1977 Honda CB750 F2 brat: Finished?!

K

koendd

New Member

• May 8, 2013

• #1

hi all of you!

I'm Koen, 25 and been dreaming about bikes, well, ever since I could sleep I guess...

Then finally after lost of persuasion (of the girl...) I bought a project last week!

A few years I noticed caferacers for the first time, and i was in love!

since we've just moved to our own house which we renovated it will be a slow moving project but we'll get there I guess..

So I went for a budget friendly bike, a Honda CB750 F2 from 1977.
A non runner with loads of work but got it cheap and I love to work on things like that in my garage...

when we collected the bike..

and then unloaded in the garage and had a good look...

electricity has been "messed with":

removed the rear light and the 15kg heavy exhaust :

 

K

koendd

New Member

• May 8, 2013

• #2

Re: 1977 Honda CB750 F2 from belgium

more disassembling:

together with the daily (vw) and my first project (opel kadett c 1977)

brake upgrade for the rear, from a bol d'or, double piston:

Bit on a tight budget on the moment and not in a rush to finish it but I'll try to update frequently...

first job to do:
renew the whole ignition, incl coils, leads etc...

 

deepwaterimports

Over 1,000 Posts

• May 11, 2013

• #3

Re: 1977 Honda CB750 F2 from belgium

I'm on board this one mate.

 

burnicarus

Oliver

• May 20, 2013

• #4

Re: 1977 Honda CB750 F2 from belgium

4real

 

K

koendd

New Member

• Mar 9, 2014

• #5

Re: 1977 Honda CB750 F2 from belgium

let's blow some dust of off this one...

finished some projects cars and gave the garage a make-over so now it's finally time for my bike...

when to a cafe-racer fair a a few weeks ago here in belgium and found all the parts I needed for the new ignition.
New electronic ignition
new coils and leads
new spark plugs and caps.
Installed everything last thursday

(this is offcourse temporary...)

Despite all the new parts couldn't get the sparks plugs to do their thing.

I think this has something to do with it...

lose wires everywhere, bad connections etc.
Coils only got around 8.5V so not enough to get the spark right I guess..

So I ordered a new starter solenoid and a combined regulator/rectifier as well

also ordered a new fuse box since the old one is broken as well...

Next thing to do will be cleaning out all of the electrics and removing all that I don't need (blinkers, horn etc.)

Also scored some better looking wheels allready

Plan to go with the looks is bratstyle and might add a removable cafe rear end later on...

thx for checking!

 

NagChampa

Troddin' through the valley

• Mar 11, 2014

• #6

Re: 1977 Honda CB750 F2 from belgium

You are doing great work koendd!

Subscribed!

 

K

koendd

New Member

• Mar 22, 2014

• #7

Re: 1977 Honda CB750 F2 from belgium

thx!

some small progress made...

new starter cable

much better then the old soldered one

Then some issues, I think this one is broken? doesnt let current through from - to +?

at work..

another problem, the 2 wires that go to the clutch lever were smashed so I removed the tape and found them somewhat melted together.. They both work as a ground now? I don't think that this is meant to be?
The green one is ground I suppose? The green/red goes to the (broken?) diode, correct me if I'm wrong...

new set-up on the battery tray, made a new fusebox, installed the rectifier/regulator, new starter solenoid should be arriving soon...

and I still have no spark on the plugs :-[

 

yorkie350

If it runs ride it if it dont polish it & dream !

DTT BOTM WINNER

• Mar 22, 2014

• #8

Re: 1977 Honda CB750 F2 from belgium

Keep at it mate the wiring / electrical side of my build drove me insane just kept testing / connecting/ trying until everything worked ok not sure how i did it to this day ??? ya doing the right thing changing connectors and parts i pulled a lot of the sleeving off the main loom was quite brittle to reveal a lot of fraid wiring underneath sure would have been quicker to buy a new loom but hey i was up for a challenge haha

 

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K

koendd

New Member

• Apr 6, 2014

• #9

Re: 1977 Honda CB750 F2 from belgium

haha ok, maybe yours was worse then mine...
but will make a new loom from scratch as well, let's see how that will turn out...

some new parts from DCC, love the seat, it's perfect!

and parts from a dutch supplier

got some time in the garage this morning

frame before the seat mods:

chop chop

cut the seat lock off as well, won't be needing that no more...

mounted the seat but wasn't flat, the strip of metal with the number 1511 in it was sitting to high so cut it out and re-welded it a bit lower

scrap metal...

then mounted the battery tray and realised the back mounting was to high, grinded it down and cut 2/3 of the rubber damper and mounted with a flat screwhead bolt and problem solved

test fitting the seat...

welded in a strip of metal to mount the seat

unfortunatly the front mounting bolts on the seat are sitting right on top of the battery so will have to find another mounting method for those 2 bolts or I won't be able to get the battery in or out...

 

yorkie350

If it runs ride it if it dont polish it & dream !

