Topic: A Tale of Two Fenders and Three Tail Lights (and Now Four)

[kyle750]

I have no clue what I am doing and need so many parts for the restoration of my CB750.  My rear fender is ugly, dented, rusted through holes - a goner.  So I looked online and a very good used fender in the USA showed up at a very reasonable price.  While looking I set my criteria for no dents or dings and no rust (some minor rust OK).  This fender turned up and I quickly bought it.  Arrived looking much better than I expected. Chrome is in beautiful condition. 

The newly arrived fender has the later HM- 16RC tail light and it is monster size HUGE. I was shocked when I first saw it.   IMO way too big for the bike.   Unfortunately my JDM  tail light the backing plate  is welded to the mounting bracket so it cannot be removed. Also the lens is cracked and I cannot find a replacement lens (very unusual shape).  The  mounting bracket is a 2 piece welded construction unit that IMO does not look as good as the 1 piece stamped bracket.   So I ordered a new, smaller 11RC tail light from Yamiya and will swap the big tail light out with the smaller. 

[CycleRanger]

Very interesting about the welded-on tail light. I've never seen one like that.

[kyle750]

Very interesting about the welded-on tail light. I've never seen one like that.

I think I may have solved the mystery of the tail light mounting bracket and I don't believe it was originally designed for the CB750.  I will be posting photos soon. 

[kyle750]

Here is a tail light bracket from a 1971 CB350 that has been powder coated silver.  Notice the 2 piece construction.

[bryanj]

You will have a problem switching just the light assemblies as the mounting bolts are at different centres on the small light to big light. You will have to use the bracket for the small light

[kyle750]

You will have a problem switching just the light assemblies as the mounting bolts are at different centres on the small light to big light. You will have to use the bracket for the small light

Thanks.  I did not know the width of the mounting holes on the 2 different light assemblies (11RC AND 16RC) are also different.  Indeed this looks like it is going to be a problem?

As a possible work around.  Could I drill new holes to the smaller 11RC tail light backing plate to match the holes in the bracket and then install with new nuts to the other side of the backing plate?

[bryanj]

Use shouldered bolts with rubber mounts and nylock nuts and yes

[kyle750]

I was totally shocked at the size of the 16RC tail light

Perhaps I need to learn how to love the supersized big gulp cherry tail light.  Like they say "Go Big or Go Home"

[BenelliSEI]

You may have to go with the “big” taillight. The smaller lamp and bracket mount to a different fender…… the 1969-71.

[Stev-o]

  Like they say "Go Big or Go Home"

The '69-71 CB750's had a smaller taillight than the later models.

[kyle750]

  Like they say "Go Big or Go Home"

The '69-71 CB750's had a smaller taillight than the later models.

Yes that is my understanding and I think the smaller tail light looks better.  I thought the 69-71 CB750's used the 11RC tail light?

[seanbarney41]

You have purchased a k2-k6 fender.  It will only accept the K2-k6 tailaight without modifying.  I don't know where you are getting your numbers from (11rc?)  If you want to use the small tail light you have to get a K0-K1 fender.  That is all ametrican market info though.  Japanese market may be different.

[PeWe]

Our K2 and K6 in Sweden had the earlier rear lamp and blinkers as K1 had.
The rear fender was not as K1 with only one hole for the mudflap. It had more holes for the mudflap.
Oval holes on the sides. Hens teeth are very common compared to this!

Photos.
Swedish K6 stock fender holes for mudflap. The K2's looked like that too. Those I have seen, 72-75.

My brown K2 built on parts. K1 rear fender. NOS from DSS.

My K6 with its stock fender and rear light.
It got new glass from Yamiya, Japan style with yellow reflexes on the sides.

Bike will not look worse with the K1 rear fender, lamp and blinkers.

But stock style as your bike was delivered back in the days is one way to go too. If you know for which market and how it should look like.

Rebuild by bolt off, bolt other parts on is never wrong as long as original parts are saved.

[Little_Phil]

My 550F1 came from the US with the jumbo style rear light. I don't remember having much trouble removing it and fitting the UK smaller lamp. The US complains about our big registration plates and the UK complains about the US big lights and blinkers.

[newday777]

The rear fender was not as K1 with only one hole for the mudflap. It had more holes for the mudflap.

Per
In the US the single hole in the rear fender was not for a mudflap. It was for a cone shaped rubber bumper

[newday777]

#9

[PeWe]

Aha! No mudflap.
Thanks for the info. I did not know that.
Place for an additional reflex?
All stock mudflaps here were destroyed by a hole drilled in the Honda circular print for a reflex.

Bike did not pass the vehicle inspection without mudflap and extra reflex. It had to be an E marked reflex. Reflex in rear light not ok  ....
This was in the 70-80's.

[bryanj]

The small light will bolt onto the big bracket but not with the correct rubber mounts as distance between bolts is different

[Don R]

 I always assumed the #9 was a bumper for those countries with a taller license plate.

[Oddjob]

Called a corn plug IIRC, they were fitted to stop number plates vibrating IIRC.

[kyle750]

My 550F1 came from the US with the jumbo style rear light. I don't remember having much trouble removing it and fitting the UK smaller lamp.

This tail light is from a seller in the UK (same 16RC stamping to the back plate).  Is this the smaller lamp you are referring to?  This tail light does look smaller than the jumbo US tail light. Would this tail light fit the newly arrived rear fender mounting bracket?

[Oddjob]

That’s what was fitted to the 550k3 over here in the UK and no that’s the bigger version. You need a tail light off a UK 500-4 or the 550F model, you can tell the difference by the amount of screws holding the lens on, 2 is the smaller version, 4 is the bigger version.

[kyle750]

There are times when searching for Honda CB750 parts that I feel like I am a Dog chasing its own Tail

[kyle750]

Photo of the newly arrived K2-K6 rear fender mounting bracket and 16RC tail light backing plate.  Based on previous comments (Thank You!) I learned that the earlier smaller tail light 11RC (used on the KO and K1) the mounting holes are spaced differently (more narrow) and will not fit the later K2-K6 mounting bracket which use 16RC tailights.

Therefore if I want an original Honda tail light without modifications I need to find a 16RC tail light that is smaller than the US version and the UK/EU 16RC - B  (shown in the earlier post)  looks like it fits the bill. If I run faster will I eventually catch my Tail.

[kyle750]

Here is another smaller version 16RC tail light from Germany.  From the stamping on the back plate housing it looks like Honda gave this smaller version tail light an updated model number of 16RC - B