Topic: CB400f 466cc pre-build questions. Need advice

[MotorFist]

Hello All,

Its been a while since I have posted.  This past May, the worst thing that can happen to a motorcyclist (outside of death) happened.  My Shop burned down with 11 motorcycles in it, including my beloved cb500 and my lady's cb400.  A true tragedy in my mind.

The garage rebuild is coming along and it's time to start rebuilding the "fleet" so to speak.  I purchased a run down cb400 to make another project for the mrs.  There were things about her last bike that I was not stoked about so I intend to make this bike better in every way possible.  The bike hasn't been torn apart yet as the garage is still being built.  I am just starting to gather parts and with Christmas coming, another opportunity to spend money on bits and bobs!

First item of business, is I purchased a 54.5mm big bore kit from Yoshimura Japan via Yoshimura USA.  Great customer service from Don Franzen at Yoshimura R & D of America I might add!  I've searched a bit on the forum and haven't found much on a detailed 54.5mm build. 

I want to buy an electronic ignition and wonder if there is any specific recommendation for the big bore?  Also, should I be looking for a performance camshaft or any other internals to get the most reliable performance as possible out of the 466?

Thanks in advance!
Josh

Before:


After:

[calj737]

I lost my shop last year to snow, but fire is a whole different animal. Terrible to hear, but glad you and the Mrs are safe.

Kevin Bidgood (www.ttr400.com) is about the worlds most authoritative source for 400s that I've encountered. He's in South Africa, but his site and he are wealth of knowledge.

Traditionally, displacement increases should be coupled with valve train improvements to extract the most benefit. Any transistorized or electronic ignition will be improvement over stock. Some good looking bikes to start from.

[rickmoore24]

That's terrible! But really glad you are both OK, but the bikes....man that hurts.  :/

[Tim2005]

There's a lot you can do with a 400. Depends how far you want to go really & what your plans are for the bike's use? Cam, porting, ignition, oil cooler, bigger or bored carbs, exhaust, rods, oil pump, are all worth considering, but depends really on how you plan to use it- if you're planning to use it on the track & want full throttle power from 9000-12000 that's quite a different build to a street motor with the stock bike's 6000-9000 power.  Neither is all that cheap, but you've a great start with a proper Yoshi kit, top quality and compression is nice and high.  Probably best posting this in the high performance forum to get the attention of people too. 

[MotorFist]

I lost my shop last year to snow, but fire is a whole different animal. Terrible to hear, but glad you and the Mrs are safe.

Kevin Bidgood (www.ttr400.com) is about the worlds most authoritative source for 400s that I've encountered. He's in South Africa, but his site and he are wealth of knowledge.

Traditionally, displacement increases should be coupled with valve train improvements to extract the most benefit. Any transistorized or electronic ignition will be improvement over stock. Some good looking bikes to start from.

Sorry hear about your shop too!  Thanks for the nod to Kevin, I am hoping he comes across this thread sometime, otherwise I will tart badgering him directly. Ha!

That's terrible! But really glad you are both OK, but the bikes....man that hurts.  :/

Thanks Rick, I am VERY grateful no one was injured too!  I was working in Vietnam when I got the phone call as it was burning so I felt impossibly helpless.  Aside from our CB's pictured above, we lost a 1973 Yamaha AT3 That I had literally just finished restoring about a week before the fire.  It was a gift to my oldest son to use to get his motorcycle endorsement.  I also had a 73 RD350 that I had just torn to bits to build an AHRMA racer but luckily no parts had been purchased yet. The rest of the bikes had no sentimental value.  Dirt bikes and a KZ650.  I had my BSA Lightning, cb160, dt250 and CL350 AHRMA Bike stored off site so not all was lost!  Maybe it was the Big Man telling me to thin the herd?

There's a lot you can do with a 400. Depends how far you want to go really & what your plans are for the bike's use? Cam, porting, ignition, oil cooler, bigger or bored carbs, exhaust, rods, oil pump, are all worth considering, but depends really on how you plan to use it- if you're planning to use it on the track & want full throttle power from 9000-12000 that's quite a different build to a street motor with the stock bike's 6000-9000 power.  Neither is all that cheap, but you've a great start with a proper Yoshi kit, top quality and compression is nice and high.  Probably best posting this in the high performance forum to get the attention of people too. 

Thanks Tim!  My goal for the bike is to make a reliable, performance-minded back road burner for the Mrs.  She loved her 400 before and I just want to make this one lighter and more powerful.  It may see a track day or two but I do not intend to have her race it.

