81 CB650 Brat/Cafe Build

dmable44

dmable44

Been Around the Block
Hey guys, I just stumbled upon this site from the SOHC/4 forum. Figured I'd join and post here too.

Hey all, my names Derek. I bought an 81' CB650 with 9700 miles on it back in the fall and have plans to build it into a Brat/Cafe style bike. This is my first bike and I have a lot of questions and need a lot of help with it. It is cosmetically rough but starts and runs great. Its a project, which is what I wanted, and for the price I paid, I can't be happier.

I have torn it down to the frame already, taking pictures and labeling everything and have done some modifications to the frame already but it needs a lot of parts and a lot of work yet. The plan is to get some clip ons, a 4-1 header with a cone muffler on it and a custom seat that I already have an idea for. Other than that, I already got a CB750 tank for it as the original one was shot. I'll need a chain, sprockets, tires, turn signals, tail light, headlight, an electronics pan, brake master cylinder, brake components and some other odds and ends like exhaust studs. I snapped a few removing the pipes. I also want to find a set of 82' CB650 carbs to get away from the pressed in main jet issue. I'm in college so I'll be working on a college budget but the goal is to get the bike road worthy by spring time.

Here is the bike the night I picked it up:




Here is the frame as it sits now:



And the tank:

 
Got some steel sheet metal and made a seat pan and welded it to the frame. I need to invest in a better welder.

Also figured out the tank mount and its finalized.

Next step is to figure out a seat base, put the foam on it and cover it. Also need to stop by Honda and get some fork nuts, oil, oil filter, chain, sprockets, fork seals, fork oil, exhaust studs, and some other odds and ends I am probably forgetting. Still need to find a set of carbs, a 4-1 exhaust, clip ons, tires, new lighting, fabricate an electronics pan/rewire wiring harness, and get the frame powdercoated.

 
While I'm finishing up the seat, I am trying to figure out an electronics tray type of thing or something to do with the battery and connections. Any ideas/tips/opinions?
 
Figured out an idea for the battery tray and ended up cutting some of the seat pan up in the front for top access. I'm going to mockup the tray with cardboard hopefully tonight. I'll post pics when I'm doing it.

Also scooped up a great condition 17" rear wire wheel with a good tire on it from an 82' 650. Waiting for that to come in the mail.
 
Was able to get to the Honda dealer in hopes of rebuilding the front forks today but had to order the seals and fork oil in. I did get all new exhaust studs, oil and oil filter for when the motor goes back in though. Where is the best place to buy a chain and set of sprockets? Still working out a battery tray design.




 
Hey man, welcome to DTT. There are some important new builder questions that will get asked of you soon. Hahah.... be ready.
 
canyoncarver said:
Hey man, welcome to DTT. There are some important new builder questions that will get asked of you soon. Hahah.... be ready.
Click to expand...
Thanks! I have no idea what that means but I'm ready haha I'll be asking a lot of stupid/already asked questions I'm sure.
 
dmable44 said:
Thanks! I have no idea what that means but I'm ready haha I'll be asking a lot of stupid/already asked questions I'm sure.
Click to expand...




Well then here's the first and most common when "bratting" a bike. REAR TIRE CLEARANCE. With the shocks fully compressed with a ratchet strap, does the tire hit anything? If so, ........
 
One note, from personal experience, you will regret running clip-on handle bars with the stock foot peg location. Do you plan on also running rear sets?

If not, I would suggest Super Bike or Daytona bars. MUCH more comfortable.

dmable44 said:
Thanks! I have no idea what that means but I'm ready haha I'll be asking a lot of stupid/already asked questions I'm sure.
Click to expand...

Do you have rear shocks sorted? One of those questions is going to be whether or not you have enough clearance under the seat with your new seat pan.
 
treitz said:
One note, from personal experience, you will regret running clip-on handle bars with the stock foot peg location. Do you plan on also running rear sets?

If not, I would suggest Super Bike or Daytona bars. MUCH more comfortable.

Do you have rear shocks sorted? One of those questions is going to be whether or not you have enough clearance under the seat with your new seat pan.
Click to expand...

I was not considering rear sets at all, but now that you have mentioned them and the reason why, I may be looking into them. I know the 650 can be a bit tricky finding parts for so hopefully rear sets are not one of them. I do not have the rear shocks figured out. I do know that I would like to go with a stiffer/longer rear shock though.
canyoncarver said:
Well then here's the first and most common when "bratting" a bike. REAR TIRE CLEARANCE. With the shocks fully compressed with a ratchet strap, does the tire hit anything? If so, ........
Click to expand...

