BRAT build

work9to5

See you in the wind.
Ok guys gonna start my build thread here I guess. Picked up a 1978 CB550k about a month ago. Engine had almost no oil in it and the previous owner couldn't get it to keep a battery charge. Everything seemed to be in decent shape except for those issues. Filled the oil and found where it was shorting out about a week after i got it home. started it up right away with no problems. engine runs fine no knocking or any other warning signs. carbs have to be syncd but im gonna tear the thing apart any ways so i put that on hold. I should say that this is my first "build", have owned 3 bikes before and have maintained them myself for the most part tho. i picked up a cb450 earlier in the year but decided to sell it because the engine repairs where beyond my skill level and i want to ride this summer (summer's short here). The idea with this one is to pick up something cheap and turn it into something more functional/fun to ride and change the look around a bit. Ride it for the summer and next winter take down the engine. i'm going for a "brat" look, low to the ground, 2 up if need be, simple lines. I ordered a whole bunch of parts last week and started tearing the bike apart a couple of days ago.
removed the seat. old one was taped up and needed to go.
cut the back "hump" off the frame with a grinder to acomidate a flat seat.
removed back fender and plastic fender guard.
removed all signal lights and brake lights.
front fork spings where saging so found decent used springs on ebay. *note to anyone removing front forks- watch out! for that triple tree nut when you un screw it! i learned the hard way! hit me right in the chin!
removed stock headlight attachments.
removed levers.
tried to remove handle bars, having troble with screws on the brake side, gonna try again tomorrow.
removed mirrors.
removed air box (that was annoying!).
started to clean the thing up. brillo pads are awesome for this so far.
started the seat build. had a decent thick piece of cabnetry board laying around in my work shop, shaped it into a nice seat and pluged it back onto the bike in the stock lock plug and hinge. am going to want to reinforce it with metal plate on the bottom i think to keep it cleaner and strudy. i think i'm going to reinstall the rear fender by bolting it to the bottom of the seat (after i cut it) but have to think on that for a minute.
tomorrow im gonna start adding things back on again. have started some adds already couldnt wait. bought a ton of stuff from dcc for this, listed below.
blk culbmans
art deco signals
gaitors
triuph style bar end mirrors
round tail light
k+n's
header wrap

take a look at the pictures, ask questions, give me some advice.
Oh am looking for advice on my exhast/intake situation im getting myself into in the near future. my mufflers are shot, all but one has holes along the bottom. I'm planning on putting on k and n air filters and cutting the exhasts so that there's no mufflers? only running headers as the exhasts for now until i can afford 4 into 1 pipes. (yes i know it will be loud as hell/yes it will prolly cause a rejetting nightmare) what am i gonna have to do to make this possible? change jet size? secondary jet? let me know if anybodies done this to a 550 before. thanks guys hope you enjoy my build.
 

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seat pic
got some gray heavy duty vinly and some foam padding today. taking it to a friend tomar to have it sewn up.
 

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Hey man I'm build a bratstyle cb550 too and the jetting actually won't be too hard. 115s and the needle in the middle position seems to be where most people run these bikes with pod filters and open exhaust.

I'm not planning to run mufflers either and I'm just going to run 4 into 4 open headers with some simple turn outs welded to the open pipes so that they end right before my rear wheel.

I don't know if you've owned a CB550 or CB500 before but what ever you do don't over tighten the bolt on the oil filter cover!! The biggest pain I've had with these things(I'm on my second one).
 
xtpx i have a 78 750 supersport and i noticed my bike was getting low on oil so i went ahead to the parts store to buy some more oil and figure id change out the old oil i had in it just to clean her out, well after taking the pan off the bolt and draining the oil from the pan and side cover i filled her up with new oil and noticed about 10 minutes later a huge puddle of oil under the pan. So i go to take the pan off check it out and it looks fine and go back to put the bastard back on and the damn thing is fucking stripped -__- and i barely turned the thing. Luckily i had a parts bike from a 78 k and just took the pan and gasket off that and threw that on mine and waaaaa laaa problem solved. After looking online for a bit to research it i noticed i wasn't the only person that had that problem so good to know i wasn't the only one in the boat
 
http://www.randakks.com/Engine%20Parts.htm#1

Best thing I ever bought for my 500 and my 550!
 
