Author Topic: 21 inch cafe? (Read 62125 times)

Industrial Cafe · « **Reply #175 on:** January 08, 2009, 08:47:36 PM »

thanks for the info havoc, I take all the stuff people say into consideration. (especially if it makes sense.)

754, you got any pics of that swingarm?

I think I know what you mean, but.... add to the front?

754 · « **Reply #176 on:** January 08, 2009, 09:01:21 PM »

Do you have a lathe to use and a welder?

If so it will probably cost under 40 bux cash, I can walk you thru, it.

basically a machined tube to hold your bushings, 2 tubes for between that and the stock arm.. gussets optional..
I thought up a new trick that i did not use that will easily get it within.020 of parrallel.

1080 · « **Reply #177 on:** January 08, 2009, 09:38:19 PM »

Here's 754's swingarm/bike IC.

Industrial Cafe · « **Reply #178 on:** January 08, 2009, 10:09:50 PM »

My father in law has a lathe with a bad motor, and I have a broken welder.
my dad has a machine shop, but he's busy, and I can only get in there when I'm in St. Pete. (180 miles from here)
754-
With that extending idea you have, will I have a deep enough crotch in the swing arm to accomodate a 21" wheel?
I really don't like the stock swingarm, that seam on the side...

I want to make or get one that's smooth, like the RC engineering swingarm

Industrial Cafe · « **Reply #179 on:** January 08, 2009, 10:30:43 PM »

754's back wheel has it's own zip code.

Bob Wessner · « **Reply #180 on:** January 09, 2009, 05:07:08 AM »

Would sure make one do a double take if seen on the road.

Soos · « **Reply #181 on:** January 09, 2009, 06:40:51 AM »

sa3w that bike on TV being built, awesome rims to say the least.
I believe he started with a set of wheelchair rims for the rear.
modified to run bearings on the OD and bolted the mid section to them.

Wicked idea to say the least.
I wonder how long the bearing last though.
Rebuild might be pricey, but it would pay for the oogle factor and them some.

l8r

Industrial Cafe · « **Reply #182 on:** January 09, 2009, 07:02:07 AM »

oh wow...

that thing is cool.

Geeto67 · « **Reply #183 on:** January 09, 2009, 09:16:25 AM »

Lots of bikes use steel box section swingarms: fzr600, harley Sportsters, Early CBR, etc. I have the RC swingarm, it is pretty heavy but it also have three shock mounts and three positions for the rear axle. Were I to build one like it I would probably make it lighter.

To add to the front you could add to that section between the pivot and the forks of the swingarm, but even still the stocker is not the best solution.

Industrial Cafe · « **Reply #184 on:** January 09, 2009, 11:31:25 AM »

hey Geeto, is that RC swingarm for a CB750? if so, you wanna get rid of it?

Industrial Cafe · « **Reply #185 on:** January 09, 2009, 12:15:19 PM »

ok, so I did some measuring, I'm gonna need a 6 inch extended swingarm for it to fit like the picture.

Geeto67 · « **Reply #186 on:** January 09, 2009, 12:20:34 PM »

Quote from: Industrial Cafe on January 09, 2009, 11:31:25 AM

hey Geeto, is that RC swingarm for a CB750? if so, you wanna get rid of it?

yes it is for a cb750 and no I am not going to part with it. Mine's chrome and setup with a Kosman rear hub and grimeca caliper (dragbike), part of a big dragbike stash I bought a while back. I was going to use it for the landspeed project but I am using a cb450 instead so now it is earmarked for the cb750 bracket bike I plan to build someday.

754 · « **Reply #187 on:** January 09, 2009, 08:22:07 PM »

Ind Caf, Not sure how you arrive at 6 in. That can be a bit of a PITA, I run that length and am probably going to shorten an inch or two. At 6 over I can run stock gearing with 120 link chain, but can no longer put my 54 T sprocket on, just part of the reason.

To clearance arm for 21, if it get too tight at front for tire, notch it out and weld in a plate.

To whoever said the bike is too wide for a 21, tell us what you think of a CBX with stock rear tire..

Re welding to an aluminum swingarm,
If it involves a small section like chainguard mount, without heating too much of the arm, go for it. Shock mounts, I wouldnt.
Basically you have to put a lot of heat into the welded piece and the arm, and it will be annealed when you finish.. and be around 60 % of the strength of the arm and the part you are welding (if it was billet). To me that is not enough. Saftey and lokking good is a preferred combination. Some welders may say otherwise, but they wont be riding it, will they..?

Industrial Cafe · « **Reply #188 on:** January 09, 2009, 08:46:16 PM »

the 6 inches is to stretch it out so it's "too long"
I want a good gap between the frame and the wheel, otherwise it's inside the frame and i don't wanna buzz my cowl over hard bumps.