I have no idea. I guess I'll have to put the new 17" rear wheel and the shocks back on and try that.
 
dmable44 said:
I was not considering rear sets at all, but now that you have mentioned them and the reason why, I may be looking into them. I know the 650 can be a bit tricky finding parts for so hopefully rear sets are not one of them.
Click to expand...

Don't assume rear sets are the right answer. Bars are cheap and require minimal effort to try/swap out. Clip-ons and rear sets are much more involved, and also put you in a much more aggressive riding position (typically less comfortable and more wearing on your body).

Taking this to the roots... What are your plans with the bike? Simple commuting and daily enjoyment? If so, go with higher bars like I mentioned. Performance? Considering clip-ons and rear sets ONLY after you have completed all of your other performance related upgrades.

dmable44 said:
I have no idea. I guess I'll have to put the new 17" rear wheel and the shocks back on and try that.
Click to expand...

This is the same question I was asking. Make sure you have your final shocks on there when you do the test. No reason to do it with shocks you are going to replace.
 
treitz said:
Don't assume rear sets are the right answer. Bars are cheap and require minimal effort to try/swap out. Clip-ons and rear sets are much more involved, and also put you in a much more aggressive riding position (typically less comfortable and more wearing on your body).

Taking this to the roots... What are your plans with the bike? Simple commuting and daily enjoyment? If so, go with higher bars like I mentioned. Performance? Considering clip-ons and rear sets ONLY after you have completed all of your other performance related upgrades.

This is the same question I was asking. Make sure you have your final shocks on there when you do the test. No reason to do it with shocks you are going to replace.
Click to expand...

The bike will be a commuter when applicable and weekend rider. This is my first bike so I don't want anything really performance oriented other than improving how it will run. As far as engine performance, I would like to do a 4-1 exhaust with a cone muffler and some pods after I find a set of carbs that will work and don't have the pressed in jets. I was going for clip ons for the looks honestly. Plus I thought that was a "cafe/brat thing to do". What shock brand/type is a good one? I'm working on a college type budget until I sell my airride from my previous project car.
 
It's going to hit. The question is whether or not and how you will address it or if you will ignore it.

Longer shocks might not be a good solution on a chassis that was designed to sit low in the rear. It might put your steering neck at a rake angle that makes the bike unstable at certain speeds. It can also quicken the steering in a positive way on some of these old dogs, but more often than not that comes at the expense of extra steering effort. That's fine with some people.

I really like bikes that are set up with superbike bars and stock control positions. They are well suited for aggresive yet comfortable riding in a wider range of environments than a sport bike is designed to perform in. For example, a cb650 with the right bars, seat, pegs and shocks can, in my opinion, outperform a modern sportbike in many situations. If you go turning that old design into a half breed, you can easily lose the positive attributes and gain some harsh ones.

There's acurrent trend of lowering the front with a modern front end and then having to raise the rear for a flat seating area. Why, i don't know, but what that does is create a rake angle that gives you very small trail numbers. This can be SUPER dangerous.

Worst I have seen is a bike that handled fairly well during normal riding, but if you attempted to put too much effort into a leaner it would dig in and kick the front wheel around. If you don't understand suspension on a motorcycle it is best not to modify it.

Even my last newer bike an 06 919 Hornet had conservative and upright foot positioning combined with low rise superbike bars. It's a blast to ride. If I bought anything this year new it would be a Yamaha FZ-7, which has the same configuration. They are also a blast to ride.

Gosh, I really can't wait for riding season.
 
So....a cafe and a brat are really two different distinct styles. Most new builders/people using the term cafe/brat don't know that and that's fine until you learn the differences. In general, a cafe is an effort to increase from stock, the positive aspects of performance and handling. Most brats are sacrificing some performance/functionality from stock in favor of asthetics. All of that is fine, just understand the differences.
 
DohcBikes said:
It's going to hit. The question is whether or not and how you will address it or if you will ignore it.

Longer shocks might not be a good solution on a chassis that was designed to sit low in the rear. It might put your steering neck at a rake angle that makes the bike unstable at certain speeds. It can also quicken the steering in a positive way on some of these old dogs, but more often than not that comes at the expense of extra steering effort. That's fine with some people.

I really like bikes that are set up with superbike bars and stock control positions. They are well suited for aggresive yet comfortable riding in a wider range of environments than a sport bike is designed to perform in. For example, a cb650 with the right bars, seat, pegs and shocks can, in my opinion, outperform a modern sportbike in many situations. If you go turning that old design into a half breed, you can easily lose the positive attributes and gain some harsh ones.

