Author Topic: CB400F Project  (Read 2606 times)

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Offline noexit

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CB400F Project
« on: December 04, 2009, 11:49:13 PM »
I thought I'd already posed a build thread on here, but I didn't. So here it is.

About a 2 years ago, a friend bought a CB400F. He got a really good deal on it, plus he got two parts bikes. He didn't need them, nor did he have anywhere to store them, so he gave them both to me, with one title. There were two complete engines. One in a kind of rolling frame, and one in a half rolling frame.



So that and a small box of parts is all I got.

I don't know what the previous owner was going to do with them, because the one that looks most gutted, was the one with a title, the one with a less thrashed engine, and the one with a straight frame. Only problem is that the side stand was broken off, and took a chunk of tube with it. I'll have to cut the side stand and some tube off the bent frame to weld in.

So engine first. Took the top ends off to get them out of the frame. I don't know how easy it is to get them out of the frame with the top end assembled, but disassembly sure makes it easy.


Bagged and tagged everything. Large items were wrapped in news paper and everything was stored in a big plastic tote. I spent last winter polishing side case parts, but not a whole lot more. I moved into a new place earlier this year that has a decent work space, so I started work on case. I stripped and cleaned the case and oil pan, and painted all the bits to paint, cleaned the cylinders and head as best I could. They look pretty good, but I have no pics.



I misread the torque specs on the M6 bolts on the case and broke one and stretched the others, so I have an order in at my local shop. They should be in Monday, then I can seal and bolt the case halves together.

Today was visualization day. I went to my dad's shop, where the frame is, and set it up so I could stare at it. I spent most of the day trying to figure out what I was going to do with the battery box, air filter, etc. When I stuck the seat on the frame, I realized how much bigger the 400F tank is than the CL350 tank that I stuck on there. I guess I need a tank...


Spent the rest of the day trying to learn to MIG weld. I think I like TIG better.

Offline clayman74

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Re: CB400F Project
« Reply #1 on: December 05, 2009, 12:21:45 AM »
spent my whole life on MIG and have yet to learned TIG. im jealous.

excited to see how this turns out!

Offline noexit

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Re: CB400F Project
« Reply #2 on: December 05, 2009, 10:06:13 AM »
I learned TIG when my dad bought a machine and picked it up pretty quickly. I practiced on some scrap for a while, then welded up a rotisserie for my Karmann Ghia body to sit on, and it turned out great. I like having the voltage controlled by a food pedal.

I guess the part of my frustration with MIG last night was that I was trying to butt weld ~22 gauge sheet metal. I got a lot of burn through and warping. When I tried some 1/8 angle scrap, it went okay. I didn't quite the the penetration I wanted, but I only made two welds. I feel more comfortable with the control I have over TIG for welding the kickstand on my frame.

Offline Ogri

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Re: CB400F Project
« Reply #3 on: December 06, 2009, 02:20:00 AM »
Haha,, TIG welding has spoiled you! If welding with TIG is like using a surgical scalpel then MIG welding is like using a chainsaw.

Those crankcases look very good indeed & personally, I like the CL tank on it - I don't have a problem with a bit of space around it.

Will it be a cafe-racer or chopper ?

Offline noexit

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Re: CB400F Project
« Reply #4 on: December 06, 2009, 09:45:24 PM »
I'm going for a clean Cafe look. I like the squarish look of the stock tank. The friend that I got the bikes from has one that he's going to give me. For the electrics, I'm thinking about making a shallow tray in the location that would be over the stock battery/air filter box, and removing the battery box and all the mounting tabs for the side covers and everything. I'll probably mount a solid state regulator/rectifier under the tray, and have the battery, blinker and everything else in the tray keeping a thin profile under the seat. I'll make a fiberglass cafe seat, using the existing hinge and lock.

I haven't really thought about color yet. I kind of want to play with gilding with gold leaf for lettering or pin striping on the tank. Maybe a pearl or something for paint.

Offline clayman74

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Re: CB400F Project
« Reply #5 on: December 06, 2009, 11:39:03 PM »
ugh color... thats one of the toughest choices to make.

Offline noexit

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Re: CB400F Project
« Reply #6 on: December 07, 2009, 08:21:11 PM »
So I've decided that I'd better figure out where I'm going to put the battery, and what I'm going to do for a wiring harness. I'm thinking I'm going to do my own custom harness, so I need to get it mocked up first. It all depends on where the battery is going to go though.

I started off by discovering the LiFePO4 battery as used in the SpeedCell Battery. A couple hours of interweb searching, leading me to this thread on another motorcycle website has convinced me that if I buy 4 2300mAh A123 LiFePO4 batteries from eBay for about $8 each, I'll have a battery pack about 4"x2.5"x1" that will be able to charge off the bikes charging system and start with the starter. That's a perfect size to either fit in the stock plastic tool tray under the seat, or in a custom tray.