Topic: cb 750 f2 brat - top end rebuild in progress..

[koendd]

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 

[koendd]

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:

[koendd]

inished 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!

[mihai.i]

I really miss Jupiller beer...
Nice project too...where did you get the rectifier and the fuse box?

[koendd]

hehe, good beer isn't it

I ordered them on ebay america
just check rick's motorsport electrics and you'll find them.

will be around 170eur incl shipping and taxes for the two.

[SOHC4 Cafe Racer Fan]

Mihai brings up an interesting point . . .

Is there any difference quality/durability wise between the many regulator/rectifiers out there??

[flybox1]

Hey Koen.  Nice find and good work so far.  It looks to be like a solid motor with no oil leaks.
Might want to verify the engine VIN as, at least in the US, the F2/3 engines were black.
The earlier F engines were not painted.  Might be one of those....
good luck with your project.

[Roland]

Great work so far, you can do the same upgrade on the front brakes.  Look on ebay for the brake brackets and calipers front and rear for 81-82 CB900F, rebuild them and bolt them on!

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

[SOHC4 Cafe Racer Fan]

Great work so far, you can do the same upgrade on the front brakes.  Look on ebay for the brake brackets and calipers front and rear for 81-82 CB900F, rebuild them and bolt them on!

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

I heard that mod also included the 85 CB900F and 82 VT1100C.

[Roland]

From what I could find 81-82 900F was the only bike that had compatible front and rear, there are a handful of bikes earlier and later that would use the same front or rear but not both.  Even a few bikes that you could use only one side of the front set due to the way they were mounted.

Great work so far, you can do the same upgrade on the front brakes.  Look on ebay for the brake brackets and calipers front and rear for 81-82 CB900F, rebuild them and bolt them on!

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

I heard that mod also included the 85 CB900F and 82 VT1100C.

[koendd]

jep,  I know about the front brakes.
Will fit the rear brake first and see what that does...

I've heared that before about the engine being black but it's been repainted before.
And the engine number is correct on papers so I guess/hope it's the original one..

[dakota]

Goed bezig. Heb zelf ook een F2.
http://forums.sohc4.net/index.php?topic=97323.msg1083564#msg1083564
Waar heb je dat bord van Interelectra gehaald?
grtz
g

[andy750]

Looking forward to seeing what you do with this - cool garage set up!

Where in Belgium are you?

cheers
Andy

[koendd]

Goed bezig. Heb zelf ook een F2.
http://forums.sohc4.net/index.php?topic=97323.msg1083564#msg1083564
Waar heb je dat bord van Interelectra gehaald?
grtz
g

knap ding!
staat toch te koop nu?

En dat bord van interelectra heb ik ooit eens toen ik nog klein was meegebracht van op chirokamp ergens in limburg. Geen idee meer waar dat toen was...

Looking forward to seeing what you do with this - cool garage set up!

Where in Belgium are you?

cheers
Andy

thanks!
I live near Bruges, not that far from the coast

[brandEn]

Looks like good progress.

[HedNut]

Love it!  Great bike to start with!!

[koendd]

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 

[koendd]

So...

I threw the hole electric lot out yesterday, will make a new harness from scratch since there's quit a few things that aren't going back on the bike anyway...

But I was wandering, wat does the clutch switch on the lever do? Do I need it?
I mean these two wires:


thx!

[koendd]

some parts arrived, thanks DCC!

the seat is looking excellent!

[Menno]

Nice work Koen, ziet er goed uit.

If you need a kick ass paintjob on the tank and covers... Mail me..
Cheers, Menno.

[koendd]

thx!

some more parts arrived yesterday:


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...

[koendd]

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

[koendd]

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

[koendd]

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

[raymond182]

It is probably too late to answer your question about the clutch switch since you have made a custom wiring, but you do want it; it prevents starting the bike while in gear (unless the clutch is engaged). Nice work!