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the one on franks smiths 350 is pretty lightened. if you ever have the chance. there isnt a thng on the bike that hasnt had a knife to it.

jc
 

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Discussion Starter #22
I just put up a webpage doing a comparison of the 305 and 450 drums with side by side photos of a few examples out of my brake collection.

Here:
http://www.jrbranson.com/showandtell.htm

JohnnyB


JohnnyB,

Just curious as I search for my front end setup. Seems like it's hard to come by the cb450 drums but there's alot of 305's out there. I dont have any data infront of me but not sure if all 305's superhawk, dream, scrambler cl77's have identical drums for my cb350?

Better yet, anyone getting rid of a hub or complete wheel that can be adapted to my cb350 for sale. If so holler at your boy.

Peace
Alex

Whodaman!
 

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what about a carbon liner to replace the normal cast iron? would that be legal? i know that it would take a s*** load of weight out of the brake. thoughts?

tex
 

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Alskee,
I know the CB77 from 61-68 and the CL77 from 65-68 had the same 200mm 2LS brake. I've seen some minor differences in how the actuating arms connect to the cams and other minor details. Nothing that would prevent one from working on a CB350. All use a 15mm axle.

Decent outline of the strong/weak points of various brakes at:

http://vintagebrake.com/drumspec.htm

I'd part with my 450 hub...(seen in the photo)...problem is it's got some pitting in the liner....I'm not sure if it will clean up, a couple of them are pretty deep. I'll try to remember to drop it off to be turned this week.

Tex,
The problem with carbon might be getting it to adhere to the aluminum. And I'm not sure if carbon would work backed up with aluminum....they'll get red hot in use sometimes..they have no mass to soak up the heat so they get very hot very fast. But yeah...it would be very cool if that would work...except it would probably cost a few thousand to do it....shoes probably have to be lined with moon rock or something.
JohnnyB
 

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I've been working on some 305 brakes the last couple of days. Got them down to 9.6 lb. without getting too radical. Can probably get another couple of oz. off. Which puts them about 1 lb. heavier than a t-500....not bad.

I've found identical hubs that weigh up to about .5 lb. different, apparently due to liner thickness.

I drilled the outer rim with 3/8" holes between the spoke holes. 36 holes in all...was good for close to 1/2 pound...and thats off the outer rim where it counts the most. A mill and rotary table makes it a snap.

A person could get real fancy and drill out the center of the cams and pivot bolts, put holes in the shoe webbing, turn the cooling fins deeper, get some Ti hardware and end up with a pretty light brake.
JohnnyB
 

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Are the superhawk (cb77) drums and dream (ca77) drums the same? Wheels for 305 dreams are a heck of a lot easier to find than cb77 rims. Plus anytime you see a part advertised as coming off a superhawk it tends to be twice the price of the same part on a dream.
 

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Geeto,
I'd like to know the answer to that myself. They look the same in the pictures...doesn't mean much I guess. There can be subtle differences in the arm ratios, width of the cam face etc.

Maybe I'll find one on ebay and buy it to compare.
JohnnyB
 

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If someone has a superhawk drum I have a couple of dream front rims laying around to measure. Just gotta tell me which measurements to take. I don't have a digicam otherwise I would snap pics. I am pretty sure the 305 scrambler is the same as the cb77.
 

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hey jb, discovolante also has some massive 4ls brakes and some pretty trick looking 2 ls.

just ncase you didnt know. like that happens.

jc
 

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Joe,
Pretty nice aren't they. I look at them sometimes and rub one off.

But...hey whose got $1600 lying around.

I'm trying to come up with a design that could be machined from solid stock and bolted together....something cheap like $600. Frank C. ought to help us out and do one up CNC for us.
JohnnyB
 

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quote:
Joe,
Pretty nice aren't they. I look at them sometimes and rub one off.

But...hey whose got $1600 lying around.

I'm trying to come up with a design that could be machined from solid stock and bolted together....something cheap like $600. Frank C. ought to help us out and do one up CNC for us.
JohnnyB
I hope you have a good understanding of engineering, metalurgy, and finance. I am pretty sure the billet chunk alone will cost close to $600. IIRC, most drum housings are cast to keep the price down. Drum brakes are subject to stresses that far exceed disc hubs. The intallation of metal liners alone will probably set you back a good chunk and you still have to figure out which drum setup you will use. There are so many drum brake bikes out there from which to steal you are probably better figuring out a way of converting big rear discs off larger bikes than you are making your own drum out of cnc.

