Topic: CB550 rat/cafe (complete?)

[icecoast]

Ive never been  a huge fan of pristine paint and glossy finishes. Not that i don't appreciate craftsmanship and attention to detail, its just not what appeals to me. Raw metal, rust and black are the things that catch my eye and that's where i decided to go with my build.

The bike is a 77 cb550 and this is the second rendition ill be documenting as the first wasn't much to look at. It made its way to me in a couple boxes and within a couple weeks i had her back together and running. Any parts that were missing i filled in with whatever i could find in the old parts boxes i had kicking around from former builds and bikes. Rearsets off a gsxr600 tank from a cb500 and a bunch of misc stuff that just seemed to fit.

So this is what I threw together with a couple hundred bucks and some free time. Carbs and forks were rebuilt and i threw on a new back tire and started to ride.



The seatpan was really thrown together, basic sheet steel and the taillight was one of those cheap round pieces with the "STOP" thing on the brake light. Always hated it, looks like a terd sticking out the back but for free i couldnt do much else.



And i really rode. Put about 5000 miles on her over the course of the summer, fall and even a bit into winter.



I was really surprised it held up to my abuse. I beat the snot out of her on a daily basis. Some things started to give at the end, the master cyl started to leak and i believe one of the shift forks was a little tweaked, popped back into N from 2nd and 3rd on hard accelerations.

Over the past winter a lot has changed and this is where the real progress starts.

[davidtime]

Looks like a good start for you.

[icecoast]

So a couple months ago the tear-down began. All the quick and shoty work I did last season had to be undone and redone. The motor had developed a nasty leak at the headgasket so it was pulled only to find that someone in the past had replaced the gasket and in the process put some deep gouges in the mating surface. I managed to find a good 650 motor for less than a $100 and decided it was cheaper to swap in than machine work to fix the head. Carbs were sourced off a late 80s zx600, rebuilt inside and fitment is perfect.



Since the mockup went well I trimmed more tabs, braced the frame and made new tabs for rear fender liner and passenger pegs. Frame painting is just primer and satin black spray can job to cover the bare metal.



I got a line on a cheap front-end for a 76 gl1000 so for less than $80 I fixed my leaky master cylinder and added another caliper up front. Simply ground out the old stems and swapped them around for a perfect fit. Rear suspension is 14" progressive.





Still waiting on spokes but i have a cb750a rear hub and 17x3.5 excel rim for the rear and 18x2.15 ready to be laced up. Tires are 110/90-18 front and hopefully the 150/70-17 fits into the rear without much modification.

Here are a couple shots of the carbs if anyone's interested. The great thing is they give me an extra inch plus to work in an intake system. Whether it be velocity stacks or filters Im still not sure. I did have to cut and weld a new end onto the throttle pull cable to make the length correct. To start Im gonna try a 120 main 40 pilot and work from there.





My availability is limited so I can only put in a couple days a week on the bike. Ill try and update as often as possible. The plan is to be riding by my birthday which is less than a month way so the push is already on.

[davidtime]

This may sound dumb but I am new to these bikes and am just curious what the tank is from or is it modified?

[Bankerdanny]

That tank is from a 75-76 CB500T twin. A pretty rare bike.

[davidtime]

Awesome. I have seen quite a few with tanks similar to it.

[icecoast]

Laced up the rear wheel with some old spokes just to get a feel for the larger tire. Good news is, it fits. Not 100% centered as its just a loose lace-up but its only about a 1/8in off.

[davidtime]

Did your tank mount the same as the 550 tank?

[icecoast]

It took a bit to get the tank to fit, some of the work wasn't required. I had to trim the front posts and rubber mounts down about 3/8in each side and made a new rubber mount for the rear of the tank. I also cut out the old mounting bracket and welded in a solid plate so the seat and tank bolt down together.



The seat pan is from the same aluminum I used on the rear mudguard, just scraps I had lying around the shop. The foam is off the old seat reshaped and covered with some pho leather from I couch lying on the side of the road. Total cost: free. So I don't really care how janky it looks.

