Crack in weld behind forks......

I noticed a weld was cracked on a piece that I think is just to limit the length the handlebars can turn. It's below the triple tree on the underside of the frame....a small piece of metal is welded on there and sticks down. When you turn, the bottom of the tree hits it and stops from turning any further. This piece is cracked on my SBA. I checked last night on my buddies SBA's and all are the exact same way. Anyone else come across this?

Khand187 took a pic, i'll try to get him to post it.

I don't think its very harmful to the integrity of the frame strength.....hopefully.

We think it is the result of "crashes" and the handlebars coming in contact with the ground which puts excess force on that little nub sticking down.

Just wondered if anyone else noticed the same problem.

It shouldn't affect the strength of the frame, but I have noticed on some pitbikes, that little tab is welded pretty poorly. You shouldn't have any problem having a good welder secure it better for you. Just make sure they are experienced and won't overheat the area and make your steering tube out of round. That would make the bearing races off and cause other problems.

mighty_mace's SBA:

welds003.jpg

khand187's SBA:

welds005.jpg

thats seems to be just the Steerng stop comming off

Top one looks like a bad weld. It didn't stick to the stop well at all. Bottom one looks like it just took a bad hit and is splitting right in the middle of the bead. You should be able to find a heliarc welder who can fix them up. You'll have to do some disassembly though.

Yea, i was pretty freaked out when I first noticed it.....Afraid of the forks separating from the frame, but after taking a closer look it appears that tab is for steering stop only. Theirs a lot of force exerted on that little tab if the handlebars hit the ground on a crash.

Pound it back and have a guy weld it for $10 Should be a real easy fix.

They're both good examples of lousy welding technique ...... most people think you can get hold of a MIG and it makes you a good welder ...... LOL .....

The top weld pic is of a cold weld that didn't "wet in" or fuse ... it has just rolled over the top of unprepared metal and sat there like cooling candle wax (probably done too quickly down hand) .... and the bottom is simply too flat with not enough reinforcement (aka build up) .......... The secret to strong MIG welds is to use globular transfer (almost semi spray) and swing ahead back and forth as you travel to fuse the root where all the strength is ........ also grind scale and smoothness off every joint to get the metal to "wet in" ......

When you swing ahead keeping the wire aimed at the dead centre of the root ..... the arc gouges the parent metal for superior penetration .... then the swing back adds reinforcement build up to achieve a good looking weld that just simply won't let go unless the actual parent metal tears out beside it .....

What these chinese guys aren't doing is beefing up the weld right down at the bottom end where the stress riser starts ... a tiny weld across the bottom of the steering head from the inside would be totally adequate to stop the tearing from starting .... also if the flat bar had another piece welded on along its length to form a "T" piece , it'd be stacks stronger ....

Then again if you look at it from an engineering point of view ..... IF they WERE stronger ... the steering tube might have started to tear from the force ...... The bottom line is DON'T crash the bike ...... LOL .......

I'll keep that in mind. LOL haha

and what china bike is this????????????????????

and what china bike is this????????????????????

He mentioned it in the first post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now