gggGary's latest XS project "madness"

[gggGary]

Thanks kind sir but the problem's not the rod. s'more pics.



I see now someone had ground the hex off the bottom of the rod cuz it IS tight but the end of the MC piston getting pushed in by the swing arm when the shocks are compressed is the problem.
This is a fairly thin 4130 custom swing arm.
Just a pic from a junkerMCin the bins but the piston end exposed

 

[gggGary]

I'll see if I can shave a bit off the MC mounts to move it outwards a bit. But it's close to the frame too.

Um yeah this HAS been going on a for a while.
I installed longer shocks years go, reducing the amount it hit.

 

[Jim]

I'll see if I can shave a bit off the MC mounts to move it outwards a bit. But it's close to the frame too.

I think you could safely take a mil or two off of both the frame and M/C bosses. Flatten frame edges a bit as required for fit.

 

[Adamc]

Well this is embarrassing!
View attachment 323720
I've been riding this bike off and on for twenty years. While doing "Jim created" work I pulled the swing arm for paint and a look see at the bushings etc. It wasn't til I was testing swing arm drop with no shocks attached that I realized why the rear brake rotor and pads showed more wear over the years than I would have expected, since this bike has a VERY effective front brake. I think this has been going on ever since a PPO installed the custom swing arm back in, oh the 1990's
It's not real obvious.... Like I said, didn't notice til I was running the swing arm through it's range up 'n down.
Don't have a definitive solution yet.
The rod doesn't touch the arm when the brake pedal is on the pivot shaft that's not the problem....
Kinda lucky it didn't cause a nasty surprise, though I did do a lurid rear wheel slide entering a corner when I first got it that I ascribed to a too old tire!

Ooooopsy!

 

[gggGary]

Brake interference all fixed, 5 little "improvements", plenty of room now.

One item down fifty to go...

 

[Jim]

Pure "Madness!!"

 

[MrBultaco]

PURDY...

 

[5twins]

So, what were the 5 little "fixes"? I think I see a bit of a "groove" ground into the top corner on the swingarm. A little off the MC mounts too I assume?

 

[gggGary]

So, what were the 5 little "fixes"? I think I see a bit of a "groove" ground into the top corner on the swingarm. A little off the MC mounts too I assume?

Thanks for your interest.
The swing arm is a custom so....
Backed up that swing arm rectangular tube on a 2x4 in a vice, used an impact socket as a form and beat it into the tube to create a "J Dent" in the tube, the amount of effort with a big ball peen to do that was impressive. That swing arm is light, but seems to be VERY strong/rigid. Was very well made, machined, welded. Checked afterwards and the sleeve still rotates smoothly in the tube. The swing arm has a pivot grease zerk installed.
Filed a bit away from the MC mount pads and inside face of the frame bosses moving it way from the swing arm. (counts as two items)
Filed a bevel on the end of the MC piston,
Added a needed shim to the RH swing arm pivot grease seal, shifting the arm slightly left allowing the sleeve to flush with the bronze bushing face.
It now moves with light hand pressure when the (full size thread) pivot bolt is tightened, before it dropped of it's own weight. All together it moved the parts apart to create adequate clearance. Allison came down and assisted with rear wheel installation, with all the mix n match custom parts there's an unusual assortment of spacers, washers, bushings in the axle assembly.
Removed the safety wired master link checked everything over on the X ring chain, put on new safety wire and I think it's good to continue on in service.
After that, lawn mowing and stump cutting occupied the rest of the day.

 

[gggGary]

Before the fix was in.

 

[gggGary]

 

[willis]

That’s a nice looking setup there Gary. Looks like it drops your feet about an inch too.

 

[gggGary]

I've got a small story and an apology to make.
Did the R&R on the back brake, it was time, hadn't opened the hydraulics on my watch. (more than 10 years?
Nothing bad just the usual spooge and build up. It's been sitting dry on the bench for a while, installed the MC, see above about push rod interference. Yesterday, did the patented gggGary caliper fill, install line, push in piston, fluid goes up into the reservoir and done routine. AND that didn't get a hard pedal. Did some bleeding, got a little air out. Allison helped with pedal pushing. Still no joy. grr.
Looked and thought a bit.
p.s. all through this caliper is off the bike, no pads installed, using a 6" c-clamp to keep the piston from coming all the way out.

So the drill was;

• caliper piston travel blocked with c-clamp
• paper towel under the banjo area to catch a bit of brake fluid
• Allison on the lever
• I crack the banjo loose. Allison slowly pushed pedal, tighten banjo, repeat one time.
• Done, hard pedal
• pumped the caliper piston out near limit, checked for air at caliper bleeder one more time, fully pushed in the caliper piston and assembled, installed, pads and caliper

So apologies to those I've told the gggGary bleed will fix a rear no pedal problem. With this high area in the path that's just not enough. Add the banjo crack bleed and you should have solid rear brakes. In a perfect world there would be a bleed valve tapped into the top of the MC.
Later model Yamaha's with complicated brake circuits do have extra bleeders at high points.
Could change to a bleeder style banjo bolt there...

C