I will try and contact a moderator to get the thread moved.  Thanks!

[innovativems]

Sorry to hear about your shop! 

I've been talking to Kevin with ttr400 alot as I'm in the beginning stages of my cb400 big bore build.  I was going to do the ebay seller every likes that sells the 466 big bore.  Have Mike R do a stage 2 port on the head, bore the carbs, webco cam, heavy duty cam on my bike.  I'm going to run stock rods and run an oil cooler.  Kevin says the upgraded oil pump is really only needed for bikes that will see alot of track/race time at high temps.  The oil cooler really helps.

Good luck with your build and i'll be following it!

[thirsty 1]

Don't Forget about a little suspension work along with some head set bearings and swing arm bushings. These are cheap and easy upgrades that make a difference.
Good luck and Cheers from a fellow 400 guy.

[rickmoore24]

I just picked up a 75 CB400F last weekend and have been researching the bike heavily trying to learn it (it's why your post piqued my interest), I've only ever really owned and worked on the 750's. The bike looks like a lot of fun, mines rough and will be a full tear down to the frame, just over 14K on the odo. Unfortunately, my frame suffers from the common side stand, bottom rail rot and will need to be addressed.     In any case, I'll watch your build closely when you start, I have a lot to learn about these bikes.

[ofreen]

Its been a while since I have posted.  This past May, the worst thing that can happen to a motorcyclist (outside of death) happened.  My Shop burned down with 11 motorcycles in it, including my beloved cb500 and my lady's cb400.  A true tragedy in my mind.
Before:

Jeez Josh, I admired those bikes, as you know.  Just great craftsmanship.  That after photo is tough to look at, quite a loss.  But I know what you come up with next will be exceptional.

[BomberMann650]

Damn that fire must have been hot.  What a shame 

[Bodi]

I had a friend with a van that burnt with 3 bikes in it... same thing, all aluminum gone. Just fallen frames with the cranks and gears in piles under where the engines had been.
Anyway... the 400/466: should be fun! I would suggest a mild cam, Yoshi street or megacycle 131-00, or whatever webcam has that's similar.
Boring the carbs opens up the top end, but the stock rods are getting rather stressed above 10500 or so. You could take a second mortgage and put in Carillos of course...
Stock airbox is good, a free flowing filter might improve breathing, pods are a right bugger to tune but can work well if you take the time to tweak the carbs.
A Yoshi or OMT replica exhaust - and I'm sure there are others - will improve upper rpm power, both are rather loud in anger but tolerable when putting around the neighborhood. Many love the stock exhaust and it's not really bad.
Suspension should be upgraded. Good shocks for sure. The forks are thin and flexible... but good springs, new seals, and some fiddling with fork oil viscosity is worthwhile. Upgrading is an option: Honda 450 triples are the right offset and their forks are much better than the 400F... but are getting rare. I have seen sportbike triples and forks on a 400, it looks like too much work for me and I don't know what the geometry does to handling.
Tires - the stock rims (1.65/1.85-18) are too narrow for tires much wider than stock, but a 3.5 (90 metric) is ok up front and a 4.0 (100) works on the rear. You need wider rims to go bigger without rolling the tire profile under. Much more than a 90 may not fit into the forks, maybe a 100 will?
The front brake is sufficient but not excellent. Not much is possible because of the very limited space for a caliper between the fork leg and the spokes. Good pads, SS lines, and a drilled disc are pretty much all that's usually done. The front brake (and all Honda SS discs of that era) is somewhat scary in rain but drilling it gets rid of the 1/2 second of "CRAP! NO BRAKES!" with a cold wet rotor.

[MotorFist]

Thanks for all the replies everyone!  I've reached out to MReick to start the headwork process and will look in to getting the carbs bored as well.

Now time to go work on the garage so I have somewhere to tear the bike down!

[RAFster122s]

Josh,  that is a heartbreaking photo of a couple of beauties.  I hope insurance covered a lot of the loss.
Sounds like a fun build for the wife and a crusher for your son's bike as I am sure he was waiting with baited breath.

David

[innovativems]

How goes the build?


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[MotorFist]

I'm still quite a ways out.  I work in the snowmobile industry so winters are pretty busy for me.  Plus I have to finish roughing in the electrical in the new garage so I can get it inspected then install fireplace and put in lights and blah blah blah!  I am hoping for a down afternoon so I can pull the motor and get the head sent to Mike and the rest to my engine builder that I use locally.  At least get something happening. 

Off to a slow start, but thanks for asking!

Josh