Author Topic: 21 inch cafe?  (Read 61913 times)

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Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #100 on: January 07, 2009, 11:51:13 AM »

I want to do an integrated tail light-turn signal setup. I think I'll cut the seat box at an upward swept angle, and mount the tag under the seat with the opposite angle. ehhhh... with lighted bolts or whatever.
 sort of a frenched tag mount if you can picture it.

I like the big head light for now, but i've been toying with the posibility of a 5 inch and a projector in a staggered setup.



My friend has a custom oil tank/ battery box that fits inside the frame. he's also got some painted steel pans to cover the triangle area flush. I just hafta go get em when I start.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


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Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #101 on: January 07, 2009, 12:14:59 PM »
I've revised the whole concept of motorcycles in my mind.

I'm taking all the cafe stuff off, and putting it back to bone stock.
    I now hate anything custom. You've changed me, I feel like I just got saved!

Praise Geeto! Praise be unto his holy name!

I'm a Honda puritain from now on... I've seen the light!

also, thanks for the link dude
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


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Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #102 on: January 07, 2009, 12:16:57 PM »
Additionally, I'm all talk right now cause I'm broke as #$%*.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #103 on: January 07, 2009, 12:27:35 PM »
yeah geeto,
even though I worship your holy name and all, It would be cool if you were a little quieter. like not typing on your clickity key box anymore.

The god I worshiped before you didn't talk at all.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

Offline cafe750

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Re: 21 inch rear wheel cafe?
« Reply #104 on: January 07, 2009, 12:40:07 PM »
Geeto is looking at this whole thing from a completely logistical standpoint.
He's never been one to bash custom stuff, if it made sense.
The thing of it is is that 21's on a stock CB750 frame won't logically work, and have anything near safe to use. Geometries get way too wierd, never mind custom sprockets  that  you need to remedy the gearing problem.
On a custom frame, anything is possible, Hell, you can put car wheels on if you want...but, not with a stock frame....
I will say this, If you can make it work on a stock frame, It'll be pretty damn cool...
"It's an old motorcycle, the wind is supposed to blow your head around, it's supposed to leak oil, the brakes should suck, and every now and then, it should scare you so bad you piss your pants."



Roy, Washington

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #105 on: January 07, 2009, 12:42:28 PM »
Quote
Geeto

But let's tackle the obvious here - most 21" streetbike (aka harley) rims are at most 2.15 inches wide which is nowhere near the 2.75 you need for a 120 tire. At most you are maybe looking at a 80mm-90mm wide tire.

I posted a 21x3.0inch Harley wheel with part number earlier in the thread.
you must have missed that
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #106 on: January 07, 2009, 12:59:11 PM »
The thing of it is is that 21's on a stock CB750 frame won't logically work, and have anything near safe to use. Geometries get way too wierd, never mind custom sprockets  that  you need to remedy the gearing problem.
On a custom frame, anything is possible, Hell, you can put car wheels on if you want...but, not with a stock frame....
I will say this, If you can make it work on a stock frame, It'll be pretty damn cool...

I got the gearing down already. 15t front 48t rear. Maybe a tad high, but not too bad.

What do you suggest in lines of a custom frame?
are you thinking the point where the swingarm mounts should be raised... or lowered? cause i thought with a 4 inch extended swing, that would give me all the room I need.
there's nothing for the wheel to hit way out there, if I cut the hoop on the rear rails off.

everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

Offline Spikeybike

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Re: 21 inch rear wheel cafe?
« Reply #107 on: January 07, 2009, 01:03:34 PM »
geeto- i agree with your logic, but that doesn't give the right to be a dick , chill out





now everyone stop fighting , your all looking like 5 year olds

eldar

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Re: 21 inch rear wheel cafe?
« Reply #108 on: January 07, 2009, 01:06:21 PM »
What most seem to worry about is the height. The 750 is already a tall bike. The 21s will bump it even more. The gravity center is also high to begin with and will be even higher again.

maybe an idea would be to make a custom seat and right behind the shock mounts, whack the frame and arch it up. This way, you may be able to keep things a little lower while still having a bit of suspension travel. Depending on what you have for handlebars, you might be able to raise the forks in the trees and clip the bars onto the forks there and that way the front get dropped a bit too. Either way, once done, you will not be ridding a "cb" anymore as far as handling goes. Will it be bad? Hard to say.

