Topic: IDK Numero Dos - 1975 Honda CB400F

[minimo]

A couple of my intake manifolds had a slight crack/break in them so rather than fork over an arm and a leg for a new set I thought I’d give this heat-shrink repair technique a shot before I give up my appendages...

Ordered a length of this: https://www.mcmaster.com/#9920T16
After watching a bit off of this:

We’ll see how this goes....



Sent from my iPhone using Tapatalk

[minimo]

It was the rubber that had cracks. Aluminum is well intact.
Those Phillips screws were a real bear to remove though. Definitely prepared to switch those to socket heads.


Sent from my iPhone using Tapatalk

[strynboen]

yes it are a no go..

.that scrinck rubber can only Work one time..and then it slovly hardents up..and crack...think the old intake ones ones are teight..even they are a bit cracked..or dry hardnent..
i reused mine..just gave then some rubber softeners...

[minimo]

Ok ok. You guys have convinced me - this heat-shrink idea ain’t gonna work. Fine :-)
It was mainly the rubber on these manifolds that showed some signs of cracking that I thought I’d address. And maybe they’re not that bad after all? I mean, this would probably be the worst of the four:

Notice the crack in the rubber at the flange. All the others have the rubber around the edges of the flange flaking off (mostly at the screw areas). Taking a closer look inside these manifolds I see that the aluminum part rises up about another 1/4” above the flange surface so I’m probably safe on the rubbers as long as these cracks don’t break through the inside surface (if that makes any sense?), right?
What do you guys think? Have you seen worse? Think these might still be usable? One way to find out? Don’t bother?

Unfortunately I don’t have an impact bit version of JIS and ended up mangling the heads - these suckers were seized. So I had to try and extract some of these mounting screws with my hammering impact driver (which by the way wasn’t easy hammering through the frame triangle) and then to my Grabit Pro bits, and both were unsuccessful. So then I managed to get my bull-nosed Vise-Grips and with some generous application of PB Blaster around the heads I was finally able to set them free.

I’m gonna replace these JIS screws with stainless steel socket heads and will be applying some zinc anti-seize to the threads as I’ve learned is the thing to do to minimize galling...


Sent from my iPhone using Tapatalk

[MoMo]

It looks as though the rubber is not split all the way through so you should be good to go as is...

[seanbarney41]

Best to replace them now and not waste your time with the carbs on/off again.

I said it before, I'll say it again... Boots are not expensive but are vital to a properly running bike. Your time, your choice.

+1...even if they are expensive...I wouldn't trust those as far as I could throw 'em

[strynboen]

try to   prop/ close  it  in the end ..and fill fuel inn..and thek for leak....just find somthing" massive shaft thing" vith the carb diameter..and fit it.to close up teight..

[minimo]

Whoa boy. It’s been a while. I don’t know what got into me but I suddenly felt compelled to take a stab at some spot welding with my trusty Harbor Freight-issued stick welder. I had grounded off some side cover tabs and somehow got a little carefree and punched a slight gash in the triangular section; the right leg of the triangle on the left side. What could have easily been patched with some epoxy putty has essentially become a rusty hole-ridden can of worms. If there’s any regret so far this year - it’s early yet - it’s this right here.
Here, take a look:

Let’s get a little closer on the right, shall we

Here, a little bit closer

Ouch.
So I’m told those weird porous spots are indicative of rust on the inside but I think it’s more incompetence of the welder; me.
I’ve read around the forums here and beyond and I dunno, I think this is pretty unique. I’ve gotten some opinion from some engineers and more apt welders at work and all have different ideas and opinions - none of them are bike builders. What say all of you? I’ve already looked around for some replacement frames on eBay but those look rusty as heck and I’d like to try to see if my frame is somewhat salvageable. Ideally I’d like to repair this to make it not look like anything ever happened at all but I also don’t want to compromise the structural integrity more than I probably already have.

[minimo]

Btw, I did end up purchasing new manifolds. Two steps forward still yet major steps back (with my frame). The going mantra.


Sent from my iPhone using Tapatalk

[strynboen]

a good rule...dont weld..if you not can veld....you have to learn it before make safty relatedet vorks...it takes some time and praktis velding to get a idea of burn through..inof..and not to meld through..adjusting the amps..and the moving and the rigtt hardvare...those elektrodes(velding rods) is not all the same..

i learned it in school..ve had a metal vork as a alternative to the vood vork as vas the normal handvork..somthing they not have today..and my sons missing it..all is computing today..no hands Work..and that kills the metal vorkers in the future


take some thik metal pieces and learn to veld...its easuer to learn on small tubes /pieces angel iron or flat iron and pieces of tube..and make some velding..that you had made is dangerus to ride..and look like #$%*...
gas velders co2/argon use 0,8 vire is the right Tool to veld frames...stick velders id mostly for massive metal..hard to veld tubes vith..for non proff

the frame is fine.just cut all strange velds and blubs aut..and veld a new tube inn..its soft tube so all Black iron can be used..and no problem if it are a bit thikker valled..but dont cut straight throug..cut in the length and halvh the tube..its easyer to veld on the long vay of the tube ..

[minimo]

Thanks, strynboen.
Thanks, calj737.

I’ll back off from this and get a pro with a TIG.




