Topic: Goodbytes' CB550F2 '77 Project

[goodbytes]

Over the last years, I've been thinking about getting an SOHC Honda again. I've previously had two '75 CB400F (first four-stroke bike), a '84 CB750F and '79 CB900F (although the last two were DOHCs).

I really enjoyed my time with the CB400F, my only complaint was that the bike felt a little small for my height (6'5). So this time I decided to go for the 550.

A few of them popped up now and then on the local market. Common was all of them were about ~2200 USD for either a bad shape running bike, or a bike that haven't been started for the last 10 years.

So when a CB550F2 '78 "project" turned up for around 600, I pulled the trigger and bought it 

The seller bought the bike from its previous owner, with a non-running engine due to a broken cam chain. He started disassembly of the engine but didn't have the time to finish the project.

[goodbytes]

Pictures of the bike. Taken from when I began stripping the wiring harness and accessories from the frame.

[goodbytes]

As I bought the bike with the engine already disassembled. I needed to assess the damages and the cause of the engine failure. The previous owner bought it like this. The engine had failed on the owner before him.


Debris from the cam chain guide found below the crank. None inside the primary chain+gear or gearbox.



This was once the cam chain guide... I'm thinking this may be the root cause of the cam chain falling off. The cam chain itself was an endless type, but one of the links broke.


I will need a new cam sprocket. I think that without the guide, the chain must have come off the sprocket.


When the chain broke, it nearly shattered the rocker cover. Will need to have this welded.

The cylinder head will need some work as well, as I suspect the two inlet valves for cylinder 2 & 3 needs replacing, as well as the valve guides. There is some material of those two valves missing, although the valve face is intact.

[goodbytes]

The more I work on the bike, the more broken parts I find. It looks like the past owners has not been knowing what they were doing. I may have just bought a can of worms.

When stripping the frame, I noticed that something wasn't quite right. Measuring the frame, from the rear wheels up to the front, with a long string, and the wheels don't track! The front and rear tires are the same (skinny 110) width. So the two strings should line up perfectly. What I found was that the front wheel tracks 10mm to the left, while being at an angle. So I started taking the front end apart to diagnose.

I checked the wheels and they are both within tolerance. The rear wheel bearing is worn and will need replacement. But it doesn't have enough play to ruin the alignment really.

The upper fork legs are both straight. I took them off and rolled them across a flat surface. I am not entirely sure if the lower tripple tree is in perfect shape. One of the steering stops had broken off and someone had done a pretty lousy job replacing it with a bolt. The bolt had been bent to fit, and welded on 

With the front end off. I noticed that one of the fork legs were longer than the other. About 10mm. How did I not see that before. It could be a spacer installed in one of the legs. Maybe different spring lengths. Maybe someone assembled it wrong. I started to take it apart, when I discovered that the top fork nut was a different size on each side. WHAT!?
Maybe they are from two different models?

I thought this could probably explain why the front would track 10mm off. So I moved the longer fork leg up the tripple trees to compensate, until they reached the same length below the lower tripple.

Still the front wheel tracked wrong and still at an angle. The tire was approx. 10 mm closer to the right fork leg, than the left.

Next thing I found, was that the front axle was badly bent.

Now I basically need a complete new fork and axle, in order to check the frame for alignment.

One thing is for certain. The bike must have handled like #$%*.

[calj737]

I may have what you need, especially if you're planning on a stock rebuild. Where in the US are you?

[goodbytes]

I may have what you need, especially if you're planning on a stock rebuild. Where in the US are you?

As much as I would love to take your offer. I'm not sure you want to go through the hassle of shipping it across the atlantic to Denmark

I've done quite a bit of traveling in the US, I love the culture and the people. Over the past five years, I've done a yearly cross country road trip.

The bike has to pass an inspection before I can get it registered. So I'm going for a stock looking bike for now.

Unfortunately we have very strict laws regarding modification, basically any modification is illegal. There are a few ways around it that I'm investigating. I might do some slight modifications, such as a GSX-R front-end and wider rear wheel.

[goodbytes]

An update to the frame alignment checking.


The length difference of the front fork tubes  I've adjusted the longer one up the clamps. When I got the bike they where both level!


Leveling the frame on my dirtbike stand.




Rear wheel is level.


Front axle is toast. Likely ruined by running two different length of fork legs. Haha. This probably contributed to why the wheel was angled even after adjusting the fork heights.

I'm thinking maybe the frame steering collar is bent to a slight angle, if anyone knows of a good idea to check the angle without forks and wheels, I'm all ears!

[calj737]

I'd definitely be happy to ship you an axle if you need one.

For the steering neck, with frame levels, use a broom handle in the neck and check for plumb. Simple enough really.

[goodbytes]

Thanks! Just took the fork and yokes off to measure the steering neck. It definitely tilts slightly to the left. Over the length of the fork, that could easily explain why the wheels dont line up.

Well, that and the bent front axle, and different length fork legs!

Damnit. Now I have to try and find a new frame.

[calj737]

It's very feasible to straighten your frame. Will require some firm clamping, some heat, and a durable lever, do it is doable. You may also be able to locate a someone nearby who can make this correction too.

[goodbytes]

Little update on the frame situation.

I found this longitudinal crack in the left frame section near the side stand. I read on this forum that it was quite normal for at least the CB400F to have rust forming in this section, from trapped water/moist. But this doesn't look like rust.




Closer look. It's hard to see, but the crack bends outwards.

I will use some paint remove to get a better view.


Before i found problems with the frame, I had sent the cylinder head to a machinist. Today I picked it up. Cylinder head got skimmed and valve seats cut, need 4 new intake valves. All valve guides measured out good. Engine is now on hold, till the frame is sorted.

[goodbytes]

It's very feasible to straighten your frame. Will require some firm clamping, some heat, and a durable lever, do it is doable. You may also be able to locate a someone nearby who can make this correction too.

I've only found one company who does frame straightening in my country. I called them up on the phone, and they had to ask around the shop before they could confirm that they did in fact straighten frames. Typically not a good sign.
They wanted 320 USD to just measure it out, another 1086 USD to straighten it out   Does that sound right?

Maybe I should ship it somewhere else, if I can't find a replacement frame.

[calj737]

No, that price to straighten sounds excessively high.

That area of rust and crack is from moisture accumulating, then freezing, swellings forcing the "ice" outward. That frame has issues I suspect. I don't know the laws in your country, but if it's easy enough to swap frames, I would. Else....

Remove all the paint on the frame and identify every area of rust, rot or possible bent tubing. If you decide you want to keep the frame, you can either locate a repair shop that isn't trying to gouge you on prices, or, perhaps ship it close enough (maybe drive it?) to someplace that will repair it for a reasonable price.

[Stev-o]

No, that price to straighten sounds excessively high.

+1...wow, you have your hands full with that bike.   Too bad you are not in US, parts are easy and cheap to find.