Cradle Damage & Recommended Repairs

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T95

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I noticed two holes on my cradle that are elongated due to ware. Both are located on the right side, the first is the centerstand mounting hole.
The second is the middle hole of the three front mounting holes. This is located directly under the gear selector in the picture below.
What are my options for repairing and strengthening these mounting points?


Cradle Damage & Recommended Repairs



Cradle Damage & Recommended Repairs
 
I had mine drilled out to fit 7/16" aircraft bolts through cases and cradle for sure fit and bigger dia to take future loads. Center stand may be drilled to place a bush in to heal that slack. Some 850's bust the cradle holes out and repaired by thicker scab on plate plus bit longer bolts. I'm seriously considered doing that ahead of time on Peel project with alloy cradle that concerns me over long haul.
 
Plug weld and drill new holes. A nice chunk of copper or brass on the back side of the holes helps. You can take it to a welding fabrication shop. They should be able to do it of you can't.
 
caddy chris said:
Plug weld and drill new holes. A nice chunk of copper or brass on the back side of the holes helps. You can take it to a welding fabrication shop. They should be able to do it of you can't.
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The center stand is one part that I have not located yet, I removed it years ago, so i am having a bit of difficulty visualizing this. I understand the plug and weld. As far as the copper/brass repair are you suggesting welding on these materials as a backer plate or using them as washers?
 
Remove all paint, dirt and grease from around the hole on both sides. Grind any lips or burrs so that the area is flat. Clamp a flat piece of brass or copper on the backside of the hole. Cu is non ferrous so weld wont stick to it. It will act like a dam and will allow the weld penetrate the material and fill the hole evenly in one shot. Turn the welder up so it nice and hot. Practice on some scrap so you can get the feel for it. Start at the top and spiral around the edge till you get to the center and hold there for a moment. You should end up with a nice round domed weld with no undercut around the edges. Grind flat, flip over and weld the other side. Take care to clamp the piece solidly and let cool before removing clamps to prevent heat warpage.

Don't know if this is clear, but if you practice a few times you'll understand what im saying.
 
You could also drill it oversized and put a bushing in there.

Russ
 
caddy chris said:
Hell, just noticed you and I are neighbors! Where are you?
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Thanks for the help, I was wondering how the copper or brass came into play. You made it crystal clear.
I live in Pacifica, and you?
 
rvich said:
You could also drill it oversized and put a bushing in there.

Russ
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Russ,
I was wondering if using a bushing would be a viable solution. This is all new to me so if you could elaborate on the steps a bit more I would appreciate it!
Would you chose a shouldered bushing and would it need to be welded or mechanically fasted in place or just retained by the bolt and nut?
Thanks Gary
 
Hi Russ why not just get another engine cradle thats not wore out plenty of them around & cheap really by the time you ware out the replacement you'll also be wore out! Ziggy
 
T95 said:
Cradle Damage & Recommended Repairs
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The cradle wear/damage predominantly on the right I would guess was almost certainly caused by the bike being repeatedly kickstarted on its main stand.
 
My quick and dirty bushing technique for when you do not need a hardened bush is to drill the hole out just enough to get a pipe tap in there, then screw in a pipe nipple of the appropriate size. Cut it off on both sides, grind or file it flush. Then drill it out to the correct diameter for the bolt. I have used this often on various pieces of equipment. This might not hold up very well on the center stand hole as the pipe nipples are not very hard. Seems like a hardened bush would be good there despite the fact that the pipe might be as hard as the original steel in the cradle. I was thinking there was a thread a while back on making bushings for centerstands but I cant find it now. I suppose Grainger or McMaster-Carr probably sell hardened bushings for all sorts of applications. I haven't searched. If the bushing is held captive by the bolt I wouldnt worry about it going anywhere.
 
