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I rode the Demon last night!

 
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SRADkneedragger



Joined: 09 Jan 2006
Posts: 15
Location: West Texas

PostPosted: Tue Apr 11, 2006 3:31 pm    Post subject: I rode the Demon last night! Reply with quote

God help me!
I fired up the GT750 with the side car frame in place and took a short jaunt down the road. It was absolutly the most horrible evil handling thing I have ever had the misfortune to operate! 3cyls of 2 stroke magic smoking and popping low slung clipons NO BRAKES! Turns like a TRUCK! I thought I would die! I can't wait for MORE! (cue maniacal laughter) Twisted Evil AAAAAaaahahahahahahaha!
OK now the technical stuff:
I notice that the majority of Rigs use a leading link style front fork. Obviously the reason is that this offers improved steering,,,Why?
Is it because it allows the wheel to turn in a vertical plane or does it have to do with improved trail versus rake?
Also,,,,, I notice that alot of the race rigs have the hack on the left but I notice it on both sides on street rigs,,, any reason why one is better than the other?
I have no clue here help a guy out!
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zentime



Joined: 22 Jan 2005
Posts: 833
Location: Massachusetts USA

PostPosted: Tue Apr 11, 2006 4:46 pm    Post subject: Reply with quote

we need pictures first, then we'll help out! Laughing

"or does it have to do with improved trail"

it's mostly about reducing trail
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SRADkneedragger



Joined: 09 Jan 2006
Posts: 15
Location: West Texas

PostPosted: Tue Apr 11, 2006 10:40 pm    Post subject: Reply with quote

I'll post pics but you had better hide the women and children! This thing is even uglier than it is evil! if you can believe that!
Don't say I did'nt warn you!
The Evil Doctor and his unholy creation,,,,,, actually looks rather timid


The thing handles so badly that I found it easier to clone my wife and force her and the clone to test it rather than trying to fix stuff!


Clones are notoriously stupid and will fall for anything like"hang out REEEAAAL FAR OVER THE SIDE"

More pics



I have no clue what the 3/4" frame around the top of the hack is, but it will be sacrificed for grabrails and grabpoints. The hack will have a flat deck like Moike's Hack. The radiator will have to be moved due to the forward mount going to the steering head so the radiator will probably go on the front edge of the hack behind a duct.
Next move after that will be a 16" or 17" rear wheel for disc brakes and a lower seat height. Obviously it wont't be as low as Moike's but thats the general direction.
Anyway being the newby here and the guy with,,,,, OOOoohhhh about 30 minutes of total sidehack experience, I'm open to idea's suggestions critisism, or outright abuse! Smile
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Paul



Joined: 27 Jan 2005
Posts: 182
Location: Utah

PostPosted: Wed Apr 12, 2006 5:20 pm    Post subject: Re: I rode the Demon last night! Reply with quote

SRADkneedragger wrote:

I notice that the majority of Rigs use a leading link style front fork. Obviously the reason is that this offers improved steering,,,Why?
Is it because it allows the wheel to turn in a vertical plane or does it have to do with improved trail versus rake?


Leading link forks reduce the trail. A normal street bike will have several inches of trail - racing sidecars often have zero. A street sidecar needs some, but much less than a solo bike.

The wheel on a leading link fork still leans when it is turned - which is a problem; if you run a car tyre on the front, it rides up on one edge in a tight corner. That's why centre hub steering is a better idea.

SRADkneedragger wrote:

Also,,,,, I notice that alot of the race rigs have the hack on the left but I notice it on both sides on street rigs,,, any reason why one is better than the other?
I have no clue here help a guy out!


Sidecars belong on the left side.
It's those strange Americans who drive on the wrong side of the road that put their chairs on the right hand side. Big Grin
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zentime



Joined: 22 Jan 2005
Posts: 833
Location: Massachusetts USA

PostPosted: Wed Apr 12, 2006 7:41 pm    Post subject: Reply with quote

ok......I can see there are a LOT of other 'issues' but what the hell is the deal with the rear shocks Question is that a West Texas thing. Laughing

What's your ultimate goal with this?

Should be a hoot once you get it all sorted out.

