Author Topic: A 1975 CB400F 102.000 km (65000 mi) complete engine rebuild (Read 46558 times)

Kevin · « **Reply #100 on:** January 27, 2015, 10:21:36 AM »

Hey Jensen,
Kevin @TTR400.com just finished a large order of the cam chain tensioners for David Silver Spares. They should have them in stock now.

Good luck with your project!

supersports400 · « **Reply #101 on:** January 27, 2015, 10:39:00 AM »

Thanks Kevin, will check it out @ David Silver.

strynboen · « **Reply #102 on:** January 27, 2015, 10:43:55 AM »

super..its nice you have all the bikes you need...i hope to find a nice home for my cb77..somday it vill be .......i just have closed a deal on a ekstra 400 four..rthe first i started on for years ago..endet on the attic..end gear bearing ,and pitted gears..make me drop the engine reno..hope the new find..get deleviring in marts ,,,so vaiting both for bike and spring time...so i can test the new bike for cam tensioner ..hope the bolt can be loosent vitaut to break..and there are more adjusting back...thain eating the engine are ..a problem i see..

andy750 · « **Reply #103 on:** January 27, 2015, 11:34:49 AM »

Quote from: jensen on January 27, 2015, 08:01:36 AM

Hi Andy,

You are located in Boston, bike was in the Netherlands, shipping would be too expensive I think ?

Jensen

shipping is $750 roll on roll off and I have always wanted a well maintained Africa Twin. Also who said I'd be shipping it to Boston when my Mum - with garage- lives in Scotland - would be a good start for a RTW. Anyway I hope it went to a good home. How did you like it?

supersports400 · « **Reply #104 on:** January 28, 2015, 12:11:27 AM »

My CB400F will be my daily driver

supersports400 · « **Reply #105 on:** January 28, 2015, 07:07:14 AM »

Hi,

Over the last few years I changed my goal with the CB400F a little bit.
I did 20.000 km on this bike before taking the engine out. After that the CB450 K0 came across my path.

In the beginning the CB450 K0 was an old bike with low handling capability's. Over the years I worked on the bike, I modified a lot of things, not noticeable, keeping all details of the CB450 K0 intact. I changed the inner parts of the suspension (front and rear), chose for modern tires (BT45), new steering stem bearings, bronze rear fork bushings etc. The list is too long to display here, but all these modifications made the CB450 K0 a much better bike, not only at handling but also in reliability.

For who is interested in the details : http://www.hondatwins.net/forums/58-frame-suspension-steering/11936-upgrading-handling-refurbishment-cb450-k0.html

Now the CB450 K0 is finished for now, I think I will walk the same path with the CB400F, with the same goal, no modification should change how the bike looks like, not even in details. I do like my bikes stock, but reliable and safe.

The CB450 K0 is now a very reliable bike and brought me save home after a lot of trips. But one things makes the CB450 K0 a bad commuter, and that is the (on longer trips) irritating vibration mostly in the lower frequency's. I know, it's a twin, and thus part of the deal, but not for me. I like the bomber for nice tourist trips with many stops.

It rides very nice at high speeds, above 130 km/hour, only then the engine feels like a turbine, with only some high frequency vibration, but it's not possible to do that constantly (law).

The CB400F on the other hand, is not particular vibrating at any given speed, making it a much better commuter. The only things that lacks the CB400F is torque at lower revs and top end power. I don't think I can give the CB400F more torque at lower revs (unless using a big bore kit), but I thinks the top end power can be raised a little to meet the power of the CB450 K0 (my goal is 35 HP at the rear wheel).

By comparison the dynocurves from my CB450 K0 and CB400F, and you see what I mean (rear wheel power and torque curves)

@2500 rpm the CB400F has a torque of 20 Nm, the CB450 K0 28 Nm.
@8500 rpm the CB400F has 30 Hp, the CB450 K0 has 32 Hp.

The differences seems not to be much, but should be seen relative.

Jensen

supersports400 · « **Reply #106 on:** January 31, 2015, 03:17:46 AM »

Hi,

Does anyone have to happen some dynocurves of a CB400F, preferably standard ?
I like to compare curves between different bikes and mine. I searched this site, but apparently I'm the only one who dyno'd a CB400F.

Jensen

Kevin · « **Reply #107 on:** January 31, 2015, 06:27:36 AM »

Here you go:
Completely stock '76

supersports400 · « **Reply #108 on:** January 31, 2015, 06:32:43 AM »

Hi Kevin,

I highly appreciate your dyno result sheet of a stock bike, now, finally I can compare both bikes,

Thanks,

Jensen

Kevin · « **Reply #109 on:** January 31, 2015, 06:41:58 AM »

No problem Jensen!
BTW, this '76 was/is the best running stock CB400F that I ever came across, and I've had over 40 of them.
All the motorcycle gods were smiling on the Honda factory the day this baby was assembled.

supersports400 · « **Reply #110 on:** January 31, 2015, 07:05:47 AM »

Hi Kevin,

You must be a CB400F lover, having owned and own so much CB400F's.
What is your reason to like these small Honda's ?

33Hp @ the rear seems to be very good indeed, what is the elevation of your location?
Torque curve is very smooth too, I'll try to overlay both runs for comparison.

Did you / do you dyno all of your bikes ?

