Project Gretta....seat action.....

[chrisf]

Re: A way to waste money: The evolution of a confused '74 360

Kanticoy is right: learning to weld is just a matter of sitting down and doing it. Troy is spot on as well. That is how I initially learned to weld. For two months, I'd weld a bead, then cut it open and see how it behaved. After a while, I got comfortable with the whole thing and got to real work. I learned on a MIG though; not so much a fan of stick/fluxcore welding--though I certainly understand why Troy uses it.

On that note, did you get your buddy to check/x-ray your swing arm? That still makes me anxious. There is just so much stored energy in those mono-shock springs. On that se7en I built from scratch, I used R6 dampers. Those had a spring rate of 554lbs/square inch. Stout stuff man. Be careful.

On a plus note, the upper mount looks really good. It looks like it should transer the loads effectively.

Looking at the system, one can visually tell the rear suspension is regressive--meaning it gets progressively softer as the swing arm travels through the arch. This is typically considered a bad thing, though I'm honestly unsure how that will effect your bike. I am very interested to see how she rides, so keep us updated!

Oh, yeah, flap wheels are awesome. I don't even buy grinding disks anymore. I follow up the flapper with roloc disks.
--Thanks, Chris

 

[cafePete]

Re: A way to waste money: The evolution of a confused '74 360

Thanks for the flap wheel tip. What grit would you
go with on the frame ( stock brackets ).
Thanks

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Hey Chris, thanks for the reply man.

I did in fact get the swingarm X-rayed. Everything is very well penetrated now. My buddy TIGed all of the joints, and then went back with a high build MIG over that to create joint contour. It is very very strong now. I thought a lot about what you were saying with the tubular structure, but I have seen various tubular monoshock swingarms in production that work effectively. I feel that mine is plenty strong enough to withstand the load. The best examples are the 05-06 Ducati SportClassics.

I designed the suspension to be mixed/regressive for a reason. In a regressive system, a higher spring rate is needed in order to make the suspension handle effectively without slop. The Ducati shock is designed for a heavier bike and therefore has a higher spring rate than would be desired for my bikes weight. the Duc is 410 lbs dry, and the cb360 is stock 380lbs dry. The cb360 is actually much less than that now with all of the excess parts removed. So the shock would obviously be overkill for my application when mounted in a progressive manner. The swingarms are the same length with similar geometry (mine vs. the stock ducati), but I am guessing there is at least a 50lb. weight difference if not more...which is a lot in terms of suspension geometry and bike weight. It would have performed more like a hardtail. So I designed a regressive system for the bike that still performs within the arc of suspension travel to absorb some of the spring rate that is generated by the Showa shock. It actually feels very similar to stock now when I jump from my stock 360 to the new modified 360. I think that because of that it will handle very well. I do have plans to build a few gussets for the bottom swingarm mount just for bracing purposes, and they will help transfer the load of the mounting point. I am very confident, and am trying my best to make sure that each part is overly strong before road testing it. I don't want you to think I'm being overly careless with my life! I really appreciate your input though man, I respect what you have to say for sure. That Se7en is badass BTW. Love what you did there.

And Pete, I would start with a cut off wheel to get the tabs down close to the frame. Be careful not to get to the frame with the cutoff though, it will bite hard and leave holes. After the bulk of the bracket is removed, then use a 60 grit flap disk to grind it down smooth. Then like Chris said, use a roloc to finish it off if you want. It's basically sandpaper on a disk that spins, and it comes in all different grits. 120 or so would smooth it down very nicely. Hope this helps.

Thanks again Chris, your input is appreciated.

 

[chrisf]

Re: A way to waste money: The evolution of a confused '74 360

Hi:

Everyone has a different approach to these things, which keeps life interesting. My comments were based on my experience with this stuff. If you're comfortable with what you've got, you should run with it.

Neither here nor there now, but I--personally--would just tacked everything up with your stick/flux welder, then taken it to your buddy for final welding. Jamming too much heat into a joint is not the best idea. Since you already welded everything and sanded the joint down, going back over with the MIG should have been more than enough. I probably would not have sanded each joint afterwards--well, unless the MIG welds were ugly.