I don't know if you've looked here yet but there is a lot of good basic sidecar advice on SCT
http://autos.groups.yahoo.com/group/SCT/

Nice work on the cloaning!
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Bandit Bill



Joined: 31 Jan 2005
Posts: 202
Location: Hamilton, Ontario, Canada

PostPosted: Thu Apr 13, 2006 12:39 am    Post subject: Reply with quote

Seems like an interesting project.. and it looks like you've got some work cut out for you Smile

As Zentime has indirectly indicated (I think), maybe you should step back a bit and re-evaluate what your base setup is now, and where you want to take it to, in terms of overall handling/performance/suitability for a sidecar rig. What you have IS a project, and is going to require work to get it to where it'll be a safe, well performing setup. Find Hal Kendall's sidecar info on sidecar.com and read up on some of the theory that's been outlined in it in terms of chassis setup .. it'll set you on the right track.

Please don't take the following the wrong way - I just want to assist you to plan things out, based on what you have, and what you need to do to make a rig that you'll enjoy, and more importantly, won't have you center-punching a Mack Truck if it doesn't handle in a corner the way it's supposed to handle. Safety and stability with any rig is of paramount importance.

The GT750 as memory recollects, is a relatively top-heavy, thirsty, and just plain heavy 1970's sport-touring road going barge.. the best thing that could be done with it, honestly, is keep it stock and enjoy it solo.. or get a kneeler or 'squatter' type chassis made for it. I'd even suggest you look out for an Equalean or similar pivoting sidecar chassis .. it might be more ideal modified in that form than taking it all the way to get it to a kneeler chassis.. you've got a lot of work cut out for you at present.

I do see you've been attempting to lower the bike's height, but it's introduced issues with the overall setup - the rear shocks is but one obvious indicator of this.

Lets start with the basics..

a. Handlebars, racey yes, less than ideal, hell yes. You need flatter and longer bars for leverage needed to keep it stable and under control, especially with your stock front end under all that additional stress.

b. As can be obviously seen, that poor front end is sacked out to the limit of it's suspension travel, just sitting on the driveway. Not good. Even with additional/heftier springs and/or shims in there, then you are going to have a harshly handling rig, at best. As i see it, you've got to deal with all three corners of the triangle in terms of the suspension design. What you have there, and where i think you want to take it, are two different things..

I'd look into converting the rear end over to a monoshock type rear suspension - the sky is the limit here. It'd open the door to putting in a substantial air-shock into the rear end. Use the swingarm out of a GSXR1100, or Bandit, or whatever have you - as long as it is of substantial construction.

The front end - at the least, you need a Leading Link type front end, with as narrow profile a front tire as you can find - as Paul has indicated, the wider the tire, the more the tendancy for the tire to 'ride-up' in cornering - the amount of contact patch reduces the more the front end is turned in cornering - and in braking, if you have too much front brake grabbed while cornering, the front wheel will lock and you'll lose directional control - this is why center-hub front end varients are now considered 'a must' for front ends of HP rigs - but center-hub designs are deep-pocket cost and hard to impliment as a DIY design. A homebrew LL front end, using a 135 series automotive tire would likely be the best compromise going for performance vs cost on a rig as yours. Just make sure you build it stout, do not scrimp in terms of materials. I'm guestimating that your present setup has appx 4 1/2" trail on the front end - at present i'm betting it steers like a Mack Truck with shot power steering. A properly designed LL will restore the power steering, so to speak.

My personal theory of where the chair goes, is in fact ruled by which side of the road that the road travel is on... It's only right that if the rig pilot fecks up, he or she should be the first to pay the price in crossing the double-yellow, not the monkey! Also, on North American roads with traffic's direction of travel always being on the right, the pilot needs to be able to see beyond the vehicle in front for any hazards in the form of oncoming traffic straying over the centerline. If the pilot is tracking on the passenger side of traffic, the pilots observation of any imminent oncoming threat is delayed, along with any corresponding reaction to evade/correct.

Good luck with the project.
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Ralph



Joined: 27 Jan 2005
Posts: 591
Location: Lexington, Ky

PostPosted: Thu Apr 13, 2006 12:52 am    Post subject: Reply with quote

Hehehe a water buffalo and twins Clapping Life is GOOD Cool
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SRADkneedragger



Joined: 09 Jan 2006
Posts: 15
Location: West Texas

PostPosted: Thu Apr 13, 2006 6:30 am    Post subject: Reply with quote

GREAT! This is what I needed is input!Thanks for the tips! Big Grin
This will probably go the "Squatter route due to the fact that I don't want to build a full frame to get down to kneeler territory.