Sent from my iPhone using Tapatalk

[minimo]

forks is not made for boots..but i have used them on more cb..so it can be done..
use the konnektor box..and put a BIG pod at the back side..then you got the best from both..and it can be set up looking cool...and yes this bikes is hell to get running on pods

Stynboen, I wanted to come back to this idea of using the connector box and putting a single big pod filter at the back as opposed to four small pod filters. Do you have a cool pic or link to showcase this? Is this on a 400F?

[strynboen]

it vas on a 500/550..but can easy be done..just make a plate cut a 50/60 mm hole and veld a tube on..vho fit the maxi pod..and drill 4 holes in the corners--and bolt it on the filter housing..then you have a autdoor filter..
you can also make smalller tubes and have 4 or 3 or 2 smaller filters as you like..

[minimo]

Thanks for that, stryboen.

I'm making such grave efforts though to keep the triangle clear and opened. If I did this mod, then the triangle might be obstructed, like this:



...which isn't bad, it's just not the look that I'm after.

[minimo]

Spent some time recently trying to nice up the wiring a bit. It’s always a zen-like experience I have doing the wires. I sorta lose myself and lose track of time. I seriously spent the entire weekend cutting, tucking, and extending wires all weekend and I’m still not done.

I was able to make a gauge mount for my Koso TNT-2 and here’s the dry fit test:



Don’t mind the tape - it’s for protection.
I’ll be painting the gauge-mount bits or maybe anodizing the parts a matte black; the bracket is 1/8” aluminum.
Personally, I’m feelin’ the side view but I can’t help that the top view, rider’s view, the protrusion seems quite pronounced. I would still need access to the mode buttons on the gauge (located at face front). I have plans to trim the bracket length a bit - a half inch which should still allow for access in the buttons. We shall see.

Making moves again on this 400Four build.


Sent from my iPhone using Tapatalk

[minimo]

I’m having an issue with the neutral. It seems the only way I can get the push button start to engage the starter is by pulling in the clutch, which means that the neutral switch is working somewhere, right? However, when I have the gear in neutral I’m not getting the N light to illuminate on the gauge, which follows that the push button start doesn’t turn the engine over; push button does momentarily shut off the headlight and running lights.

I have the Lt Grn/Red wire under the left side cover connected here

I’m getting continuity from this point to the bundle under the fuel tank. Lt Grn/Red connects to Purple on the Koso gauge

I tried cleaning the silicone diode by the reg/rect. I even tried unplugging the diode and I’m getting the same result by pulling in the clutch.m and engaging the starter.

What am I missing?


Sent from my iPhone using Tapatalk

[strynboen]

is there diode light in the unit..then it can give problems..it block for the pover flow to get to the solonid..like diodes does..light diodes have some kommon vith diodes..theu just lights as a bonus..but still blok for flow in one direktion...and your erth kontrolled safty system make the power runs from positive to ground..oppersit then the rest of the bikes idiot lights..

[minimo]

Thanks, strynboen. Would a set of these Morimoto Pindicator lights give the kind of problems that you’re suggesting?

I had read elsewhere too that the Neutral switch might be the culprit. If the 750 is anything similar to the 400f:

Check the neutral switch for a 750 under the engine on the left side by the shifter cover. Ground the lead, if the indicator lights, the switch is bad. If it dont light, check the bulb. If it still dont light, check the connector in the headlight shell or the engine harness connector.

Anyway, I may have to come back to all the wiring again since I’m tearing the bike all down again to the frame - gonna try to start tonight. I found a guy who will fix my dumb welding mistakes and he wants it down to the frame so he can clamp it all down on a table. Makes sense. Anyway, this will help too since I plan on getting the frame and other parts sandblasted/powdercoated.


Sent from my iPhone using Tapatalk

[strynboen]

looks like the diagram is giving negative impuls for the neutral light..so that vill not give any problems.
the signals light led can give other problems..but use a elektronic blinker relæ..and take care of the singel/dubbel  kontrol light..vill cure any problems in that setup..have been done before...(somtime some diodes must be used to split the left from right side..but that problem vhen ypu gets there

[minimo]

Thanks, strynboen.
I do have an electronic LED blinker relay set up in this. What is the single/double control light light you’re referring to?

While I had the frame off for repairs, I got into some late night painting of some other bits.

Here’s a before and after (I wasn’t hating on what it was before but I was bored).



Rattlecan black - Duplicolor DE1635 engine enamel with ceramic. Such a sweet sweet smell.

[strynboen]

mine is the euro modell..have not all that safty/main light turn off....stuff..make it simpel and easy..if there not is power to the solonid..try to go back from it..untill you find power or ground..

[minimo]

It is nice to have friends who know how to TIG weld. I was able to get my frame fixed with some chromoly tube. With slight bend to match the upright on the other side




Figured while I had access to some fabrication, may as well get the rear hoop in order. Even got handy to integrate one of those LED tron lights




I’m a little concerned that I may have clearance issues on large bumps to the rear but we’ll see once I get my slightly taller shocks on there. Next worry is how I’m getting a license plate to look nice mounted back there (and get that to clear too). Thinking of fabricating something to look cool to act as both a fender and a license plate mount. We’ll see.

Aiming to get this all moving and hopefully a light ride out before I strip it down again for powder coat.







Sent from my iPhone using Tapatalk

[spuds]

great looking profile.

[strynboen]

you get vater in the frame..so drill some drain holes...

[SOHC4 Cafe Racer Fan]

You shouldn't have clearance issues with the angled hoop and taller shocks.