Topic: 78 F3 Brake Question

[Wayne Meuir]

Ok, I started going through the brakes on the F3 I bought yesterday.  The brakes had frozen up from sitting and the PO took the calipers and pads off so he could roll the bike.
I am in the process of taking them apart and cleaning them up.  Pistons look pretty good, a couple of very small pits, but I think they will work.  Pads are good so I am going to use them.
Here's the question.  I have a part that I think is an anti-rattler but I am not sure how it fits or if it has to even be there.  Cannot find a pic of an F3 anywhere, so I am looking for help here.  The part appears to fit on the back of the outer pad against the piston because of the wear pattern on the back of it. There are three of them, they all have an arrow which I assume means it should point forward.  Two are alike, so I assume they go on the right front and the rear.  The other one is a mirror image, so I assume it is left front.

Here is a pic of the part and the bike:




What is this part, how does it fit, and does it have to be there at all?

Bike ain't bad for $500 assuming the engine is not toast.  PO said it was running when he parked it in 2003 but he just got too old to ride it.

Thanks,

Wayne

[scondon]

 That part clips over the back of the brake pad on the piston side(between piston and brake pad), arrow pointing forward towards front of bike.

   You've got everything figured pretty well

[jtb]

You are correct.  I believe mine are chromed, if I remember.

[Wayne Meuir]

Mine are not in very good condition, but they were chromed at one time.  Is the only place where you should use silocon grease at the four contact points where the pads slide on the caliper bracket?

Wayne

[mick750F]

That part clips over the back of the brake pad on the piston side(between piston and brake pad), arrow pointing forward towards front of bike.

   You've got everything figured pretty well

Yeah...What he said.  Any idea what the exhaust system is? Looks like a 4 into 2 with a 1/4, 2/3 set-up?

Mike

[Wayne Meuir]

Nope, no idea. It's 4 into 1 but number 4 crosses over number 3 and sorta goes under the oil filter and back out.  What this configurations does is put the whole thing pretty much under the bike.  It you rash this one its because you fell off.
It looks to me to be black chrome and all of it looks good except the muffler and someone let brake fluid get all over it and it is stained and etched and it will not come off.

Wayne

[scondon]

Mine are not in very good condition, but they were chromed at one time.  Is the only place where you should use silocon grease at the four contact points where the pads slide on the caliper bracket?

Wayne

    There should be two chromed "shoulders" per caliper that the two contact points of each pad rest on. No grease needed.   
 
  Remove the two bolts that hold each caliper to its mounting bracket and clean and re-lube the sliding pistons behind them.  Take care to notice that the "nut" side is held still by only a flat edge held against the caliper body and as the mounting bolts come out the "nut" can back out of position and spin against the caliper causing gouging if not careful.

[Wayne Meuir]

Scondon, I assume the nuts you are talking about are the little threaded parts that have two flat sides attached to the outboard end of the sliding caliper guides.  I will look at them before I remount them and make sure I know how they go, or I'll be back asking more questions.

How well do the brakes work on these bikes?  I am putting calipers from and 87 ZX7 on my H2 because they are WAAY better than the stock ones.  I would be fairly easy to do that on this F3 if the stock brakes are not up to the task.  It is a two piston caliper both on the outboard side of the rotor and they work quite well.  It's the same caliper used on a Kaw Concours through 2006 and about a zillion other bikes, so they are easy to find and realtively cheap.  All it takes to mount them is an adapter bracket and a couple of bolts.

Wayne

[UnCrash]

The brakes on my F3 work great. 

Good looking bike for the money!

[scondon]

Scondon, I assume the nuts you are talking about are the little threaded parts that have two flat sides attached to the outboard end of the sliding caliper guides.  I will look at them before I remount them and make sure I know how they go, or I'll be back asking more questions.

   That's it exactly. It's not so much how they go but more that they should be held in place against the caliper body while tightening the bolt. If they are allowed to spin freely its possible to "torque" at the wrong moment and round off the flat edges (ask me how I know). The sliding caliper guides are the part that need lubing as they allow the pads to relax and not bind.

  For the front brakesI've been using rotors/calipers/mounting brackets from the '82 Honda Supersport (750,900) or CBX. The same rotors and calipers are used on a number of early 80's Honda bikes but the caliper mounting brackets need to be from the above mentioned models. Same 5-bolt rotor as your '78 except the inner third of the rotor face has cutouts making them a little lighter. The two piston calipers have a wider, less tall brake pad than the '78 and the pads are available in better compounds which provide a bit more stick and longer life. This is a bolt on mod with no fabrication necessary.

   The stock brakes should work pretty well and I wouldn't expect you'd want more as long as you keep it under 110mph in congested areas

[Wayne Meuir]

I ran into another problem.  The PO had removed all the front brakes because they were locked up.  Well, I am missing one of the little chromed "shoulders" that the brake pad ears slide on.  I have looked up the caliper on the fiche, and guess what, that part ain't even on the picture or called out in the parts list that I can find.

Does anybody have one of these they can spare or maybe even tell me where to go and buy one?  I can't put the left caliper back on until I get that part.

Wayne

[Wayne Meuir]

OK, I looked up the parts fiche for the 79 CB750F and the part number and pic of the part I need is there. Fiche says the caliper body is the same as a 78, but the mounting bracket has a different part number.  The part number for the part I need is 45112-410-006.  I have not ordered one yet, but I am going to see if it is still available.

Wayne

[scondon]

  Looks like it still may be available. List is $5.91. If you don't have a Honda dealer nearby you can try servicehonda.com. If it's discontinued let me know and I'll see if I have one left in good nick

[Wayne Meuir]

I ordered them from a place called Direct Line Honda Parts for $4.55 each.  I went ahead and ordered a couple extra.  and I ordered new pad shims while I was at it for like $4 each because mine are a little rough.  If this stuff does not turn out to be discontinued, I am all set except for getting the broken bleeder screw out of the rear caliper.  If I screw that up, I guess I will be trying to find a used caliper somewhere.  At least it already has a hole in the center to help get the drill started straight.  I'm going to heat it a little and then use a left hand bit.  If that does not get it out, I am going to get a left hand tap and thread it and try to screw it out with a left hand bolt.  If that don't work then 

Wayne

[Wayne Meuir]

Scondon, are you using the rear brake system of the 82 as well or just the front?  The rear from an 81-82 is also a two piston caliper, but I don't know if the 82 bracket will fit a 78 F model bike.
I have not yet been successful in getting the broken bleeder screw out of my old one, so I am going to have to change it anyway, so if the two piston one will work, I may as well change to that since I would assume it works a little better..

Wayne

[scondon]

 The two piston caliper will not bolt to the '78 rear bracket. The 81-82 bracket is very similar in design to the '78 and I'm tracking a ebay auction now for a bracket/caliper so I can see if the spacing is the is the same. Would be nice if the rear is a "bolt on" mod like the fronts. If I win the auction I should have something to post about this in a couple weeks.