welding brake stay to fork bottoms

[LeighW]

hi all iv put a set of 84 cr 500 43s on my cr 250 and need to either make a plate up or weld a block to the fork bottoms for the backing plate on the bottoms but being cast or forged etc will the weld hold to the fork bottom as I know nothing about aium welding cheers leigh

[SON]

DANGER Will Robinson DANGER

[tony27]

Did it years ago when converting a Ty350 to disc front brake, there is a lot more than welding needs to happen so I'd be looking at the bolt up plate idea

[Branchy]

maybe look at the fronts or suzuki's that had simmons fitted in the late 70's ? i have a similar issue to do soon on a non lug simmons fork leg to be fitted to lug brake backing plate ona Zook 400T

someone might just have already done this sucessfully , without fencing wire and racing tape

[topari]

A new lug is doable. I will try and find some web pictures. Generally a lug with surrounds are welded to the fork leg. I have seen a few where disks brake caliper lugs were welded to a fork leg.

[bazza]

welded lug on Beteor forks on my B44 ,no trouble after 4 seasons

[MaxPower]

Ive seen where someone will fit a 87 cartridge fork to a drum brake bike by running the tubes and the internals and use the older lowers. I havent done it but been told its relatively easy to do. there is a washer or spacer that had to be used but nearly just a switcho changeo

[djr]

one problem you can have after welding is distortion to the inside of the fork bottom which can cause binding when the forks compress . this can be overcome with machining or perhaps position an old fork tube inside when you weld to help it hold its shape.

[Slakewell]

I have done this job.
First off you need a dam good alloy welding trades person.
Second measure or mic the area inside the fork where you going to weld. Set the fork bottom up in a lathe and check centre line. Weld your lug on and try and cool the fork leg slowly to lessen distorion. I would place it in a bucket of lime.
Onced cooled remeasure the area around the weld and if it's more than 20 thou out you will need to machine the leg useing the centre line you established before hand. If it's just a bit out use a engine bore honning stone tool.
As it's dam hard to get the lug in perfect placement I made the lug over size and then milled it to size afterwards.
I did this job when I owned a machine shop and a tig welder so It may be cheaper to try other meathods. Goodluck.

[rocketfrog]

I fixed a disc front wheel and caliper onto an old YZ drum fork front end.

I loaded Aluminium wire into the mig and tacked a bracket into place with the caliper squeezing the disc and my fabricated bracket bolted to the caliper. Next I removed the fork and disassembled the tube to access the lower which I filled with water to help with the distortion while I ran full welds.

This worked a treat, I was very proud that my limited engineering and welding knowledge at age 14 had achieved such great results. I rode that bike for years without incident.

Would I recommend doing this again - Nooooo Way!!!!!!

A bolt fell out of the front caliper of my KTM whilst trail riding, locked on the front brake, and damn near killed me!

I thought back to my modified disc set up and counted my blessings that lady luck was on my side for those years, things could have gone soooo Wrong!!

Read danger danger!!!