Topic: 1974 CB550. Racetech Monoshock. JMR Head. Built Engine. "BLAC"

[BLAC]

YAY!   

Gaskets and seals are starting to get delivered! Still waiting on 39 more, all OEM 

[SOHC4 Cafe Racer Fan]

Im waiting for my cases! I will get them on the 7th =)

@noblehops, you aren't making me go hungry this time, are ya!?

You got the Skittles Bryan, you are good to go. :-).

 

[BLAC]

I got the monoshock mounting points done and tacked up.  Now I just have to take it to RaceTech and hopefully they say the geometry will work!

[SOHC4 Cafe Racer Fan]

Great looking last shot.

[Restoration Fan]

Great looking last shot.

It really is.  Nice looking work there, Bryan!

[grcamna2]

Will RaceTech hook you up w/ a custom rear shock ?

[BLAC]

Yes it will be a custom length, springrate, dampening etc.  I'm having it made with an adjustable height option too

[Ericcb750]

Bryan, Such an awesome job on this man....seriously I love seeing this kind of stuff. THe type of bike that you'll probably never sell because you've put so much of your own work into it.... I wish we lived closer so we could go tearing around together.....

Finally got all my stuff out to Nils, He is the f'ing man...talked to him on Saturday over the phone. I am so darn excited to build a perfectly clean motor....

I can't wait to see this one all done up too.... looking great man.

[BLAC]

Thanks and I agree, it's too bad you live so far away!

I bought a junk tank to mess around with, I dont love how it came out but I think there might be something to this that I like... Ill keep messing around and then take my crappy sample to someone who knows what they are doing to make the final version for me..

what do you think and are there other cb550k tanks you have seen that are interesting?

[calj737]

With the seat cowl lower edge being straight, I'd tend towards carrying that profile forward through the tank. Recesses in the tank is fine, but the curvature of your seat and tank should flow together in some way.

I've seen a 500T tank that looked pretty decent on our bikes. Even an XS tank (blasphemy, I know).

[BLAC]

Yep, that is the main reason I don't like the current mock-up.

I like the idea of putting some concave to it, but not as much as this mock up has and with keeping the bottom edge straight like you mentioned

[SOHC4 Cafe Racer Fan]

Just my $0.02 but there is certain "chopper" aesthetic coming from that tank with that shape indent.  The lines are not flowing together.  The rest of this bike says race.

[calj737]

Honestly, I love the stock tank's lines. The only things I dislike about it are: filler neck, seat/tank union and the pinched lower edge.

Given your investment in this bike, may I suggest you remove the stock neck and install a recessed cap (in fact, Jeff Stephens Asian Orange has something similar for example) cut off and extend the side panels to the bottom plates and get rid of those edges, and resolve the mount/cavity at the rear of the tank.

Do those things and you have a completely custom tank that to the average eye will look completely stock. But like everything else on your bike, its not. Not flashy, not ordinary, but discreet and extraordinary.

[BLAC]

Don- I agree with you, I originally liked the idea of the concave along the factory decal line to keep a "stockish" vibe while being custom... But it isnt working like I had hoped...

Cal- I agree on all of those points, I had considered the flush fill cap and finishing off the back of the tank, but not being experienced in sheetmetal work (at all), im a little hesitant to do it myself..

Im considering calling Cliff and having him make me a "stock shaped" tank out of aluminum with these changes and being aluminum I could connect the tank and seat cowl all one piece which I think would let it flow beautifully.

also I love your term "discreetly extraordinary". 

[SOHC4 Cafe Racer Fan]

Honestly, I love the stock tank's lines. The only things I dislike about it are: filler neck, seat/tank union and the pinched lower edge.

Given your investment in this bike, may I suggest you remove the stock neck and install a recessed cap (in fact, Jeff Stephens Asian Orange has something similar for example) cut off and extend the side panels to the bottom plates and get rid of those edges, and resolve the mount/cavity at the rear of the tank.

Do those things and you have a completely custom tank that to the average eye will look completely stock. But like everything else on your bike, its not. Not flashy, not ordinary, but discreet and extraordinary.

