Making fork yokes

I usually have the steering damper set to the minimum drag. It is only there to stop the ultra high speed tank slapper which can bring total destruction, and I've been there about 4 times in 12 years of racing my old triton.

My worst tank slapper happened when surprise wheelie Ninja front touched down and bounced at 120 mph w/o a damper to catch it. The bounce must of really reduced the rake twitch angle. Should of died, almost did. On other hand when Peels rear tire blew out and off rim so rear tried to pass front I broke off stop tab and dinged IS tank to save the hi side, just barely did by decreasing tank slapping freak out till back in line going 20-ish for control to stop.

No matter what I tried I could not induce tank slap in Peel only one half cycle to self center automatic thank goodness. An unFlappable bike can explore reversed controls states, so I did w/o upset again and again. Do you know what a relief it is be a hormonal charged Scorpio male that's got more thrilling images to dwell on than sex all the time.

I mostly ran my damper at bare minimum too then realized it really wasn't helping much at the low resistance and didn't like it any higher then it prevented a crash recovery I found I was better off on my own arm dampening with a feathery to white knuckle grip function -> short of freaking letting completely go to grab tank like some space cadets have done. I do not feel very skilled or practiced yet to level I want to be but I have definite set sequence of things I do to learn bike and my limits pretty early on - involuntary loud noises from under helmet tell me I'm getting close enough.

I never hold onto the bars tightly, I tend to find out where the bike is going naturally, and guide it gently. My brake is usually set to operate with one finger. If I inadvertently grab it too hard, I can get the tank slapper - crash mode. Danger time is when I haven't raced for a while.

Acetrel your descriptions of your wonderful 850 Seeley combos behavior sounds as good as it gets to me, as far as a one piece rigid mounted engine/swing arm/frame fork bike might be. The lighter the pilot steering forces needed the more grip and stability reserves there is and less tire vector conflict to compensate for in frame compliance and pilot efforts. i get off putting myself in your Seeley saddle setting fork & lean then just ride it out on high throttle to end up lined up for the open easy path out of there.

I slapped Peel handle bars from hwy speed to over 120 to see what happened but only got one half cycle of my slap then bars self centered w/o a jiggle through frame or me. I've tried that on un-tamed Cdo for all hell to break loose to grab bars back fast. I practiced beating up on Kieth Code philosophy about what really steer a bike a hi speed and power, by body slams against Peel hands off 110-120 to see how sharp she'd turn by leaning rear only with big wind screen interfering with wind eddies like a sail but didn't bother Peel a bit. Once I found I couldn't upset Peel that way I then developed real power steering ease with only throttle grip mattering, to trip Peel down w/o any fork or lean action by me. Forks snatches into straight steer for a instant of frame tremble that passes through transparently. I only really have to hold bar strongly during drifts or slides, which I abhore but then just stops slide in one way to leap off another, d/t planning ahead to be going fast enough I'd crash trying hold full traction just then.

There is really only one fella I care to impress with the funnest motorcycle ignoring forks so the rear can Rule The Roost: Master Code. Tony Folae can then try to mathematically describe what's going on in phases 3 through 5. I just want the most fun before the end.

Ok so anyone decide what offset, rake/trail I should run For added info, keeping the 19inch wheels for now. Perhaps someday Ill switch to 18s for more tire options.

I would have thought a standard commando with 19 inch wheels would use about 2.5 inch offset. My offset of 1.4 inch on the Seeley with 18 inch wheels, would probably be far too short on your bike. I'd be thinking about 2.0 inch might be an improvement, however I'd measure the standard top yoke first. I think that the increase in wheel size means that in comparison with my bike,you would need to use slightly more offset'. I think you could safely reduce the offset on a standard commando by 0.325 to 0.5 inch. If you do that,sneak up on the handling when you first try the bike with the change, and feel for the difference in handling. When Peter Williams built the first commandos, he used race geometry, and guys got chucked up the road after riding over the 'cats eyes' in the centre of UK roads.

the very first Commando had 2-1/4" offset
later Commando had 2-13/16" offset

Apparently the commando with the racing geometry was quite OK, but inexperienced riders could get caught out if they got into difficulties.If the later commando used 2-13/16 inch offset,with 19 inch wheels, I would reduce it to halfway between the old 2-1/4 inch offset, and the newer. The later value would be the more conservative (safer).

acotrel said:

Apparently the commando with the racing geometry was quite OK, but inexperienced riders could get caught out if they got into difficulties.If the later commando used 2-13/16 inch offset,with 19 inch wheels, I would reduce it to halfway between the old 2-1/4 inch offset, and the newer. The later value would be the more conservative (safer).

Click to expand...

The head angle also changed though, and I think I read somewhere that the forks on the 850 are not parallel to the stem

the first 750 Commando used the Atlas 2-1/4" offset yokes , then changed to 2-13/16" offset, The 750 Commando never changed its steering head angle of 27 degrees, so there would be a difference in handling of the early and later Commando's, I wonder how those 2-1/4" yokes would work on an 850 with 28 degree head angle as opposed to the 750 27 degree head angle.

