CB550 Project Scruffy Racer

[Sderbyshire]

Following the success of my CB390 project and likely to be bored self-isolating for a while I’ve bought a fresh in from the US CB550 project

i’ll document here how i’ve sympathetically restored it to running order with some subtle upgrades to brakes, electrics etc.

for today here’s how it looked when it arrived, very original but nothing works!,

and a teaser to where i am with the project as of now

https://1drv.ms/v/s!AhDJKiWSrX7_tXMdX3KPIAV2g0Q5

i’ll be looking for help and advice along the way i’m sure, i learned so much here on my CB390 adventure.

Steve

 

[Psychopasta]

That's a very nice looking bike you've got there Steve

 

[CarbsAndCylinders]

I always thought that these were nicer-looking than the 750.

 

[Maritime]

Oops meant to post that in a diff thread. I like that 550

 

[Sderbyshire]

Thanks guys.
i’ll try to post a lot more details of the process with photos, maybe at the weekend.
steve

 

[Jimbonaut]

Damn the thing looks mint! Beautiful bike, great find. And yes, I wish it was mine.


Sent from my iPhone using DO THE TON

 

[Sderbyshire]

I’m going to need to order some tyres.......

after much reading, and previous good experiences with Avon Roadriders and Dunlop K82s, i’m thinking of going with the new Avon Roadrider Mk2s

for the standard rims am i right in thinking the optimal size choices are 90/90-19 Frint and 100/90-18 rear?

i quite fancy going a little bigger on the rear, but 120/90-18 is probably too big for the standard rim ? ( avond don’t seem to make 110)

steve

 

[Maritime]

Check the universal fornthe 110. They make f, r and f/r Universal in the RR lineup. You just mount it per the arrow for F or R on the sidewall depending on mounting

 

[Sderbyshire]

Check the universal fornthe 110. They make f, r and f/r Universal in the RR lineup. You just mount it per the arrow for F or R on the sidewall depending on mounting

Thanks Maritime
i can see 110/90-18 Universal in the AM26 version, but not in the MK2.
i’m guessing am26 is the old mk1 version?, but probably ok?
steve

 

[Maritime]

Yep, more than likely they have stock of the mK1 they want to use up before they make that size in the MK2. I loved my MK1 RR's on my CM450T, they were excellent tires. I wouldn't hesitate to mix the MK1 and MK2 if you need too for sizes.

 

[Sderbyshire]

Cool Maritime, thanks.

Searching some more i see that there is a 110/80-18 option for the MK2, as opposed to 110/90-18, and the lower ratio would be ok with the bigger width.

So now i need to decide whether to go 90 or 100 on the front, probably 90, and 100 or 110 on the rear, i'm thinking 110.

comments appreciated from those experiences with the CB550 !

steve

 

[Maritime]

My only advice. Avon lists min max rim sizes for tyres. Don't go over or under those or you'll regret it for safety and handling reasons.

 

[NoRiders]

Cool Maritime, thanks.

Searching some more i see that there is a 110/80-18 option for the MK2, as opposed to 110/90-18, and the lower ratio would be ok with the bigger width.

So now i need to decide whether to go 90 or 100 on the front, probably 90, and 100 or 110 on the rear, i'm thinking 110.

comments appreciated from those experiences with the CB550 !

steve

When going 'low profile' bear in mind the gap between tyre and guard/fender....sometimes it works out too large and looks odd....unless you modify the mounts?

Gorgeous looking 550.

 

[Sderbyshire]

I’m liking the roadrider option, but their site isnt helping with size choice!

just checked the bike and i have 1.85 rims front and back
front is 19 and rear is 18, and they are original i believe

front tyre is a 3.25*19 amd i believe is the original tyre
rear is a 3.75*19 and is not original, and should be a 3.5 i think.

