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Discussion Starter #1
would like to know how much work it is to switch from front disk brake from a 74 cb350 to drum. like the look of real old school.
and what drum should i look at for best braking. thanks.

thanks eric
 

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Best braking...or good braking?
Best will cost you a bundle...say $1200-1500 by the time you get it laced up. (big Grimeca, Fontana etc)
Very good will cost you $500-600 laced up. (Suz GT750 220mm)
Good will cost you around $300-400 laced up. (Honda 305/450, Suzuki T500, Yamaha 650, Kawi h1 (early) 200mm).

This includes a spoke kit and probably a new alloy rim. Spoke kits go for about $80, decent alloy rim (Japanese or Euro, not Chinese) $150. Most of the time you can't use the orginal rim because the spoke holes in the rim are angled different since they are aimed at the small OD disk brake hub....when you throw on an 8" diameter drum hub the spoke angle is way different.

Might be cheaper to go with the entire front wheel of one of these bikes...assuming it's the same diameter, uses the same axle size, is not too wide. But then you'll have to deal with things like a different speedo drive, different brake stay arrangement etc.

To do it right it's a considerable undertaking. And you'll probably end up with a brake that doesn't work as well as a well setup single disk.
JohnnyB
 

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Discussion Starter #3
johnny b

say i want to go with a t500 hub and a 18in. wheel from a yam.xs650.
would it work? thanks


eric
 

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Good choices.
You can lace that hub to the XS alloy wheel no problem. The T500 is a 15mm axle...so you'll need to take that into consideration...I'm not sure what the axle size is on the Honda but I'm guessing it's 15mm also. The T500 hub uses a "lug" style stay on the hub....the honda forks are disks so they won't have a lug or a stay bolt....typically you can make your own stay and bolt to a caliper bolt hole in the fork...a little more difficult on the drum side....I've drilled and tapped the bosses on either side of a T500 lug and used those to mount the stay to the drum. Or you can fabricate a piece that bolts to the Honda fork and engages the lug on the T500.

The T500 drum may have to be narrowed up a bit to fit between the Honda forks...and of course the speedo drive is going to be all different. It can be done...and has been done by plenty of people racing the Hondas....but they don't have to worry about a speedo. A lot depends on your access to tools...if you, or a friend can use a lath and milling machine you can make any parts you need to make it work.

It's not a bolt on proposition...but neither is it that difficult. I run a T500 drum on my race bike with Honda 550/4 disk forks.
JohnnyB
 

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Discussion Starter #5
johnny

the speedo is not a problem old school look. a tach is all i need for this one head light , tail light and the tach. i have a friend that is a tool and die. by the way do you have any pics. of your set-up that i could see.

thanks eric
 

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Eric,
Sounds like you could get the bugs worked out no problem.

Here's a page with some pics of the bike under construction and pretty much as it sits now.

http://www.jrbranson.com/HondaRacer/CB175/cd2a_is_born.htm

If you look close at the front brake you'll see the black brake stay rod at the top off the drum (attached by two smallish bolts threaded into either side of the lug) and running up and back to one of the old caliper mounting holes.
JohnnyB
 

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quote:
would like to know how much work it is to switch from front disk brake from a 74 cb350 to drum. like the look of real old school.
and what drum should i look at for best braking. thanks.

thanks eric
I'm assuming that your74 cb350 is an F bike (4 cyl) and not a twin. I am 90% sure the cb350 twin drum front ends are a direct swap to the later cb350Fs (and the twins). Since you are doing it for looks and not that concerned with actual braking power (or else you would keep the disc) the stock cb350 drum should be good for most street riding.

When talking about heavier bikes (like the 350/400/550/750 fours) there is far and away advantages to running discs. Those bikes are heavy and any weight savings is a blessing, espically reciprocating weight so discs have the advantage right off the bat. But more importantly drum brakes heat up quicker and retain heat longer than a disc setup and on bikes like the 750 would burn through brake shoes faster than a disc with a drilled rotor. For the Kettle (Gt750) suzuki used a 4ls front brake because the bike weighted in excess of 500 lbs and previous expirements with drums brakes showed them to be inadiquate in fade, longevity, and overall stopping power. Now a 350 four isn't going to wear out drums like a big old 750 but why peanlize yourself with the weight.

Unless you need a drum brake for a racing class, leave the drum at home. By the 1970s most race bikes ran disc or dual disc drilled front brakes which can look just as cool as a drum when executed properly (like with a set of lesters and a polished airheart caliper).
 

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Discussion Starter #8
really the cb is a little twin. and i like the look of the drum
brake and i really dont plan on ridding hard like the sport bike guys. would like to prove that it could do a ton and look good too.
johnny did you do the ventting on the drum? and do you do it for others?

thanks eric
 

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Eric,
Yep I do all the work on the brakes....typical stuff is shown here:

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

I also sell 305/450 Honda hubs all ready to go, around $225 including new shoes, bearings, vented, lightly polished. The same for T500 around $325 (prefer to save these for race customers as they are getting harder to come by).

These are not "bolt on", they are generally intended for racers that know the in's and out's of how do adapt a drum to their bike. So they don't come with a lot of customer support :)

I've sold a few to the guys here that race. That said....in general on a street bike I agree with Geeto...I'll take the power of the disk brake. I'm assuming you have a CB350G (1973) with the smallish single disk up front. I love disk brakes....only reason I do the drums is cause I need them in my race class...and I have the machines to do the work.
JohnnyB
 

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Discussion Starter #10
johnny
i would like to try my hand at raceing with my toy and keep it on the street if i could. all i see around here are h/ds and sport bikes. i like to shake it up and see what those guys say when its not a v tiwn. thanks for all the info. now i need to find a t500 wheel.

thanks eric
 
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