Topic: 1975 CB400F -> Project "something fun to build and ride"

[gsnorcal]

I just saw this on some other moto forum, so perhaps there is hope???

VHT aluminum exhaust paint. Turns brown at first and you get all pissed, then the brown goes away and it looks nice.

I'm not holding my breath just yet.

Dave

[gsnorcal]

I'm pretty sure it's the clear coat that is turning brown. The areas that I skimped on the clear (such as the underside of the fins) aren't browning. Also, I never cleared the breather cover, because it was my test piece that I did before the clear arrived in the mail. It's not turning either.

I'll be on the phone to VHT on Monday, but I'm sure they'll just have some easy out--blame me on prep or whatever. Not sure what I'd expect them to say anyway.

[Syscrush]

Relax.  The good news is WAY more important than the bad in this case.  The bike is running right, looks awesome, and you've got a very high spec front suspension and brakes, and an impossibly cool survivor paintjob on the tank.

I'm not an expert on these engines, but those temps sound just fine to me based on my experience with Suzuki air/oil-cooled I4 engines.

Ride it for the rest of the summer and fall and see what happens with the paint - you can fix it up over the winter, there is a solution somewhere.

CONGRATS ON AN AWESOME BUILD!  Stop trying to talk yourself into being unhappy.

[gsnorcal]

Relax. 

Stop trying to talk yourself into being unhappy.

Good advice. I'm on board with the "next winter" program. I haven't "rushed" per se, but I have chosen to leave some things undone until next winter, just because riding is more fun and the season is now.

Thanks again for the encouragement!

Dave

[Syscrush]

Thanks again for the encouragement!

It's a great bike!  Now ride it and be happy.

BTW - I disagree 100% with whoever made the comment in the video that it's not loud enough.  I've had loud bikes and cars, and the main thing it does is make me paranoid about cops and afraid to go WFO.  Yours sounds great, and those pipes are beautiful to look at.

[gsnorcal]

BTW - I disagree 100% with whoever made the comment in the video that it's not loud enough.

Me too!

I probably didn't highlight it enough in my earlier post, but the bike is functioning beautifully! I couldn't be more pleased with the suspension upgrades and the front brake's operation. The bike turns better now, too. She's purring!

 

[FunJimmy]

Hey Dave

Wow, you sure get a lot done in a short period of time. The bike looks great and sounds sweet too. Sorry to hear about the engine paint. That’s pretty frustrating after all the crap you’ve been through with the POR15 only to have more disappointment with this stuff.

Can’t help but notice how may time you rave about the brakes. For a single disc, they really do work well on these old lightweights Eh? You don’t find the 11mm master cylinder too soft for your liking I hope.

Anyway, it’s riding time and you should get as much of it in as possible. You can get back into the shop again next winter and sort out anything you’ve left undone at that time. Let’s meet for a beer somewhere in Oregon to compare notes.

Cheers
FJ 

[gsnorcal]

Can’t help but notice how may time you rave about the brakes. For a single disc, they really do work well on these old lightweights Eh? You don’t find the 11mm master cylinder too soft for your liking I hope.

Hi Jimmy,

I like the 11mm. I seems like a good match for this bike/setup. It's sort of like you don't get the power of the big brake unless you ask for it a little. A light pull and the bike feels like a "normal" bike, not overwhelming, but pull with just a little force and you are rewarded with very authoritative stopping. Of course, hard to put the feel into words. Suffice it to say I'm VERY happy with it.

Oregon sounds like a great idea! Let me get a few more "confidence" miles on the bike and I'll start heading north!!!

I should say this, now that I am sort of "phase complete"... Your bike's level of refinement and finish is ASTOUNDING. I have a whole new appreciation.

Dave

[gsnorcal]

I rode another 30 miles or so on Sunday out in the country. Man, what a FUN BIKE!!!!!!!! 

I can't believe how awesome the mods are. The handling of the bike with this front-end is even better than I had hoped. Pure joy!!!

And the motor is really purring. I need to fine tune the timing, just because I haven't yet. And synch the carbs. The only running problem I noticed on Friday is that when the bike got hot, she had a stumble off idle. I suspected the 42 pilot was too big. So, on Sunday I brought tools with me and started backing out the air screws once the symptom started. At 3 turns out, it's almost gone. So, I'll put my 40 pilot in next.

Dave

[gsnorcal]

I got off easy today. What luck!

http://forums.sohc4.net/index.php?topic=91924.0

[gsnorcal]

Yesterday my friend, who is also the previous owner, came by to see the bike for the first time. We did a little photo shoot. He's the camera guy.







Then we went off for a ride. It was great to let him ride the old girl again and to also get his feedback about how the bike feels compared to original. Great fun!

Dave

[Greggo]

You sure did get off easy Dave!  The bike came together nicely, I bet your friend is happy to see its reincarnation.

[gsnorcal]

Today was tune-up day after riding the bike a few days last week. I re-torqued the head bolts (minor scare linked to above). Re-adjusted the valve tappets after that.

And tonight I got my timing all dialed in. I got a dwell meter and timing light from Amazon cheap enough. It took a while and a lot of reading and digesting of everyone's tips for me to get it figured. I had one of those "sloppy" points plates. Instead of just rotating, it could also move up/down/left/right. So, I read about shimming, but then saw a post about peening the retaining castings. I went the peening route since it's more permanent and repeatable. Now the plate only rotates and is held firmly even when the retaining screws are loose.

Following some other tips, I got 1-4 dialed in first, gap then timing, then moved to 2-3, gap then timing. I checked it with a timing light and also with a dwell meter. It's all looking good and sounds to be running a little better.