Has anyone ever bought these 4 into 1's from this guy on ebay? link- http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemNext&item=251092361828&pt=Motorcycles_Parts_Accessories&autorefresh=true
 
@work9to5,

Hey, I got a 78 550k too, curious to see where you take the bike. On another forum they have some guys that were concerned about the loudness of the pipes as well as the removal of the center stand. Since you are brat-ing this thing, I don't think that matters too much.

The ebay guy looks like carpy, I think this is off of his site.

Good luck with your build, can't wait to see the progress. Oh btw, when you cut off that rear hump, are you going to add a rear hoop connecting the two sides again?

Doh, past link was bad, here is his site:
http://www.cb750cafe.com/products-page/exhaust/cb550-4-into-1-exhaust-system/
 
Ok got the material back for the seat today. Planning on cutting the foams up tonight and finishing the seat in the morning. Vinyl looks amazing gonna make a sweet seat I think! Also ordered 115 jets today as the next step after the seat is to get this engine running correct. planning on taking down the carbs tomorrow as well. hoping the screws dont frustrate the fuck outta me wish me luck! Checked out Carpy's site, wow! Had no idea! sweet site check it out - http://www.cb750cafe.com/
@steakifedi- I'm not actually planning on putting on a rear hoop. (right now that is) I cut this seat so it hangs out over the frame 3" it hides the space between the two bars. also i mounted my rear signals in the mounting hole left from the removal of the fender. so it looks as if there's no empty space left back there. Im planning on mounting a rear fender very close to the back of the seat (maybe even attached to the bottom of the seat partly) to also "fill" the space. I think that I will weld a plate on top of the two bars to create a little more stability.
@xtpx- am so gonna buy those pipes as soon as I can afford them! Looked at your build, its tight. am following it. These what your looking for? http://www.ebay.com/itm/1978-CB400t-Front-Wheel-Rotor-and-Axle-Comstar-/130723676166?hash=item1e6fbd0006&item=130723676166&pt=Motorcycles_Parts_Accessories&vxp=mtr
I'm going to a motorcycle scrap yard over the weekend I'll keep my eye open for em if they are.

Had one question does anyone know if 750 4 into 1 headers would fit my bike? Seems to be a lot more of those out there for sale than for 550's.
 
bump!

Had one question does anyone know if 750 4 into 1 headers would fit my bike? Seems to be a lot more of those out there for sale than for 550's?
 
Those were the wheels but I'm going to go in a different route now.... 16" harley drop center rims front and rear with some chunky Coker tires, as soon as my bank account allows it of coarse ::)

But sadly I dont think the 750 headers will work. I dont actually know for sure just guessing here but I think the piping is a different diameter and the space between the header pipes is different as well. But I could be completely wrong here... How is the build going?


I havent had time to update my build thread but I had a bit of bad luck which ended with an electrical fire and now I'm on the hunt for a new wiring harness. If you see a bike out at the scrap yard one day with a decent one could ya pull it off and ship it to me? If you find one just lemme know a price and a shipping quote.

Thanks man
 
hey 9to5,

I've been asking the same thing, but I don't think the headers from a CB750 would fit our bikes. I have in my notes that the engine interface of the headers of any 71 - 78 CB500/CB550 are the same. Might make it a little easier.

You can try to make it fit, but you might have to get creative if you are going to try to keep the center stand and clearance for turning/riding. I hope that helped. How is the build going?
 
Ok guys need help with this. The bike is done except i'm doing the final tuning rejetting and waiting on new tires. I'll post pics and discrips of the whole build after i get it finished. I'm having problems with the carbs though. can anyone identify the model of the carb in the picture? is it a keihin pwk? Here's the story- I bought a gasket kit and push in jets for what i thought was the stock 78' 550 carbs and they dont fit at all. the jets in this carb are the screw in type and ive never worked with those before. Im at a loss as to what gaskets will fit this and what jet size will do the job. I was going to put in 115 mains to make up for the pods and im running just headers (no mufflers), but all these screw in type jets come in sizes im not familar with. any insight as to what size i should order, so i dont have to keep reordering and frustrating myself more?!!!!! SO CLOSE NEED HELP!
 