There's acurrent trend of lowering the front with a modern front end and then having to raise the rear for a flat seating area. Why, i don't know, but what that does is create a rake angle that gives you very small trail numbers. This can be SUPER dangerous.

Worst I have seen is a bike that handled fairly well during normal riding, but if you attempted to put too much effort into a leaner it would dig in and kick the front wheel around. If you don't understand suspension on a motorcycle it is best not to modify it.

Even my last newer bike an 06 919 Hornet had conservative and upright foot positioning combined with low rise superbike bars. It's a blast to ride. If I bought anything this year new it would be a Yamaha FZ-7, which has the same configuration. They are also a blast to ride.

Gosh, I really can't wait for riding season.
Click to expand...

I'll be honest here, I have no clue what all the angles and terms are or how they interact. I am very leary about doing suspension modifications because of this. I am going off what I have seen been done. My idea was to lower the front forks slightly in the tree and get longer shocks. My thought was to level the bike out like you mentioned, and as cool as a modern fork swap looks and sounds, its out of my budget/knowledge to do.

I like your idea with the super bike bars actually. Could they be inverted such as the clubman bars are? I really would rather stay away from rear sets.

canyoncarver said:
So....a cafe and a brat are really two different distinct styles. Most new builders/people using the term cafe/brat don't know that and that's fine until you learn the differences. In general, a cafe is an effort to increase from stock, the positive aspects of performance and handling. Most brats are sacrificing some performance/functionality from stock in favor of asthetics. All of that is fine, just understand the differences.
Click to expand...

I was under the assumption a cafe and brat were totally different but not exactly classified one being from another, hence brat/cafe haha I like some aspects of cafe racers and some aspects of brats. In the end, its probably going to end up being a frankenstein of styling.
 
canyoncarver said:
Don't invert regular bars. Please..... They always look upside down, always. Good superbike bars are lower than stock. They look and perform better than clubmans or clipons and they won't kill your back with stock footpegs.




Also, we like frankenbikes here too.


An example: ( couldn't find one cheaper ) http://www.edgextremesports.com/store/Emgo-Street-Handlebar-Superbike-Bend-23-12571.html?gclid=CKHejLn-xcoCFZKCfgodYfEDLA
Click to expand...

I like aluminum, is there a good aluminum option or brand out there? I was looking at Renthals. Don't mind spending $50 on a set of good bars. I do like the look of the low slung clip on bars though! haha However, I am on board with the super bike bars.
 
I use Renthal Road Low bars on my ZRX. I love them. I posted the pic as a reference to the type and because they are dirt cheap and you mentioned budget.
 
dmable44 said:
I'll be honest here, I have no clue what all the angles and terms are or how they interact.
Click to expand...
Ok, that's no problem. Hurco has a very easy to understand diagram that he posted for another cat recently, and i will look for that and post it later. The frames rake angle is the angle of the steering stem in relation to the ground when the bike is at rest. If you raise or lower the front or the rear in any way, and there are many, this angle changes. You can also get raked trees to further deviate from the steering head angle. That alone will affect the steering characteristics, but the more important measurement to keep your eye on is trail. The trail is a measurement of where the axle center is in relation to the end a straight imagined line running from the top of the forks all along the center to where if it would touch the ground. This measurement will almost always end up between 3 and 7 inches. Optimal trail depends on many factors, and it is always best to make small changes and test.

dmable44 said:
I am very leary about doing suspension modifications because of this.
Click to expand...
Good. That means your are sane and at least somewhat intelligent. Things are looking up already.

dmable44 said:
I am going off what I have seen been done.
Click to expand...
Go off of what you have ridden. Make your own choices as to who you think knows and who doesn't. If you see an asshole trying to help, he's likely right.

dmable44 said:
My idea was to lower the front forks slightly in the tree and get longer shocks.
Click to expand...
This is not a good combination. I already explained why.

Also, that bike is already low in the front. You said you want a 4 into 1. Those also require ample clearance. Inline 4's have wide cases, they will scrape in turns if you lower it too much.

dmable44 said:
My thought was to level the bike out like you mentioned, and as cool as a modern fork swap looks and sounds, its out of my budget/knowledge to do.
Click to expand...
That bike has a cruiser frame which has an overall bias to sit lower in the rear. It will take a lot of skill and knowledge to get it to handle well in the opposite configuration.

dmable44 said:
I like your idea with the super bike bars actually.
Click to expand...
It wasn't my idea. But it is a good one.

dmable44 said:
Could they be inverted such as the clubman bars are?
Click to expand...
No. Run them as they are intended, be happy with your commute.

dmable44 said:
I really would rather stay away from rear sets.
Click to expand...
Good. That's actually outside the box thinking these days.
 
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