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Discussion Starter #1
So i know this question has been asked, you wanna know how i know, i did a search for it. But I didn't find exactly what i was looking for.

I am wondering if there is 'easy' disc brake conversion for the 350. I know about the CB350 G, I also know how hard it is to find a front end of one. so has anyone done, or know about another front end that would be a good match for the 350? Also i have read that the early disc brakes aren't shit to write home about, how true is this? the only disc brakes i have experience with are rather new. I wouldn't be apposed to a more modern set up, as long as it didn't look frankensteined in the end.
 

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CB360 - same forks, wheel, trees, etc. as CB350G.
 

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CB360 - same forks, wheel, trees, etc. as CB350G.
 

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the stopping power is slighly less impressive than your drum provided it is set up properly. It is however a repeatable crappiness, where as your drum fades with each successive pull.

cb360 front if you just want the disc. CB450 or cb550 front end trees to tire if you want bigger forks (the bike needs it) and the ability to convert to dual disc (which will actually feel like modern brakes).
 

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the stopping power is slighly less impressive than your drum provided it is set up properly. It is however a repeatable crappiness, where as your drum fades with each successive pull.

cb360 front if you just want the disc. CB450 or cb550 front end trees to tire if you want bigger forks (the bike needs it) and the ability to convert to dual disc (which will actually feel like modern brakes).
 

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CB550 with a dual disc for the win
 

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CB550 with a dual disc for the win
 

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Discussion Starter #8
Awesome guys, I wouldn't really want to go through all that work to just get slightly better overall stopping power. Looks like i will be going in the duel disc direction. you two will be happy to know that shitty seat is finally off the CL, though the seat I had waiting to put on, is not the seat the seller said it was. correct year, wrong model, therefor wrong latch, and length by two inches. Gonna sell that, but have the proper one coming. Ill be keeping an eye out for a 450 or 550 front end.

Will did you end up picking up that 450 in LI the other day? not sure if you saw it on craigslist, but was pretty cheap and in your area.
 

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Discussion Starter #9
Awesome guys, I wouldn't really want to go through all that work to just get slightly better overall stopping power. Looks like i will be going in the duel disc direction. you two will be happy to know that shitty seat is finally off the CL, though the seat I had waiting to put on, is not the seat the seller said it was. correct year, wrong model, therefor wrong latch, and length by two inches. Gonna sell that, but have the proper one coming. Ill be keeping an eye out for a 450 or 550 front end.

Will did you end up picking up that 450 in LI the other day? not sure if you saw it on craigslist, but was pretty cheap and in your area.
 

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wrote this in another post:


At this point I will remind you that your brakes are only as good as the traction your tire has. The single disc has the ability to lock up on a stock bike, but it takes effort and there isn't a lot of feel up at that top range. The stock drum has a lot of fade and generally any disc conversion is considered an upgrade. What you want ideally is the ability to easily use the entire range of your brakes from light touch to locked up with the maximum amount of feel.

but before we get to the good stuff I will answer your question about the cb550/450/750 dual disc conversion. You are correct those bikes did not come from the factory with dual discs. However honda at one time planned a dual disc conversion accessory kit for all three bikes and did at one time sell one for the 750 for a breif period. The forks have lugs for both discs and basically you convert a stock one sided caliper bracket to bolt to the other side by shaving one of the mounting points and making a spacer for the other. You also reverse the caliper by pulling a crush pin in the caliper so the line exits the opposite side. Search cb750 dual disc conversion and you will find tons of articles on it, the 450 uses the same caliper and fork legs but are shorter, the 500/550 uses similar pieces and the method is the same but only the wheel interchanges. The 450/500/550 forks are preferred over the 750 since the forks are shorter. We will talk about how to mount them up later.

There are two major approaches to improving your bikes braking which is what I assume what you really want to do. A lot of it depends on how the overall bike is setup. If it is closer to stock I would almost say take the weight penalty of dual discs and bigger forks just because it a) looks more impressive, b) is going to add more rideability, and C) you are understressing components which are normally used to working on heavier bikes.

