Author Topic: My CB550F mongrel (Read 4119 times)

ralt12 · « **on:** June 16, 2020, 04:01:12 PM »

I started out on a CB550F in 1976, and memories are only positive. So after a rare positive trip to Vegas, I bought another that I thought was ok, but like all eBay things, better look it over first.Good thing I did, the Prior Owner loved silicon sealer.

ralt12 · « **Reply #1 on:** June 16, 2020, 04:07:20 PM »

So back about 10 years ago, I shortened the front fender, went to a MAC 4 into1, pods, ditched the turn signals for little bitty ones, went with a Euro CB400F handlebar, put new shocks and rims on it, and put emulators into the forks. The emulators were probably a mistake on my part, not because I had them, but they were adjusted way too hard. Regardless, I rode that for a couple of years before terminal carb leaking turned into a chronic pain in the butt. So I parked it.

ralt12 · « **Reply #2 on:** June 16, 2020, 04:31:11 PM »

Late last fall, I decided to take a shot at making a bike that as seriously light, agile, had more poke, and most importantly, was comfortable. I read a couple of dozen project threads before deciding on the pitfalls of doing this and just plain pleasing myself, which, at the end of the day, is the key. I'd been having some trouble with my computer, so putting this down as a project thread took more time than I'd like.
BUT:
I decided that the front forks had to go, and I never got around to the fenderectomy that I was going to do on the rear, mostly because my wife still entertained thoughts of riding. Things change when you get the solo nod. The more I looked at the stock bike, the more I thought that dragging it kicking and screaming into this decade would be an interesting challenge. So weight has to go, and there's no shortage of it on the stock bike. I started by taking the whole thing apart:

ralt12 · « **Reply #3 on:** June 16, 2020, 04:36:41 PM »

I wanted to use the Cognito Moto rearsets, but for the 550F they interfere with the brackets for the passenger pegs.

ralt12 · « **Reply #4 on:** June 16, 2020, 04:48:54 PM »

Since I got the solo nod, I could do away with the passenger brackets. On the left, no problem, but on the right....hmmm...since the exhaust gets located there, maybe a little alteration would work. Time for the grinder to start taking bits off that I won't be using.

ralt12 · « **Reply #5 on:** June 16, 2020, 05:02:28 PM »

Smoothing out the frame to take out the bits you won't use takes a lot more time than you think it will, it's tough stuff.

ralt12 · « **Reply #6 on:** June 16, 2020, 05:05:12 PM »

I'm no expert when it comes to unlocking power from the 550 head, but I do know who is, so I sent my block and head off to MRieck. Boy, he does nice work. Now it's a 572.

ralt12 · « **Reply #7 on:** June 16, 2020, 05:11:16 PM »

I also ended up going with 2017 Yamaha R6 forks, which are really nice.

ralt12 · « **Reply #8 on:** June 16, 2020, 05:19:23 PM »

My gas tank was a victim of California gas, in one way, and me, in another--if you don't exercise vintage equipment with regularity, you're asking for trouble, and I had plenty. The tank was, in my view, beyond resurrection. So a new tank from somewhere, and I came across some of Benji's work, and it looked like it fit the bill.

Stev-o · « **Reply #9 on:** June 17, 2020, 02:42:29 PM »

Subscribed to see how this one goes.

Your pics may be too big to post.

ralt12 · « **Reply #10 on:** June 18, 2020, 05:35:50 PM »

Engine work was largely left to a mildly upgraded engine, a slight overbore to 572, Mike's stage 2 head, heavy duty studs, the least aggressive Megacycle cam, and new hardface rockers. Nothing too drastic. The cam cover on my '75 had been changed out to the later cover, so that's a nice touch the PO did, even if he did slather on the silicone.

ralt12 · « **Reply #11 on:** June 18, 2020, 05:44:10 PM »

So Cognito Moto uses the 550K for most of their stuff, and the 550F sometimes has fit issues. For the rearset brackets, the brackets reside on the swingarm mount and the lower engine bolt mount. The swingarm mount is really close, but the lower engine mount needs to be quite a bit longer. But they both needed to be longer, just to be safe. One is 14mm, the other is 10mm.

ralt12 · « **Reply #12 on:** June 18, 2020, 06:37:35 PM »

