Topic: 1977 CB550 K cafe racer build

[traveler]

Hello all,

Well....I made it home, picked up my bike, and immediately started the transformation.





The ride home was uneventful, thankfully.  On the way home I dumped in a bottle of carb cleaner and a gallon of 91 octane gas to help "fix" the kindness of the seller in giving me a tad bit of old fuel and running it through the carbs.  I can now report that the one float that was sticking is now freely operating again.

So anyhow, I started by removing the seat and rear fender and assorted bits.



And then tied up the headlight, popped off the top tree, and got rid of the factory headlight stays/fork tube covers.  I cannot tell you how much I was happy to find the tubes in MINT condition...no rust at all!



The previous owner somehow decided it would be a good idea to actually glue 500 emblems on to the sides of the covers....

Front fender went bye bye as well....oh, the mirrors, chainguard, and other bits are now gone...no blinkers.

Although this is my first cafe, I am an "old hand" at the chopper/remove all which is not necessary, so this kind of work goes quickly for me.

Anyhow, it's a start for the first day

~Joe

[traveler]

Day two.

I decided it was time to tackle the "triangle" and do it the way I really wanted it...









In taking the triangle area apart, I decided that I would make a shelf out of 16 ga. steel and would hide the electrics in the bum stop.  

I decided that I wanted to run the airbox, but got a great idea from a fellow member on here "nvr2old".  He basically removed the rear part of the box, and fitted a K&N filter to the rear.  The following pics show the end result that will be obtained:





To pull this off, I purchased a filter made for use as a valve cover breather on a Sprint race car, which is K&N reuseable type, but only cost 13 bucks at the local speed shop.  I also talked the owner into a piece of tube with which the filter can be attached to the plate which will be bolted to the airbox.  It is the breather tube for an early chevy 283 V8.  1.5 inches in dia.  I will cut off a 1 inch piece and weld over the hole cut in the center.



You can see in the pic, that I traced and made a template for which I could weld the tube on to a piece of steel plate, and then bolt it on to the airbox.  Where to find a good piece of steel to do so??  How about a commercial electrical box cover?  only a buck fifty at Ace hardware!  I marked up the mods necessary, and will now cut a piece of the pipe about 1 inch long, and then drill out a 1.5 inch hole in the center of the plate, and weld the pipe on to the hole.  I then will cut around the edges of the plate to fit against the airbox, and will drill 6 holes and bolt the adapter to the airbox with 8/32 screws with locking nuts.



more updates to come.

~Joe

[Zaipai]

Dang, that's a very good start. Nice when you have a good bike to start with. Can't wait to see what you do with it.

[traveler]

Thanks!

This bike photographs well....in person it dosen't look quite that nice....little bit of corrosion on stuff, especially the rear hub, and the spokes are rough...

~Joe

[traveler]

Sean, over at Roc City Customs is making me an alloy CR750 style tank and seat in alloy, and then polishing it for me.  Once done, he will also upholster the seat, with 1 inch thick foam and black vinyl.

The tank is currently about 50% done, and I received this pic of the progress.



~Joe

[JRK5892]

Joe she looks great man! I love the air box idea! let me know if that affects your tune at all! glad you got her man!!!

[Zaipai]

Sweet looking tank.. Lucky dog you. While your at it look at getting a Jell insert for the seat, helps with long rides and is not that expensive if you do it while the seat is being made then its a lot easier and cheaper.

[traveler]

Thanks Joe, it means alot coming from you.

Those who don't know Joe Knapp...he is basically the "king" at building stuff....so the "props" are much appreciated!

I just hope to make a decent representation of a "nice little 550 four".

~Joe

[traveler]

Sweet looking tank.. Lucky dog you. While your at it look at getting a Jell insert for the seat, helps with long rides and is not that expensive if you do it while the seat is being made then its a lot easier and cheaper.

Actually, that's a darn good idea!  I've known about that...but somehow forgot to talk about that with Sean over at Roc City Customs.

Appreciate the comment, and Happy Holiday's to ya!

~Joe

[traveler]

Okay folks...airbox is DONE!

Got off work early today, and spun by the base auto shop and with the help of a sawzall, a electric drill and some bits, and a die grinder I was able to get the bracket for the filter ready for welding.  I then took it over to my friend Brandon at All City Customs in Rapid City, where I talked him into helping weld this thing up and sandblast it for me.  I then gave it a good coating of gloss black engine block paint from Duplicolor, which has a ceramic additive.  Think of it as "poor boy's powdercoat"





Then I bolted it on to the box, again using 8/32 bolts, and fasteners.  I decided on forgo the wax coated nuts and go with regular nuts.  Why?  Because it was a hell of alot easier to do!