L.A.B. said:
The cradle wear/damage predominantly on the right I would guess was almost certainly caused by the bike being repeatedly kickstarted on its main stand.
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L.A.B.
Nice detective work. That was the only way I started until I took the centerstand off due to a broken spring, and a broke owner. From then on it was just a balancing act as I kicked her through.
By the way is the notch on the bottom of the cradle a stop or just more wear?
 
rvich said:
I was thinking there was a thread a while back on making bushings for centerstands but I cant find it now. I suppose Grainger or McMaster-Carr probably sell hardened bushings for all sorts of applications. I haven't searched. If the bushing is held captive by the bolt I wouldnt worry about it going anywhere.
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I was looking around for centerstand repairs prior to posting and I couldn't find anything. I also looked at McMasters. Ooooooo, me likes all the special little parts! That is also why I know about shouldered bushes.
 
T95 said:
By the way is the notch on the bottom of the cradle a stop or just more wear?
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The notch also appears to have been caused by the stand stop hammering against the cradle from "on stand" kickstarting, so it needs a weld repair.
 
That's a great picture of just how soft the cradle is and that it's a matter of both wear and stretching of the metal. The problem is that it's only around 1/4" thick on the load bearing surface. It's been a long time since I modified my centerstand so the dimensions are approximate. The holes in the cradle and the centerstand were so clapped out that new bushings didn't make any difference so I totally rebuilt it. I turned a couple discs out of plate to fit into the holes in the stand with 3/8" holes in the center and had them TIG'ed in. I got some 5/8" bar stock that I turned to a length that was just proud of the outside surface of the cradle and drilled out the holes in the cradle to match. The bar has 3/8" threaded holes in the ends. A section of tubing was welded into the cradle that has an inside diameter a few thou over the diameter of the bar. The bar is coated with grease and the ends of the stand are bolted to it. The stand is stronger because the ends are bolted together and the bearing surface is greased and stays reasonably clean.
It is sort of a major production and the cutting and tapping has to be done on a lathe to get the lengths right and square, but each step is about as simple as it gets.
 
bpatton said:
That's a great picture of just how soft the cradle is and that it's a matter of both wear and stretching of the metal. The problem is that it's only around 1/4" thick on the load bearing surface. It's been a long time since I modified my centerstand so the dimensions are approximate. The holes in the cradle and the centerstand were so clapped out that new bushings didn't make any difference so I totally rebuilt it. I turned a couple discs out of plate to fit into the holes in the stand with 3/8" holes in the center and had them TIG'ed in. I got some 5/8" bar stock that I turned to a length that was just proud of the outside surface of the cradle and drilled out the holes in the cradle to match. The bar has 3/8" threaded holes in the ends. A section of tubing was welded into the cradle that has an inside diameter a few thou over the diameter of the bar. The bar is coated with grease and the ends of the stand are bolted to it. The stand is stronger because the ends are bolted together and the bearing surface is greased and stays reasonably clean.
It is sort of a major production and the cutting and tapping has to be done on a lathe to get the lengths right and square, but each step is about as simple as it gets.
Click to expand...

Sounds like a solid fix! Unfortunately, I neither have the skills or the equipment to make the repair. I am thinking about getting a welder, but without any real experience I envision myself burning holes or mounding on massive infective welds. I took a machine class 30 years ago and got to play with welding, a lathe and a milling machine. You can imagin how far I can go on that skill set!
 
I sure don't have enough skill or welder to DIY either, nor want to invest the time and money to DIY. At least if ya do have it welded up the bead will be very hard compared to the mild steel cradle. If ya can't send to expert like Bob Patton I'd go with bushes for center stand or expect need to repair again some time later.

7/16" bolts solved cradle and case holes beat up in Ms Peel and only required cases in cradle drilled at machinist then AirCraft Spruce bolts stuck in. These could be weld filled then machine shop redrilled with cases installed to help align the bores. About once a year I hear of someone's horror to see their 850 cradle cracked. They almost all do preventive repair with extra plate welded or bolted over the 3 hole weak section. I've not heard of 750 fracturing here, just holes beat up, but assume 750 can fracture too.
 
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