How do I weld motor mount?

[Jeffrey gagnon]

Well first i never build anything on aluminum and second i appreciate your concern as far as being a novice when it comes to welding but what alot of people on different forums ive been reading say tig is the way to go for a bike frame welding. Although im a novice to welding i have my dad for one he knows how to use all the welding equipment and for 2 you can learn pretty much just about anything nowadays with youtube and thirdly im a very quick learner plus i had a different ideal for my bike build.

So with my new ideal what im thinking is extending the bike by 6 inches to allow room for the 125cc engine

So i plan on cutting top and bottom tube 3 inchs forward of the seat tube.

Take a 10 inch long steel tubing with the O/D just small enough to fit 2 inches on each side of where it slip fits inside the frame.

Next i will drill 2 small holes 1 inch in from slip fit on top going down and side going throug the frame through the slip fit tubing and once again through the frame on other side i will do this to all 4 connections. The point of this is to use the tig welder to put a tack on the inside part of the extension slip fit tubing.

Next once i have one side done with the extension slip fit tubing i will also use a tubing thats the same diameter as the frame to cover the extension which would be cut at 5 7/8 inch so when i slide the 2 peices of the bike frame back together it would leave 1/8 inch exposed for to weld all 3 together.

Once the frame is done i will take a 1/2 thick steel plate that would have a c < cut out on both sides so it will wrap the frame tubing which would then get welded to the frame as well

I was also considering welding a steel tube under the motor plate from the seat tube to the bottom tube

So with something like this i think i would want the precision that a tig welder gives you over a mig from what ive been reading.

Or can this project be done with a mig i plan on taking extra care and want it to look as professional as possible.

 

[Frankfort MB's]

Well first i never build anything on aluminum and second i appreciate your concern as far as being a novice when it comes to welding but what alot of people on different forums ive been reading say tig is the way to go for a bike frame welding. Although im a novice to welding i have my dad for one he knows how to use all the welding equipment and for 2 you can learn pretty much just about anything nowadays with youtube and thirdly im a very quick learner plus i had a different ideal for my bike build.

So with my new ideal what im thinking is extending the bike by 6 inches to allow room for the 125cc engine

So i plan on cutting top and bottom tube 3 inchs forward of the seat tube.

Take a 10 inch long steel tubing with the O/D just small enough to fit 2 inches on each side of where it slip fits inside the frame.

Next i will drill 2 small holes 1 inch in from slip fit on top going down and side going throug the frame through the slip fit tubing and once again through the frame on other side i will do this to all 4 connections. The point of this is to use the tig welder to put a tack on the inside part of the extension slip fit tubing.

Next once i have one side done with the extension slip fit tubing i will also use a tubing thats the same diameter as the frame to cover the extension which would be cut at 5 7/8 inch so when i slide the 2 peices of the bike frame back together it would leave 1/8 inch exposed for to weld all 3 together.

Once the frame is done i will take a 1/2 thick steel plate that would have a c < cut out on both sides so it will wrap the frame tubing which would then get welded to the frame as well

I was also considering welding a steel tube under the motor plate from the seat tube to the bottom tube

So with something like this i think i would want the precision that a tig welder gives you over a mig from what ive been reading.

Or can this project be done with a mig i plan on taking extra care and want it to look as professional as possible.

I was just informing you that Tig welding can be a pain if you don't get used to it, I'm not saying it's impossible to be good your first time.

They can be very precise but you have to have very clean metal, a good grinder, and a lot of practice

A Tig welder, if you didn't know, they use tungsten rods (what the electricity comes out of) and the rod will eventually dull flat.... I've always had best luck with making the rod as sharp as you can possibly can

 

[Jeffrey gagnon]

I was just informing you that Tig welding can be a pain if you don't get used to it, I'm not saying it's impossible to be good your first time.

They can be very precise but you have to have very clean metal, a good grinder, and a lot of practice

A Tig welder, if you didn't know, they use tungsten rods (what the electricity comes out of) and the rod will eventually dull flat.... I've always had best luck with making the rod as sharp as you can possibly can

Yeah i knew you weren't discrediting me on what skills i have or dont have was just making my opinion on stuff ive read about tig and mig.

