Author Topic: 1975 Honda CB400F Build  (Read 24387 times)

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Offline inv3ctiv3

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1975 Honda CB400F Build
« on: February 10, 2014, 03:35:21 PM »
Washed the bike yesterday and went for a little ride/shoot with my buddy who just biked up a super nice little CB200.

After cleaning her up I realized what I need to do it:
Valve Cover Gasket is leaking oil
Loses power above 6k RPM (need to trouble shoot)
Front spokes are rusted - I want new wheels I think instead of rebuilding my current ones (can anyone recommend the best looking size)
Powdercoat triple tree, brake caliper, etc
Clubman bars and new grips
Shorter cables for bars
Sync Carbs (I have a carb sync)
Change oil/filter
And I'm debating on doing a seat hoop, fender and seat
New tires (I really like the look of the fat tires a lot of guys put on cafe racers)
Rebuild front forks
New rear shocks
New left side cover (PO layed it down lightly)

Is there anything you guys recommend I do? Any suggestions or DIY's are greatly appreciated!









1975 CB400F

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #1 on: February 10, 2014, 04:36:45 PM »
Too nice to cafe, leave it stock.   Fat tires will make the handling worse.  If the rims are good, new spokes aren't all that expensive.  The low power could either be timing off or blocked midrange emulsifier jets.  Valve cover can be done in the frame.  Nice bike...Larry

Offline thirsty 1

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Re: 1975 Honda CB400F Build
« Reply #2 on: February 10, 2014, 04:47:00 PM »
+1 for Larry! That's to nice! Spokes are cheap, some new cables, grips, gen cover and fix the carbs. Nice bike!
73' CL125, 75' CB400F, 16' KTM 1190R, 05' KTM 525EXC

75' CB400F  -  http://forums.sohc4.net/index.php?topic=127295.0

My 79 CB750F for fun   ----   http://www.dotheton.com/forum/index.php?topic=19923.0

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #3 on: February 10, 2014, 05:03:24 PM »
The photos are a tad misleading, it is a clean bike but some stuff definitely needs to be painted/powdercoated and refreshed. I'm not sure I wanna go full cafe, I'd like to get a smaller tail light for sure, clubman bars, new cables, spokes or wheels and tires. I'm not comfortable rebuilding the wheels so I'd have to pay to get that done, the rims are nice enough with no dings or dents but the spokes definitely need to be replaced.
1975 CB400F

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #4 on: February 10, 2014, 05:53:06 PM »
Try steel wool on the spokes.  I have sold 400s that look similar to that for a couple grand...Larry

Offline nvr2old

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Re: 1975 Honda CB400F Build
« Reply #5 on: February 10, 2014, 06:12:58 PM »
Yeah, that's a nice lookin' 400F.  I agree, try some SOS pads on your spokes, maybe a grey Scotchbrite pad and some polish.  You'll be surprised what will come off.  I wonder if that's the correct front fender..it looks like it's off a bike with a 19" front wheel.  That one's a little too nice to change..much.  I know the allure, though, I couldn't leave mine alone either. 
'76 CB550F-'72 XL250-'82 MB5-'82 CX500 Turbo-'77 naked Goldwing-'75 CB400F cafe'-'79 Suzuki GS1000S..hey, it's a Wes Cooley..

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #6 on: February 10, 2014, 10:46:38 PM »
A lot of what I want to do is a pipe dream but I know I want to:

Replace valve cover gasket
Clubman Bars
New Cables
Re-paint front caliper, triple tree, etc
Rebuild front forks and clean up the fork tubes
New rear shocks (are the ones on Dime city pretty good?)
Clean up wheels
New tires (not sure on what tire or size is best and would love some recommendations)
Figure out timing/fuel issue
1975 CB400F

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #7 on: February 11, 2014, 01:15:54 AM »
While repainting the front end throw in a set of All Balls tapered bearings,  check wheel bearings when you have the wheels off and look at  Hagons for the rear shocks as they are not all that outrageously priced and do work well.  I'm spending your money aren't I?   Firstly though is getting it running correctly before investing any more money...Larry

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #8 on: February 11, 2014, 09:44:55 AM »
While repainting the front end throw in a set of All Balls tapered bearings,  check wheel bearings when you have the wheels off and look at  Hagons for the rear shocks as they are not all that outrageously priced and do work well.  I'm spending your money aren't I?   Firstly though is getting it running correctly before investing any more money...Larry

Obviously number one priority is getting her in tip top running shape but I'm the type of person if I'm going to be working on it I'm going to do it all at once since it's all already apart you know? So my question for you guys is this, what are your favorite online shops to order from? What is your favorite de-greaser/engine cleaner (the PO was a habitual over chain luber and it's been leaking oil so I have some gunk build up).

