Kerker exhaust dent

  • ThatGPzGuy
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Kerker exhaust dent

05 Apr 2022 08:41
#864950
Hey All, the exhaust is off the GPz for a bit while I do some engine work. I really hate the finish on my pipes and was thinking of having them ceramic coated. i would like to have this dent repaired beforehand. Ideas? I'm thinking it would need to be cut out and replaced. 
Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
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  • Wheelhop
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Re: Kerker exhaust dent

05 Apr 2022 08:58
#864952
I've seen a buddy of mine seal off both ends of pipes making them air tight.  Put a valve stem into the end somehow.  Heat up the dented area "red hot" and blow compressed air into pipe.
I would make sure you do your own research on this method as I don't know if it was air or some kind of inert gas that won't explode when heated.

 
1978 KZ 1000B (73 tribute)
1977 KZ1000 project
1976 KZ 900
1976 KV 75
1976 Honda Elsinore MT250
1974 Z1 900 project
1971 Honda CT70
2000 ZRX 1100
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Re: Kerker exhaust dent

05 Apr 2022 09:13
#864954
wrote:
I've seen a buddy of mine seal off both ends of pipes making them air tight.  Put a valve stem into the end somehow.  Heat up the dented area "red hot" and blow compressed air into pipe.
I would make sure you do your own research on this method as I don't know if it was air or some kind of inert gas that won't explode when heated.


 
Usually done with compressed air but water ( hydroforming) can also be used as it does not compress like air so much less danger if the pipe splits.
Air method is to pressurise the pipe first then work the dent with carefully applied localised heat .
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/23-for-sale/611992-air-c...lide-mikunis?start=0





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  • Wheelhop
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Re: Kerker exhaust dent

05 Apr 2022 09:27
#864956
Thanks for clarifying my post ! 
1978 KZ 1000B (73 tribute)
1977 KZ1000 project
1976 KZ 900
1976 KV 75
1976 Honda Elsinore MT250
1974 Z1 900 project
1971 Honda CT70
2000 ZRX 1100

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Re: Kerker exhaust dent

05 Apr 2022 10:38
#864963
A easier  way  with minimum  tools is to use a slide hammer / dent puller  
A body shop uses a spot welder to fasten a rod  to the panel then  clamps a dent puller to the rod and  pulls the dent out
Use heat  to soften the area and pull
Check  u tube  for demo's
Dave

Original owner 78 1000 LTD
Mr Turbo Race Kit, MTC 1075 Turbo pistons by PitStop Performance , Falicon Ultra Lite Super Crank, APE everything. Les Holt @ PDM's Billet Goodies . Frame by Chuck Kurzawa @ Logghe Chassis . Deep sump 5qt oil pan. RIP Bill Hahn
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  • kzstreetfighter71
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Re: Kerker exhaust dent

05 Apr 2022 11:44
#864967
Watched being done on 2 stroke pipes, i tried it my self on a 4 into one about a year ago, didnt work, i was afraid to put up the pressure to high though, kinda chicken'd out.
06 Gsf 1200 bandit, 08 Triumph tiger 1010
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Re: Kerker exhaust dent

05 Apr 2022 11:51
#864968
This is an older Kerker so the metal is plenty thick. And, where the dent is is right at the bend. I'll probably take it to welder and get an opinion. I know a guy who teaches welding and is sort of the local guru for motorcycle frame welding. hopefully he's still around. 
Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
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  • Wookie58
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Re: Kerker exhaust dent

05 Apr 2022 12:32
#864971
You can weld washers edge on to the dent and use a two legged puller against the pipe either side of the dent, that way you can apply constant tension while you heat the area you want to move
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www.kzrider.com/forum/11-projects/617631...-82-begins?start=192
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Re: Kerker exhaust dent

05 Apr 2022 16:18 - 05 Apr 2022 16:44
#865000
I had this guy remove dents from a kerker header a few years ago.  The exhaust looked great and the price was reasonable.

motocrosspiperepair.com/

Edit: Here are pictures he sent of my own pipe when he finished it.

 
'78 Z1-R in blue , '78 Z1-R in black, '78 Z1-R in pieces
My dad's '74 Z1
'00 ZRX1100
Last edit: 05 Apr 2022 16:44 by DOHC.
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  • TexasKZ
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Re: Kerker exhaust dent

05 Apr 2022 19:10
#865008
I do not see it on his website, but Pete removes dents from headers.

www.kwick.biz
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
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www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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Re: Kerker exhaust dent

05 Apr 2022 19:47
#865012
I've seen dents in pipes removed with large ball bearings, maybe look into that .
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  • Ian_B
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Re: Kerker exhaust dent

06 Apr 2022 03:58
#865029
Either use dent balls: 
 
or weld bits of metal on and pull the dents out with a slide hammer. Either should work. I'd probably try the balls first.

Ian
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