Bill:
Bars, sexy, yes usefull no boy are you right This is what was on the GT750 and I just moved them over out of convience. GSXR clipons are coming soon, flater, longer.

Front end is fresh not sacked out if you look a little closer it is actually moved up quite a way through the triple clamps(about 3 "} I have it Way down there till I get the bars and clipons and gauge mounts sorted.

Rear shocks:hahahahahaha What shocks!? those are spring holders! they are SHOT! They were actually moved to the rear position while I was trying to get an idea for ride height. (Somewhat pointless till new units arrive, but it made me feel like I was doing something)
Thank you All for taking the time to give constructive criticism. This is what I need and want because this is pretty much unexplored terratory for me!
I'm going to hit the links you guys posted tonight or tomarrow and look for more answers but here a few more:
I hope the illustrations I whipped up help explain what I am asking.
OK
MOTORCYCLES
Rake: you increase rake and the bike becomes MORE stabil but turns more SLOWLY.

DECREASE rake bike turns quicker but becomes more unstable


Trail basically has to do with the bikes ability to "self Center" the steering

Are these principals the same with Sidecar rigs?

Leanout: A small amount of leanout counters the drag from the hack and helps rig drive straight? Correct?


Hack alignment: Cars have a small degree of towin which helps the front end remain centered rather than "Hunting" Is this true of Sidecar rigs? where would you start? how many degrees approximate.


OK last but not least: I have heard and been told the closer you move the rig into a "Triangle" configuration the better. Therefore I am assuming that the farther the hack wheel moves forward(axle centers) the better?


OK let me finish up by saying this:
I have been roadRacing MOTORCYCLES for 15 years and have a ton of trophies to back that claim up,,,,, But here I AM The Dumbguy! I am absolutly clueless and as such will accept ANY and ALL suggestions!
I don't know how many times I was talking with some new racer that had screwed around with his suspension settings until he was completely lost dispirited and overwhelmed. So I had to take him to square one then start making the steps one by one, check the preload, set the sack, look at dampening and rebound, look at rider position, make adjustments, look at control position make adjustments,,, you get the idea.
The problem here is I know so little about sidecars I can't evewn tell you guys how lost IAM! hahahah
So I know I'm working with some pretty rough stuff here but my heart is pretty much set on this combination. I just realize its gonna be a lot of work and I need ALL the help you guys are willing to offer. Thanks for all the input so far, and any in the future
SRADkneedragger
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Last edited by SRADkneedragger on Thu Apr 13, 2006 6:44 am; edited 1 time in total
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SRADkneedragger



Joined: 09 Jan 2006
Posts: 15
Location: West Texas

PostPosted: Thu Apr 13, 2006 6:38 am    Post subject: Reply with quote

Oh heres a few 2 wheeler pics
the wife



The wife and her RaceBike


Me playing around on the street(no officer I was'nt speeding!)


My picture without the helmet and leathers

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Bandit Bill



Joined: 31 Jan 2005
Posts: 202
Location: Hamilton, Ontario, Canada

PostPosted: Sun Apr 16, 2006 4:35 am    Post subject: Reply with quote

Download this .PDF format sidecar manual from sidecar.com and study it http://www.sidecar.com/Files/SC%20Manual.pdf - I really can't explain it much better than Hal Kendall - it will help explain a lot of your technical questions regarding rig setup. Smile

Basically, what it comes down to, each rig is different - there are so many variables, no rig is the same - setup even reflects the owners personal preference in terms of handling traits. There are no set rules, just guidelines.

There are a few more articles on the sidecar.com site under the books and articles link - basically thats the best technical resource available online at this point of time .. setting up a rig, properly, has always been considered something of a black art, there is no definable science applicable to it Smile With a project such as yours, it is best to plan adjustability into the sidecar/motorcycle strut connections - because you will need to adjust - very very rarely do you get it right the first time setting it up - and sadly, some people never get it set up right ever.
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