need advise on damaged frame issues

[david a luciani]

hi guys,
i just got back from a little pick-up mission in Pa.
i got two karts. one a margay mk2
the other i'd thought was possibly a bug but on getting it i'm thinking maybe a gk1200 as it has an aluminum seat and tray.
the steering hoop is narrow which is what is confusing me .
i will post pix as soon as my @#$%^& digital camera is fixed.
THE PROBLEM
both frames have been repaired.
the margay was repaired right at the steering hoop/frame connection on the engine side. the frame seems to have cracked there. the repair is crappy welds bloobed on and the frame is sagging there so i have to do a new repair. i was considering adding a tube insert inside the frame tube to help spread the load . or will a just well done weld and annealing be a safe repair?

2nd repair.
from what i've read in the posts this one is worse. the right side of the front axle has been welded on the axle tube. it looks really good as far as the work but i've gotten the impression that a repair/welded front axle is a big no, no. please advise as to what needs to be done.

as i've said as soon as i fix camera issues i'll post pix thanx for any help dave

[jmendoza]

Sounds like nothing a tubing cutter, cutting torch, grinder, tube bender, and MIG welder cannot fix. Hack off the bad, weld on the new! It's just s bit of work, but can be done.

[david a luciani]

Come-on, i'm way more anal than that!!!

And, i guess i'm being a wimp about these repairs.
buuut at 60 + mph i would hate to just think and hope i guessed correctly on these repairs.
i suppose the people racing with me would also like me to be sure what i had in mind was safe too!!!
Anyway, i didn't view it as a big problem and i never thought it's impossible.
if it was a harley bike it'd be fixed already.
Although i doubt i'll be pulling out a cutting torch on anything as they're pretty indiscriminate as to what gets cut .
my point is I'm not familar with were stress areas becomes a major factor on racing karts.
What several people have suggested off line was along the lines i was thinking.
that is to grind and hand file the crappy weld away and expose the crack.
if it's not badly burned away i'll cut thru the tube and fit an insert inside to spread the load a little.
then a slot on one side to allow the tube to be slide back in the other side .
bevel the weld areas and then off to my welder cause his welds are strong and pretty.
the front axle,from the advise i've heard , needs to be replaced , so i'll have to order new tubing for it .
i'll probally photograph the projects so it can be viewed by anyone new to a major frame repair in this hobby.
if anyone sees a flaw in my plan please let me know. thanx dave

[Rob Voska]

Pictures would help a bunch. Help us help you......

[allan savins]

Hi,
Sounds like mild steel welding rods have been used upon a Chrome Moly frame. Not good!
I have found to repair small sections of frame (if they are straight sections) you need to get some tube with the same outer diameter, but greater wall thickness. Cut out the damages section of tube. Machine the new section tube down in a lathe, so you press the new section of tube into what is left of the old tube and then weld up the joint. Strong joint and tends to end up straight. I should post some photos.
Hope this helps...
Cheers,
Allan

[Dan Dettmann]

Another method I have used (on a sway-backed King) is to cut out the offending section (in my case about a 6" long section on both sides at the steering hoop) of the frame tube and replace it with a new piece of the same o.d. and wall thickness after installing an additional piece of tubing with the same o.d. as the i.d. of the tube you're replacing (to act as a dowel so to speak). This could run the full length of the replaced tube or just at the joints. Drill a hole in the main frame tube and plug weld the dowels in, then do a butt weld on the new and existing tubes to complete the job. Aircraft Spruce is a great place to get tubing and other stuff.

[paul pollaccia]

Under no circumstances stick or mig weld it if chrome moly. Gas weld or tig weld. If you can,t do it yourself have it done by a competent welder. I hate to tell you it could cost upward to 75.00 dollars an hour.

[david a luciani]

ok. all the repair advise on each forum is about the same.
turns out the kart with the welded axle is a bug.
got a new axle sent to me from k&p great guys thanx tons.
and thanx rob for pointing me in the right direction.

i have an awesome welder ($ 40 per hour)
he does all types of welding for us.gas - tig - mig - stick - ect,. etc.
usually Harley repairs.
he even will weld up a crack in a used gas tank.

the gokarts is something i'm gonna surprise him with.
one thing i hope is that he can do build up welds on magnesium.
i figure to have him tack the new axle in place then do 1/4 weld passes on each bead to keep heat to a minimum.
will probably photo the repair process.
will post when i'm done
dave

[Dave Brillhart]

FYI, if gas welding is used, mild steel rods are corresct for 4130 tubing, thousands of aircract cannot be wrong. The mild steel is much less resistant to stress cracking than chrome moly rods, an imporytant factor in kart frames.