[Retro Rocket]

On the  CBR600 Honda use a 130x17 on their 3.5x17 inch rims, 140 is as big as you should go on a 3,5 inch rim..... 150 is recommended for a 4- 4.5 inch rim, you change the way the tire works and its shape by having the wrong size tires on any given rim , it also causes the tire to wear out prematurely or wear out in the middle first {square off} .......

[icecoast]

Avon recommended rim range for that tire is 3.5-4.5. If you've never pushed a wider than recomended tire on a rim and ridden on it then don't dig. Most people wouldn't be able to tell the difference.

[icecoast]

Rewired the harness so all the components can mount far back in the rear fender near the shock mounts. Next week ill be picking up a couple HEI modules and start troubleshooting the rest of the system (not that anything is wrong but there's bound to be some complications). Im using the 550 mac system I got with the bike and extending the headers by a 1/2in or so to clear the oil pan. I figure people run the same exhaust on bored 550 motors so why cant it flow enough for a stock 650. Once again its free so why not try.

[icecoast]

And just for reference. 16x3.5 with a 150/80-16 is stock on my thunderbird.

[Retro Rocket]

Avon recommended rim range for that tire is 3.5-4.5. If you've never pushed a wider than recomended tire on a rim and ridden on it then don't dig. Most people wouldn't be able to tell the difference.

130 is stock size and 140 is maximum recommended , I have done just about everything known to man with motorcycle tires and suspension, thats my thing bud, I went through all this 30 odd years ago and have since worked in the motorcycle industry and owned some pretty hot bikes, The shop i worked for ran road race teams as well as motocross teams {Aussie champion} .  I am telling you what is widely known in the M/C industry and over sized tires are a no no on any bike if you want it to handle the way it was designed to and get maximum use out of the tire. You can't compare a 16 inch rim to a 17 either, doesn't work like that,  a 16 inch rim blows out wider on tire sizes, but only slightly, the smaller the rim the wider the tire, but again, only slightly,  Check tire charts and you will see.  look at cruisers, some manufacturers over tire them for looks but the middle is the first part of the tire to wear out prematurely which also effects handling.
I suspect you are building this more for looks anyway because if you wanted it to handle its best you would have gone for an 18 inch rear rim and retained the original ride height...   I wasn't trying to talk you out of anything just inform you as to what works best.... Build away....

[icecoast]

I get what your saying about the higher aspect ratio on the 16vs17. It still doesn't change the fact that the tire is designed to fit that rim. All bikes and tires are different, late 80s early 90s katanas came with a 3.5 rear and mfg recommended 150/70-17, I know I had one. I'm not saying that over-sized tires are great and to stretch whatever you want on a given rim, just that in this application with with the tire and rim given, it shouldn't change the profile a noticeable amount. If it gets a bit twitchy in the rear I will swap it out but at this moment its not of much concern.

I still appreciate your contribution and respect your opinions but please understand I'm not setting out to build another racer just something to tinker on. This bike is really just a compilation of extra parts and ingenuity so if it turns out to function well then so be it. At this point my build total is set to be under $1200 (including the bike) so I'm not expecting too much.

As for the rear shocks, yet another "I have these laying around from a previous cbx so why not?"

[SF]

interesting development you have on the go

[Retro Rocket]

I get what your saying about the higher aspect ratio on the 16vs17. It still doesn't change the fact that the tire is designed to fit that rim. All bikes and tires are different, late 80s early 90s katanas came with a 3.5 rear and mfg recommended 150/70-17, I know I had one. I'm not saying that over-sized tires are great and to stretch whatever you want on a given rim, just that in this application with with the tire and rim given, it shouldn't change the profile a noticeable amount. If it gets a bit twitchy in the rear I will swap it out but at this moment its not of much concern.

I still appreciate your contribution and respect your opinions but please understand I'm not setting out to build another racer just something to tinker on. This bike is really just a compilation of extra parts and ingenuity so if it turns out to function well then so be it. At this point my build total is set to be under $1200 (including the bike) so I'm not expecting too much.

As for the rear shocks, yet another "I have these laying around from a previous cbx so why not?"