Offline Geeto67

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Re: 21 inch rear wheel cafe?
« Reply #109 on: January 07, 2009, 01:12:07 PM »
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(there goes the $400 budget)
this was just a figure he threw out. Maybe you missed that or maybe he needs to use smaller words. (remember that one)
[/quote]

I remember it fine. He still put it out there and it was one of your earlier comments that It was possible for the figure he quoted.

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I had no interest then to do it because it is an unsafe idea overall (oh and it looks stupid).
 this is just YOUR opinion. Maybe your workmanship may not have made it safe but you do not know what his workmanship is like.


Fine, my opinion and not physics says that the rim bottoms out before the suspension. You know since my opinion magically makes two physical objects come in contact with one another.

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So now you have a really heavy bike on a really narrow contact patch that frictionally will not be able to support the lateral load of taking any kind of turn at speed.
that may be true but you are not sure of his riding style OR his bikes actual weight. While it may not be a feather, it also may not be much more than a 500 in weight.


500lbs bike on a 80 or 90mm tire? seriously? you don't thnk that even a 400 lbs bike on a 90mm tire is heavy? look at the bikes that run 80-90mm rear tires and their weight - there isn't a one of them over 300lbs and that includes the rider. those tires are not even rated to carry 500 total load.

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but to make the whole thing taller will bring any handling problems (speed wobbles maybe) right to the front.
you have no proof of this. It could if not done right but again you are assuming.


You are right, the collective motorcycle engineers of the world spend all their time devloping this technology and the companies spend millions on R&D because and don;t to this to any of their bikes because I fial to waste my time educating you on the last 100 years of motorcycle devlopment. Read a book once in a while - you know the things without centerfolds. Changing the tire tread on cb750s changing their handeling characteristics, you don't think jacking the thing up a collective 3.5 inches (1.5 for the rim and 2 for the 15" shocks) and racking if forward is going to negatively effect the handling? I can tell you from my own personal racing expirence that raking the bike along a little as 1/2 an inch makes a huge difference in the way a bike handles. I can tell you that raising the center of gravity in a cb750 does make it more unstable, but you don;t have to take my word for it, just watch motorcyle racing once in awhile, you don't see an moto gp guys sitting up as tall as possible while racing.
 
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Motorcycle rims are not like car rims.
 WOW I did not know that. Is that why they are curved and not flat?  ::)

Motorcycle tires are curved and not flat. Motorcycle rims are not like car rims either, desipte a similar look, since the size of the rim affects a motorcycle's handling on different axis than that of a car. With cars you can increase the size of the rim and not the size of the overall package (ie make the sidewall smaller) and it generally has a positive effect on handling. With a motorcycle you can increase rim size without increasing overall package size and it has a different effect on handling (because of the shape of the tire).

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We have wasted 7 pages on this nonsense already, the dare has been laid out - you want to do it so hard then do it already - at least babyfood's first post was a pic of his actual project in progress.
 And yet here you are. You have clearly made your opinion know so why not go away now? Also he is ASKING opinions and ideas. Does a person have to start a project BEFORE he asks for ideas? You have said your opinion. You have no ideas. What more are you here for?

Do you work for the TSA? You sure like to throw your opinions around like it is fact.  So again, you have voiced your opinion, quite rudely too as is your way, so what is left for you here? I mean if there is something legitimate, fine, but I see you offering nothing at this time.

I do not care if you want to make fun of my bike. It is not yours and therefore your opinion of it means nothing.

really I must ask this. Are you and ed brothers or related?

