Crazy Frame Fab Question

[Gmorrone1214]

I know this may sound idiotic but I have a frame modification question. I currently have the TC bros hardtail welded onto my 1979 xs650. Now would it be possible to take the tc bros hardtail and make it a drop seat?

Nothing crazy just something like

Would it be possible to detach the top railing and just bend them down to something similar to the above picture and weld back up?

I know I might get flamed for this but worth asking.

 

[fredintoon]

I know this may sound idiotic but I have a frame modification question. I currently have the TC bros hardtail welded onto my 1979 xs650. Now would it be possible to take the tc bros hardtail and make it a drop seat?

Nothing crazy just something like View attachment 54673

Would it be possible to detach the top railing and just bend them down to something similar to the above picture and weld back up?

I know I might get flamed for this but worth asking.

Hi Gmorrone,
well, I'd flame you for removing the rear suspension in the first place but it seems that ain't allowed.
Yes, that'd work, why not? Usual caveats about ANY frame mod needing good welds, of course.
Not sure about the Kawi green paint job though.
But what do I know about colour? My XS11 rig is painted tow truck orange.

 

[Gmorrone1214]

Ha, was not going to go with that Kawi green at all, was just using the bike as a reference to the drop seat.
As for the welding I can mig and have gas set up for it, but I rather go get it tig welded by a professional as I did originally.

 

[fredintoon]

Hi Gmorrone,
that's the safe and sensible way to do frame welds. Or indeed, any weld you are trusting your life to.
Once that hardtailed low rider is on the road again you can safely ride it to your chiropractor's office.

 

[chizler62]

That's not a huge project and can be done easily. Just note that the seat stays hold the majority of the vertical load of the frame. When decreasing the drop out angle you also decrease the load the bike can take. The inner angle of the tubes off the axle plate. Bottom being the chain stay and the top being the seat stay. When that angle decreases it will lower the load it can take. Think of angles that bridges are made out of.
What's pictured looks to be ok. Perhaps not for a 300lb rider for years tho

 

[member3480]

You can just cut away top tube and replace it with new bent tubes. This frame and bike was done as a drop seat with a TCB kit.

 

[rusty rocket]

My old boss used to say nothing is impossible the impossible just costs more.

 

[59Tebo]

...and Evel Knievel once said "it's only impossible 'cause nobody's ever done it before"

 

[Gmorrone1214]

Alright, thanks everyone for the info. Its def something I will prob do later down the road.

New question regarding the solo seat mounting.
Should I weld it to this location in the picture.


Or do I have to weld a small bracket inbetween the frames and make it sit on top of that

 

[hard_y_rd]

I welded mine low like that cause i didn't want my seat all cocked up high in the front. Make sure you have the carbs mocked up or the hinge may interfere with the air filters and other things.

 

[Gmorrone1214]

You can just cut away top tube and replace it with new bent tubes. This frame and bike was done as a drop seat with a TCB kit.

Would I have to buy the tcb hardtail kit to do this?

Or could I just cut off the tubes that are already welded and just change the angle. Then cut away at it since it will be to long and re-weld it back up?



How would I go about removing the original tubes?

Or would it just be easier to buy the frame kit and do it over again( which I really dont want to do lol).

 

[member3480]

You can just take out top tube and if you do it right you can lower them. Both ends have to be cut free.

 

[Gmorrone1214]

Daddyg, you think it would be alright to do this without a jig but the rear tire and frame inside the bike?

 

[member3480]

If you can set it up on a table and make sure its level I think you would be ok

 

[Gmorrone1214]

I know this topic has been beaten to death already but I have the eastwood 135 mig welder. I been using it on this bike for odds and ends, but im not sure if I should use it to attach the frame rails to the axle plates and so forth.

Here are some pictures of the welding I did with it alrready, lmk what you think sorry for the bad quality.

'
The first one is mig welded seat bracket

The 2-3 are arc welded i think 3/16 steel

The welder will weld up to 1/4 with arc it states, I wouldnt mig the frame rails as I believe the welder cannot get hot enough.

 

[member3480]

Are you using gas with the mig? 135 with gas would do ok.

 

[Gmorrone1214]

yeah 75-25

 

[member3480]

Then your fine just get some good heat penetration.

 

[Gmorrone1214]

okay thanks. Ill prob try and tackle this tomorrow and will update how it goes. Just one last question (prob killing you with them haha just want to make sure before I go hacking away).

In post 11 the axle plates are slotted. After I cut the weld away and get it free(obviously cut the top off as-well), do you believe I can change the angle enough to get it to look as post #6 hardtail that you did? Since I wanted to keep the line straight and not bend it as in the first picture I posted.

 

[member3480]

Yes you can only lower a little or you will have carb placement problems
This is a stock bottom rail and a lowered top.