I was thinkin' the 1980-ish cb750 swing arm. Cut it where it straightens out near the wheel mounting flange, and extend 3 inches. cause that swing arm is already 2.45 inches longer than the one I have on it now. that would give me 5.45 inches of stretch.
I know the wheel wouldn't be centered without---
bushing up the wheel with the stock 80 spacers and use the sprocket mount from the 80. (its about an inch taller) me thinks... I'll have to research it a little more to be certain.

whats a PITA?

Industrial Cafe · « **Reply #189 on:** January 09, 2009, 08:48:24 PM »

oh... pain in the ass

how come nobody cusses in here?

#$%*#$%*#$%*

Industrial Cafe · « **Reply #190 on:** January 09, 2009, 09:01:02 PM »

i pulled this from another thread.

Quote from: ratSOHC on November 20, 2008, 03:02:23 PM

Here's three swingarms for comparison

top to bottom, left to right... '74, '77, and DOHC.

(ignore the obvious screwup with the 10&15/32"... it's 10&7/16" but I can't be bothered to go back and modify the pic)

To swap the DOHC swingarm into my '74 frame I;

trimmed the swingarm with an angle grinder and a plastic ziptie as a guide. ALL the meat comes off the "lopsided" side of the swingarm.
Deburred the cut end
installed new bronze bushings
Installed. Greased.
Used the early hub, late model cush drive and spacers, late model axle. Perfectly aligned sprockets.

it was easy.

754 · « **Reply #191 on:** January 09, 2009, 09:10:24 PM »

well i offered up (explain how to) that swingarm stretch a few times on here, plus my make it in an afternoon fork brace (with minimal tools), and everybody always wants to do it a harder more expensive way

anyway I discovered a way to align the new part on the stretch that is near idiot proof, and just thought up another way to make it even easier..buy a cheap swingarm on ebay and cut front off, or get them to cut it off where the wheel cutout ends..cheaper shipping..

Keep in mind you are just trying this out, after you try it you may want to change things a bit, so maybe keep it simple at this point..

Industrial Cafe · « **Reply #192 on:** January 09, 2009, 09:50:44 PM »

Don't think I'm not thankful for your advice, it's a great way to do it easy. (which is my motto)
but check this out man.
is there any drawbacks to this?
I'd make a slide jig up first...

I'm a certified pipefitter/welder if that helps.

would you think it'd need bracing?
I'm trying to avoid bracing it up if I can.

754 · « **Reply #193 on:** January 09, 2009, 10:10:24 PM »

That woulb work great..
if the tubing was straight..

still cheaper faster to mod yours..a lot easier setup..

Industrial Cafe · « **Reply #194 on:** January 09, 2009, 10:22:34 PM »

oh you ain't lyin,
but I have that "welded halves" one. and I don't like the seam.

Bouncer · « **Reply #195 on:** January 10, 2009, 03:44:19 PM »

Quote from: Industrial Cafe on January 07, 2009, 11:51:13 AM

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.

Do you happen to have a picture of it, i have been searching for a good looking oil tank to sit inside the frame but have come up short.

crazypj · « **Reply #196 on:** January 10, 2009, 04:02:01 PM »

As your a weldor, I would think it would be easier to cut out the front pivot, (about 3"~4", before end of stock bracing) notch it and weld in a box section. You won't be getting front hot enough to distort or damage bearing area's. That way you can get the RC type you want with minimal work.
The stresses on pivot area are minimal in normal motion, lateral will increase but if your not fitting a sidecar it wont be a problem
The problem with stretched swing arms in general, they may look 'drag bike' but the extra leverage causes things to flex more and occasionally break.
PJ

Industrial Cafe · « **Reply #197 on:** January 10, 2009, 04:48:49 PM »

I'm worried more about buzzing the stock bracing area with the 21'' tire, and getting a moderate gap between the frame and the tire, without going too far back.
I'm not really looking to go "drag bike", cause the bike isn't fast.

i gotta get out and pick up a free rusty old 21inch wheel and tire for mock up.

you said weldor. sounds like some sort of shop gremlin. heh heh!

Quote

Bouncer said
Do you happen to have a picture of it, i have been searching for a good looking oil tank to sit inside the frame but have come up short.

I'll get one for ya, PM me so I remember who to send it to.

crazypj · « **Reply #198 on:** January 10, 2009, 08:27:37 PM »

Weldor is the person who welds.
Welder is the box
another piece of useless information

PJ

Industrial Cafe · « **Reply #199 on:** January 10, 2009, 08:51:08 PM »

oh yeah... duh.
I remember reading that in a book somewhere.

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Author Topic: 21 inch cafe? (Read 62125 times)