You have made no friends with me here.  As far as replacing the broken windo in my glass house it is on my list of things to do after I finish my Land speed turbo cb450 and run at bonneville. I would post it here but this is kinda the wrong forum for it. But I am sure you know how to use the search function here so you can find pics of my other bikes. you'll be disappointed as none of them have 21" in rims or spinners or bling or what have you, I measure and use real motorcycle chassis principles. I tell you what I'll save the search function, I am building this and have been doing it off again and on again for 5 years (most of that has been reading lots of engineering journals, books, and other publications on motorcycle chassis design).it is the first h1 500 chassis to use the FZR400 swingarm conversion, it is the first to use the fzr600 front end (and I didn't see a lot of guys doing stem swaps on triple clamps before I started posting about it in 2002):



ok your turn. I may be ineliquent when it comes to posting, but at least I don't take the aproach of "let's slap it together and see if it kills me" to bike building.
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Offline DaytonGuy

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Re: 21 inch rear wheel cafe?
« Reply #110 on: January 07, 2009, 01:28:09 PM »
Is it just me or is it getting a little HOT in here?   :o

If there is a Mod listening...PLEASE STOP THIS INSANITY!  There is nothing productive happening in this thread.  I say delete the whole d@mn thing.

eldar

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Re: 21 inch rear wheel cafe?
« Reply #111 on: January 07, 2009, 01:44:32 PM »
daytonguy, if you cant take it, then dont read it. there is more exchange of info here than fighting. If anything, this is fairly mild.

Offline andy750

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Re: 21 inch rear wheel cafe?
« Reply #112 on: January 07, 2009, 02:01:42 PM »
besides pj and geeto, your counts are quite high yet I never see anything from either of you 2 except what you post so you might want to replace that window in your glass house.

??????

I dont know why you are so anti-knowledge in this thread Eldar?? Opinions (informed) both good and bad are all welcome.......Geeto and PJ are two of the more experienced and knowledgeable guys on this Forum with a proven track record.....you have been around long enough to know that..........next time watch the syntax...yours isnt making any sense (see above sentence).

take it easy,
cheers
Andy

Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

eldar

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Re: 21 inch rear wheel cafe?
« Reply #113 on: January 07, 2009, 02:12:46 PM »
So now you are the grammar police, Andy?

Also, explain how I am anti-knowledgeable when I merely stated certain things were nothing more than opinions and I in no way said my opinions were fact?

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #114 on: January 07, 2009, 02:15:59 PM »
I like kittens.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


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Offline Geeto67

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Re: 21 inch rear wheel cafe?
« Reply #115 on: January 07, 2009, 02:25:49 PM »


When I disagreed with geeto at first, I was not being a dic. It is called common courtesy.

 

no I am pretty sure you were a dick from the word go.  Doesn't matter much, this is the internet and not real life - if the server crashes tomorrow it would be like none of it ever happened. I come off like a dick, I know this I accept it, my value in life is not measured by this forum or anything else done on the internet

One issue I have had consistently with this forum is the number of unsafe ideas being thrown around somewhat loosly. Someone will say "I want to put a hinge in the middle of their bike" and then 30 people will chime in "oh that is awesome, it will look so cool" so that by the time the one person with sense chimes in and says hey this isn't a good idea he is greeted with jeers.
« Last Edit: January 07, 2009, 02:34:47 PM by Geeto67 »
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eldar

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Re: 21 inch rear wheel cafe?
« Reply #116 on: January 07, 2009, 02:32:08 PM »
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And that is why god made opinions also...so when you say "I think it will look cool" and I say "it is a stupid idea" we can both be right.

Your post right there. before I said anything to you or even posted once. So clearly, you did start it. But whatever, we can just ignore you on the rest of this thread.



Cafe, I like kittens too. Puppies are also nice.

Offline Really?