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Hey Work9to5,

those are the stock carbs that come with the 78 CB550K. They are PD46C carbs and the only place I have found the gaskets/carb kit is at cycle recycle.

carb rebuild kit from cycle recycle:
http://www.newmotorcycleparts.com/fuel_system_parts/carb_kit_hon.html

Jets and carb kits at siriusconinc
http://www.siriusconinc.com/search_result.php?make=1&model=cb550k&part=1&partno=&x=52&y=4&search=search

The carb kits are hard to find, and the jets you could probably match up, but just make sure you get the right ones. In the sirius link you can click on view detail and it will tell you which bike the parts fit. There are some parts that fit our cb550k with cb750k.

Good luck!
btw, I am not sure what pods you are using but the previous owner on my bike had the uni filters and he was running pretty stock, except he had 100 mains, everything else was stock. Make sure you set the right float height. The manual for our bikes do not have any information on our version of the carbs, so I have read at sohc4.net that people have had good success with a float height of 14.5mm.
 
Ok hopefully my last question. Trying to find a cheap set of dual sport tires that fit. Found these sinko's http://www.bikebandit.com/shinko-244-motorcycle-tire that I want but never had to deal with tire size conversion. anyone know if these will fit my current sizes are 100/90 19" and 120/90 18"s. any recomendations welcome, budget is tiny though.

Steak, thanks for the info on where to find those gaskets. They should show up tomorrow in the mail!
 
@work9to5,

Where's the pics mang? All this work and no pics? j/k, lol I know you can get ahead of yourself and forget the pics but I really enjoy seeing other peoples work especially if they are working on the same bike.

Anyways, back to your question, here's how to read the tire:
100/90 19" = 100 is the tire width in millimeters, 90 is 90% of the wheel width. So 100mm x .9 = 90mm. Obviously 19 is your wheel diameter.
120/90 18" = 120mm x 108mm on 18" rim.

100mm x 90mm = 3.93701in x 3.54331 in
120 x 108mm = 4.72441in x 4.25197

What you can get away with I am not sure because I am not that far in my build yet. I would email their customer service and ask questions. The comments on that tire seem to have responses from their customer service. Might be worth a shot to make sure you get the right one and not waste time/money. I have read that the widest you can get away with on the rear is 120/90 as chain clearance will become a problem. I dig those tires though, depending on what kind of riding you are going to be doing I'd be curious to know how those feel on the street.
 
hey work9to5, how's the build coming? Just figured I'd check in and see if you got any headway on the carbs.

I've got some headway on mine, I'm actually pretty excited about it. I also have a 78cb550k and managed to fire it up this weekend! I cleaned the carbs and did a bench sync, I have pods on the bike and the 100 main jet, 42 slow jet, IMS is 1.75 turns out, my pipes are rusted to crap so they might as well be open pipes. I could only get it to idle around 1500rpm with the choke pulled all the way out, finally have 15 minutes of a warm up i got it down to a hair over 1000rpm with the choke closed but once I gave the bike a little twist on the throttle it died trying to get back to idle. I think I'm close, just gotta keep at it.

Hope you've got some work done :).
 
Just pulled her out of the build space and took her for her first ride! I'd like to say she's finished but the minute after I parked I knew I will never stop tinkering with this bike as long as I own it. So I'll do a little recap since it's been a while since I started and a lot of things have been changed around. It's a 1978 CB550 K3, bought three months ago for the purpose of building a brat type bike. I think that I've been able to accomplish most of the things I set out to do with this build. It is my first build and I was at a definite learning curve with most things. I do have to apologize I didnt take a bunch of pictures during the build, it just didnt make sense to pic up my phone while my hands are covered in grease and crap. And most of the brakes I did take where out of frustration and nicotine addiction. But ask questions and ill give you details on any of the steps I went through. And I'll post some more picks tomorrow.
Ok so when I last left you I'd bought a couple parts from DCC. Bought a whole bunch more crap since then.-
blk culbmans
art deco signals
gaitors
triuph style bar end mirrors
round tail light
k+n's
header wrap
carbs

Striped the bike down. Took off-
turn signals (front / back )
head light bracket
seat
shocks
cut rear bump on the frame
handle bars
headers and pipes
drive chain

