A Kiwi build from scratch

Nice pics. Did you notice how the steering stem pretty much points to the axle? Big different to your set up. There's a reason for that.

Yep, sure did.


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my first real dirt bike was and isdt sachs 80cc but it was full size not a mini 80-
it had same frame as the 100/125's minus front engine cradle beatiful leading link front with german boge shocks
however
the gbvearbox mostly hunted for and found one of the 19 neutrals it contained, telepathically, you dint even have to move your foot yet to change gear that lil nazi bike was way ahead of the hapless rider
but it was a dream on carving corners ,bumpy straights and best of all long steep rough downhills and after all it was the only place i had to keep up with the richie rich kids on there new 250 and 400 huskies (we rode the santa cruz mountains up by mt uminum and loma prieta)bazai downhill handling like a dream because it had proper rake and trail numbers line the greavsze-es did
you guys dint hit on the blind luck building this one i have had my share of dumb luck but once in a while itll bite you
the leading link front end is absolutely no different from a tele front end , in its need to have the front tire contact patch in the correct very narrow range of what works its all intertwined with the rake and ofsett at the triples
sorry but that one you show is absolutely gonna be a hazard to try to ride,i say try because it will be impossible to ride in any fashion whatsoever,a hazard not to just the rider ,hapless civies will be mowed over if the fool who rides it is able to obtain any velocity on dry pavement, sand it aint hapnin at all, nope but please take some vidieo of the first "ride" ;D

I'm afraid Xb is correct in his assessment of the "drivability". In fact, I believe that you will be well served to just try to push someone around the shop on it once you make it a roller. You will find the "refuses to go straight, will only move forward at right or left full lock" very pronounced even at parking lot speed. This is because the center of effort (the tire contact patch) is far in front of the center of rotation (steering pivot). The center of rotation (imagine a line running through the steering pivot and intersecting the pavement)needs to be a little bit in front of the tire contact patch. This way the forward motion of the bike tends to cause the steering to self center and drive forward in a straight line because the contact patch drags behind the center of rotation. The larger the distance the greater the inherent stability, but it comes with a price. There is a limit to how far the contact patch "trails" (hence the term) this center of rotation because as the distance gets longer the force required to move the system away from center becomes greater. Make it long enough and it becomes impractical to work in small radii. The mid point is with the center of rotation directly over the contact patch. The result is zero stability (but at least it is not INstability) but also zero steering effort - ie you can steer with zero feedback at any speed. The arrangement you have is going in the opposite direction - inherent instability and large negative values for steering input. In other words the system inherently steers itself in either direction - the violence of which is determined by the degree of negative trail (which looks to be considerable!) and the speed.

It would steer better if the motor ran in reverse!

I don't know why rear-wheel steering never caught on.

Crazy

i am still scratching my head trying to figure htf it became
i suspect some window pane may have had part in the construction
its very hard to grasp believe me i have tried to grasp it but its too slick, its real slippery ... so i liken it to building all yer toilets and shitters down a hill and expecting gravity to fill the septic tank at the top of the hill
frankly i really like it though and goddamit somebody has got to do some test riding onnit pronto

Maybe if you put some self centering springs on it like a Swing Bike it would be cool??

xb33bsa said:

the gbvearbox mostly hunted for and found one of the 19 neutrals it contained, telepathically, you dint even have to move your foot yet to change gear that lil nazi bike was way ahead of the hapless rider..

sorry but that one you show is absolutely gonna be a hazard to try to ride,i say try because it will be impossible to ride in any fashion whatsoever,a hazard not to just the rider ,hapless civies will be mowed over if the fool who rides it is able to obtain any velocity on dry pavement, sand it aint hapnin at all, nope but please take some vidieo of the first "ride" ;D

Click to expand...

haha that is some well written funny shit man

Bump... I know its been a while, but I wanna see more of this thing..

Any updates?