Right now I have the following parts in wishlists and am about to order but before I do I want your guys input on what else I may want or need (I've rebuilt many old honda ATC's and dirtbikes but never a street bike so I'm wanting all the info I can get (from dime city and bike bandit):

Valve Cover Gasket
(8) O-rings (for the caps on the valve cover)
Tachometer Cable
Honda 24" Speedometer Cable
"Retro-Slim" Black & Chrome Eye to Clevis Shock Absorbers - (320mm/12.50")
(4) Carburetor Rebuild Kit
Arrow Deco Style Turn Signals
"Cafe" Clubman Handlebars
Vintage Style Fork Dust Covers
OEM Honda Grips
And a bunch of random bolts/nuts/washers that are rusted or need replacing
I plan on having the forks rebuilt by a friend who does it for cheap and is a pro

Now I need some recommendations on where to get the all balls steering kit or Timkens? Also what wheel bearings do you guys recommend? And do I need shortened throttle cables or should I run OEM with clubman bars?
1975 CB400F

Offline Operator

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Re: 1975 Honda CB400F Build
« Reply #9 on: February 11, 2014, 11:29:56 AM »
Good Luck...I'll be watching as I am starting a 76 400F cafe build in the near future
If ever there was a creator of bastard sons, it is the open road, for she has claimed so many young men yearning for freedom......

1973 CB750 K3
1976 CB400F (Cafe Project)
1979 Yamaha XS400 (Currently up for Sale)

Offline strynboen

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Re: 1975 Honda CB400F Build
« Reply #10 on: February 11, 2014, 11:39:27 AM »
just hate to see cafes made of fine stock bikes..  . before /after ...photoes.. make it worse .. ???
if i get president i make a law against it...

its yours bike ,,,do it as you like...
« Last Edit: February 11, 2014, 11:43:30 AM by strynboen »
i kan not speak english/but trying!!
http://forums.sohc4.net/index.php?topic=60973.0
http://forums.sohc4.net/index.php?topic=144758.0
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Offline Operator

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Re: 1975 Honda CB400F Build
« Reply #11 on: February 11, 2014, 11:49:56 AM »
Plse excuse the momentary hijack...

I just started my build thread and will post more detailed photos, there is not much stock that could be salvaged in my case.

At the end of the day it's a judgment call by the owner. Own what you want, want what you own......

Good luck with your build inv3ctiv3!!  Have fun!! I'll be watching and hopefully some of my questions will be answered along the way as well.  Some already have been!!
If ever there was a creator of bastard sons, it is the open road, for she has claimed so many young men yearning for freedom......

1973 CB750 K3
1976 CB400F (Cafe Project)
1979 Yamaha XS400 (Currently up for Sale)

Offline nvr2old

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Re: 1975 Honda CB400F Build
« Reply #12 on: February 11, 2014, 11:54:52 AM »
just hate to see cafes made of fine stock bikes..  . before /after ...photoes.. make it worse .. ???
if i get president i make a law against it...

its yours bike ,,,do it as you like...

I agree, for the most part, especially if they're really clean and original to start with.  I was torn between a perfect restoration of mine, too..right down to the factory decals and stickers, but then decided to modify mine in a way that will hopefully maintain a look that is faithfull to the iconic original, but with a "what if the factory had gone in this direction" approach.  Everything I do to mine could easily be returned to factory stock, no chopping or cutting allowed.  All the correct factory parts are being carefully stashed away and safe guarded for the future. 
'76 CB550F-'72 XL250-'82 MB5-'82 CX500 Turbo-'77 naked Goldwing-'75 CB400F cafe'-'79 Suzuki GS1000S..hey, it's a Wes Cooley..

