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Post by stevellew on Aug 16, 2014 17:53:30 GMT
Does anybody have any experience or any knowledge of cutting the frame totally out from the front of the seat to the head stock and replacing with a narrower one any tips / advice might be of help but that is what's happening to mine hopefully in the next month well my mate Craig who's a good welder reassures me it's in good hands and I trust him 100% but anybody seen this done tips/ advice  |
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Post by caprinix1959 on Aug 17, 2014 10:32:26 GMT
Only thing to be careful of is alignment , once the top section is cut out the headstock will be free to move about so I would make sure that any work done is undertaken with the engine in the frame to keep everything in the right place. It might make more sense to just grind sections out ,leaving the main spar in place just make it smaller/narrower. There was a chap building a bobber on the old site and he modified the top spar to allow a smaller tank to fit,think he is on here but has not been working on the bike for a while,I'll have a look thru the members list and see if I recognise his name. Best of luck buddy! Nix
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Post by grahamb on Aug 17, 2014 10:36:14 GMT
was it Gissmo50 ?
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Post by stevellew on Aug 18, 2014 4:56:45 GMT
Cheers and I'm sure it was gissmo50 shame as his bike was coming along good, we do intend to leave the engine in place the plan is to cut straight through the frame at one point first , one clean cut and see if there's any movement if there is we are going to weld a jig in place to hold it where it is before we cut it completely out.
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Post by caprinix1959 on Aug 18, 2014 7:56:09 GMT
Good plan! Yep it was Gissmo,anyone know where to find him? I had a chat with him only a week or so before the old forum disappeared up its own arse.
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Post by caprinix1959 on Aug 18, 2014 8:05:44 GMT
Have pm'd gissmo so hopefully we will get an update and more of his superb pictures of his beautifully engineered bobber
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Post by Harold on Aug 18, 2014 8:24:56 GMT
Why do you want a narrow top tube Steve, is it to fit a different tank if so the easier option would probably be to rework the tanks tunnel and base than trying to cut out and replace the top section of the frame. If you do decide to cut and shut the frame I would suggest using a jig as the movement may not occur when cutting the frame but will almost definitely occur after welding it due to the heat involved and the contraction of the metal after cooling. Also how would you mate the narrower section to the thick box section part of the frame that would remain behind the engine for the engine, swingarm mounts etc. ?
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terryc
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Post by terryc on Aug 18, 2014 8:46:45 GMT
Have pm'd gissmo so hopefully we will get an update and more of his superb pictures of his beautifully engineered bobber Gismo spends more time on facebook than on here so I've sent you a friend suggestion on there Nix, his name is Kyran Hawkins |
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Post by caprinix1959 on Aug 18, 2014 8:54:53 GMT
Nice one Tel !
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Post by stevellew on Aug 18, 2014 11:08:50 GMT
Here's the link to the tank I've bought www.ebay.co.uk/itm/141367111158 Hi Harold my mate craig who's doing the welding has the patience and dedication of a saint !! lucky for me. He said rather than cut the tank apart he feels it would be easier to cut the top frame out and put a narrower section back in place and where the new smaller tube meets up to the original frame he's going to weld plate and shape it to look good and for strength . |
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Post by Harold on Aug 18, 2014 11:46:16 GMT
I have a similar sportser tank Steve and the tunnel is just a little too narrow to go over the frame, however there is a bit on the SD frame top rail where it bulges out, another (and simpler) option would be to remove the bulge and weld flat plates over it to narrow the frame, which may allow the tank tunnel to fit over it. You could then remove the tank mounts which are for round tube and replace them with ones that would mount to the side of the frame at the front and rear. Also if you haven't bought the tank yet a high tunnel tank may be better as it would sit down over the frame more. Unfortunately SD frames do not lend themselves well to custom tanks due to the box section frame and I think it would be hard to mate a round tube to the square section neatly, Another option would be fat bob tanks as they are split and you just mount one half either side of the frame.
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Post by listey on Aug 18, 2014 12:28:36 GMT
Why do you want a narrow top tube Steve, is it to fit a different tank if so the easier option would probably be to rework the tanks tunnel and base than trying to cut out and replace the top section of the frame. If you do decide to cut and shut the frame I would suggest using a jig as the movement may not occur when cutting the frame but will almost definitely occur after welding it due to the heat involved and the contraction of the metal after cooling. Also how would you mate the narrower section to the thick box section part of the frame that would remain behind the engine for the engine, swingarm mounts etc. ? He's right you know.  I'd also suggest cutting the tank. I offered a mustang tank up on mine and obviously had the same problem with the frame as you. The tank has a very shallow tunnel, and I found it wouldn't sit right. Even with the frame narrowed I think it'll sit too high and you'll see the frame peeping out underneath it. I was going to chop the tank and fab a new tunnel, deeper and wider to clear the stock frame and then I could position it exactly where I wanted. I kinda fell out with it and got a good bid from one of the locals so the tank escaped unharmed and I wound up chopping about a 400T tank instead. Another thing to be aware of is the registration/legality minefield of modifying your frame. If you can keep the frame standard you avoid these issues. Wouldn't mind seeing some progress pics if poss. |
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Post by stevellew on Aug 18, 2014 12:31:23 GMT
I know what you mean with the wide parts on the frame craig did mention trying that first to see how it works first before we go any further and the Harley tank I think would look far to wide on it plus I've already got the tank which looks the dogs Tesicles !! With that solo seat that I have, so I think we will just have to see how we get on. I have looked and looked for a suitable tank before going down this road there is some nice ones that slope all the way down to the seat but dident get any narrower as it butts up to the seat so fingers crossed we might get a chance to do it this weekend now bit lime u said a jig would be a good idea cheers Harold
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Post by Harold on Aug 18, 2014 13:50:03 GMT
I'm just thinking narrowing the frame where it bulges may be difficult too as I think the top engine mount brackets mount there. This is something else to consider if fitting the new top tube. I'll watch this with interest Steve and good luck whichever way you choose to go.
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Post by stevellew on Aug 18, 2014 16:28:11 GMT
No pressure then !! I'm lucky craig is a good welder with lots of patience and a good friend so I should be ok I'm hoping to start it after work on fri then leave the bike up Craig's and if things go ok it should be done sat / sun at the latest, I will take plenty of pics just to put craig under a little more pressure lol . So if we did decide to chop the frame what would be the legal procedure
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