at apex its to get the frame to unwrap which forces rear down- so its Right*There*THEN I want to put as much Torque into it as I can to spring off the diving board launch to spend what others do in crashing in no loss of momentum-fastest way to twist on CoG to completely change direction for the landing on rear patch smash down so I can nail it Right-there- again for another leap out of there like you can't believe. Oh have i tried to practice this on other bikes but they are so limited I can't even practice Peels lines I love so much.

I want engine to operate tire into and out of sonic traction zones at will.
I think hi BF may translate into better power pulses inline with drive train than
90' to it. You know the feeling-sight-sound of a drive tire right at max grip, its chirping and jerking but not spinning to melt. As speed rises takes rising power to keep it that way, but can't rise so fast tire just smokes so the G's hesitate. I think what Peel seeks is fast rising torque curve not a flat one that seems so popular to everyone else. I think the slightly heavy flywheel may tame response to my level of reflex and clutch feathering.

Hum, grind, howl, chirp and squeal hobot

In terms of BF its worth having a close look at what they use on speedway motors, as in this application traction is obviously extremely important, as top motors are making almost 80bhp from 500cc, with all up weight less than 200lb.

Speedways sure got good power to wt ratio ~1 hp to 4 lb but they are solid mount engine so suspect they have ~80 BF d/t frame and pilot tolerance not traction, but they are singles so wide power pulses for tire to adapt too. Yet that higher BF may be helping them hook up better than if lower BF, don't know yet.

But Speedway and flat trackers are not my model to go fast around turns, they spend too much time spinning to get much acceleration forward in turns until they flick in a bit of straight steer to line up with the straight then they can even wheelie out of there. Also these dirt tracks look life wide open smooth freeways to me, who has no luxury to slide or drift much on the loose 'Stuff' or hard tarmac. They also hang off and put a foot down very often and no way can I get away with that extra luxury to relax in turns. I don't consider crossed up sliding as all the exciting, but fun way to ease a turn if room and time available. Crossed up sliding to Peel is just a failed turn at limits of phase 2 handling. I have to do it now and then - if I fail to enter fast enough to be able to enter phase 3 and above handling. Crossed up slides are merely a saving recovery method of Peel not a faster way around. Spun rear relieves loads not adds to them.

What I seek is harsher hooked up acceleration to spiral into faster decreasing radius. Also the hill climbing hook up or laid down low drag racer locked in posture through turns. Ice spiked oval racers and MX bikes with rear locked in a rut on wall of a steep bank are examples of phase 5 turns Peel can do on the level if rear can be kept in max grip/grind state, like parking lot turns with a tire smell. Picture a slick bowl upside down and start at base and try to get to top fast as ya can, then cover it in sugar sand, that's what Peel finds most fun condition or most scary if forced into it by surprise hazards.

If ya can't picture a faster way around than race bikes use on tarmac or flat trackers drifting lazy, then ya don't know what ya missing out on w/o rear linked articulated flying carpet.

Light weight cranks will generally mean reduced torque, and make bikes harder to ride through the turns. On modern speedway motors the crank weight is often increased, and as well as greater inertia for starts, this means better grip, as tungsten inserts are carefully positioned for more grip.

For bikes used on the road properly sorted carburetion and ignition are very important, but lots of people are still using parts which are very poor, yet spending large sums of money on other changes, which are not likely to work properly with bad carbs and ignition systems.

Carbonfibre said:

Light weight cranks will generally mean reduced torque, and make bikes harder to ride through the turns. On modern speedway motors the crank weight is often increased, and as well as greater inertia for starts, this means better grip, as tungsten inserts are carefully positioned for more grip.


For bikes used on the road properly sorted carburetion and ignition are very important, but lots of people are still using parts which are very poor, yet spending large sums of money on other changes, which are not likely to work properly with bad carbs and ignition systems.

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I would have thought a reasonably heavy crank would have been benificial to an under powered pile of crap with a wide ratio gearbag, it would be alot less likely to drop it's lolliepop between changes,and you ain't bgoing to launch from idle are you.

Good grief Mr Fiber, you'll get blackballed, or at least a written warning for suggesting that some forum members have more money than brains :wink: :wink:

splatt said:

Carbonfibre said:

Light weight cranks will generally mean reduced torque, and make bikes harder to ride through the turns. On modern speedway motors the crank weight is often increased, and as well as greater inertia for starts, this means better grip, as tungsten inserts are carefully positioned for more grip.


For bikes used on the road properly sorted carburetion and ignition are very important, but lots of people are still using parts which are very poor, yet spending large sums of money on other changes, which are not likely to work properly with bad carbs and ignition systems.

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I would have thought a reasonably heavy crank would have been benificial to an under powered pile of crap with a wide ratio gearbag, it would be alot less likely to drop it's lolliepop between changes,and you ain't bgoing to launch from idle are you.

Good grief Mr Fiber, you'll get blackballed, or at least a written warning for suggesting that some forum members have more money than brains :wink: :wink:

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I have no money and no brains. Where does that leave me? :wink:

I have no money and no brains. Where does that leave me? :wink:[/quote]


In the same place as most working class stiffs

Hey! I resemble that remark. :lol:

Light weight cranks will generally mean reduced torque, and make bikes harder to ride through the turns. On modern speedway motors the crank weight is often increased, and as well as greater inertia for starts, this means better grip, as tungsten inserts are carefully positioned for more grip.

For bikes used on the road properly sorted carburetion and ignition are very important, but lots of people are still using parts which are very poor, yet spending large sums of money on other changes, which are not likely to work properly with bad carbs and ignition systems.

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I love the feedback and even the disbelieving attitude, all just fun and games to me before we are gone. Chris's comments are exactly what I faced on deciding what flywheel to get when pre-Peel crank found bent before my time but not noticed in any way. I loved light flywheel on both P!! and Peel, though suspect the P!! was rather lower mass than Peel ~5 lb lighter smaller OD crank.

So my conjecture with some experience now is no matter how light ya make a Norton crank its still on heavy side of crank scope so don't run into the power off stalls or trouble with off idle clutch engagement creeping around.
I do way more creeping pussy footing than tarmac pressing so when first told the BF would shoot up to hi 90's my thought was maybe I'd like that 'extra' mass for the ease of low down creeping zone sounds bats get attacted into stem cables and under tank and helmet lip. We know mid 50's work great in isolastics and mid 80's in solid mount so I wonder if I can even sense a change of BF in this range on Peel. Fun is finding out someday.