Yeah, cool, wasn't trying to talk you out of it, just information,  I recently had a similar conversation with a guy that was doing a 3.5 rim conversion on a 400 but wanted correct tire sizes for handling, thats why i commented here. later on in the 80's, Honda raced their production CBR's with 130 and 140 size tires on 17x3.5 rims....   I was reading somewhere that your {USA} Katana's {some models ?} had 16 inch rear wheels in 3.5x16..?   We had 17's and 18's on the rear of the Katana's in Aus, 18's were the better wheel at the time {and lighter than the mags wheels in 17inch} as the choice of tires in 17's was very limited at the time and the tires weren't much good. Our models were more race focused, none had 16 inch rears, one model GS1100 had a 16 inch front....  Its quite amazing some times when you look at the differences in some models you guys got compared to us, the "cruiser" style seemed , or seems to dominate your market where as the race style dominated ours, we got a lot of sporty models you guys didn't get like my 1984 CBX750 Honda, delicate engine but great performance sport tourer at the time with around 100hp....

If your interested, here's a little info on the Aussie Katana's...

http://www.suzuki-katana.net/index.php?p=1_622

[Blitzburgh207]

Cool ride man. What bike are your passenger pegs from?  I want to do the same but I was having trouble figuring which pegs would work w/ the angle of the frame.

[icecoast]

The pegs are from an 05 gsxr 600. The angle works out pretty well, the fact that my girl is only 5'3" helps as they might put a taller passenger (upwards of 5'8") in an uncomfortable possition. I mocked them up and they cleared the shocks by a few inches and left enough room between our feet so I just welded on mounts.

[icecoast]

Does anyone know if the shift nuckle is the same size and spline count on newer cbrs as our cbs? I have a sneaking suspicion it may be but don't have one on hand to check.

Currently I just have the old shifter lever cut with a rod end and shaft I made but I'm looking for something that's a bit stiffer.

[spdygnzlz]

I think I remember seeing parts from a cbr when he made his rearset setup.  You should check out his Interceptor build...it's in there somewhere.

[icecoast]

I thought that's where I had seen it before, thanks.
So I sourced the knuckle and linkage from a cbr600 and it fits and looks much better than the previous setup I was running.



Unfortunately Ive only been able to put a couple hours in over the past weeks and progress is really slow. The headers had to be extended about a cm and with everything apart I decided to hack it up and get the muffler mounted a little better (I think). No more clamp in the center, more clearance, and a little smoother line along the side.





Tail light and turn signals are mounted along with a homebrew license-plate mount.



I think I need to drop the headlight down and have it more inline with the tank, it looks a out of place that high. This could be the lack of instruments too.



The wheels still aren't done, My schedule and buchanan's hours don't line up very well to discus the rest of my order but it should be sorted soon. I just laced up the old rear rim to the front hub and threw a tube in the rear to get it rolling. Next week Ill be pulling it from the shop so I can work on it "here and there" in my free time at home.

Seems like the smaller the job is the less time I have to do it and hopefully bringing the bike closer lets me knock my checklist down a little faster.

[cheftuskey121]

I dig the look, after doing my restoration, I really want to tackle something like this. worn and ready to rock.

[db22]

Following -- today I'm picking up a '74 roller 550 I got for $75. Estimate three years minimum to make a rider. Will be taking notes from your build. Thanks for posting it.

[icecoast]

Projected finish times have come and gone, delays and lack of time are some of the main reasons but really its just my attitude about working on this when i have so many other things to do.

The good news is, I built the wheels and mounted tires and finalized all of the electrical besides battery mounting. Ive had everything set for a couple weeks now and she does run although very lean at idle and cuts out when throttle is applied. I started with 38 pilots 120 mains and the needle from the stock cb650 carbs as they have a narrower end and more taper. My local shop was ordering me some new pilots but they've been on backorder for a couple weeks. Im starting to think I should have just ordered them myself but I always prefer to support local businesses whenever possible.

Im also thinking about redoing the seat. Maybe a charcoal or black waxed canvas, and this time get it professionally upholstered.