75 CB360 - bad omen "yatagarasu" build

MiniatureNinja

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cut down the instrument mounts off the top triple clamp. probably will finish this a little nicer - but I would eventually like to get a Ripple Rock dropped triple kit just not liking the $700 price tag right now

I am undecided about shaving down the bar mount holes as well - not that I will use them for anything. just more work

 

crazypj

Split personality, I fake being smart
Almost forgot, remember to soak the friction plates in the engine oil your going to use for 24 hrs or so. I used to 'wet' them and then put the set in a freezer bag (uses less oil plus keeps the dust off)
That's really nice yoke set but $700.00 is way too much for me (seems pretty expensive anyway) Of course, you have to start with some very large (expensive) chunks of alloy to be able to whittle down to correct size and shape. Haven't priced 2" thick 6061 for years, it put me off making them though. I've seen a few CB550 and 750's where the holes were plugged and welded then carved down to give a 'factory race shop' look but never on 350/360
 

MiniatureNinja

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crazypj said:
Almost forgot, remember to soak the friction plates in the engine oil your going to use for 24 hrs or so. I used to 'wet' them and then put the set in a freezer bag (uses less oil plus keeps the dust off)
That's really nice yoke set but $700.00 is way too much for me (seems pretty expensive anyway) Of course, you have to start with some very large (expensive) chunks of alloy to be able to whittle down to correct size and shape. Haven't priced 2" thick 6061 for years, it put me off making them though. I've seen a few CB550 and 750's where the holes were plugged and welded then carved down to give a 'factory race shop' look but never on 350/360
it will be almost a month before I'm ready for the assembly phase. I remember from the manual that the plates should be soaked for a minimum 1 hour. but I figured overnight wouldn't hurt it

now, I worked late into the night welding, and I'm not very good at it but I am proud of what I have accomplished


The bracket for the under seat electronics and battery tray, still needs holes drilled - spacers made of carbon fiber will have the tray sitting about 10mm below the frame


here is the tab for the front brake cable. Master cylinder will bolt onto a bracket utilizing the original coil mount holes - non-standard coils will be mounted lower probably where the keyswitch/horn mount holes are - again, hole needs drilled and tapped for cable adjuster


and the pièce de résistance: shock mount tabs and frame hoop FINALLY all welded up and square. this was much more difficult than I thought it would be but in the end it turned out great and I don't recommend anyone do it. it was probably completely unnecessary and a pain in the ass - shock mount slugs still need to be welded, once swing arm is done and mounted so I can figure out how long they need to be
 

crazypj

Split personality, I fake being smart
Rear shock mounts are really bad.
You should not have the corner welded it creates a stress point. (I tried to point it out earlier) You may be able to drill a hole in corner to 'convert' it to a buttress? All ther stress is now going into centre of tube.
Find Tony Foals book on chassis design, the relevant pages are available online and maybe on his site? (may also be on, Euro Spares Michael Moore's site?)
I looked it up
http://www.eurospares.com/frame.htm
 

MiniatureNinja

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crazypj said:
Rear shock mounts are really bad.
You should not have the corner welded it creates a stress point. (I tried to point it out earlier) You may be able to drill a hole in corner to 'convert' it to a buttress? All ther stress is now going into centre of tube.
Find Tony Foals book on chassis design, the relevant pages are available online and maybe on his site? (may also be on, Euro Spares Michael Moore's site?)
I looked it up
http://www.eurospares.com/frame.htm
I won't argue with you - you've been doing this much longer. I will have to look further into it.

I did read through Toney Foals frame mods page and it covered folded gussets and a way to stiffen the frame and basically said that triangle gussets as mounts have very little effect - I brought your point up to a fab shop (they don't do motorcycles, but they build offroad buggies and race trucks) and they said that amount of flex there will be near non-existent because anything behind that triangle bears no load, none - not even a tail lamp will be there

