Measurements for the rear indicator brackets

[alexdecker]

Hey all

I bought a complete set of rear indicator light with stems and brackets for the CB550F line. I have the F2 from 1977 myself. But upon receiving them, they don’t seem to fit. I am not aware if the brackets themselves are the wrong type, or maybe I have the wrong passenger brace on my bike. I took some measurements, and was hoping that someone in here with a similar model would be so kind as to confirm if this is in fact the brackets for the 550F models?

[Oddjob]

Those look like 550F rear brackets. However the hole in the grabrail is bigger on the 550F than on others, especially the 500/550K. As such the rubber fittings etc tend to be bigger as well.

[alexdecker]

You don’t happen to know the width and height of the hole in the grab bar on an F model, do you? Just measured the inner width of the rubber piece, and it is too wide to fit in the hole in the grab bar! The inner width of the rubber piece is 35mm. The hole in the grab bar was something like 25mm maybe…

[Oddjob]

Yeah, I've got a NOS one in the loft. I'll pop up and measure it.

[alexdecker]

Yeah, I've got a NOS one in the loft. I'll pop up and measure it.

Thank you! Also, stem diameter is 14mm. Didn’t they change as well for the F models?

[Oddjob]

35mm x 16mm is the grab rail hole size Alex. Sounds like your grab rail is the wrong one.

[alexdecker]

35mm x 16mm is the grab rail hole size Alex. Sounds like your grab rail is the wrong one.

Damn. Yet another thing I have to source. This bike is killing me 😳😂 Well at least it would seem to be the right brackers. And I assume that if the stems match the brackets, they are correct as well. Saw a reproduction set on 4into1.com, and they claim that the 550F stem was supposed to be 22mm in diameter. Mine is 14.

Thank you for taking the time to measure it!

[Oddjob]

You're grasping the wrong end of the stick there Alex. There are 2 types of indicators fitted to the 550 in general. The smaller type which is what your pic shows and a much larger type which is what shows on 4into1.com, those are the USA market type indicators, they are bigger in diameter and also in stem size. That type of indicators were commonly found on the UK version of the CB550K3, not sure if they were also found on European versions.

I might have a spare of rear stems that will suit your existing grab rail, I found them a few hours ago when I was looking for something else, might even have some front stems as well, both brand new if I can find the front ones.

Have you got any of the rubbers that fit your existing grab rail? if so measure the holes width and the hole sizes etc.

[alexdecker]

You're grasping the wrong end of the stick there Alex. There are 2 types of indicators fitted to the 550 in general. The smaller type which is what your pic shows and a much larger type which is what shows on 4into1.com, those are the USA market type indicators, they are bigger in diameter and also in stem size. That type of indicators were commonly found on the UK version of the CB550K3, not sure if they were also found on European versions.

I might have a spare of rear stems that will suit your existing grab rail, I found them a few hours ago when I was looking for something else, might even have some front stems as well, both brand new if I can find the front ones.

Have you got any of the rubbers that fit your existing grab rail? if so measure the holes width and the hole sizes etc.

Ah, that makes sense! Thanks for that! I think I will try and source a proper grab rail instead of replacing the stems, as the grab rail seems to be the one out of place. If I can find one that is. A quick google search tells me they are rather rare it would seem. Find a reproduction model on eBay, but would be nice to find something original…

[mickwinf]

Ok can you confirm that the stems you have fit on those brackets? if the locating peg and the mounting screw hole line up then they are correct for the 550, therefore the grabrail is incorrect. However all 550 f1 and f2 use the larger hole so your rail must be off an earlier model. now i do have a grabrail with the correct size holes from the earlier k1 k2, which looks identical to the 500 except for the bigger indicator mount holes. Depends on if you want original or not as the rail on the f is a different shape

[Oddjob]

I'm unsure Mick if the earlier shape is suitable for the F model due to the longer seat it got. It would probably fit but the rail would be so close to the seat it might be unusable for the passenger.

[mickwinf]

Thats what i wondered Ken, the bar he has must be for a different 550 as all the F models used the bigger mounts, has the grab bar been trial fitted with the seat?

[alexdecker]

The stem, bracket and rubber fits perfectly together, but the hole in the grab rail is too small. So the grab rail is wrong. It does look like it fits though, which is why I never thought about it before getting the correct brackets for a CB550F model. You can see the grab rail on this image. Does it seem out of place to you guys? But from the images I've seen of the correct grab rail, my version doesn't seem to bend upwards quite as much perhaps?

[Oddjob]

Doesn't seem to be high enough at the back.

How much metal is left around the outside of the bracket hole, I'm thinking you could measure the plate and see if you can enlarge the present opening enough to accept the correct rubbers?

[alexdecker]

I could, but feel like it would be a pity to ruin the grab rail. I might just see if I can sell it and then try and source a correct version of it (although they seem to be rare)…