On the suspension front, I understand what you're saying WRT the weight difference. That's where where the math formula gets a bit complicated. You have to determine the proper leverage ratio for the bike weight and take into consideration the damper angles; the two are entwined. Does that make sense? What I'm saying is that you could have gotten the proper wheel rate and still had a progressive system. I hesitated when you were mocking this stuff up, but I really should have sent you the math/trig formula to get this right.

You've got what you've got now, so I say give it a go and see how she does. You may like the way she feels. Because you got the upper mount right, you can always go back and do a new swing arm later. If you do decide to redo your swing arm, PM me, and I'll walk you through the process.

--Thanks! Chris

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Thanks Chris.

I appreciate it man, and honestly, I'm glad that I have done the research and "winged" it on my own here. It's the only way I'll learn the way to design these things the right way. I read a book called "Motorcycle handling and chassis design: the art and science" By Tony Foale before starting this built and am applying my knowledge that I learned there to designing custom suspension. I started a lot of "first time" procedures on this one, and I am learning tons at a very fast rate. I'd love to sit and "shoot the shit" with you about a lot of the theory when it's all said and done. I'm not saying that everything I've done is the right way, or the best way. i am looking for the effective way, and I think I've achieved that.

The next bike I build, I will be doing something similar, so I'll take you up on your offer, or at least know that I have somebody to bounce ideas off of. It's a far cry from restoring bikes to actually innovating and one-offing them, and there's a lot of knowledge that is needed to transition between the two. I'm just taking those steps a little at a time. Hell one day, I'd love to build my own frames. But baby steps, ya' know! Again, I appreciate your reply, and your input is always welcome. Have a great one man!

On a side note, I'll be working on her the rest of the day, so maybe some more updates tonight!

 

[cafePete]

Re: A way to waste money: The evolution of a confused '74 360

Can't wait to see some updates, reading chrisf and your posts
really show how much planing is involved. Thanks for the tips,
off to get me some disks. ;D

 

[cafePete]

Re: A way to waste money: The evolution of a confused '74 360

Hey Kanticoy, came across this while browsing cb360's.
Thought I would share, crazy frame design, cb360 motor.
http://hellforleathermagazine.com/positions/buildyourown/lounge-layout.html

 

[troybilt]

Re: A way to waste money: The evolution of a confused '74 360

Damn man, thank you for sharing that! That 4 link front end is just wicked and the turbo 360 should kick her down the road quite well! That is if the 360 stays together.

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

That thing is badass! Wonder where the rest of te bike is?! And I wonder how that 360 handles a turbo...crazy! Thanks for putting that up!

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Few updates today. I'll make it quick, I'm going to a show tonight. Today after lots of contemplation and the arrival of the tank pending, I knew the measurements on the tank and decided that the sat rails that I fabricated were too short. Today I extended them by 4". I also finished up the rear drum brake stay with a new custom one made to fit the new swingarm and the wider than stock rear tire. Tank should be here Monday according to the tracking #. Kinda stuck until then (not really, there's so much to do!) So here's some pics of today's progress. More to come Monday since that's my next off day. Work really impedes progress, but hey, I'm happy to have it!

New seat profile:

New rear brake stay. I like it!

Also got the Tarozzi rearsets on to mockup brake linkage. The brake stay is solid 3/8 rod. Should work great! I needed something beefy. Let me know what you guys think, and have a wonderful night!

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Today was a day of brakes. The rear brake had to be figured out because

1: I am using rearsets and the attachments and such are different, and
2: The swingarm is longer and I was kind of scared to use a rod due to the length and how it would behave as the swingarm flexed.

My solution was to use a cable. I had to build various brackets and then cut down an old front brake cable to make it work, but it was a success. I still have to put a return spring on the pedal, and a pedal stop to keep it from rotating too far up tomorrow, but the fabrication portion and the mechanical portion are done, and it works GREAT! I left enough slack in the cable to allow it to move as the swingarm does without stretching or kinking. I noticed some old AHRMA conversions that used this route and it gave me the idea to pursue it. And heck yes!

Let me know what you guys think. Much more tomorrow, and maybe a tank too...it didn't make it today. Here's hoping!

