any of you guys did built his own vinduro bike from the frame?

[ghostdancing]

i'm searching info and real stories about  frame fabrications from scratches..plenty for harleys and choppers, nothing for vinduro\cross\twinshocks dirty thumpers?

[Slakewell]

Its something on my list of stuff to do. Currently modifying frames to get what I want.

[Tomas]

Its pretty easy to build a herley frame. You just get some plumbing pipes from bunnings get your grinder,pipe bender and stick welder and of you go
With offroad frames it is a bit harder. CrMo tubing is harder to buy(unless you want to buy a ton) and cost lot more. Than you must be good with Acetilene or Tig torch and CrMo tubing is harder to bend and shape. Then when you got as far as finishing your frame you really want to have it heat treated so it does not crack after a couple of jumps. You don't find a place that heat treats frames on every corner. Custom/replica frame will cost you around 4-5 thousand dollars for a reason.

[ghostdancing]

thankyou guys; actually i'm now thinking to modify a BETA 250 1977 frame to put in a yamaha XT250 2 valves motor (the goal is to build a little HL..do you now if this particular frame is made in cromoly? can i stick weld on this? if yes what rods i should use? the bike will be not raced or jumped in any ways..actually i use the bike on tarmac for 99%, albeit roads are not so smooth here

[djr]

I don't know how you would identify the steel used on a frame easily ,
but you could have a close look at the existing welding for a clue
if the existing welds are - MIG or Stick , then its probably not CroMo
if the existing welds are - TIG or Bronze welded then it more likely is CroMo or something similar
whatever steel it is I would try and avoid stick welding if possible

[Slakewell]

Beta frames are a bit rare , try not to cut one up to fit a XT motor.
What are you really trying to do here? It maybe easier to modify the XT frame to get what you want. Explain in detail and I will try and help.
Stick welding frames is not a good method. If you can post photo of what Beta stuff you have.

[ghostdancing]

here in italy these BETA frames (and also complete bikes of this era) are pretty commons and low priced too..actually i already built a twinshock XT250 with the original XT frame (KLX250 swingarm\IT250 forks);  the bike is nice and goes well, has been my daily drive for the last 4 seasons (april - october i use only 2 wheels for everyday moving)..only problem: it's a bit too long wheelbase (1500mm): this doesnt hurt the handling at all: i can U turn at low speed just as with a Vespa.. it's the look that i dont like 100 percent..

back to the welding: i guess back in the days these frames where welded with oxy\acetiline torch..

[ghostdancing]

well i just tried to glue a piece of mildsteel to the cromoly(?), 3mm thick both parts, used 6013 rod 95 amps, looks not bad..unfortunatelly i'm not so good to upload pics on this board yet..

[Tomas]

Hi. Brazing is the way to goo. Check this http://www.mojomotorbikes.co.uk/yamaha.html  No heat treatment needed.

[skypig]

Hi. Brazing is the way to goo. Check this http://www.mojomotorbikes.co.uk/yamaha.html  No heat treatment needed.

Wow - some frame porn on that link!!

[Nebo]

   My Brother has aways used CIG/BOC PINK Nickal/Bronze Rods for Gas Welding. They are flux coated.

   He has used them on Maico Frames for repairing upper and lower shock mounts and on one frame that had a crack at the
   steering head area.They have never failed. Also cracked or broken brackets and fitting a threaded mount for a chain roller.
   He has fitted this mod to some ten Maicos.
           
   The Welding does not Crystalise the metal and only requires the flux to be completly cleaned off .

    Note .  There are some Chinese made rods of this type. They are rubbish.
     

[Momus]

Hi. Brazing is the way to goo. Check this http://www.mojomotorbikes.co.uk/yamaha.html  No heat treatment needed.

Brazing is pretty archaic. The poms used WW2 Spitfire frame leftovers and Reynolds tube for building car and bike space frames and brazed this hard to work with material.
The pragmatic and better resourced Yanks developed 4130 Chrome moly specifically for ease of welding- TIG, MIG etc.

[Tomas]

Most of "Reynolds" tubing is CrMo, MnMo or stainless hardened steel tubing.  Can be tig/acetylene or mig welded. 4130 simply refers to one of many kinds of CrMo steel that is weldable etc..Only diference between acetylene and Tig welding/brazing is a source of heat. Not many fabricartors/welders can tig/acetylene weld and thats why it is not commonly used but its not archaic . Mig welding was simply developed for ease of use. Can probably train a monkey to mig weld.

[GMC]

4130 Cr-mo can be welded with a MIG, TIG, Arc, Oxy or brazed,
Arc welding thin materials (1.5mm and under) is difficult

I don't believe any of the motorcycle manufacturers used 4130 as they wouldn't want the hassle of having to heat treat all their frame.
Most aftermarket frame builders use 4130 but the Poms also used Reynolds tube.

A forum member had a Maico frame analyzed a few years back and it was much the same as 4130 but with less Carbon.

Carbon is the magic ingredient for making hardened steel

[80-85 husky]

i'm searching info and real stories about  frame fabrications from scratches..plenty for harleys and choppers, nothing for vinduro\cross\twinshocks dirty thumpers?

ever seen a GMC HL replica frame? thats how its done...