CB550 Chop

[Maxmac]

Hi,


I'm located in the UK - I bought a really ugly CB550 chop for a good price. I really like the CB550 engine.

I've hit a hurdle with the front end. The bike has stock triple trees, but some forks from a Yamaha, and a 21" dirt bike wheel with a small drum brake which is pretty cool.

Sadly the PO has done some shit engineering to make this work, loads of spacers on the axle, and parts of the drum brake shaved off, the brake stay doesn't reach the forks so he's put a bolt through it with a nut on (will provide pics at some point)

The forks on it are 34" and I believe that stock cb550 forks are 28"?

I've been looking for a 1976 GL1000 front end as i've read that these are a direct swap but they seem to be pretty rare in the UK.

Anyone got thoughts/advice on where to go with this?
I don't think I will have enough clearance for the frame/exhaust if i drop down to stock forks...

I like the look of the current set up, but I'm not happy with the integrity of it...
and I think i probably want a disc brake.


Before pic



Current progress

[Tattooo]

Looks nice........... A 550 motor is a really nice motor.............

[TriNortchopz]

Not so ugly...from a distance, you can see more than us.
Lots of options for a simple fork leg/front wheel swap as the 550 has 35mm tubes, same as Honda 650, 750, CBX, Yamaha xs650...for easy longer than stock forks, XL and Xr honda forks are also 35mm, a simple slide in, but a bit more adapting for a disc...unless you get a fork and wheel with a disc from another model with 35mm tubes; see link to list below:

Fork tube Diameters list

https://www.dotheton.com/index.php?threads/fork-tube-diameters-list.20950/

In the first pic, it looks like that was a 4-1 exhaust with a muffler on the right side...are you gonna run 4 into nothin'? If so keep the pipes in the same order and have all 4 pipes in original location, so they fit right.

[Maxmac]

Not so ugly...from a distance, you can see more than us.
Lots of options for a simple fork leg/front wheel swap as the 550 has 35mm tubes, same as Honda 650, 750, CBX, Yamaha xs650...for easy longer than stock forks, XL and Xr honda forks are also 35mm, a simple slide in, but a bit more adapting for a disc...unless you get a fork and wheel with a disc from another model with 35mm tubes; see link to list below:

Fork tube Diameters list

https://www.dotheton.com/index.php?threads/fork-tube-diameters-list.20950/

In the first pic, it looks like that was a 4-1 exhaust with a muffler on the right side...are you gonna run 4 into nothin'? If so keep the pipes in the same order and have all 4 pipes in original location, so they fit right.

Hi,

Thanks for the info.
I like the idea of the XR/XL swap - wonder what the dirt bike front ends ride like though.


I have a set of cocktail shakers that I was going to build onto the exhaust with 2x 2-1 collectors, but I haven't got around to it yet, as I need to find some chrome headers to make it all look right. So for now im leaving it as 4 pipes, not sure how that will go though.

[Luky]

I would change the front wheel to a Honda or Yamaha Disc brake front wheel and lower the forks in the triple clamps a little.

[TriNortchopz]

I see that the XL/XR, CB550, CB650 and CB 750 (plus many others) have 15mm front axle, so this will help with wheel swaps:

Amazing List of Fork Tube Sizes, Neck Bearings, axle Diameters

https://www.customfighters.com/forums/showthread.php?t=29199

Thinking the XL/250 would be a good fit.

A few comments here (pg. 109) about xl tubes in cb750 lowers, and seal swaps:
The Honda XL (and other vintage singles) thread!

https://advrider.com/f/threads/the-honda-xl-and-other-vintage-singles-thread.424841/page-109

[Maxmac]

Thanks for your help guys.
I've managed to score a stock cb550 front wheel with disc, and a set of 34" stock forks for them...will post pics when the forks arrive

[Maxmac]

Thanks for your help guys.
I've managed to score a stock cb550 front wheel with disc, and a set of 34" stock forks for them...will post pics when the forks arrive

Finally got the over stock front end and stock front wheel, all seems much better. just need to rebuild the caliper for the disc now.

[TriNortchopz]

Looks good, how much is that frontend extended?

[Maxmac]

Looks good, how much is that frontend extended?

I suppose 6".
stock is 28, those are 34.
Also now back on a stock wheel at 19 instead of the 21 that was on before.

[Maxmac]

I suppose 6".
stock is 28, those are 34.
Also now back on a stock wheel at 19 instead of the 21 that was on before.

quick update;
coronavirus has given me enough free time to get moving on this build.
just got round to rebuilding the forks i got.
Both had quite a lot of sludge in them, I took them all apart and cleaned them with spirits/rags n shit until they were all cleaned out.
One leg works perfectly now, compresses/depresses silently and smoothly.
The other leg was in worse condition internally, and now its back together I can hear the spring rubbing against the internal wall of the fork. The internal wall was quite rusty, but I've ground all the surface rust off it - its just not very smooth. Anyone know how to fix this, or if it even matters that much?

Cheers

[Maxmac]

nicer photo of it currently

[TriNortchopz]

Looks good.
How deep are the grooves inside that one fork tube? do you have stock springs?

[Maxmac]

Looks good.
How deep are the grooves inside that one fork tube? do you have stock springs?

Hey mate,

the grooves are not as deep as they seem in the pic, i think that's mostly the end of the threads at the top of the tube.
Hard to say exactly how deep, more of a rough textured surface you get on metal after removing surface rust.

The internals are stock, but theres an extra 6" spring under the large spring to accommodate the extra length over stock.