But let's talk about the first approach for a second. The lightness approach or the understressing method. If your bike overall is 50-100 lbs lighter than stock or more (if that is possible) then it may behoove you to work the lightness to your advantage. The simplest way is to get a cb360 disc front end (same as the 350G) and slide it right into your trees. Since the 33mm forks are pretty spindly I would add a fork brace, a tweak bar bolted under the bottom clamp (a fork brace bolts to the sliders, a tweak bar bolts to the fork tubes in case you don't know the difference), an aluminum rim (18"), braided hoses, and a modern master cylinder with a piston size 14mm or one size larger than that. Make sure your fork springs and rear shocks are paired nicely and setup for your weight.

What you gain is braking improvement by making your overall package work less hard. The only unsprung weight you add is the fork brace, and you remove the heavy drum. You get rid of brake pressure loss due to hose flex by using braided lines, and the new master works like a new master so you probably get back some efficiency there. Plus you keep your stock speedo gauge and because the 360 one has the same ratio as the old one and you just run a cable.

What you lose is the increased rigidity of a thicker tube front end and the ability to get better parts like cartirdge emulators and cheap mass produced fork springs.


If your bike is closer to stock weight (and by now I hope you have figured out you need to be weighing your bike), then while the above approach will work it won't improve the handling, won't improve the feel too much, and you will still be stressing your components as they were stock, which means the brake will feel shitty.

Enter the neck bearing chart:

http://scandalon.com/2009/06/motorcycle-steering-stem-bearing-size-chart/

cb350 uses: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB450/K1-K7: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB550K/K1: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB750K (1969-1978): 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

See a pattern here? Unfortunatly what you don't see is that the stem heights are different for all three bikes, with the 450/500/550 being the closest to the cb350 stem height. You will still have to make a spacer that fits under the top clamp to allow the nut to tighten down properly, and you will have to measure that yourself, but basically you bolt the entire front end Triple trees to tires right into your 350 neck. You will also need to make new steering stops - you can buy dirt track bolt on ones, or you can drill and tap the stock stops in the clamp and put a bolt in there. either way, it is pretty easy. Now you can stop here and already you would be miles ahead of the game, however, if you got a 450 front end you can search out a hondamatic 750/ GL1000 front rim and upgrade to alloy. You can also run braided lines. Again, better springs, maybe cartridge emulators, and a fork brace. no tweak bar unless you really want it. But even stock the components on the bike will be underworked and will be an improvement over your stock 350 stuff. It is at this point if you really want to go overkill you can do the dual disc converion that many 450/500/550/750 owners have done for 40 years.

As with anything nobody is gonna write you instructions. It isn't fair to us or to you who needs to learn not just how to do custom work but how to be brave enough to plunge into custom work with little more than a well reasoned idea of how it goes together.
 

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wrote this in another post:


At this point I will remind you that your brakes are only as good as the traction your tire has. The single disc has the ability to lock up on a stock bike, but it takes effort and there isn't a lot of feel up at that top range. The stock drum has a lot of fade and generally any disc conversion is considered an upgrade. What you want ideally is the ability to easily use the entire range of your brakes from light touch to locked up with the maximum amount of feel.

but before we get to the good stuff I will answer your question about the cb550/450/750 dual disc conversion. You are correct those bikes did not come from the factory with dual discs. However honda at one time planned a dual disc conversion accessory kit for all three bikes and did at one time sell one for the 750 for a breif period. The forks have lugs for both discs and basically you convert a stock one sided caliper bracket to bolt to the other side by shaving one of the mounting points and making a spacer for the other. You also reverse the caliper by pulling a crush pin in the caliper so the line exits the opposite side. Search cb750 dual disc conversion and you will find tons of articles on it, the 450 uses the same caliper and fork legs but are shorter, the 500/550 uses similar pieces and the method is the same but only the wheel interchanges. The 450/500/550 forks are preferred over the 750 since the forks are shorter. We will talk about how to mount them up later.