And yes i heard about the making the tungsten tip pointed i have plenty of power tools and air tools as well which does include a grinder or theres even the craftsman grinder i have as well either will get the job done now its just a matter of saving up the money for this build with tools and material im looking probably at $1500.00 right now

 

[Jeffrey gagnon]

So here is the plan layed out getting really excited too bad i still have to wait i want to build this bike now oh well so let me know what you guys think the plan is to stretch the frame 6 inches and add extra support let me know if i missed something or if im good to go with this plan as its laid out

 

[FurryOnTheInside]

View attachment 73414
So here is the plan layed out getting really excited too bad i still have to wait i want to build this bike now oh well so let me know what you guys think the plan is to stretch the frame 6 inches and add extra support let me know if i missed something or if im good to go with this plan as its laid out

Yeah you might have missed something..
The frame in the picture has a very tapered top tube. A piece of ordinary tubing will not fit snugly 2" into ether side.
The two tubes, top and down tubes, are at an angle, not parallel, so that a straight piece of tubing cannot fit into both. Somewhere there has to be a bend or angled, butted joint.

If you do have the tools to create the parts and a jig to hold them in place, but you don't have a welder, or mask, or gas, wire or welding skills, why not just pay a professional welder to do the dangerous bit? Then you don't have to buy a welder or materials, or practice for ages, or risk burning a big hole in the frame that you spent ages making parts specifically for.

 

[Jeffrey gagnon]

Yeah you might have missed something..
The frame in the picture has a very tapered top tube. A piece of ordinary tubing will not fit snugly 2" into ether side.
The two tubes, top and down tubes, are at an angle, not parallel, so that a straight piece of tubing cannot fit into both. Somewhere there has to be a bend or angled, butted joint.

If you do have the tools to create the parts and a jig to hold them in place, but you don't have a welder, or mask, or gas, wire or welding skills, why not just pay a professional welder to do the dangerous bit? Then you don't have to buy a welder or materials, or practice for ages, or risk burning a big hole in the frame that you spent ages making parts specifically for.

Yeah and you might have missed the part where i told the other guy im fast learner, and you might have also missed the part where i said my father knows how to use all the welding equipment. You also missed the part where youtube in todays era is another form of education i cant tell you how many countless videos there are on youtube as far as basic to medium to harder difficulties of welding

So whats gonna cost more paying a welder to to do some custome work or buying the equipment and having a lifetime of learning experiences, and further more why am i gonna pay someone to do my hobby for me whats the fun in that.

Im the guy that likes to get his hands dirty and do the whole tinkering thing, so paying someone to do it for me takes the fun out of it

You do make a good point on the angles in the frame i had noticed that and ive done pipe bending before with my exhaust pipe. On my original 29 mountain bike the pipe was hitting the pedals so it had to be bent inward by a hair. Yes i know it would require a specific bend. You pointed one good thing out that i had missed, but next time try not to be so much of a pr*ck

 

[Jeffrey gagnon]

Oh and yeah i noticed the tube diameter is larger closer to the handle bars but near the seat post its at its straightest as well as closest in size, and to compensate for any wiggle is why i will be adding 2 holes one vertical and the other horizontal at each of the joints to be able to tack the internal part of the joint these holes would be very small in diameter basically just big enough to get a tack in

 

[FurryOnTheInside]

Bit strong, mate. You did ask for people's thoughts.

You asked if it is "good to go as its laid out". The plan as laid out will not work. I was supposed to say it will?

If you want to make it yourself I have no objection to that. It was merely a suggestion. Try to read things in the spirit they were written.

 

[Jeffrey gagnon]

Yes im asking if it can be done, no really im asking the best approch of what i have in my ideal in my head? asking what i left out? I know this kinda thing can be done ive seen it on youtube.

However my friend i was not asking you to criticize on my skill level or tools that i plan on purchasing

 

[Jeffrey gagnon]

What if instead of cuting the tube and adding a peice to make it longer. How bout i cut them off completely and replace with longer steel tubing and just weld them back together at the seat tube and neck not sure if thats right but the part of the frame where the handlebar and fork assembly go?