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Re: 21 inch rear wheel cafe?
« Reply #117 on: January 07, 2009, 02:34:43 PM »
If you want to get to know Industrial Cafe (aka manchicken3) a bit more, he has a youtube page linked on the left of his posts..  To make it easier, it is below.

http://www.youtube.com/manchicken3

To me, the bike sounds perty good.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

eldar

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Re: 21 inch rear wheel cafe?
« Reply #118 on: January 07, 2009, 02:44:05 PM »
Manchicken3! :D  That is awesome!

Nice idea on the seat angle. It does seem to make more sense than a straight back.

Offline Retro Rocket

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Re: 21 inch rear wheel cafe?
« Reply #119 on: January 07, 2009, 02:49:50 PM »
Referring to the you tube clip, the reason the seats don't angle down towards your bum is when racing you want to be "locked" into position due to the increased forces brought on by racing, the last thing you would want while under extreme acceleration is to be sliding up the back of the seat, thats why they aren't sloped. Also, who gives a sh1t if this guy wants to build a bike with 21 inch wheels, i hear "the geometry is wrong it wont work and all these "qualified" statements and i am going to say SO  WHAT!!!! Today bike makers are still changing geometry to get it "right" and right throughout the history of motorcycle manufacturing there have been multiple changes in wheel sizes, it is still happening. If this guy does his homework he should be able to build a bike that would be safer than a lot of production made bikes over the years, anyone ever ride an early 80's gsx 1100 with the "16" inch front, these bikes were dangerous right out of the box, terrible high speed stability. My point is "geeto" if you don't like it great, give your opinion and be done with it, i may think your bike is a piece of sh1t as well but i wouldn't carry on like a spoilt little child that can't get its own way, we all know your opinion so be done with it. This bike is feesable, it just needs to be thought out well before building.

Mick
« Last Edit: January 07, 2009, 03:03:08 PM by retro rocket »
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
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Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #120 on: January 07, 2009, 02:52:56 PM »
haha, my youtube! 
I do what I can.
Referring to the you tube clip, the reason the seats don't angle down towards your bum is when racing you want to be "locked" into position due to the increased forces brought on by racing, the last thing you would want while under extreme acceleration is to be sliding up the back of the seat, thats why they aren't sloped.

Mick
that makes sense, and I thought of it after posted the video. (i hurt my back if i'm not pressed into the seat and open it up.)

Eldar-
kittens are actually better than puppies... ju wanna fide aboud it!?
i have a myspace too if anyone wants to see my dumbness.
www.myspace.com/brianferguson
my youtube is great, it's me in my garage messin' around with the junk I have back there.

I'm also writing a book if anyone is interested.
Brian's handbook of half-assery.

It'll be out in a year or two.

p.s. i am awesome.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

eldar

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Re: 21 inch rear wheel cafe?
« Reply #121 on: January 07, 2009, 02:55:49 PM »
Was it something worth trying though? At least you tried it and found out the seat did not work for you. I think the meager padding on the seats would hurt! ;D

Nope, ferrets are better than kittens! but now I am torn, coatimundis are really cool too!

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #122 on: January 07, 2009, 03:19:12 PM »
Oh that seat is UNCOMFORTABLE right now.
 My dad does upholstery at home, so he'll hook me up with some diamond goose action on that seat.
the video was for a friend that was making her own seat. she made it squared off and i was just showin her the comfort of having a slight angle.

coatimundis are pricey.
everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE

eldar

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Re: 21 inch rear wheel cafe?
« Reply #123 on: January 07, 2009, 03:27:00 PM »
Ok good! padding is required or else you might end up with wood balls. :o

Offline Industrial Cafe

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Re: 21 inch rear wheel cafe?
« Reply #124 on: January 07, 2009, 03:31:17 PM »
you mean they'll demetamorphose into wood?
they're aluminum now... I don't want to go back a step in my "ball toughness" evolution.

I wish they were brass :(

everything I say is pure speculation and
I have no idea what I'm talking about  ._.


                                    Marla              .:71CB750:.CAFE