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CBR1000RR BEC, F1000ish design.
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Author:  Acerguy [ May 8, 2019, 8:03 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Looking great! :cheers:

Author:  Johnsinski [ May 18, 2019, 3:28 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Diff cage is basically done, need to cover up a few tube ends. I must be really bad at fixturing for welding cause it took 3 tries to get the top arm and the lower arm connected with the 2 vertical braces without it moving all over.

I had the diff cage mounted to the engine (12mm bolts just sitting in clearance hole on the engine and the diff mounted to the cage tightly. Then I clamped and tacked the vertical braces in. The first time I swear it moved an 1/8" or more after I finished the welds.

But third time was the charm (well, not charm really, more like f-it close enough!)

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Author:  Miatav8,MstrASE,A&P,F [ May 19, 2019, 6:07 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Yeah, I can see how that would move on you while welding. Needs a 4 point jig to hold it.

I suggest using motorcycle type chain adjusters. They are jambed after adjusting so even if the clamp is lost at the bolts, the tension doesn't immediately go away. I think they will be important to have considering your threaded into aluminum. 3/16 strip double hole washer with flanges/boxed edge, 3/8x3 bolts and nuts to jamb and adjust, blind nut plates on the cage.

Author:  Johnsinski [ May 19, 2019, 3:17 pm ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Yeah, I was thinking something more than what I've got on there, like a screw stop would be nice.

Author:  Johnsinski [ May 20, 2019, 4:31 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

I thought while I was having welding success, I'd try to plug some of the holes in the diff. I'm not sure what the diff case is, I'd guess cast steel, but it worked pretty good. There was a bit of sputtering and smoke and it seemed like I could only weld about 3/8" long until I felt like I should stop and clean it with a brush.

I assume those four ends were open to allow some oil circulation where the screws are sliding when "diffing". I think that would be a good place to put some grease zerks. There are two more holes like these on the other end.

But then there are the two big openings in the middle of it. One is needed for access to remove a central spacer thingie so the whole diff can be dissasembled. The one opposite, I'm not sure, maybe to balance out the needed opening. Not quite sure how I'm going to seal those since the needed one is, well, needed. I guess I could make a bolt on cover for it. The BEC book guy suggest a cooking pot, NOT!

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Author:  Johnsinski [ May 26, 2019, 1:24 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Fitted some grease zerks to the diff and made some chain adjuster stops.

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Author:  Miatav8,MstrASE,A&P,F [ May 27, 2019, 4:44 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Looks like that'll work too. I was suggesting something like this extra crude drawing.

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Author:  Johnsinski [ June 1, 2019, 12:45 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Got a quote for my 2 roll hoops. 1 3/4" x .109", 10" CLR. Over $500 for both. Now before I completely blow up, I get it, it's special work and all, but Holy F! That seems a bit steep.

Not that that's off the table, but I'm designing my own bender now (based on various internet research). The problem with buying one is I can't even find 10" CLR dies. Did I just design the roll hoops wrong? 10" CLR seems nice (for a single seater).

The large arc is cast steel. Not sure how I'm gonna do that one! Probably won't.

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Author:  Miatav8,MstrASE,A&P,F [ June 1, 2019, 5:23 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

With such a large radius, have you considered a roller bender (3 small die type)?

Author:  rx7locost [ June 1, 2019, 11:36 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

What determines your chosen tubing dia , wall thickness and radius?

A lot of us have used Rollcagecomponents.com to make our custom roll bars. That is where I had mine made. And Jack gets his made by him too, at least he used to. I can't say if he has changed suppliers since. They have 1-3/4 x .095 and .120 wall DOM available. I'm not sure what radius tooling he has. You might try giving Jimmy a call to talk about his available options.

Author:  JackMcCornack [ June 1, 2019, 1:48 pm ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

rx7locost wrote:
And Jack gets his made by him too, at least he used to.
Yep, I still do. Jimmy's terrific.

Author:  KB58 [ June 1, 2019, 2:24 pm ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Unless it's really necessary, a chassis doesn't require a fixed bend radius. The Midlana plans only fix the end points (and overall width and height), giving builders the freedom to use any bend radius within reason.

Author:  Johnsinski [ June 2, 2019, 2:06 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

A couple reasons for the design:

1. The BEC book specs that tube (in metric).
2. One of the SCCA roll tube specs was 1 3/4 x .109 (for a bigger car though)
3. The radius is large because it made sense to me for a single seat roll tube. It covers a large area on the sides.

The tube size is probably way overkill, but I do like the large radius. I could go smaller, but I still can only find around 7" dies.

I'll check with Rollcagecomponents.com

And I'll see what I can find on a 3 wheel roller/bender.

I found a youtube video of a guy making a large radius die by cutting a slightly larger tube in half, then making many cross cuts so it could be bent to the desired radius. Then welding plates and such to it. One side plate omitted for clarity.

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Author:  rx7locost [ June 2, 2019, 9:51 am ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

I've also seen dies being made with hardwood. It only has to survive a few bends. Google will get you there.

Author:  Johnsinski [ June 2, 2019, 10:43 pm ]
Post subject:  Re: CBR1000RR BEC, F1000ish design.

Oh that's interesting, a hardwood die. That's got me thinking I have some out-of-date tooling urethane I should use up. Cast that thick enough and back it with the steel plates and that should work. Like you say it's only gotta work twice.

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