I pulled some inspiration from a DCC build, and This Build which both seam to have done the same thing I have
 

crazypj

Split personality, I fake being smart
If you really look close at the 'Sausage' (trust me, the original 'Savage' badge didn't look like 'savage')
Anyway, if you look close you can see the triangle is on the outside centre line of tube plus looks a lot like the original. You buggy builders are doing whats cheap rather than right. Any suspension mount is a high load area, you also have torque twisting the plate and 'flexing' weld as it's going to be offset. Correct thing to do would be make 4 plates total, weld them on the outside center of tube then have a bar to mount shock.Moving the mount inwards about 1" will also put them at an angle they won't like, the rubbers will be at or above maximum flex (unless you move lower mounts inwards or use Heim joints both ends of shock body to compensate for the angle)
I think Husqvarnan MX/Enduro bikes used that type of mount to narrow seating area, probably around 1980?
It will work as is but is highly likely to fail in use.
More bad news,
Diaphragm is damaged, looks like a screwdriver mark where someone tried to pry top off carb or something?
third pic is of JBM diaphragm, still trying to get a new one under guarantee. I've never had one break before but looks like the 'guarantee' is 'your SOL buy another one' so I'm no longer recommending them
 

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MiniatureNinja

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I have some turned mounts for the shocks, that stick out about 18mm, the shocks won't be at an angle - they will be straight as they are supposed to. Also, the mounts are not on the center of the tube, they are about 3/4 the way to the outside on the top tube, and cross the center line for the down tubes (since they are at a weird angle)

I brought this up in my post while mocking it up, that I was considering using 4 plates on the outside of the frame how you describe, but decided against it as I saw 10 builds the way I have done it, and only 1 the way you described. TC bros, Dime City Cycles, Cognito Moto all have "kits" that do it this way, and i called Cognito, they assured me it was plenty strong for a bike shock mount. if it were indeed a gusset on a frame for strength or a car - things would be different


I very much appretiate your input and I am not dissagreing or discounting it. We've talked about "experts" before that steer people in the wrong direction and I know you're not one of them. i just feel confident in what i've done so far. If it turns out to be a problem (and it will be monitored) then I can always redo it... it's just metal
 

irk miller

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crazypj said:
You buggy builders are doing whats cheap rather than right.
I'm not arguing whether his bracket is right, but those guys are building rigs that go through a helluva lot more intense abuse than what we will ever throw at these motorcycles. And they cost into 6 digits. I trust those guys.
 

MiniatureNinja

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irk miller said:
I'm not arguing whether his bracket is right, but those guys are building rigs that go through a helluva lot more intense abuse than what we will ever throw at these motorcycles. And they cost into 6 digits. I trust those guys.
I was doubting what I did - and I brought my frame into them, wasn't just a phone call too.

still doubting it when someone is so adamant about it. :-[
 

crazypj

Split personality, I fake being smart
I use CAD, (cardboard aided design ;D )
I'll draw a picture as it's way faster than trying to explain and quicker than a computer 'drawing' .
What thickness plate did you use? (1/8", 1/4"?)
Here's a very basic pic of what you have and what you sould have. The right side (IIRC) is about 4 times stronger but requires more welding plus is a little more than half the weight of a single 1/8" plate but lighter and stronger than 1/4" plate. Frame tubes share the stress on each side instead of all the stress on the centerline one side. (the extra lines are to represent the down tube, left it out on right side drawing) It's a quick sketch so I didn't label all the 'movement' arrows


irk miller said:
I'm not arguing whether his bracket is right, but those guys are building rigs that go through a helluva lot more intense abuse than what we will ever throw at these motorcycles. And they cost into 6 digits. I trust those guys.
I would like to see some pictures of what they actually build, 1/4" wall thickness pipe would be lot stronger than the 0.080" frame tube Honda use. Lot of people will tell you one thing but actually do something completely different. If they don't have a structural engineer or at least copy design that has been through 'the math' they could be just jumping on a band-waggon with no real idea what they are doing.
The welds themselves don't look too hot for a 'professional' welder.
I've seen better from people with zero welding experience after a 3 hr course (yea, I was certified MIG at one time, many many years ago)
 

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MiniatureNinja

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I have been getting jerked around by the guy who promised me he could powdercoat my stuff. it's VERY hard to find powdercoating in CA, let alone Northern California. No one does it (regulations?)

so I painted my swing arm and engine mounts to see if I like it.
satin black VHT frame/chassis paint. turns out durable and nice - just not sure if I like the satin or if I want to go gloss.