There are two major approaches to improving your bikes braking which is what I assume what you really want to do. A lot of it depends on how the overall bike is setup. If it is closer to stock I would almost say take the weight penalty of dual discs and bigger forks just because it a) looks more impressive, b) is going to add more rideability, and C) you are understressing components which are normally used to working on heavier bikes.

But let's talk about the first approach for a second. The lightness approach or the understressing method. If your bike overall is 50-100 lbs lighter than stock or more (if that is possible) then it may behoove you to work the lightness to your advantage. The simplest way is to get a cb360 disc front end (same as the 350G) and slide it right into your trees. Since the 33mm forks are pretty spindly I would add a fork brace, a tweak bar bolted under the bottom clamp (a fork brace bolts to the sliders, a tweak bar bolts to the fork tubes in case you don't know the difference), an aluminum rim (18"), braided hoses, and a modern master cylinder with a piston size 14mm or one size larger than that. Make sure your fork springs and rear shocks are paired nicely and setup for your weight.

What you gain is braking improvement by making your overall package work less hard. The only unsprung weight you add is the fork brace, and you remove the heavy drum. You get rid of brake pressure loss due to hose flex by using braided lines, and the new master works like a new master so you probably get back some efficiency there. Plus you keep your stock speedo gauge and because the 360 one has the same ratio as the old one and you just run a cable.

What you lose is the increased rigidity of a thicker tube front end and the ability to get better parts like cartirdge emulators and cheap mass produced fork springs.


If your bike is closer to stock weight (and by now I hope you have figured out you need to be weighing your bike), then while the above approach will work it won't improve the handling, won't improve the feel too much, and you will still be stressing your components as they were stock, which means the brake will feel shitty.

Enter the neck bearing chart:

http://scandalon.com/2009/06/motorcycle-steering-stem-bearing-size-chart/

cb350 uses: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB450/K1-K7: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB550K/K1: Upper: 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

Honda CB750K (1969-1978): 26 x 48.5 x 15.2 Lower: 30 x 50 x 14.4

See a pattern here? Unfortunatly what you don't see is that the stem heights are different for all three bikes, with the 450/500/550 being the closest to the cb350 stem height. You will still have to make a spacer that fits under the top clamp to allow the nut to tighten down properly, and you will have to measure that yourself, but basically you bolt the entire front end Triple trees to tires right into your 350 neck. You will also need to make new steering stops - you can buy dirt track bolt on ones, or you can drill and tap the stock stops in the clamp and put a bolt in there. either way, it is pretty easy. Now you can stop here and already you would be miles ahead of the game, however, if you got a 450 front end you can search out a hondamatic 750/ GL1000 front rim and upgrade to alloy. You can also run braided lines. Again, better springs, maybe cartridge emulators, and a fork brace. no tweak bar unless you really want it. But even stock the components on the bike will be underworked and will be an improvement over your stock 350 stuff. It is at this point if you really want to go overkill you can do the dual disc converion that many 450/500/550/750 owners have done for 40 years.

As with anything nobody is gonna write you instructions. It isn't fair to us or to you who needs to learn not just how to do custom work but how to be brave enough to plunge into custom work with little more than a well reasoned idea of how it goes together.
 

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quote:Originally posted by jimmyBK

Awesome guys, I wouldn't really want to go through all that work to just get slightly better overall stopping power. Looks like i will be going in the duel disc direction. you two will be happy to know that shitty seat is finally off the CL, though the seat I had waiting to put on, is not the seat the seller said it was. correct year, wrong model, therefor wrong latch, and length by two inches. Gonna sell that, but have the proper one coming. Ill be keeping an eye out for a 450 or 550 front end.

Will did you end up picking up that 450 in LI the other day? not sure if you saw it on craigslist, but was pretty cheap and in your area.