Take care people!

New rear brake cable:

I will probably build a new bracket to attach it to the rearset to keep the travel more linear. We'll see how that goes.

 

[sabres7th]

Re: A way to waste money: The evolution of a confused '74 360

really cool !!! i know what it is like when you can't put the welder down. can't wait to see whats next!

 

[diesel450]

Re: A way to waste money: The evolution of a confused '74 360

pretty cool idea. How does it return? I don't see a spring.

 

[diesel450]

Re: A way to waste money: The evolution of a confused '74 360

Duh, internal shoe springs, nevermind. :

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Thanks fellas! And I'm gonna put another spring on the pedal along with a pedal stop to keep it in the right position for riding. It'll be nice and smooth then! i'm of to the shop today again, so who knows what's next! Gotta get my oxy/acetylene filled today, and then back to the wrenching!

 

[MarcW]

Re: A way to waste money: The evolution of a confused '74 360

Looks great!!

I'll be pulling that other motor apart tommorrow or thursday, hopefully the slippers are good in it!!!

Keep up th killer work!!

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Thanks Marc! That would be awesome. It hasn't been that big of a hurry since (obviously) I haven't gotten around to finishing the motor yet. I appreciate the compliments though man. Means a ton!

Today I spent almost all day tweaking the rear brake. I re-built the bracket that holds the cable by the rearset. Originally I used aluminum flat bar to make it, but I noticed when I pushed the brake lever that it was flexing the bar. Today I build a new one out of steel and braced it. It also includes a spring mount on it for the return spring, and a hole was included to attach teh rear brake light switch. I also welded in a pedal stop for it. It turned out great!

I spent a lot of the day chasing parts and crap. I went out to fill my oxy/acetylene tanks and didn't realize it, but apparently the gauges that I bought off of my neighbor are old enough that they take a different type tap on the bottle. The gauges I have are female ended (where it screws on the bottle), and the new bottles take a male fitting attached to the regulator. So I had to drive back to the welder's supply and get an adapter to make it work. A good torch cleaning and new hoses and a new hand made cart, and I am in business. Hot stuff.

I also went to a friend of mine's house today who is a fellow cafe racer. He has owned (and still does) two Thruxtons and a Speedmaster. Cool bikes. Well, he sent my way a set of really nice aluminum bar end mirrors, and he gave me a fairing off of a Ducati 900s. The fairing is cracked, but if there's anything uscafe racers know, it's fiberglass, so it can easily be fixed. Even came with the mounting hardware and brackets. Don't think it'll be going on this bike, but it sure is cool!

Anyway, here's some progress pics. They're iphone pics, sorry, I didn't wanna drive 30 minutes back to get the camera. But you'll get the idea. Still no tank. It'll probably come tomorrow while I'm at work :. Good news is, I have 5 days in a row off after tomorrow, so bike shiznit, here we come!!!

Brake bracket mods. Works like butter now!

New Bar end mirrors. Very nice quality. He paid $150 for these and just sent them my way!

All balls steering stem bearing kit. SOOO Nice. installed now.

The Ducati Fairing. How cool is that!

So much to do in the upcoming days. I am stoked. Let me know what you guys think as always. I value your input. Have a good night guys!!

 

[jwdmotorsports]

Re: A way to waste money: The evolution of a confused '74 360

I like the new brake cable routing. The old routing looked like it had some pinch points in the cable.
Looking great. I check back every couple days to see how my old bike is looking.

 

[Kanticoy]

Re: A way to waste money: The evolution of a confused '74 360

Haha, a little different from when it roled out of the garage, huh? Thanks man, I appreciate it. And yes, the new system is much better. The pedal stop acts as a tensioner. That's plastic sheathing that you see slipped over it. It's VERY smooth and easy to operate now. Makes me wonder why it wasn't done from the factory.

 

[troybilt]

Re: A way to waste money: The evolution of a confused '74 360

I like the new brake cable routing. The old routing looked like it had some pinch points in the cable.
Looking great. I check back every couple days to see how my old bike is looking.

+1 ;D looking good! I can't wait to see what you do with 4 days! Keep us posted!