BTW a cb77 drum costs way less than $600, as does a T500 drum, and there is a GT550 with 4ls on ebay for $200 (the whole bike).
 

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Boy that sounds like a loaded answer.

so anybody wanna tell me what to measure on my dream front brake so it can be compared to the superhawk.
 

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Branson - Speaking of engineering, metalurgy, and finance. Let me know when you want to do Phase 4 of your pistons and I'll send moolah.

Geeto - You can't run disc brakes in the vintage race classes we run.


Aaron
 

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Well....liner ID would be a start. I'm guessing it's 200mm. Shoe width next...should be 30mm. Axle diameter...should be 15mm. The rest gets more difficult...cam paddle width and height, actuating arm length from pivot to cable end, pivot pin diameter.

My guess is they are same except for variations in hub width and speedo drive setup maybe. Hub width is no big deal, can be milled down or spaced out.

If the liner ID is less than about 195mm then it's different enough to go with a Superhawk brake that's 200mm.

I just checked with Moorse and center drilling the cams and pivots to 6mm, 1/2" hole in the paddle, drilling the spoke flange, and the shoes between webbing is all good. Narrowing the paddle is a no-no. Also if you are anal you can deepen the grooves between the cooling ridges to lessen weight and increase surface area.
JohnnyB


PS. Aaron...gimme a couple of months max. I'll probably order three sets. 13:1 here we come!



Edited by - jbranson on Oct 17 2005 6:46:57 PM
 

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Aaron,
Find out if Hutch deals with "NeWay", they make valve seat cutters. K&L sells NeWay stuff and I bet Hutch deals with them.

I'm going to piece together the part numbers for the tools necessary to cut 175 intake and exhaust seats. Should be about $200 instead of spending the $1000 on a full kit. We can ship the tool around to whoever needs it and save some cash. Just a couple of turns on the cutter to freshen up the seats every year or so.
JohnnyB
 

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Some shots of the work I just finished on a 305 brake.
Got it down to 9.4 lb.
One could probably get a bit more radical but more than what's seen here offers diminishing returns. Alloy or Ti actuating arms would be nice...another few oz there.

JohnnyB

http://www.jrbranson.com/showandtell-2.htm

PS. Matt... I know you are reading but can't post. Dude! Used more of that Plexus stuff to seal the back of my broken (again) Scitsu Tach. That's stuff gets you real high...real fast. I might have to take up old school huffing again.
(BTW...knocked my bike over in the shop....could be yet another $250 Scitsu down the tube)



Edited by - jbranson on Oct 18 2005 08:27:01 AM

Edited by - jbranson on Oct 18 2005 08:30:43 AM
 

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"use in well ventilated area. open windows and doors"

jb, i cant see why youd be knocking into stuff.

jc
 

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Hi,
I have been lurking for a while and thought I could add a little something to this discussion. The setup I have on my race bike is 72 XL250 forks in the stock cb350 trple clamps. I reamed the 350 clamps out to 35mm with an adjustable hand reamer to a snug fit with the pinch bolts loose. This kept the original axle spacing. I have the original cb350 front brake laced up to an alloy wm-3 rim. This brake works ok but I am going to ventilate it and get better shoes for next season. I have big forearms and squeeze the lever pretty hard to get it stopped. I haven't really had to much brake fade in a sprint race, but I would like a little more without adding more unsprng weight. I also have fitted a trimmed CL350 front fender which adds some rigidity to the front end without trying to get a fork brace fitted. Finally I mounted a OEM GSXR steering damper and tapered steeing head bearings to it. I have been really happy with this front end. I had the frame seams welded, the swing arm lengthened and braced and the frame braced at the swing arm pivot plates and Ohlins shocks installed. This chassis really handles well and the front suspension is not a limitation at this point.I will try to get a picture posted soon if anyone is interested. I think I have some shots from Mid-Ohio. Plus if the brake is a little weak, it encourages me to keep my corner speed up. Remember with a 350, any momentum lost will NEVER be seen again until the end of the next straight.
For those that are not bound by the rules of racing and want a disc brake, I used a Yamaha RD 350 front end complete and just swapped steering stems in the usual manner. It worked really well and looked pretty good too. There are lots of fiberglass front fenders for that front end and make for a very tidy looking street bike.
Right now my bikes are in WI and I am in western Alaska,so I won't get any time to work on them until Christmas break. Then I will get a week or so to get some stuff done and then I won't see them until June, right before my short race season starts.
Ken

AHRMA 412
Vintage racing - old guys on old bikes
 
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