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Author Topic: Jared's 1982 CM450C Cafe Project  (Read 25239 times)

Offline coyote13

  • Posts: 1200
Re: Jared's 1982 CM450C Cafe Project
« Reply #50 on: Aug 25, 2016, 13:02:24 »
The shape of the hump is a little funky to me, but this whole thing is looking pretty badass.  Carry right on sir.
Half the fun's in the get there...

Offline advCo

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Re: Jared's 1982 CM450C Cafe Project
« Reply #51 on: Aug 25, 2016, 13:09:02 »
I have to agree, I think something a bit more streamlined would look great on this thing. Maybe squashed down vertically a bit would give some nicer proportions. Overall the bike looks great though.

When glassing over foam, I always use clear packing tape to cover the foam first, overlapping each coarse about 1/8"-1/4". Mold release wax from Meguire's or the like also helps your finished product to pop right off the mold allowing you to keep the plug.


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Offline johnu

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Re: Jared's 1982 CM450C Cafe Project
« Reply #52 on: Aug 25, 2016, 13:25:32 »
Hey Jared, if it were me I would use the look of this Honda NSR125 tail as my inspiration http://www.airtech-streamlining.com/hondaz/RS1252004-06.htm and then go from there.  Take away the sharp lines and replace with larger rads.  Kind of like a scaled down Suzuki srad GSX 750 (not sure what year).  Glad you didn't get mad at me ;D  It really is an awesome bike you're building :)
« Last Edit: Aug 25, 2016, 13:29:52 by johnu »

Offline jaredc7

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Re: Jared's 1982 CM450C Cafe Project
« Reply #53 on: Aug 26, 2016, 15:31:57 »
I finished sanding the new mold last night, here's a picture. I was trying to mimick the gradual downward curvature of the gas tank, and make it more streamlined. I am still wanting a seat that is "cafe-ish", and I didn't think any sharp lines or edges would work with the existing "bulb-like" tank. Thoughts?

Jared

1982 Honda CM450 C

Offline goldy

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Re: Jared's 1982 CM450C Cafe Project
« Reply #54 on: Aug 27, 2016, 09:40:38 »
That looks better, I think you might be right trying to get the shape to 'flow' with the tank. Interesting work you are doing, I always thought I would like to convert one of these myself.
1948 Norton ES2
1955 AJS 20B
1956 Triumph TRW
1968 Triumph T100 special
1969 Norton Commando
1975 XS650 Yamaha

Offline xb33bsa

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Re: Jared's 1982 CM450C Cafe Project
« Reply #55 on: Aug 27, 2016, 20:09:34 »
you are sure adding tubes and stuff but i think it still has a well oiled hinge in the middle its probably fine for bar hopping but be carreful if you ride hard
the tail looks sweet
i think you might want to check the clearance of the shock spring to the crossed tubes,which i really like but as the wheel comes up every bit of movement brings the shock spring closer to those tubes
taking the spring off the shock is what you should have done before fabrication but its not to late
you cant redo a rear suspension with the springs on the shocks anyway,because you dont know how far the wheel comes up ,see

Offline jaredc7

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Re: Jared's 1982 CM450C Cafe Project
« Reply #56 on: Aug 30, 2016, 18:46:08 »
Thanks for the thoughts XB33bsa. Not sure what you mean about the "well oiled hinge in the middle", could you please explain? You are right about it generally being a bar-hopping bike, with all the custom frame and suspension work, I'm definitely not expecting high performance out of it.

I did do the calculations on if the rear spring would stay clear of the subframe tubes... Using the full stroke distance of the rear shock (50mm), I was able to find the arc length and total swing of the rear wheel when the shock is fully compressed. There should be about 1/2" clearance on either side at that condition. It's not a ton, but it's enough for me.

The other tubes are mainly for outboard supports for the swing arm and for the rearsets. This swing arm (NT650 Hawk) was originally designed with all it's supports on the outside, so I was trying to address as much of that as possible.

Thanks again for the thoughts! Hope you stay tuned for the rest of my progress   ;D ;D
Jared

1982 Honda CM450 C

Offline xb33bsa

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Re: Jared's 1982 CM450C Cafe Project
« Reply #57 on: Aug 30, 2016, 19:23:46 »
hinge its just that what you have done the tubing work which looks fantasic by the way ,please dont ruin it with a flux core wire feed \either use a mig tig oxy ace it
hinge the tubing didnt really do much at all to help in the i guess lateral direction
the swinger has a ;lot more leverage than stock i the direction of bending in the middle like if you pushed on ther swinger bolt and kept the wheels from sliding that direction ,it neerds some way to be stiffer but its almost impossible without large outboard structure al the way up to the steering head
all that said it wont be an issue putting around town ..if you get the inkling to do so,just be wary and careful pushing it hard through bumpy turns at speed,thats all
« Last Edit: Aug 30, 2016, 19:26:17 by xb33bsa »

Offline Brent

  • Posts: 76
Re: Jared's 1982 CM450C Cafe Project
« Reply #58 on: Aug 30, 2016, 20:41:52 »
Jared, with a degree in mechanical engineering I would have thought that the bikes ability to function safely, properly and better then stock would have been your goals. I don't see anything in your thread regarding the bikes geometry and I, like xb33bsa, have real doubts as to whether your mono shock/framing systems are safe. I just don't see the point in putting time and money into something that isn't usable in real world application, but it's not my bike or thread so I'll bow out.

Offline jaredc7

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Re: Jared's 1982 CM450C Cafe Project
« Reply #59 on: Sep 06, 2016, 13:50:24 »
hinge its just that what you have done the tubing work which looks fantasic by the way ,please dont ruin it with a flux core wire feed \either use a mig tig oxy ace it
hinge the tubing didnt really do much at all to help in the i guess lateral direction
the swinger has a ;lot more leverage than stock i the direction of bending in the middle like if you pushed on ther swinger bolt and kept the wheels from sliding that direction ,it neerds some way to be stiffer but its almost impossible without large outboard structure al the way up to the steering head
all that said it wont be an issue putting around town ..if you get the inkling to do so,just be wary and careful pushing it hard through bumpy turns at speed,thats all

Good point with the flux core wire feed, I was just using it to tack the tubes in place to finish the geometry in my garage. Since the fiberglass seat is pretty much done now, I will be taking the subframe to a welding shop to have everything professionally welded up. I don't want to be worried about welds that I did while riding!

Bracing the swinger laterally from the outboard sides was defintely a concern. I beefed up the swinger bolt housing inside the frame big time, which should help a lot. The only places I could transfer loads from the outsides of the swinger bolt were the two engine bolt points (one above the rearsets and one below, tough to see the one below) and to the rear shock top mount. But you're right, the outsides of the swinger pivot point needs all the help it can get.

The OEM swinger was 508mm long, and the Hawk NT 650 swinger is 545mm, so about 7% longer. It will have more leverage, but the main difference I found in my research was that the aluminum single-sided swingarm AND the new forks (CBR600rr) will transfer more loads to the steel frame on account of them being much stiffer than OEM forks and swingarm. We will see how it holds up and of course I will be taking it easy when riding, but short of paying an engineering consulting firm $5k to $10k for a full FEA analysis, there's no way of knowing for sure.
Jared

1982 Honda CM450 C