A 1975 CB400F high mileage complete engine rebuild

[jensen]

Today it was the last riding day, very cold and rainy on the way to work, and when I rode back to home, I had snow the last 15 minutes. Tonight the local governement will spray salt on the roads.

Last picture of the bike this year, after the CB450 K0 is ready, this bike will be next to be put on the bridge for maintenance.

 

[jensen]

One thing I'll change this winter is the headlight. It's dangerous to ride in darkness and bad weather with the 1974 output. The plan is to install relay's to avoid voltage loss over the handlebar switches, so the headlight has a direct (switched) connection to the battery. Maybe a LED bulb plus modern reflector too, but I don't like the white color of modern lighting. 6000 Kelvin is not what I want, 2700 to 3500 is nice and still looks original too. Backlight will be changed to LED too, winkers not, I like the way the winkers start slowly and soften slowly due to after glow.

 

[jensen]

First day of 2024, first (350 km) ride of this year to my family and relatives. Wet and cold, but my heated gloves and my modern motorcycle gear kept me warm and dry. Due to leaves and wet, some exiting moments because of the rear wheel stepping aside, but the BT45's managed well. The front brake was doing remarkably well in the wet.

Unfortunately, the bike is dirty, and I'm not a washing and polishing guy

 

[jensen]

First day of 2024, first (350 km) ride of this year to my family and relatives. Wet and cold, but my heated gloves and my modern motorcycle gear kept me warm and dry. Due to leaves and wet, some exiting moments because of the rear wheel stepping aside, but the BT45's managed well. The front brake was doing remarkably well in the wet.

Unfortunately, the bike is dirty, and I'm not a washing and polishing guy

View attachment 28310

 

[bilbikek411]

One thing I'll change this winter is the headlight. It's dangerous to ride in darkness and bad weather with the 1974 output. The plan is to install relay's to avoid voltage loss over the handlebar switches, so the headlight has a direct (switched) connection to the battery. Maybe a LED bulb plus modern reflector too, but I don't like the white color of modern lighting. 6000 Kelvin is not what I want, 2700 to 3500 is nice and still looks original too. Backlight will be changed to LED too, winkers not, I like the way the winkers start slowly and soften slowly due to after glow.

Jensen,I run an excellent aftermarket H4 style headlight in my stock,shallow original 1975 Honda CB400F headlight case and trim ring;this is a Candlepower and the front of the glass has the number #8022 molded into the bottom of the glass.
The headlight is an all metal Made in Japan quality reflector headlight bulb which is exactly the correct size for the stock CB400F headlight case and chrome trim ring and it throws a lot of light even with my 35/35wt. 12vt. bulb.
My little Honda single cylinder engine is originally from a 1983' XL200R therefore the headlight circuit runs directly off the stator with AC electricity. I tried an LED once but it burned-up;only incandescent is possible with this bike
The style bulb is a P43T Halogen and a 55/60wt. bulb works very well,although my little Honda doesn't make enough power to push a 55/60wt. bulb.

I can find the exact stock number for it if you ask me.

 

[jensen]

Jensen,I run an excellent aftermarket H4 style headlight in my stock, shallow original 1975 Honda CB400F headlight case and trim ring;this is a Candlepower and the front of the glass has the number #8022 molded into the bottom of the glass.
The headlight is an all metal Made in Japan quality reflector headlight bulb which is exactly the correct size for the stock CB400F headlight case and chrome trim ring and it throws a lot of light even with my 35/35wt. 12vt. bulb.

Thanks. I have a few H4 headlight reflectors lying around, and Halogen 35/35 W bulbs also (CB72 and CB400F share the same size headlight reflector). I was more looking into an LED direction, but not the ones in a standard reflector, but more as a complete replacement of bulb and reflector. There is a choice out there, but none of them are legal. The ones that are legal, are not fitting into the style of the CB400F and the color-temperature is way too high (above 4000 Kelvin). If I can't find anything in that direction, I will use the H4 headlight with a Halogen 35/35 Watt bulb. I already found a yellow version of it, which is period correct (for Europe at least).

 

[bilbikek411]

Thanks. I have a few H4 headlight reflectors lying around, and Halogen 35/35 W bulbs also (CB72 and CB400F share the same size headlight reflector). I was more looking into an LED direction, but not the ones in a standard reflector, but more as a complete replacement of bulb and reflector. There is a choice out there, but none of them are legal. The ones that are legal, are not fitting into the style of the CB400F and the color-temperature is way too high (above 4000 Kelvin). If I can't find anything in that direction, I will use the H4 headlight with a Halogen 35/35 Watt bulb. I already found a yellow version of it, which is period correct (for Europe at least).

I'm hoping to locate 2) spare yellow 45/45wt. w/ the P43T base;I'm using my last one and so far I still have both High & Low beams intact,it seems yellow is difficult to locate so far..

 

[ballbearian]

I'm hoping to locate 2) spare yellow 45/45wt. w/ the P43T base;I'm using my last one and so far I still have both High & Low beams intact,it seems yellow is difficult to locate so far..

Seems, P43T is the bulb base for standard H4 socket. Yeah, no 45w but did find a 35w.

H4 P43T 12V 35W Head Light Bulb FOR Moped GY6 Motorcycle ATV BB13 | eBay

Find many great new & used options and get the best deals for H4 P43T 12V 35W Head Light Bulb FOR Moped GY6 Motorcycle ATV BB13 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Edit: Seek and ye shall find...

HELLA H4 45/45WTB Bulb H4 12V 45/45W P43T T4.625 (2) 760687171409 | eBay

Find many great new & used options and get the best deals for HELLA H4 45/45WTB Bulb H4 12V 45/45W P43T T4.625 (2) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

And

LUCAS 4745 H4 HEADLIGHT BULB HALOGEN 12 VOLT 45/40W P43T TRIUMPH NORTON | eBay

Part number: 4745.

www.ebay.com

 

[jensen]

Luckily, France is closely. In France, it was mandatory to have yellow headlights in the past. There are some suppliers that supply modern yellow replacement bulbs H4, P43T socket for the France classic car market. I involved my youngest son in the search, he speaks, reads and writes French.

 

[ballbearian]

Luckily, France is closely. In France, it was mandatory to have yellow headlights in the past. There are some suppliers that supply modern yellow replacement bulbs H4, P43T socket for the France classic car market. I involved my youngest son in the search, he speaks, reads and writes French.

I've seen a few of those for the smaller singles from France. Also 40-45w halogen in UK for Lucas, Norton, Triumph on our ebay here.

 

[jensen]

And, because France is Europe, it's legal here in the Netherlands.

 

[jensen]

Quartz Halogen bulbs for motorcycles & cars

 

[ballbearian]

Quartz Halogen bulbs for motorcycles & cars

Excellent information on that site. Thanks.

 

[jensen]

Did 2750 km already this year on the CB400F, not so difficult with the weather and scenery are like this. The standard 120 km per day commuting will sometimes be doubled by 'taking the long way home". I might think that Rodger Hodgson owned a CB400F (songwriter Supertramp).

 

[Maraakate]

Looking good and you always got to take the long way home!

 

[jensen]

Tonight the way was a little bit too long. Riding the last km's highway just before the intersection where I go off the highway, the bike run out of fuel, too late to hit the reserve tab, so it stalled in a long corner right before the traffic lights. At the traffic lights, switched to reserve, and started again. When looking at the odo I saw that I did 210 km's today. I have to say that it was after 19.00 hour, so the official highway speed is 130 km/hr instead of 100 km/hr. I didn't take the extra 30-isch km/hr into account, because normally I can do 210 km with ease. I was doing 145 km/hr @ 8000 rpm for 5-10 minutes or so, now I know that at these speeds the bike certainly likes to drink

A few shots in the evening sun:





Below the route of today, my favorite when to go to work. 80% of the route are dykes, around reclaimed land, at one hand the lake (closed off sea, now fresh water, but in the past salt seawater. It's always nice to see the water level on one side of the **** is higher than the land side.

 

[ancientdad]

Tonight the way was a little bit too long. Riding the last km's highway just before the intersection where I go off the highway, the bike run out of fuel, too late to hit the reserve tab, so it stalled in a long corner right before the traffic lights. At the traffic lights, switched to reserve, and started again. When looking at the odo I saw that I did 210 km's today. I have to say that it was after 19.00 hour, so the official highway speed is 130 km/hr instead of 100 km/hr. I didn't take the extra 30-isch km/hr into account, because normally I can do 210 km with ease. I was doing 145 km/hr @ 8000 rpm for 5-10 minutes or so, now I know that at these speeds the bike certainly likes to drink

At least you have larger than 0.4 gallons reserve for that thirsty thing in those situations.

 

[jensen]

Wow, you responded quickly ! I was still busy to add some pictures ...

 

[ancientdad]

Wow, you responded quickly ! I was still busy to add some pictures ...

I'm here at VHT a lot more than most realize, it's the best way to stay on top of things.

 

[stl360+450]

Tonight the way was a little bit too long.

At least the reserve was enough to get you home.

I got my first bike (1988 Suzuki GN250) in high school and a few weeks later I ran out of gas on the way home from my part time job. I pushed it about 20-30 meters along the road before remembering there was a reserve. Then I started it up and rode the rest of the way home.

 

[AndrewJK]

Nice ride.You are not working 200 meters from Your home, I suppose

 

[jensen]

Nice ride.You are not working 200 meters from Your home, I suppose

No, 60 km's one way, and that's the shortest, boring, route you can think of. With the bike, I add occasionally another 20 to 40 km, one way, to make commuting a fun experience. For example, yesterday I took the CB400F to work, and did add 280 km to the odometer, more than twice the minimum distance to cover.



The weather was good, but beginning afternoon we got some heavy rain, luckily I could put the bike in a large shelter (unused that day).



And, as always, people feel the need to copycat, and hide my bike behind theirs, I think they're jealous



The ride home was pleasant, nice sunny weather and dry roads (I don't like to clean and polish the bike). However, there was a speed trap I saw too late, and maybe I'll have (another) speeding ticket

 

[ballbearian]

Those other bikes should be jealous.

Tell the cops their radar must be off because it's an old bike

 

[stl360+450]

I assume that is a foldable anti-theft device on the rear wheel? I haven't seen that type before.

The shelter is normally used for a professional purpose? I see that the wood planks have been set up to keep things in the shelter off the concrete.

The way the plate/taillight(?) is mounted to that middle bike is just silly.

 

[bilbikek411]

Jensen,which muffler are you running ? The bike looks wonderful.
I remember working on a customer's varnish blue 75' CB400F(very weathered compared to the nice paint on yours)and ordering an OEM Honda muffler from my supplying Honda dealer in 1992,and at that time the stock Honda muffler was still available. The muffler makes a big difference in overall performance.
I called them a couple years later for another 400F and they told me that part was now NLA

 

[jensen]

I assume that is a foldable anti-theft device on the rear wheel? I haven't seen that type before.

Yes, it's a ART-4 lock (security level), very heavy btw.

The shelter is normally used for a professional purpose? I see that the wood planks have been set up to keep things in the shelter off the concrete.

It's some kind of event tent, the wooden floor is added to keep your nice shoes dry (especially for the lady's). Pictures are taken @perron038 (https://www.instagram.com/perron038/). btw, the bottom left picture is me, giving a lecture on Machine Vision and AI.

Jensen,which muffler are you running ? The bike looks wonderful.

Original muffler, Honda 377 code. This muffler came with the bike, and is mounted at the factory. The paint is original too (varnish blue), the frame is re-painted. I have a NOS muffler, just in case this one gives up (and bought it many years ago).

 

[bilbikek411]

Jensen,I imagine you knew the history of this machine before you purchased it;the original muffler?!

 

[jensen]

Jensen,I imagine you knew the history of this machine before you purchased it;the original muffler?!

I bought the bike from an old man, who couldn't ride anymore due to balance problems, he was the first owner and cared for it like a baby.

 

[bilbikek411]

I bought the bike from an old man, who couldn't ride anymore due to balance problems, he was the first owner and cared for it like a baby.

Yes he did

 

[jensen]

Last 2 week almost every day I took the bike to work and back, sometimes the shortest route (mostly highway in the morning), sometimes the long way home, sometimes with a stretch of highway after 19.00 hours (from this time the speed limit goes from 100 to 130 km/hr). Today I had to be in Groningen, 220 km from home, a nice ride !


Both supersports bikes, a few decades of technology in between.



Endless skies, nice weather, a CB400F and time, it's all I need to have a perfect day !

 

[stl360+450]

I can't recall seeing the seat from that angle before. Is that a custom cover/foam combo?

I'm definitely jealous of the weather. This morning I was in the garage only long enough to remove and reinstall the high pipes on my 350T project yet came inside very hot and sweaty.

 

[bilbikek411]

I have seen more red CB400F models from my past.. I love that Blue one

 

[Richard Pitman]

From memory, all the ones I saw in the UK back in the '70's were blue, don't recall any red ones. And I believe the yellow ones ( my favourite colour ) were not imported here.

 

[ballbearian]

Beautiful pics Jensen. Keep that inspiration coming.

 

[Cycleranger]

That beautiful bike is just so clean!

 

[jensen]

I can't recall seeing the seat from that angle before. Is that a custom cover/foam combo?

NOS CB400F seat, bought in a time that these were affordable. I have the original seat which came with the bike as well, it's exactly the same seat, but way too soft for long rides at my age.

 

[EzPete]

The summers in the Netherlands are truly beautiful - that's a bucket list ride for most of us. I've got some serious bakfiets envy as well, can't find those around here.

 

[jensen]

There are many, many bakfietsen here, mostly from women with little children in the "bak", but also man with there dogs in de "bak".

 

[boddy]

Very nice restoration Jensen, looks like it has come straight from the showroom floor.

I admit I had to google "bakfiets" to find out it's the bicycle with the huge basket in front as shown beside you 400F at work.

 

[stl360+450]

NOS CB400F seat, bought in a time that these were affordable.