I've tried to chase a cargo loaded 850 in the twisties on my SV650 and really had to peddle the gears and grit teeth on corners to keep up with just his roll on zooms into and out of the turns - noticing his rear rather low aired, was later told yes it softens the ride and more sure footed feel. I did not like the 28' sense of sluggishness compared to the 27', but it seems only a slight extra pilot effort to make sharp turns to go around em w/o undue distress. When ya do it close to optimal its really exciting to press the last bit out for a sense of what to alter next then go out and see.

The 28 degree head angle would probably make the bike feel stiffer. It really depends on what you can handle. If you've never experienced a bike getting really out of shape, quicker/lighter and self-steering is probably not the way to go. When I was a kid, I raced regularly for about 12 years. These days it takes a lot to deck me, I ride the bike to the ground if it all goes pear shaped.With the 2-1/4 inch offset yokes and 28 degree head angle,and 19 inch wheels, you are probably still in the safe zone, but I'd be watching for oversteer when laid over under power. If you find it, and you are a larrikin, it can be good stuff.

Ugh, thank goodness I didn't have to crash in every way and bike combo so can learn a sense of it from others. The thing is I've never crashed on fast cornering - felt like it though. I've developed a bad taste of what those slight bits of resistance - to lean, to fork turn ease- to length of time judders continue after loads relieved, to find that's source of upsets that suddenly change behavior. My sense of the 28' 850 is at some point it would limit how fast you can change lean up or down in time, or fly off the edge by time steering effect kicks in enough. I ran into that on Ms Peel so switched to THE Gravel methods to change direction faster in the tightest places. I garantee you can not use road racing reflexes on fast Gravel travel.

At some point if bike pretty zoned in its like playing a guitar, many styles
that sound just as good or can be made to go around as good as any. You've seen modern racers lift front in severe turns at high speed, I learned to continue that to my advantage getting both tires flying long and far enough the frame suspension oscillations from fork hi side whip lash settled down to land on and bounce off in the right direction and angle. That's just my Graveling style to compensate and get past the suddenly too sharp rake steering limits.

I'm pensive on the changes on next Peel and will have to learn to dance with her again but prior any fool could have their clumsy or delicate ways with her and she just swallows it up no problemo. I crave the G's that pull on flesh and pool blood back and don't want to work hard to get it.

If works as expected I'll squat rear 2" and pop front up 3" like a chopper to peel over dive booming into apex then release rear and tuck front low like a dragster to resist the wheelie out of there. A side ways wheelie over steers like you can't believe and no instants of let off or loss of traction, but then ya facing the wrong way for the next turn in opposite direction 30 ft away going 60 mph in 2nd, what do ya do? You've seen hi sided bikes do it that fast, why not on purpose? It can drive you nutz on the G's...

[video]http://www.youtube.com/watch?v=0vniz3zXf4g[/video]

OHMGawD! This is what I want it to feel like on Peel again, wouldn't you?
Pay close attention to horizon angle changes, imprint on that for later...
[video]http://www.youtube.com/watch?v=BycHBgQKnQ0[/video]

hobot,
Thanks for the video. I pulled 2.5g flying Apaches, don't think I want t try it on y commando.

Ohhhh yeah Sebar some air craft and boats can pull some cornering G's. Did a few G's in as a soar plane passenger and like 6 in a trainer over Hawaii at the controls pulling out of dives and cranking over so whole flank of plane doing the turning. Did get too sharp and got in a spin but the real pilot pulled us out of it. I'd flown and crashed in ultralight so told him lets play @ 1000 ft higher than normal if handing off to you know who...

This fork thing is fascinating and frightening to me. I sue forks like everyone else, until really kicking up heels, then its more like a rudder to me to turn whole bike on CoG to get bike flank ie: both tires but especially the rear resisting or applying side forces. The few cycles I got to do slides on all tended to kick rear out so had to flip into crossed up flat tracker style still counter steering or more accurate dolly wheeling in direction of rear slide out, which to me means a ruined failed turn I had to save by giving up inward turning forces for the outward tangent. A fascinating uncanny behavior of Peel getting to this state was she didn't tend to loose rear just slide outward some w/o tripping down or hi siding up or getting crossed up still counter steering as if nothing happening so fun, then just finish the turn at exit lines up to pop up as usual. Its at this end phase of normal steering that my real fun and fascination begins. One thing to do when bored with annoying slides that prevents faster cornering in tights is to blip on and off throttle to twitch bike on CoG tiny bits about a tire width each blip for a crab-slide-grab cycle. I try to dance it to rock and roll tunes in my head at hwy speeds on THE Gravel. On tarmac all maxed out in lean and power on nice long essentially constant radius sweeper, is kick rear out enough can pop upright for an interval of better power on hook up, dragster like, then another trip down rear step out which feels like a stunt plane doing chopped up barrel rolls. This allows more power put down in shorter length of time than can be hooked up on tire edges. Doing this on inline 4 reveals it forks oscillate in fights to go down so frame shudders to step it out while in laid over state, yet my V twin fights through forks to pitch back up. Both bikes have similar fork geometry but different CoG I assume. I am spoiled by willing lovers and same with bikes now if they ain't willing or fight back, screw em it just ain't fun enough to risk. Btw good stunt air craft places center of rotation through the pilots chest, so ya feel spun around not flung around.