Jensen

Kevin · « **Reply #111 on:** January 31, 2015, 07:08:42 AM »

I've just always had a passion for the CB400F.
When I was young I lived around the corner from the first Honda dealership in the USA. when I was a teenager the CB400F came out and the older kids in my neighborhood would race them. I just loved the sound they made.
I'm not a big guy, 5'4" and 120 lbs so the CB400F is perfect for me :-)

supersports400 · « **Reply #112 on:** January 31, 2015, 07:15:08 AM »

Hi,

I see, with my lenght it's a small bike, but nevertheless it was and will be a fun to ride.
@ 130 km/hr (80 mls/hr) in fourth or fifth gear (legal speed here in the Netherlands) the sound is better then any other bike I have and have owned, even better then my stroker (Kawasaki KR1-s).

btw, I don't think the Kawasaki KR1-s is a well known bike in the US, so here's a picture.

Jensen

Kevin · « **Reply #113 on:** January 31, 2015, 09:51:05 AM »

Thanks for sharing your KR1-S, I know I've never seen one here in the USA.
I think there was one in the Kawasaki museum in Kobe, I'll have to go through my pictures again.
I didn't know that the KR1 was fastest of all the Japanese 250cc 2 strokes. You are lucky to have one.

http://en.wikipedia.org/wiki/Kawasaki_KR-1/KR-1S

Kevin

supersports400 · « **Reply #114 on:** January 31, 2015, 10:06:50 AM »

Thanks,

The KR1-s is a small bike, but definitely not a learner. It put's out more then the RD350 YPVS.
Here a picture of the good old days, I had the RD350 YPVS, my brother the Kawasaki KR1-s, we used the bikes to commute to school.
Both bikes were fun to ride, however the RD350 was more reliable and had more torque.

The KR1-s was faster then the RD350 YPVS, and handled much better.

Jensen

Kevin · « **Reply #115 on:** January 31, 2015, 10:14:51 AM »

Nice bikes!
Your parents must have been horrified!

supersports400 · « **Reply #116 on:** January 31, 2015, 12:08:36 PM »

Not really, they weren't into bikes at all. My father never rode a bike.
They only noticed that the exhasut note was different compared with my earlier XJ600.

As I think about it, my parents never said something about us having our bikes, they just accepted it, I guess.
When visiting my parents now, on my classic bikes, they always come outside to see what bike I took with me.

btw, I sold the Yamaha RD350, in favour of keeping the Kawasaki (got it from my brother), sometimes I regret it (when the Kawasaki broke down again....)

Kevin · « **Reply #117 on:** January 31, 2015, 12:51:25 PM »

My parents were horrified when I was 16 I bought a '79 Suzuki GS750ES. I bought it wrecked from a guy that had done some motor work to it and couldn't handle the power. He broke his leg and arm when he crashed it.

I was 4'11" and 80 lbs, nobody thought I'd be able to ride the bike or keep it from falling over at stop lights. I used this motorcycle to get my motorcycle drivers license and got 100% on the test. In Washington state there are three (or were) classes of MC license 250/500/750 and above, and I wanted to be licensed for everything :-)

I eventually traded the GS to a friend for his CB400F because I was so in love with that bike, and it was a much better fit for me.

My parents love all my bikes now and just like your parents want to come outside and see which I am riding. They'll even let me take them for short rides :-)

supersports400 · « **Reply #118 on:** January 31, 2015, 01:25:17 PM »

Maybe it made a difference that we where 18 years old, instead of 16. In the Netherlands we were aloud to ride bikes at 18.
Before 18 you were aloud to ride mopeds (max 50 cc), and no faster then 45 km/h. Before riding bikes @18 we already rode mopeds for two years.

In those two years we didnt get involved in any accident, maybe that helped also to accept the fact we were into bikes after 18.

I rode a Zundapp KS50 (actually 80cc), after riding a honda CD50 (which I still have in my possession).

supersports400 · « **Reply #119 on:** February 01, 2015, 01:01:07 AM »

Hi Kevin,

I suppose the dyno run you showed here is taken in the 5th gear ? Or in fourth ?

Jensen

Kevin · « **Reply #120 on:** February 01, 2015, 07:17:26 AM »

Hi Jensen,
Unfortunately I have no idea what gear that snapshot was taken in. If we had speed documented as well it would have been easy to figure out....

Hope you can gain some useful information from the results.

BTW, Your CD50 is sweet! I'd love to have one in my garage too.

Kevin

kghost · « **Reply #121 on:** February 08, 2015, 01:26:26 PM »

Jenson....you still have a KR1?

I still have my CB400 and a KR

supersports400 · « **Reply #122 on:** February 08, 2015, 10:14:23 PM »

Yes, I still have the KR1-s, I don't think I can part from that bike.
In every way it is an opposite of Honda.

What is your reason to keep the KR ?

kghost · « **Reply #123 on:** February 08, 2015, 10:20:52 PM »

I actually have 3 KR's.

Ones a "Café"....

The other 2 are in the build stage at the moment.

supersports400 · « **Reply #124 on:** February 08, 2015, 10:27:31 PM »

Nice ! I wonder how it sounds without fairing

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Author Topic: A 1975 CB400F 102.000 km (65000 mi) complete engine rebuild (Read 46558 times)