Can I weld on to the cylinder?

[YZThumper]

Bought a used 2001 KX 250 and I'm in the process of taking it apart and performing needed maintenance. I took the pipe off, and noticed one of the pipe springs was missing. Upon closer inspection, the tab on the exhaust port that holds the spring was snapped off somehow :bang: . What is the cylinder made of? Can I have someone weld a "loop" onto the exhaust port where the old tab was? If so, can it be welded without taking the engine out of the frame?

 

[biglou]

I'm sure it can be done by a competent welder. I'm sure the cylinder is made of aluminum. I bet 89'r knows for sure, though! :cool:

 

[Ol'89r]

I'm sure it can be done by a competent welder. I'm sure the cylinder is made of aluminum. I bet 89'r knows for sure, though! :cool:

Tanks Lou. ;) I don't know nutin for sure but, an edjumacated guess would be, yes.

YZThumper.

Clean the area very good and make sure there is not a bolted on flange that bolts to the cylinder to hold the pipe and springs. If there is a flange, it is most likely made of steel and you can just unbolt it and weld it.

If the pipe goes directly into the cylinder without a flange, then you would have to have a tig welder repair it. The cylinder is made of aluminum and would have to be tig welded. Just have the welder weld a little blob of weld to the area where the spring goes and then drill a small hole in the blob for the spring. Be sure to disconnect your CDI box before you have it welded. (Just unplug it.) The high frequency used in tig welding can sometimes damage the CDI unit.

Good luck.

Can I go back to sleep now Lou?? :laugh:

 

[YZThumper]

Thanks Lou and Ol'89r, I appreciate you taking the time to respond :cool: . This piece is definitely not bolted on, it looks these pipe mounts were actually part of the cast for the cylinder. I just can't figure out how the squid I bought the bike from managed to snap this piece off :think: The KX pipe fits inside the exhaust port, unlike my YZ's where the pipe mounted around the exhaust port. Should I disconnect all electrical components, i.e. Stator, Coil & CDI, or is the only possible damage going to be to the CDI?

I was actually thinking of pre-fabbing an aluminum flange with a hole in it, and having the welder tack it on the cylinder via a TIG. I wasn't planning on taking the cylinder off the bike to do this, and I don't think I could get a drill in at the right angle to drill a hole after it's been welded.

What do you think?

 

[rickyd]

I would take off the cylinder and weld on a pre-fab as you mentoned.. Since having the cyl off, would be good at possibly re-building the top end.. Plus it will be easier for the welder too weld on w/the cyl off..

A little off subject, a while back i bought a set of FMF pipe springs for my 01kx250, they lasted for about 15 minutes and disappeared.. Stick w/the stock pipe springs..
Rick

 

[Ol'89r]

Should I disconnect all electrical components, i.e. Stator, Coil & CDI, or is the only possible damage going to be to the CDI?

I was actually thinking of pre-fabbing an aluminum flange with a hole in it, and having the welder tack it on the cylinder via a TIG. I wasn't planning on taking the cylinder off the bike to do this, and I don't think I could get a drill in at the right angle to drill a hole after it's been welded.

What do you think?

YZThumper.

Just disconnect the connecter at the CDI box so that the CDI box is not connected to ground or the system. You can remove the CDI box to be extra safe but, it isn't necessary. All other electrical parts will be ok.

Pre-fabbing an aluminum flange to weld on is a good idea, but be sure to use the right type of aluminum. Some alloys are not weldable. Be sure the alloy that you use is a 6061 or 5052. Recommend 6061. :cool: