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Author Topic: saving a 1980 KZ750 twin  (Read 62431 times)

Offline clem

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Re: saving a 1980 KZ750 twin
« Reply #160 on: Jul 03, 2016, 23:17:15 »
When I worked offshore in the instrumentation world the majority of what I did when I started out was bending tubing for process and utility connections. We did mainly from 1/8th inch up to 1-1/4 inch stainless 316, 317L, monel,  inconel, 2507...Thousands of feet and the bender makes all the difference. You need a shoe with the diameter desired that is rounded out to hold the tube then a shoe to pass around the outside with the same diameter as the tube, rollers on the outside give the best bend without flattening. Most benders that I've used without rollers on the shoe flatten the tube to some degree. With all of that nonsense I just laid out you're on the right track with just buying pre-bent pieces. It'll be less headache since you don't have access to a bender.

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Offline doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #161 on: Jul 04, 2016, 00:12:56 »
Check with Megs/Cone engineering.  According to a table I downloaded a while ago, 2 into 1 collectors require an outlet of 150 to 175% area of the primary pipes.  That works out to 1.875 to 2" and use the smaller size for a more torquey motor.
yeah i wondered if that would be too big. Ill drop down to 2" and buy one of the pre-made collectors from cone engineering.

Offline Rider52

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Re: saving a 1980 KZ750 twin
« Reply #162 on: Jul 04, 2016, 02:04:24 »
Back in the early 80's I built a scrambler type 2n1 exhaust system for a Kaw 750 twin. I used mandrel bent and straight pieces from Summit.
Projects
74 Yamaha TX650
Sweep the Floor Project
3 Assorted Honda CL 72 scramblers in a million pieces
3 Harleys in constant state of sorrow and a Buell
1978 Yamaha Chappy 80 burning up the highway
Cut my motor in half Sportster to Shortster

Offline datadavid

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Re: saving a 1980 KZ750 twin
« Reply #163 on: Jul 04, 2016, 04:38:44 »
Right!  I've tried that long ago with much smaller tubing - both inside and outside but no heat.  Total failure.  I'd expect an internal spring to lose all its support strength heating the tubing sufficiently, and be impossible to remove, but it is just a guess.  I would expect the bending to seriously clamp the spring, and then contracting when cool to make it a permanent assembly!  Sand,compacting, caps, and heat definitely works though, but you need a seriously big torch!
U waz prob holdin it wrongz😁

Offline datadavid

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Re: saving a 1980 KZ750 twin
« Reply #164 on: Jul 04, 2016, 04:41:15 »
When I worked offshore in the instrumentation world the majority of what I did when I started out was bending tubing for process and utility connections. We did mainly from 1/8th inch up to 1-1/4 inch stainless 316, 317L, monel,  inconel, 2507...Thousands of feet and the bender makes all the difference. You need a shoe with the diameter desired that is rounded out to hold the tube then a shoe to pass around the outside with the same diameter as the tube, rollers on the outside give the best bend without flattening. Most benders that I've used without rollers on the shoe flatten the tube to some degree. With all of that nonsense I just laid out you're on the right track with just buying pre-bent pieces. It'll be less headache since you don't have access to a bender.

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Yes those are the nicest, did a lot of stainless piping with hydraulic benders at the nuke plant last year. Lots of bends since they try to avoid unnecessary welding.

Offline Tune-A-Fishİ

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Re: saving a 1980 KZ750 twin
« Reply #165 on: Jul 04, 2016, 08:30:34 »
Key to perfect mandrel bends is clean pipe inside and out and a well cared for wiper die, the balls and wiper need a puff or two of graphite every 10 or so bends. a cnc bender can bend a compound radius just not 100% continuous it needs to let go and rotate then re clamp several times. I bent many miles of 4" stainless for Dodge Cummins trucks and QC would not let a wrinkle go by.

I don't think Yosh is using anything inside the pipe, it's Ninja bending skill and heat  ::)
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Offline doc_rot

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Re: saving a 1980 KZ750 twin
« Reply #166 on: Jul 04, 2016, 14:58:58 »
Back in the early 80's I built a scrambler type 2n1 exhaust system for a Kaw 750 twin. I used mandrel bent and straight pieces from Summit.

pics?

Offline Tune-A-Fishİ

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saving a 1980 KZ750 twin
« Reply #167 on: Jul 05, 2016, 10:19:23 »
Check with Megs/Cone engineering.  According to a table I downloaded a while ago, 2 into 1 collectors require an outlet of 150 to 175% area of the primary pipes.  That works out to 1.875 to 2" and use the smaller size for a more torquey motor.

I have a pair of these: if you need one!




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« Last Edit: Jul 05, 2016, 10:22:52 by Tune-A-Fish »
"I didn't come here and I ain't leavin"  Willie Nelson

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Offline VonYinzer

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Re: saving a 1980 KZ750 twin
« Reply #168 on: Jul 05, 2016, 12:27:31 »
I have a pair of these: if you need one!




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What are the inlet/outlet sizes there Fish?
Like a river that don't know where it's flowin'
I took a wrong turn and just kept goin'

Offline Tune-A-Fishİ

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Re: saving a 1980 KZ750 twin
« Reply #169 on: Jul 05, 2016, 14:57:09 »
1.5 and 1.75 apx, i will put a measuring device onem and see for certain
"I didn't come here and I ain't leavin"  Willie Nelson

"love hard, live fast, die fun" Kacey Musgraves

"Like a Wreckin Ball!" Eric Church