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #13 on: February 11, 2014, 11:56:06 AM »
Guys I'm not hacking the frame or anything I just want to update it and refresh some things while making it run better! The only thing I'm really doing is clubman bars and new cables which the cables need to be redone anyway.
1975 CB400F

Offline nvr2old

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Re: 1975 Honda CB400F Build
« Reply #14 on: February 11, 2014, 12:01:45 PM »
I don't think that's wrong in any way shape or form.  Those are subtle and worthwhile changes to any bike of this vintage.  I'll be following along with interest.  You really do have a nice bike.   ;)
'76 CB550F-'72 XL250-'82 MB5-'82 CX500 Turbo-'77 naked Goldwing-'75 CB400F cafe'-'79 Suzuki GS1000S..hey, it's a Wes Cooley..

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #15 on: February 11, 2014, 01:03:09 PM »
1975 CB400F

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #16 on: February 11, 2014, 07:47:05 PM »
So does anyone know what length and what throttle cable to buy? Will this work: http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-cables-honda-cb450-shortened-throttle-cable-clubmans-clipons-x-912.html

No,  you need both a push and pull set of cables, one can get by with just the pull if you want to run a single cable.  All balls also sells  wheel bearings, the bearings are a standard size so if you have a local bearing supplier bearings could  be bought there.  I have used so many different suppliers I cannot remember all.   Ron Ayers, mrcycles, western hills honda, local dealer, Ebay, David Silver, partsnmore, motogrid, siriusconinc...Larry

Offline NobleHops

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Re: 1975 Honda CB400F Build
« Reply #17 on: February 11, 2014, 10:45:40 PM »
Have you ridden an old bike with Clubman bars but no other appropriate ergo changes? They suck.

I alternately weep and point and laugh at all the hacked-at "cafe" bikes guys are trying to sell on CL, $6,000, $10,000 "invested". Har. That fad can't die fast enough for me.
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline SOHC4 Cafe Racer Fan

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Re: 1975 Honda CB400F Build
« Reply #18 on: February 11, 2014, 11:06:14 PM »
Have you ridden an old bike with Clubman bars but no other appropriate ergo changes? They suck.

I alternately weep and point and laugh at all the hacked-at "cafe" bikes guys are trying to sell on CL, $6,000, $10,000 "invested". Har. That fad can't die fast enough for me.

Admittedly so.  Clubmans (without any other modifications) do not make for the most comfortable ergos. 

Ultimately, do what you want with your bike.  I do prefer to keep pristine bikes stock.  That said, my cafe bikes have not been the best restoration candidates -- hence the bargain prices and reason to modify them.  I am not overwhelmingly troubled by the cafe craze, which will pass, but I think that the bikes in all of their forms will still be loved by their owners, whether stock, resto-mod, rat, chopper, cafe, brat, scrambler, street/dirt tracker.  I think the current hipster trend is moving more in the tracker direction anyway.  I'm too old to really care.

Hopefully, anyone who puts the amount of time, money and effort into any of these vintage bikes does it for the love (to enjoy them because it is their passion) and not with dreams of flipping it for a profit. 
« Last Edit: February 12, 2014, 10:06:39 AM by CB750 Cafe Racer Fan »
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline bjbuchanan

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Re: 1975 Honda CB400F Build
« Reply #19 on: February 12, 2014, 07:59:56 AM »
Your bike has funky pressed in emulsifier jets, they are what the slide needles slide down in to. I get some wood chopsticks from the chinese food store and tap them out like that. They get gunked up and make it run so-so. It is one of those things that people miss and you get good deals for.

If you want to go clubmans I would suggest the more expensive clubmans (65$~) as the height and angle on them are usually better and you still get low and the clubman look. You can probably get away with OEM cables because stock 400 have low bars to begin with.

If I were you I would lube them up really good and see how they feel. With the overall appearance of the bike I bet the cables are still good. Obviously any fraying is a no go but a heavy dose of lube really makes "bad" cables a lot better. Make sure you really spray it and see lube come out the other end, don't be sparing because the difference is amazing.