Then I decided it was time to install the filter.  If you DON'T push it on at the base, instead of at the chrome end...it will buckle (like I did), and then you have to try to straighten it out.

If it continues to "bug me"...then I guess, 13 bucks more for a new one, and re-try.  Just ensure you lube the mounting points....otherwise you will never get it on there without ruining the filter!






So, anyhow...that's the airbox.  (well, one of the airbox rubbers has a rip, which I will "super glue"...as I have already looked at it, and it will then be perfect...all the rubbers are still "pliable"...how lucky can a guy get with a '77 550K??)

Now on to other items.

~Joe

[Flying J]

Ill will be curious as to how much that chokes the engine. How many less cfm will it flow then then a stock filter? I do love the idea.

[Zaipai]

Man that is some nice work.. Let us know how it works.. Seems like a great idea I hate trying to get on the stock filter, that's why I use pods..humm

[traveler]

Ill will be curious as to how much that chokes the engine. How many less cfm will it flow then then a stock filter? I do love the idea.

Less cfm?  If anything, the motor will get MORE air, not less.

When I hold the box up and look through the rubbers, I can readily see daylight....meaning no restriction, and the factory velocity stacks in the airbox "straighten out" the airflow! 

As mentioned, I got the idea from another member, (nvr2old) who did this mod.

All this filter does, is work as a quick air filter before prior to hitting the velocity stacks inside the airbox.

~Joe

[lone*X]

I agree that the fab work looks great but it will be more restrictive.  The original oval shaped opening to the plenum and filter housing is considerably larger than the tube filter adapter that you made.  Still its a good idea but I would have searched for a filter whose inside dimensions more accurately matched an original filter and made an adapter out of sheet stock to bring it all together without reducing the area of the plenum opening.

[strynboen]

think its 4 times for small,,that filter is for max 2 cylender engine 250 cc even vith venturi effekt its chokes
but fine vorks

[JRK5892]

I love it man! i am going to follow this to see how it works out! i would love to steal that idea on the wifes scoot man... love that you are building a racer now man! get tht fork bag my way so i can make that right !

[traveler]

So...the consensus is...that my airbox won't work??

When I looked at the factory setup, the air was being drawn from under the seat, down through a paper filter, and then into the airbox.  Basically alot of turns and routing for the air to find it's way to the motor.  This is a straight shot.

Either way, I'm gonna try it, and hope that it works.


~Joe

[byfbo]

Hey man do your thing.  Im sure it will work fine.  If not, then you've learned something for next time.  Lookin good by the way.

[traveler]

Thanks and Happy Holidays.

~Joe

[traveler]

Went shopping yesterday, and picked up some parts.









Getting ready to clean up the "electric panel", so that it will be compact enought to fit under the bum stop, and will probably get a small A123 battery to fit under there as well.  I am trying to lighten up the bike as much as possible, as power to weight ratio means I can have a mild and reliable motor, and plenty of power.

~Joe

[Flying J]

So...the consensus is...that my airbox won't work??

~Joe

I dont doubt that it will work, and i guarantee that it will look better then the stock airbox. If it flows more or less air then the stock air box you will likely have to rejet to get the bike to run at its best. I Would rather have an airbox that flows more air. That filter looks even smaller then nvr2olds. I looked at the K&N website and they have a million filters. You could always try a longer one to get more surface area.

http://www.knfilters.com/search/univround.aspx

[strynboen]

its not the filter diminsion i vory abaut but intake diameter,but give it a try..hope it vorks...

[traveler]

Thanks.  I'll try this filter, and then move to a K&N later on.

Who knows?  Maybe end up building a 750++cc 550K motor in the future.....

~Joe

[traveler]

Picked up some mirrors:



~Joe

[traveler]

About half way done with my electrics.  Took the factory electric board, and trimmed off one side, and cleaned up the wiring.  I removed the blinker/flasher module, and took out some excess length in the wiring.  When I got done, I realized, that I needed a mounting boss to match one side.  Easy solution?  Weld on a washer, and then grind the edges down to match.





You can see in the pics, I have drawn a crude line to follow with the die grinder, and then eyeball match it to the other side.  From the back they are father away from each other, so I will make a spacer, and then mount the board to a piece of flat stock with a 90 degree bend.  Then the whole unit will bolt on top of the rear seat span and hang down over with enough clearance above the tire.

(Darn auto hobby shop was closed today, so next week, I can finish her up and move on to other items, like the gauges and top tree!;)

Bracket has some rust in it, so need to sandblast it, then shoot it with the gloss black engine paint with ceramic additive from Duplicolor again (poor boy's powdercoat).

This will all be hidden under the seat bum stop.

Then, I have to make room, and allow for a super small "A123" battery!

This bike will be VERY minimal and LIGHT!

~Joe