This flush cap is a little less ambitious in terms of installation.  You could have a local welder do it for you.

http://www.ebay.com/itm/Weld-In-Flush-Mount-Paintable-Pop-Up-Gas-Cap-Weld-In-Bung-Hot-Rod-Chopper-/252574190704?_trksid=p2141725.m3641.l6368

[BLAC]

its not so much the welding, it is the making and shaping of the metal to replace where the factory cap was cut out.  I would want to center the fill cap if I did this mod and that would leave a hole. 

[SOHC4 Cafe Racer Fan]

its not so much the welding, it is the making and shaping of the metal to replace where the factory cap was cut out.  I would want to center the fill cap if I did this mod and that would leave a hole.

Then you have to be mindful of the gas filler nozzle striking the tunnel.

[BLAC]

Here is a funny pic from the past.. back in high school I "borrowed" my sisters electric scooter, took it into the shop class and made this... It was a death trap that did 60mph... I rode it home from school on the freeway.

(yes I made a y-pipe and it has dual exhaust)

[calj737]

That cap is a copy of Matt Hotch's original push-button filler. Its the same diameter as the stock filler, so it would weld in pretty easily. If you go the Cliff route, simplify your life and use a Rizoma. Since it's aluminum, it can weld in easily. I had to make my own stainless receiver to do this very modification to my R90 tank.

https://www.motostorm.it/en/accessories/motorcycle-parts/7043.html?ref=Google&currency=USD&gclid=CKKDw-SR_NECFU1MDQod-ksMpg

Just turn down the diameter of the flange to keep it discreet.

Mine has a super thin edge that will be polished up and use an anodized cap (this is a test unit)

[SOHC4 Cafe Racer Fan]

That cap is a copy of Matt Hotch's original push-button filler. Its the same diameter as the stock filler, so it would weld in pretty easily. If you go the Cliff route, simplify your life and use a Rizoma. Since it's aluminum, it can weld in easily. I had to make my own stainless receiver to do this very modification to my R90 tank.

https://www.motostorm.it/en/accessories/motorcycle-parts/7043.html?ref=Google&currency=USD&gclid=CKKDw-SR_NECFU1MDQod-ksMpg

Just turn down the diameter of the flange to keep it discreet.

Mine has a super thin edge that will be polished up and use an anodized cap (this is a test unit)

That's just showing off! Great looking tank mods, Cal.

[Restoration Fan]

Do you plasma cut the original out or is there a better/easier way to achieve that? 

I have a couple of spare tanks in the basement that just may need some 'experimenting'.

[SOHC4 Cafe Racer Fan]

Here is a funny pic from the past.. back in high school I "borrowed" my sisters electric scooter, took it into the shop class and made this... It was a death trap that did 60mph... I rode it home from school on the freeway.

(yes I made a y-pipe and it has dual exhaust)

How hard was it to keep the front end down?

[BLAC]

How hard was it to keep the front end down?

it wasnt very grunty low end due to the gearing.  but if you leaned back it would stand up.  it really started to pull from 20-40mph once the centrifical clutch engaged

[BLAC]

Do you plasma cut the original out or is there a better/easier way to achieve that? 

I have a couple of spare tanks in the basement that just may need some 'experimenting'.

I just used a cut-off wheel.  Its more difficult than just "cutting out and flipping the sides". the angles up front do not match up when inverted.  If I went this route I would just cut out the area I wanted to concave then take it to someone to make new panels to fit. 

 The other route would be to keep the angles more 2-dimensional like what GV did.  That way you dont have to shape the metal much more than just one bend.  His tank looks great too

[calj737]

Do you plasma cut the original out or is there a better/easier way to achieve that? 

I have a couple of spare tanks in the basement that just may need some 'experimenting'.

Do you mean the filler neck, Ron? If so, I cut the neck down flush to the tank top. Then I welded in a piece of flat stock inside the tank, below the neck. I then used a hole saw installed in a drill press (flat stock was necessary to center the hole and prevent it from walking) then cut out a slightly larger hole around the stock inlet.

My receiver had a recessed lip to sit atop the tank, allow me to weld it then body worked it away. If the tank were aluminum, I would have turned down the Rizoma flange in the lathe, cut the old neck out, and welded the new receiver in lickety-split. Having to machine 304 stainless with all the nooks and crannies took a while. But custom stuff does I guess.