Motorcycle frame question

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Can I use a Harbor Freight 65/90 amp gasless flux-core MIG to weld a motorcycle frame? I need to cut the steering stem off and relocate it for a custom bike.  I am new to welding.I tried welding on a piece of scrap from the frame after cutting, and tried all the different settings.  My best results were full power, full speed feed with 0.35 wire.  Penetration looked good like it does on the examples I found online.  It looked like a "stack of nickels" as well.  The finished weld raised about 2mm above the workpiece, and about 1mm below on the underside.When I welded, the metal got orange-hot about half an inch on either side of the weld bead.This is a very high stress point on a motorcycle, and I have been told by a friend that I can't use a flux core MIG for this application.  I'd rather err on the side of caution, so I'm posting the question to you experts.  Can I weld this with the MIG I mentioned above?What do you think?NOTE:I already did a four-inch "tack" (I'm calling it a tack because I know it isn't going to be the final weld-job here) weld on either side of the neck, and it is where  I want it to be.  I most likely will take the frame to a professional welder and have them finish the welding with whatever method they recommend, and will ask them to reinforce the area in whatever way they think is best.Jordan AkA polishbeer
Reply:Also, the frame is not tube-steel. It is large diameter box-section, about four-inches across the top and maybe seven inches high box with reinforcements inside.Thanks for your suggestions.
Reply:#1, don;t try anything to that bike, until you are confident with your welding skills. you will have to ride this thing (or someone else will), so you had better pray that it won't break.#2, don't use the HF wire that came with the welder. from what i hear it's a POS spool. get some good stuf like Lincoln electric's NR211MP from Home Depot / Lowes. try practicing with that stuff first... it'll be better. #3, no matter what kind of self-shielding Flux Core wire you get, your spatter will never be good. especially with a bike frame, you want to get the weld looking as pretty as possible, since it will always be visible, and it will drive you nuts if it looks inconsistant with the other welds on the bike. #4, I hate to say it, but your friend is wrong. if you can weld it with a true MIG set-up, you can probably weld it with flux core. Flux core is actually easier to work with (IMHO) than MIG... no gas tanks mainly. the only drawback is, like i said, the spatter can get to be a hassle.#5, if you already plan on taking it to a professional welder, i'd just have them do the whole thing. more than likely (with my limited expereince anyway), they will charge you more for something like your situation, than if they were to do the whole thing themselves. there is no way that they can give a good weld, and be able to stand firmly behind their work without them grinding away all of your stuff... grind, all your other stuff off, put one tack at each corner of the pipe, and maybe one on each side (8 total) and take it to the welder. if they have to grind, they will much more prefer to grind SMALL tacks, than a 4" layer of slag.Also, if you are getting your best results at the highest power on your welder, i'd suggest you either get a new welder, or jsut have someone else do everything. you will most likely hit your duty cycle way before you get done with a continuous weld on a 7" length of pipe.Hope that helps. other guys, feel free to correct me if i'm wrong. i figured this was a good starting point.Later,Andy
Reply:I agree with you Andy.Ask the welder how long it will take to do the job. Add 10% and offer to pay him for that time if he will walk you through what he is doing and why he's doing it that way.  Call it a tutorial session.  Then watch and learn.
Reply:I would say you need to put this thing in a jig, and weld it in place. Otherwise, the steering stem will wind up crooked, and the bike will always drive a little crooked. Also, you will want to insert solid inserts into the bearing races to keep them true round, or else the bearings will bind, or wear much faster than normal. I guess it is up to you, as better than 1/2 of all the custom choppers out there are total hacks anyway. As for fluxcore mig?? It is fine, you will be cleaning up the frame and painting it anyway.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Great advice by everyone given, and other than the usual negative comment on choppers something to think about. I don't have a dirt bike or rice rocket, yet manage not to make derogatory comments about them repeatedly. On your frame job if you aren't 110% sure don't do it, take it to a pro.