Yeah i saw it, emailed but didnt hear back.
for arguments sake the 750 is just a longer version of the 550 in terms of forks.
That said im SURE geeto has a set of forks that he would let go.
I have a 19in front alloy off of a hondamatic....

That shitty seat need to hand on a wall some place in a hall of fame!

a single disc is probably more then enough for the bike as the 350 is already much lighter then the 4 cylinder bikes. I guess the dual disc is over kill and probably more unsprung weight then is needed.
but will look bad ass....
 

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quote:Originally posted by jimmyBK

Awesome guys, I wouldn't really want to go through all that work to just get slightly better overall stopping power. Looks like i will be going in the duel disc direction. you two will be happy to know that shitty seat is finally off the CL, though the seat I had waiting to put on, is not the seat the seller said it was. correct year, wrong model, therefor wrong latch, and length by two inches. Gonna sell that, but have the proper one coming. Ill be keeping an eye out for a 450 or 550 front end.

Will did you end up picking up that 450 in LI the other day? not sure if you saw it on craigslist, but was pretty cheap and in your area.

Yeah i saw it, emailed but didnt hear back.
for arguments sake the 750 is just a longer version of the 550 in terms of forks.
That said im SURE geeto has a set of forks that he would let go.
I have a 19in front alloy off of a hondamatic....

That shitty seat need to hand on a wall some place in a hall of fame!

a single disc is probably more then enough for the bike as the 350 is already much lighter then the 4 cylinder bikes. I guess the dual disc is over kill and probably more unsprung weight then is needed.
but will look bad ass....
 

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quote:The simplest way is to get a cb360 disc front end (same as the 350G) and slide it right into your trees.

I agree, except the only trees the 360 setup will slide into is the CB350G (which already has a disc brake). In order to use CB360 brake/forks/wheel, one also has to use the CB360 trees. All other CB350 triples are narrower, and have a "bolt thru the top of the fork leg" design, incompatible with CB360 or CB350G forks.
 

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quote:The simplest way is to get a cb360 disc front end (same as the 350G) and slide it right into your trees.

I agree, except the only trees the 360 setup will slide into is the CB350G (which already has a disc brake). In order to use CB360 brake/forks/wheel, one also has to use the CB360 trees. All other CB350 triples are narrower, and have a "bolt thru the top of the fork leg" design, incompatible with CB360 or CB350G forks.
 

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A properly set-up front drum is more than adequate for any street application on a CL350. The key is properly set up. I took me 3 laps at Mid-ohio to get enough fade in a stock front drum to cause me to start having to brake sooner or harder. That was with OEM Honda shoes. It would have been at least another lap before I would have used better aftermarket shoes. There is barely any way to justify a disc conversion for the street based on performance, much less a double disc set-up. The other part of converting to a 450/550/750 front end is the 19' front wheel, which adversely affects the handling and tire selection.

Ken
P.S. Another upgrade if you really feel compelled to go with a disc is to use an RD350 front end. The easiest way is to put the Honda steering stem in the RD triples. That gives you a better caliper and an 18' wheel. They are only34mm tubes but pretty rigid with a ton of parts and experience. I did this on one of my race bikes and it worked very well.
K
 

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A properly set-up front drum is more than adequate for any street application on a CL350. The key is properly set up. I took me 3 laps at Mid-ohio to get enough fade in a stock front drum to cause me to start having to brake sooner or harder. That was with OEM Honda shoes. It would have been at least another lap before I would have used better aftermarket shoes. There is barely any way to justify a disc conversion for the street based on performance, much less a double disc set-up. The other part of converting to a 450/550/750 front end is the 19' front wheel, which adversely affects the handling and tire selection.

Ken
P.S. Another upgrade if you really feel compelled to go with a disc is to use an RD350 front end. The easiest way is to put the Honda steering stem in the RD triples. That gives you a better caliper and an 18' wheel. They are only34mm tubes but pretty rigid with a ton of parts and experience. I did this on one of my race bikes and it worked very well.
K
 
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