DTT BOTM WINNER

• Apr 6, 2014

• #10

Re: 1977 Honda CB750 F2 from belgium

cool ya got some real work done lovin the look man gauges look sweet she gonna be a head turner 8)

 

robbing

GS550 "81

• Apr 6, 2014

• #11

Re: 1977 Honda CB750 F2 from belgium

Mooi project! Succes

 

K

koendd

New Member

• Apr 10, 2014

• #12

Re: 1977 Honda CB750 F2 from belgium

thx!!

bought some parts today of a lady who once started a project but never finished it...
wheels and a few cases with numerous calipers, clipon, foot pegs etc...

mounted the front wheel

but unfortunatly the rotor is bigger in diameter and thickness. It's also a 6 bolt, where the original comstar is 5 bolt?
any idea how I can get this to fit?

also the speedo thingy is a bit to wide , can't rotate it cause it hit's the fork..

original wheel...

one of the clip-on sets fitted the CB (and I've just bought a pair of ebay, pfff... )
So I did a small mock up with some of the new parts

 

K

koendd

New Member

• Apr 21, 2014

• #13

Re: 1977 Honda CB750 F2 from belgium

Since the whole wiring was shot made a new loom with just the necessary wires...
key switch, headlight , rear light, 2 gages and steering switches: high beam low beam, kill and start switch.

started messing around with the wires and all the new parts:

will move the key switch here:

while working on the cables...

result:

(I will change the red plugs, this was just for testing everything)

and the hard work payed off! The 750 is now running!

https://www.youtube.com/watch?v=eDbUMbk8Whc

but don't know if you can hear it, cylinder one doesn't work... 3 exhaust pipes heat up, except the 1st...

Now i knew she's a runner, started tearing her apart...

test fitted the rear spoke wheel and the bol d'or dual piston brake which all seems to fit like a glove!

and a less rotten front wheel will just have to figure out how to fit the larger rotors with the stock brake calipers....

already bead blasted one of the rotors, like new

 

K

koendd

New Member

• May 1, 2014

• #14

Re: 1977 Honda CB750 F2 from belgium

here's another update for the interested

F1 forks mixed with the F2 lower tripple (dual disc conversion)

YES i know the forks should be the other way round, i was just messing with various brake calipers I had laying around...

2 discs upfront and changed the speedo pickup

now all I need are two F1 or K7 calipers

moved on to the back to make the changes for the new seat

drilled two holes, one in the frame, one in the hoop and welded to the slugs

ground the welds down and put some zinc primer on it for now

here is how it looks now, just have to find a way to finish off the rear of the tank cause it ain't pretty now...

some new parts
allen head bolt set for the engine

new bmc with brakelight switch

new steel brakelines

 

El Conio

Active Member

• May 1, 2014

• #15

Re: 1977 Honda CB750 F2 brat from belgium

Nice work already!

Can't wait to see it when it's finished!

 

K

koendd

New Member

• May 6, 2014

• #16

Re: 1977 Honda CB750 F2 brat from belgium

thx alconio ;

tackled the carbs today

since exhaust on the nr1 cylinder wasn't heating suspected the carbs so had to take them apart.

went fearly easy concidering it was the first time I did that.

Found that the needle on carb 1 was stuck. Took it apart and the spring was bend and twisted, since I didn't have another one got it straight as much as possible and that seemed to work.
Also there was a piece of dirt on the main jet, so replaced that one.

Other then that no major issues, just cleaned all the carbs, changed all the O-rings, gaskets and idle jets.

soaked the bodies in hot water with some degreaser and cleaned with a small brush.

Not esthetically perfect but they are clean in and outside so I'm happy.

I'll bench synch them tomorrow and that should be it for the carbs I hope...

 

K

koendd

New Member

• May 11, 2014

• #17

Re: 1977 Honda CB750 F2 brat from belgium

bench sync went ferfect, not that difficult at all...
Just found out you have to be really carefull not to destroy the tread in the carbs...

bought myself a little present, cognito moto top tree. But will paint it black I think...

next will be the engine removal this week, so I can paint it and renew the seals/bolts

 

F

Freb_mc

New Member

• May 14, 2014

• #18

Re: 1977 Honda CB750 F2 brat from belgium

Looking good so far man, I'm going through a lot of the same stuff on my 77 cb750f, except someone else had already hacked it up to make a "cafe" bike. lol what year/make/model did your rear wheel come from? I have been looking all over for a spoke rear wheel. I hate the comstars personally

 

K

koendd

New Member

• May 22, 2014

• #19

Re: 1977 Honda CB750 F2 brat from belgium

Freb_mc said:

Looking good so far man, I'm going through a lot of the same stuff on my 77 cb750f, except someone else had already hacked it up to make a "cafe" bike. lol what year/make/model did your rear wheel come from? I have been looking all over for a spoke rear wheel. I hate the comstars personally

Click to expand...

not really sure, but since it has a rotor I'm guessing K7/F1

removed the engine from te frame

the engine has been taking apart before (blue sealent here and there) and miscellaneous bolts and nuts have been used...

I think i'm missing this sprocket cover?

blasted the frame today

primed it in black, if there is damage it will be less noticable

had some 2 pack leftovers, one can was matte, one can was high gloss, comined the two so it would be satin but guess there was a bit to much gloss paint... not that big of an issue ...

 

H

hillsy

Over 1,000 Posts

• May 22, 2014

• #20

Re: 1977 Honda CB750 F2 from belgium

koendd said:

new starter cable

much better then the old soldered one

Click to expand...

I know I'm late to the party with this one, but it's a common upgrade to solder the wires from the stator to the regulator rectifier rather than run connectors. Connectors can reduce the voltage and impede the current flow in some cases compared to a soldered join. You now have 2 connectors per wire in your set-up and this may cause you some problems.

I say "may" because it isn't always the case. But it's worth keeping an eye on this as it may become a problem later on.