Welding up intakes: y'all got any pro tips?

Jonathan Feldman /

Dec 24, 2018 09:53AM

Lately, I've had kind of a return to innocence with mopeds. Like things that I once glossed over and didn't think twice about.. I'm finding myself revisiting ( with a little bit more knowledge than previously. ) Anyway, I recently obtained my first welder aka the OG harbor freight shitter. It's been a joy to finally embrace the match made in heaven that is.. janky mopeds and half ass welding. However there's one thing I'm stuck on...

How the fuck do you make an intake?

I've done some reading n some welding n some reading again... but for the life of me I can't get a intake to seal properly. I admit right now that I'm a beginner welder and I'm challenging myself trying this. But I'm still curious if there's any pro tips I'm missing here.

I've heard of two methods primarily for making intakes.

1. Drill the base plate to whatever size tubing is going in. Shove the tubing in and weld that bitch up.

2. Weld the tubing directly to the base plate and fill with water to check for leaks. Once you've confirmed it's leak free, then you can drill out / match the base plate to whatever intake port you want.

Method 2 originally made more sense to me cause I mean shit.. you get to check it for leaks very easily before you get too deep in the game. So that's the method I've been attempting ( key word: attempting ). But the more I think about it, method 1 seems easier to seal.

ANYWAY, before I put all y'all to sleep listening to me ramble.

What method do you use to weld up intakes? How do you like to check for leaks? Any pro tips as a whole you'd like to recommend?

As always, thanks y'all. XOXO, Jon

Re: Welding up intakes: y'all got any pro tips?

Brandon Weiss (Detective brandon to you) /

mopedallday

Dec 24, 2018 10:32AM

JB weld and paint makes you the welder you ain't!

Ive made a few homemade intakes with flat bar and the curved portions of bicycle handlebars, with a $150 forney 125 flux core MIG welder.

-Get the metal super clean. Shiny metal, and use acetone to clean the area.

-Make sure you have a solid ground to the material, might be worth investing in a better ground clamp, the HF ones are janky

-Get quality welding wire. I use Lincoln 0.30 flux core. ScooterTrash recommended Blue Demon brand in his "Fuckin around in the shed" thread.

-Auto darkening helmet is a must

-Get comfortable

-Practice on scrap too get the welder dialed in

To make it easier on yourself, you could get some solid tack welds all the way around and then seal it with jb weld, and then paint. Much easier than chasing a leaky weld, getting a solid and continuous weld on a small round object is no walk in the park. Assuming you got good penetration, it should be plenty strong.

Ive gotten better at welding since i started, but my first intake made with the above method is still holding strong after a year.(edited)

Re: Welding up intakes: y'all got any pro tips?

Dirty30 Dillon /

hydra

Dec 24, 2018 10:48AM

I'll start by saying that air can find holes that water will not.

If you're seeing air leaks at the weld, I would suggest grinding down the old weld and going over it again. If you're getting enough penetration and material to create a flowing pool, you should be able to seal up anything in one pass.

More than likely, any flange you're welding is going to warp, eve slightly after being heating and having tension applied to it. You definitely have to flatten any mating surface after welding, no matter what.

Welding takes a lot of time to get comfortable with and get consistent results. Unfortunately, running a flux-core, semi-adjustable machine makes learning quite a bit more of a challenge. Having a machine with adjustable feed/power, and ability to run shielding gas will completely change the quality of your welds.

Re: Welding up intakes: y'all got any pro tips?

JBOT Admin /

capturedbyrobots

Dec 24, 2018 01:21PM

Braze rarely leaks.

But if you weld just get a slow feed and make a good bead focusing on the thicker part and just wicking into the thinner tubing.

For big carbs the the top of mountain bicycle forks are curved and about 24mm.

Re: Welding up intakes: y'all got any pro tips?

Ben Whittle /

bsw123

Dec 24, 2018 01:47PM

The flange warping is something to consider also

Re: Welding up intakes: y'all got any pro tips?

pat splat /

ggspeed

Dec 24, 2018 01:48PM

^i've done the jb weld, the shitty wire weld, and the braze. so best method i found is clean, tack weld to hold in place, clean n flux then braze. map gas w fancy torch red hot n watch that braze suck in all those leaksssss.

Re: Welding up intakes: y'all got any pro tips?

Jonathan Feldman /

sjrat666

Dec 24, 2018 02:01PM

Man, I am glad I started this thread. Y'all are dropping some good advice. I'm all fired up!!(edited)

Re: Welding up intakes: y'all got any pro tips?

JBOT Admin /

capturedbyrobots

Dec 24, 2018 02:31PM

A fantastic flange for big reed intakes is some Simpson strong ties base plate 7/8 washer or 1in.

Like 1/4 in thick.

Re: Welding up intakes: y'all got any pro tips?

Master D. Baiter /

scootertrash

Dec 24, 2018 03:21PM

An easy start to a flange for $.50

If u can order ur wire online Amazon is way cheaper. Like $3.50 lb. versus $13.50 retail, get a big roll for cheap then u can get good practice. See if the welder fits a 10lb roll, congrats!