 

teazer

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+++ PJ is correct there. Have a look at Tony Foale's book for a little more insight into frame brackets and gussets.
 

MiniatureNinja

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crazypj said:
The welds themselves don't look too hot for a 'professional' welder.
I've seen better from people with zero welding experience after a 3 hr course (yea, I was certified MIG at one time, many many years ago)
that's because I welded them, after about 100 hours of watching how-to videos and about 5 hours of practice on scrap metal.

again, I was told it was not perfect or "ideal" but will indeed work and at least the match the bublegum looking welds honda did on the rest of the frame
 

crazypj

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In that case, welds are pretty good as it takes practice to make them pretty as well as strong.
Probably turn up amps slightly and turn down wire feed so you can burn in 'pretty welds' (you can work slower, I still remember the first time I used MIG, set up for 3/16" plate, I tried using on 1/16" sheet ;D )
I thought you were paying buggy makers to weld it. :-[
Ca. is a bit OTT with some hobby stuff, seems they only want 'professionals' with crazy amounts of extractors, scrubbers, etc to do 'anything' ($30,000 paint booth, etc)
I guess the DIY powder coating stuff from Harbor Freight isn't even available there?
There shouldn't be any volatile compounds with powder coat, unless you overheat parts as it's basically a thermosetting plastic 'covering' and the powder should be pretty inert? (although I'm sure someone can 'educate' me on the finer points?)
 

The Jimbonaut

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If you can find SprayMax 2K aerosol paint in your part of the world then it's a great option too. Very durable indeed. Pretty sure it comes in gloss, satin and matte - the can has a button on the bottom which when pushed activates a hardener inside. You then have about 12 hours before the paint goes off in the can, so line up everything you need to paint as it doesn't last inside the can unlike a normal aerosol.
 

MiniatureNinja

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crazypj said:
In that case, welds are pretty good as it takes practice to make them pretty as well as strong.
Probably turn up amps slightly and turn down wire feed so you can burn in 'pretty welds' (you can work slower, I still remember the first time I used MIG, set up for 3/16" plate, I tried using on 1/16" sheet ;D )
I thought you were paying buggy makers to weld it. :-[
Ca. is a bit OTT with some hobby stuff, seems they only want 'professionals' with crazy amounts of extractors, scrubbers, etc to do 'anything' ($30,000 paint booth, etc)
I guess the DIY powder coating stuff from Harbor Freight isn't even available there?
There shouldn't be any volatile compounds with powder coat, unless you overheat parts as it's basically a thermosetting plastic 'covering' and the powder should be pretty inert? (although I'm sure someone can 'educate' me on the finer points?)
I was so worried about burning through the thinner frame that I didn't want to move too slow. it's a fine line. I certainly could have turned down the wire speed - and more practice is needed to get to know the machine and settings (it's a 230v 50a Lincoln and using 100%co2 and .030" wire)

Unfortunately I don't have the space or heat to do my own powdercoating

But... i can buy spraymax 2k paints on Amazon and I plan to use that for the tank and seat cowl.


I second guessed myself AGAIN and went over the semi gloss with gloss... and it turned out OK but not perfect. That's one area I know I can do better in and so I'll have to redo it next week when the weather is warmer (snowing here in NorCal again)
 

jeff4uk

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Nice job there mate, I’m doing a 360 at the moment but haven’t put it on here yet as time is short ,great job on the hoop B.T. W
 

crazypj

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Semi-gloss is different, I used it on the T305 as it looked better than full gloss (plus it's easier to 'touch up' when needed ;D )
 

MiniatureNinja

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finally got the gold chain in. hard to tell under all the grease and wrapping but yea it's gold this time.
now I think I should have ordered a gear directly from RebelGears.com so I could get one in black.

so I may do that with a 33t 520 gear
 

MiniatureNinja

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OK take two here

I don't like admitting mistakes but it's important to take other's advice. I asked for it earlier but got no input until after I posted what I did, which is frustrating but hey... it's just metal. I have an angle grinder and cutoff wheels.

After looking at some other ideas and input from P.j. I've mocked up the following in fusion:


any input this time? I plan to do this on Wednesday!

I have These Shock Mounts from DCC and I really want to use them. I don't have to... but the design above allows them to be used and it's what I planned to use all along
 
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