Your forks are very easy to rebuild, I would save the money. They are the most basic and straightforward ones you will probably see. Good flushing, 8$ seals, some fresh 10w fork oil and be good to go

For the wheels check out chrome wheel cleaner, not alum or generic wheel cleaner. I'm using Eagle one right now and it works really amazing. That plus some 0000 steel wool works wonders. Gotta be 0000 tho
The dirty girl-1976 cb750k, Ebay 836, Tracy bodykit
Round top carbs w/ 38 pilots, middle needle position, airscrew 7/8ths out, 122 main jet
Stock airbox w/ drop in K&N, Hooker 4-1

Don't trust me alone with a claw hammer and some pliers

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #20 on: February 12, 2014, 08:40:32 AM »
Your bike has funky pressed in emulsifier jets, they are what the slide needles slide down in to. I get some wood chopsticks from the chinese food store and tap them out like that. They get gunked up and make it run so-so. It is one of those things that people miss and you get good deals for.

If you want to go clubmans I would suggest the more expensive clubmans (65$~) as the height and angle on them are usually better and you still get low and the clubman look. You can probably get away with OEM cables because stock 400 have low bars to begin with.

If I were you I would lube them up really good and see how they feel. With the overall appearance of the bike I bet the cables are still good. Obviously any fraying is a no go but a heavy dose of lube really makes "bad" cables a lot better. Make sure you really spray it and see lube come out the other end, don't be sparing because the difference is amazing.

Your forks are very easy to rebuild, I would save the money. They are the most basic and straightforward ones you will probably see. Good flushing, 8$ seals, some fresh 10w fork oil and be good to go

For the wheels check out chrome wheel cleaner, not alum or generic wheel cleaner. I'm using Eagle one right now and it works really amazing. That plus some 0000 steel wool works wonders. Gotta be 0000 tho

Thanks for all the tips, I'm not modifying anything including the bars until I fix the weeping valve cover gasket, getting the carbs fixed and running and cleaning up the wheels and other parts.

The bike has 25k and I got it for $1500 from a friend so it's in good shape but it has some stuff that needs attention. Is there a DIY on the jet thing? I've replaced countless jets in atv's and dirtbikes but none of been emulsifier jets but I think I know what you're talking about. I'm wondering if the jets are the proper ones as it came from a different city....Maybe it was jetted differently for that, I can check the spark plugs and see if there is any indication on how it's running.

My friend also bought a carb sync but never used it so he gave it to me when I bought the bike. And the spokes have some pretty good rust, I'll get some steel wool and see if I can get it off but who knows. My chrome is actually in really good shape but there is slight pitting/rust that I'd love to clean/polish out if you guys have any DIY's or tips on that!

Thanks again for all the help I really appreciate it!
1975 CB400F

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #21 on: February 12, 2014, 07:44:18 PM »
emulsifier jets would not be changed,  they need to be tapped/pushed(as mentioned a chop stick would make a good removal tool) out from the top down, so removal of the slides facilitates that.  First time doing that can be challenging-you may find a video on line. After removal make sure you also clean the cavity in which the jets sit...Larry

Offline inv3ctiv3

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Re: 1975 Honda CB400F Build
« Reply #22 on: February 13, 2014, 03:55:13 PM »
emulsifier jets would not be changed,  they need to be tapped/pushed(as mentioned a chop stick would make a good removal tool) out from the top down, so removal of the slides facilitates that.  First time doing that can be challenging-you may find a video on line. After removal make sure you also clean the cavity in which the jets sit...Larry

Ok I guess I just need to get the tank off and start taking the carbs out, taking 4 carbs out seems daunting, I'm worried about that part more than anything. I've worked on many carbs but they've always been single cylinder engines.....
1975 CB400F

Offline Operator

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Re: 1975 Honda CB400F Build
« Reply #23 on: February 13, 2014, 04:40:24 PM »

Ok I guess I just need to get the tank off and start taking the carbs out, taking 4 carbs out seems daunting, I'm worried about that part more than anything. I've worked on many carbs but they've always been single cylinder engines.....

I just did this last summer..a couple times. If you use a tie down ratchet style strap and wrap it around the airbox, you can compress it enough that you can pull the carb assembly back and then out the side. I learned this trick from another forum member...gotta give credit where it is due.
If ever there was a creator of bastard sons, it is the open road, for she has claimed so many young men yearning for freedom......

1973 CB750 K3
1976 CB400F (Cafe Project)
1979 Yamaha XS400 (Currently up for Sale)

Offline MoMo

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Re: 1975 Honda CB400F Build
« Reply #24 on: February 13, 2014, 04:53:50 PM »
Also, if the inlets are really tight in the manifold use a heat gun on low to soften the manifold rubber...Larry