Avon offer a 3.25*19 so thats a good option for the front
but for the rear they do not offer a 3.5*18 or a 3.75,

they do offer a 4*18 but this needs a 2.15 rim

i agree that lower profile is not the way to go, probably look silly

so what shall i do for the rear?

any suggestions as to alternative tyres/tires available in 3.25 and 3.5/3.75 sizes appreciated !

steve

 

[Maritime]

you can do a conversion on the metric sizes to get the equal to the inch size. there is no difference in the actual tires they just size some metric and some inch. You can find a converter online and plug in the 100/90/18 and it will give you the X.X inch

 

[Maritime]

https://www.mad-ducati.com/Technical/TireInfo/TireChart.html

Motorcycle Street Tire Size Conversion Chart
Front Tires​	Rear Tires​
Metric​	Alpha​	Inch​	Metric​	Alpha​	Inch​
80/90​	MH​	2.50/2.75​	110/90​	MP85​	4.50/4.75​
90/90​	MJ90​	2.75/3.00​	120/90​	MR90​	4.50/4.75​
100/90​	MM90​	3.25/3.50​	130/80​	​	5.00/5.10​
110/90​	MN90​	3.75/4.00​	130/90​	MT90​	5.00/5.10​
120/80​	​	4.25/4.50​	140/80​	​	5.50/6.00​
120/90​	MR90​	4.25/4.50​	140/90​	MU90​	5.50/6.00​
130/90​	MT90​	5.00/5.10​	150/80​	MV85​	6.00/6.25​
​	150/90​	MV85​	6.00/6.25​

 

[Sderbyshire]

Thats interesting, Thanks!

i thought i’d email Avon Tyres about this and they responded promptly!

they recommended 3.25*19 for the front and 4*18 for the rear.

i’ve queried the rear recommendation as on their website it requires a 2.15” rim..... lets see what they say

i’d be happy with those tyre which would be in keeping with my idea of a ‘Sporting Refresh’ for the 550.

on that subject, what rear shocks have we had good experience with for these bikes?

steve

 

[Maritime]

I love my new Hagons. Those are a good mid priced shock and they set them up model specific. They're not a one size fits all shock.

 

[Sderbyshire]

OK, time for a progress report for all you patient people!

The CB550 project was delivered under quarantine conditions on 7th April, so I rolled it into my workshop ...looked right at home

First job was to take off the carbs to assess their condition, would i need to rebuild them?, and take out the spark plugs to allow soaking of the pistons of the seized engine.

Carbs on the workbench in the garage, aka the 'cleaning station' and the off with the float bowls.
First two in amazingly clean condition but second 2 corroded out, float and jet mounts were gone !
How could two be so good and 2 so bad !?

Next I checked over the fuel tank and exhaust can , both corroded out which is a shame as these I specifically enquired about, but to the seller's credit they are going to replace these.......

On to the wiring..... NOTHING worked when i applied power so i stripped out all the components under the side panel and investigated the wiring, found a burned our Green earth wire which ran all the way through the loom to the earth point by the carbs. This provided the 'opportunity' to simplify and re-tape the wiring loom

I'll be adding a new regrec from Matt at Sparckmoto when that arrives in the post.

The engine was still seized so added some more Diesel and left the bike for another night, whereupon the engine turned over with no effort at all from a spanner

So off with the sump for an oil ( and diesel!) change.

with new oil the engine spins up nicely.

Thought i should also take the cam cover off to take a look and clean the oil oil out of the baths, all looks good.

At this point I'm awaitng delivery of a set of 'new' carbs from Sweden and looking for other things to do.....

 

[Sderbyshire]

..... so onto the Twin Disk conversion !

This is an easy job on the 550, unlike on the cb360/390..... all i have to do is machine the speedometer drive to fit inside the new disk, and bolt it all together.

I still need to fit a pair of suitable lower hoses when these arrive, oh i also rebuilt the master cylinder of course. I plan to see how this works with the twin disks, if there is too much lever movement then i'll replace with a bigger bore item but i would like to keep the original if possible.

Thought i would check out the ignition system, the ht leads look a bit tired and one plug cap was broken but in the absence of any new parts ( delayed in the post) I just set the timing and wonder if the system will work......

at this point the carbs arrive from Sweden, so a hasty build and test is in order.

Carbs installed, temp fuel tank connected ( fuel pours out of 2 overflows.....)

Press the starter button and after a bit of a cough it fires right up and soon idles pretty well

Carbs off and checked float height, all ok but change the two floats for another pair and reassemble, no leaks !

Even managed a 200 metre test ride and all the gears work !

Thats it for now, next steps are :

Install regrec and have a charging system test
sort out a fuel tank and exhaust
order new Avon Roadrider 2 tyres, there seems to be a £30 cashback up to July 2020
Install new handlebars, discovered the current ones are bent and so ordered a set of the Europe spec ( lower) bars

then i can think about registering it and having a proper test ride .....

Steve