Ok so I started to put humpty dumpty back together a week ago. My delay was being able to find parts and lack of knowledge and tools. I found a friend of a friend who had a build space (I did most of the take down outside in the back of a restaurant I own) and paid for a section of his shop (room) and the use of his tools for a month ($200). This turned out to be the best thing I bought the whole build. Not only did I have every tool I could ever need but anytime I was there Chris (the shop owner was there) with all the knowledge I didn't have. Such a big help!
First I started with the carbs. ran into a few issues. Ordered the wrong jets the first time, got push ins instead of screws, UGH!
Finding a carb kit to fit this was another pain. Apparently Honda switched the carbs they where using on 550 for the year (78') compared to all previous years. Its seems like the 78' 550k was the starting ground for a lot of the changes put into future years cb750. I started noting this with the carbs. I also had for reference a completed cb550 77' next to me for most of the build, a lot of minor things changed in that year for both the bikes. Anyways carbs where filthy, really bad. Had some trouble with a leak in one of them when I put them back on but worked it out for the most part. Put carbs back on.
Next was pipes! I bought Carpy's 4 into 1's. Guys these things are sick! worth the price without a doubt! So easy to install, just had to cut off the center stand, new crush gaskets and screw em on with the right pressure. I wrapped em in tan fiber wrap, that was so annoying. I never knew how quickly you could go threw 50' of wrap with four headers. If you are thinking about buying these things do it! If you don't have the money, start saving! Honestly the only thing I would change about them is I like em cermic coated in black. Something I'll prolly do in the future. I'll try to post a vid so you can hear the sound.
Next put on a new o-ring chain in gold. The whole thing I'm trying to do with this build is replace all the parts which really could be improved on this bike. The honda engine was solid so why mess with it. I dont wanna oil a chain (or feel bad for not doing it) every two weeks, so on goes a new o-ring style. Next was shocks, bought black 12.5" progressives from DCC. They're nice, definitely worth the $90. I should mention at this point I ordered a lot of stuff from DCC, most of it was great, butter than great. And they're costumer service was outstanding. Herm even ansewer and email about the carb sizes on these bikes and went into great detail. But i do have to say some of they're low price parts, you get what you pay for.
So rolled it outside, hopped on, started first kick! I was pretty amazed. With all the stuff I touched on this bike to not screw it up considerably was awesome. Let it run for five minutes, it was back firing a bit but that didnt worry me to much. And then it did something scary all of a sudden it shot a ton of water a and oil out the pollution tube from the engine. I had changed the oil when I first got it three months ago and saw nothing weird but this was not good but it had been out side all that time. turned it off let it sit and restarted it 20mins later. Did the same thing. At this point I was pretty worried so I called a friend of a friend for some insight. He said that he's ridden this oil/water out of honda's before and because the liquid was milky brown it didnt worry him too much. If it was dark brown it would and that fact that it had started on the first kicked helped his diagnosis. I was inclined to change the oil again but with these pipes you cant change your oil with out removing them. So i decided to bluckle up the rest of the bike and see what happened.
Next all the signals went on, head light went back on with new brackets and spacers. Wired it, replaced the blinker relay, pretty simple. Had two side covers, one of them had no tabs on it so drilled tiny holes and zip tied it to the old tabs. (Remember not a show bike THIS IS A BRAT PEOPLE) Next was the seat. I had shaped a piece of wood to fit into the old tabs. I cut up the old cushion for a center strip of solid padding. A girlfriend had sewn some vinly with pleats for the cover. In between the pleats I put low density foam and then glued and mounted it all together. Then stapled the vinly to the bottom of the wood. The seat didn't come out as "pretty" as i wanted it but not bad for a first try. And it's actually really comfortable.
I just took it out for 10-20 mile ride. It's pretty sweet. Have to change the clutch cable immediately. It a really pain to get it into 4th. Had a bit more of liquid come out of the tube in the first part of the ride but no much. (opinions please). Really happy with it over all. I'll add more tomorrow, i'm tired.
 

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Not the greatest pics. As you can see it needs some refinement now. Paint on that tank, prolly gonna go dark copper. Smaller gauges or just go to one gauge. Seats ok, could be shaped better. Oh and tires too. Those mirrors from are pretty useless, need to be replaced.
 

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