It's a surprisingly modern looking design to my eyes for a 1975 street bike, especially with that short slope up in the back. I like it.

 

[jensen]

Another great ride home tonight, the weather was nice, temperature good, not many insects. Sometimes you think you took all the possible roads from work to home, but then you find another hidden gem (ok, I added 30 km to the shortest possibility of 62 km). Not in a rush, and doing a very smooth 30 mls / hour in sixth gear with 2250 rpm, no or very low vibrations and not possible with the CB450 K0 or K1. Tomorrow again !, adding more and more km's to the odo (and it seems that the bike get's smoother and smoother with adding more km's after rebuild).

 

[RobMan]

BTW wanted to thank you for mentioning "Zen And The Art of Motorcycle Maintenance" a while back and it jogged me to get a copy as I have been intending to read it since it came out. My eyes get tired now so a bit of a slow read so far but enjoying very much. Not delving too much into the hidden meanings yet but very concerned about the engine overheating and tappet noise. Thanks again.

 

[jensen]

Yesterday, for the first time after rebuild, I pushed the CB400F to its limits in Germany, just over the border. After reaching 9500 rpm, in fourth, I changed gear into fifth, and again it hit the 9500 rpm. Since the sixth gear is a kinda overdrive, I didn't expect to hit the 9500 rpm, but it did (while I was lying flat on the tank, with my arms and legs as close to the bike as possible). It took a while, and highly illegal speeds in the Netherlands but not in Germany, I finally reached the red line @10.000 rpm. I kept it there for 3 seconds, before shutting down the throttle. The engine didn't explode, and kept pulling all the way. I found a parking spot and parked the bike to let it cool down a bit, the engine was really hot. The top speed (on the speedo, no GPS), was over 180 km/hr (no time to have a good look). The bike didn't feel insecure, but didn't feel safe at the same time. The rear shock absorber couldn't handle the bumps, it wasn't severe, but enough to not do it again with these shocks. The front shock did hold up, since I modernized it with progressive springs and modern front fork oil. The stiffness of the frame was better than the CB450 K0 at these speeds, the sound of the four cylinder was great too.

Compared with a modern bike, like my XRV750 AT (sold years ago), the experience on the CB400f was way more intense, as I took the XRV regularly to these speeds (in Germany). One of my co-workers has a Yamaha R1, that bike can reach more or less the same speed in first gear alone

 

[RobMan]

Kudos on your build and that is a heck of a successful stress test on a 50 year old machine.

 

[AndrewJK]

(...) was over 180 km/hr (no time to have a good look). (...)

Crazy speed indeed. I have tested KTM 390 ADV yesterday and it was out of comfort above 100 km/h. Four cylinders are waaaaay smoother than single pump.

 

[jensen]

Since I ride my CB400F every day to work (average around 160 km / 100 mls a day), the km's add up quickly, so my rear tire needs to be replaced within the season. Normally I wait until winter, but the tire is almost square, and it's behavior in cornering is not what it was. Since the commuter roads are straight, and many traffic lights (good for sprints), the tires (mainly rear) tend to get square. This will be my first in-season tire replacement. The total mileage of the rear tire is 7500 km, which is less than expected. I think it has also something to do with the original Showa rear suspension, which is not damping as it should.



Picture of the rear tire. The depth of profile is on the edge, but with the bad weather coming up soon, I don't feel secure anymore. The front tire is fine, and will good enough for the next season.

 

[jensen]

It's that time of the year again



Almost 65 km through heavy showers, but the bike performed well. It actually did run a little better then under warm and dry circumstances.

 

[ballbearian]

Good to know it runs well in the rain. I wonder why it's better. Heat dissipation, air density?
We should be getting some rain soon, but I won't be purposefully testing any bikes in it.

 

[jensen]

I wonder why it's better. Heat dissipation, air density?

Yes, both.






A few things that seems odd when compare the above bikes with mine:

- The CB400F has the highest mileage.
- When you add the mileage's of the other bikes together, the CB400F still has the highest mileage.
- My bike contains the least plastic of the four bikes in the picture.
- The rear tire is 50 % smaller than the rear tires on the other bikes.
- The CB400F is the loudest bike in the row.

 

[ancientdad]

A few things that seems odd when compare the above bikes with mine:

- The CB400F has the highest mileage.
- When you add the mileage's of the other bikes together, the CB400F still has the highest mileage.
- My bike contains the least plastic of the four bikes in the picture.
- The rear tire is 50 % smaller than the rear tires on the other bikes.
- The CB400F is the loudest bike in the row.

- The CB400F looks more like a street-use motorcycle than any of the other bikes. They all look like you could take off the fairing and go dirt riding with them, plenty of rear suspension clearance and wheel travel (and WHY is the question).