On Wednesday I'm borrowing a manometer at my friend's shop and will get the carbs synched.

I also hooked the oil cooler back up. And I deflated, lubed, and re-inflated the tires. The beads were not seated squarely making them run un-true.

Dave

[gsnorcal]

The bike came together nicely, I bet your friend is happy to see its reincarnation.

Thanks Greggo.

He was thrilled with the amount of work and care I have given the bike so far. Naturally, when it comes to aesthetics we don't have the same vision, but I think he appreciated where I have taken the bike. He loved the front brake and the clipons. He didn't love the rearsets. Overall he thought the bike had the same power that he remembered when the bike was newer (like in the 80's), but didn't seem the think the 466 added noticeable power. Maybe getting the timing and carb sync straight will fix that. He thought the suspension was improved, but that it needed a little front-rear balance, so we softened the front end dampers up to give that a try (I haven't ridden with that setting yet).

Overall, he was really pleased with how much attention the old gal has received during her 6 month stay in my garage.

Greg, when are we gonna ride?

Dave

[Syscrush]

Overall he thought the bike had the same power that he remembered when the bike was newer (like in the 80's), but didn't seem the think the 466 added noticeable power. Maybe getting the timing and carb sync straight will fix that.

Don't give that any credence - there's nothing less reliable than a butt dyno, especially when emotions and nostalgia are added to the mix.

[gsnorcal]

Been slowly working out the kinks...

Yesterday I went for a ride into San Francisco. As the highway ended and became urban, I realized my throttle was stuck open (extremely high rpms). With the help of the kill switch, I pulled over, kind of sorted it. Then it happened again. That time I found the root cause. The "B" or "safety" cable was loose at the carb end, and it's housing was actually holding the carb open a bit. So, I just removed it for now. I need correct length cables for my setup.

Then, on the way home, just as I got done with some highway miles I came to my first stop. Now the bike wouldn't shift into 3rd. I made it the few blocks home. Luckily, it seems to have been a loose bolt in my shift linkage. Shifted fine after that correction.

Today I performed a vacuum sync of my carbs. They were way off. Now spot on.

Finally, I think I have a little bit of the old "hanging idle" problem (slightly high rpms). Sometimes she races a bit when I get to a stop. Then I can sometimes get her to settle back down. I'll look for an intake air leak next. With new boots and o-rings installed, it seems unlikely to be more than an assembly problem if that's even the cause. Otherwise I'll keep looking.

I'm definitely having fun out riding! And it's kinda fun to work through all the little things. It's a great feeling to have built the bike myself, so that if anything breaks, I know how to fix it.

Cheers,
Dave

[Greggo]

The bike came together nicely, I bet your friend is happy to see its reincarnation.

Thanks Greggo.

Greg, when are we gonna ride?

Dave

Well, hopefully someday I'll have enough time to use my bike for anything aside from commuting to and from work!

[cgarbe]

Do you have pictures of the electronics/battery? I just started building a 1975 CB400F Cafe Racer and am not really sure where everyone is putting the battery and electrical components?

Thanks and awesome build!

Chris

[gsnorcal]

Do you have pictures of the electronics/battery? I just started building a 1975 CB400F Cafe Racer and am not really sure where everyone is putting the battery and electrical components?

Thanks and awesome build!

Chris

I'll try to get some pictures.

[cgarbe]

Awesome! Thank you!

[gsnorcal]

Do you have pictures of the electronics/battery? I just started building a 1975 CB400F Cafe Racer and am not really sure where everyone is putting the battery and electrical components?

Thanks and awesome build!

Chris

Sorry for the late reply--been away on vacation.

Here is the battery box I built between the frame rails. The battery and all the wiring is in there, including starter relay, a single fuse for the whole bike and the turn signal relay. It's mildly messy, but also really simple. It's all gold-plated bullets with silicone boots.

Also, a comment on the battery choice. This battery is more than enough for this bike with this Electrosport reg/rec. I have confirmed this with an ammeter. At a cold, stumbling idle there is about a 2 amp deficit with the headlight on (8A out, 6A in). Open the throttle to 1500-2000 RPM and we see 10+ amps into the battery, so a 2A surplus (charging). And in practice, riding it, the battery has remained well-charged at all times. I say "poo" to the naysayers. Measure your loads and choose accordingly. I also wired the headlight with an OFF position, to conserve if/when needed. I typically start and warm the bike up with the headlight off.



The regulator/rectifier sits atop the rear wheel frame arch. I still need to fasten it properly.



If you read back through the thread, you'll see a point where I was concerned about rear wheel travel being limited by the common mod of just putting a flat battery tray between the frame rails. Indeed, you would run into clearance issues. The rear wheel breaks the plane of the frame by quite a bit, hence Honda putting that arch up there.

Dave

[lucky]

Centre stand = recycling bin. 

I'm glad someone else said it first.

Bad idea ,do not throw away that center stand. Many people restoring Hondas want the center stand. Extra money for lunch.

[gsnorcal]

Centre stand = recycling bin. 

I'm glad someone else said it first.

Bad idea ,do not throw away that center stand. Many people restoring Hondas want the center stand. Extra money for lunch.

Well, I still have mine. Send me some money. I'm hungry!

[gsnorcal]

Hi all,

I've started machining copies of some of the same parts that I used on this build. If you need:

* custom hub carriers
* big rotor adapters
* triple clamps
* complete wheel builds
* anything else...

Please let me know. I have 4 axis CNC capability in-house now.

Dave

[kajtek]

whoa.... very interested in custom hub carriers and rotor adaptors..

ashley