I wanted real stopping power, since I thought that in the real world the old 550, even when mine was new, wasn't quite as effective as I want. I ordered up Devin's rear disc conversion, and while I was there swapped out the 530 sprocket for a 520. Like the rearset bracket bolts, the rear spacer for the axle/wheel combination had to be made; the wheel is set up for the 550K, but the 550F has a different spacer. So I made one up. The rotor is from a Ducati Monster, as is the caliper; the rear master cylinder is from a GSXR 750.

ralt12 · « **Reply #13 on:** June 18, 2020, 06:45:22 PM »

We did a little welding to relocate the passenger peg bracket (though now all it does is provide a locating point for the exhaust) and welded on a small tab for the remote rear master cylinder reservoir.

ralt12 · « **Reply #14 on:** June 18, 2020, 06:56:35 PM »

Once the welding was done, I sent it off to the powdercoater. This is another one of those instances where what you thought you were getting was a shade different in real life, but I didn't want black. The tank/seat/headlight/fender paint is still TBD.

ralt12 · « **Reply #15 on:** June 20, 2020, 09:43:03 AM »

It starts to come together. A little mock-up.

ralt12 · « **Reply #16 on:** June 20, 2020, 09:49:33 AM »

Why we needed the longer bolts. If I wanted to use the Cognito brackets with the F model, the stock lower bolt was just way too short.

ralt12 · « **Reply #17 on:** June 20, 2020, 09:56:06 AM »

The engine came together nicely. I didn't anticipate a project thread when I started this, so there aren't many assembly shots of the engine build, but it was standard specs thoughout, all within factory tolerances, and was sludge and debris-free when I took it apart. I had feared the worst after the silicon situation on the cam cover, but I never found any evidence of an issue that needed to be addressed when it was apart. Looked like a fairly low mileage bike to begin with--the 12,000+ miles on the odometer might have been real.

ralt12 · « **Reply #18 on:** June 20, 2020, 07:20:44 PM »

Being careful to mate the engine and frame so not to foul up the powder coat.

flatlander · « **Reply #19 on:** June 20, 2020, 11:46:59 PM »

lots of work is going into this...
which pistons did you get, the dynoman 10.5:1 set?
and are you keeping the points ignition?

dkihlgren · « **Reply #20 on:** June 21, 2020, 02:10:10 AM »

This will be a very nice bike. Good work!

ralt12 · « **Reply #21 on:** June 21, 2020, 02:50:56 PM »

Hi Flatlander, yes these are the Dynoman 10.5:1's for a 572cc size. I do have the Dyna 2000, but I've found over quite a few years of racing cars that making incremental changes is the way to go. I've used Hondaman's ignition for years, and it is an impressive piece of kit, the bike ran better than it ever did, so for now I'm going for that. I also have a new clutch that I'm going to wait to put in. Don't want to make significant changes until I'm sure of what I have and how it behaves.

The R6 forks look the business.

ralt12 · « **Reply #22 on:** June 21, 2020, 03:02:58 PM »

The Cognito rearsets are really nice. Here the right crankcase isn't bolted on yet, as I wanted to make sure there weren't any clearance issues before I tightened things up. I'm using Euro CB400F bars with Messner Moto's switches, the Yamaha master and clutch, the Honda throttle, and vintage grips (these were spares for an old MV race bike). I'm using Cognito's large tach/small speedo combination, that has a GPS speedometer with a LCD display. Not pictured are Messner Moto mirrors and bar-end turn signals. If you clean up the stock coil mounts, they look pretty nice !

ralt12 · « **Reply #23 on:** June 21, 2020, 03:32:59 PM »

Now the finer details start to crop up. I decided not to go with crazy-wide tires, but I did settle on 130 in the rear and 110 in the front. I am going to try to see if the tiny AntiGravity battery will make this work, mounting it upside down under the seat. That, I thought, needed some protection, so I made up an inner fender/license plate thingie.
The key driver going forward is getting the front wheel. Cognito makes an off the shelf item for the R6 up to 2016, but in 2017 Yamaha increased the size of the front axle (by a lot!), so we've been waiting for a front wheel with spokes to match the rear. That influences quite a number of things going forward, like whether I go with a single headlight or do I have to use smaller dual headlights. So right now preliminary routing and placement are issues, since the area under the seat is largely open. Using the m-unit opens up a lot of possibilities since it replaces quite a bit of the electrical system.

BenelliSEI · « **Reply #24 on:** June 29, 2020, 06:47:22 PM »

Nice Laverda. What is it???

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Author Topic: My CB550F mongrel (Read 4119 times)