Ok, you motor heads. Answer this question.

[team burrito]

I have a Kelly set-up with a P/S X12 arm. It's a very fast motor, but the can bushing unsolders itself while racing. There's a big gap around the bushing, so I filled it in with solder. After testing, the solder around the bushing was gone. Not a trace anywhere. So I tried Slick 7 high-temp silver solder, rated at 700 degrees. After racing, the same problem occured. Can anybody explain what's going on & how should I fix it?

[glueside]

I have the same gap on my motors, but have used the high temp solder and it has not been a problem since.

[Cayo71]

Try sending your arm for rebalancing services. That happened to me twice and both times I've lost the Tag on the arm during the race causing it to go waaaayyy out of balance. It might not be your case if you still see the tag but if the arm is out of balance you should experience the same problem. The vibration breaks the solder joint, specially when using silver solder which is less elastic than regular 60/40. It is not a matter of heat but mechanical stress due to the vibration.
Sorry if it is toooooooooooooo much information....lol :eek:
Good Luck!

Ricardo.

:)

[ViperJerry]

If I recall, there was a bad batch of can bushings going around about six months ago. I think Monty @ BOW had a few.

You can try opening up the can to accept the larger Koford can bushing, or try another arm. My money is on the bushing.

Viper

[Gary NJ]

...of bad bushings. Bushings from this batch were unsoldering from the cans with setups and arms that hadn't had problems previously.

[RocketRod]

The bushing trouble I knew of didn't deal with unsoldering but the size of the hole for the armature shaft.

Make sure you clean that area thoroughly -- and use some acid flux on the first go round of tinning.

[Slidergreg]

Switch over to Alpha 5mm flangless bushings and line ream the whole setup with a 2mm reamer. You will not see any more of this happening on your motors.

Greg G. :eek:

[zamzickles]

There was talk about some problems with that batch of S7 bushings. Using a counter sink tool, slightly make the inner and outer edges of the hole countersunk. This relieved the problem for most people.

But ALWAYS keep in mind that problems with bushings usually indicate that the arm may be "leaning on" the bushing. If the natural centering of the arm, within the magnetic field wants to pull the arm up against the bushing, it will create heat. Not only does this create heat but it takes away from the rotational forces of the arm by producing angular forces which detract from the overall goal of producing RPMs. You may need to remount the magnets a couple of thousandths higher in the can. Not too high or you'll end up melting endbells.(same problem different end of the can)

Also be sure that you do not end up with an ALUMINUM spacer next to a bushing. Aluminum spacers should only be used next to ball bearings or to fill the gap between an arm and a bronze/brass spacer.

[JayGee]

Didn't I tell ya that you need to stop using bubblegum to glue those things in!

Justin and I are headed up to Santa Rosa tomorrow to practice for NorCal. Call me if you wanna join us.

-Jeff

[Mark Manion]

T.B. Let me see one at the next race, I can help.

[HurricaneLarry]

You are not get a clean solder joint on the can and bushing. Try using a small diamond tip tool to scuff up the can and the bushing, then acid flux to solder it in with.


What looks like is happening is that you solder the bushing in and think it is good, you race the car and the bushing is spinning in the can as it spins it cleans all the solder off both can and bushing. sound about right?

[Monty @ B.O.W.]

From approx. February through June of last year, there were large numbers of bushings floating around that were definitely less than desireable. As Zammy notes, they were most easily recognized by burrs forming a convex formation around the exit of the shaft bore. Countersinking them allowed more oil in, which helped but did not cure the problem. They were definitely MELTING out of the can in hot power conditions. I switched to a higher temp solder, which helped, but the real cure came with just replacing the bushings with newer ones. Both ProSlot and RJR are currently delivering good bushings.

[Joe SSS]

ive had this problem also..when u solder in the bushing..look inside the can and see if the solder flows around the bushing from the inside of the can..if its not..get a small file and file down the surfuce where u put the bushing in..then it will flow..also try makin the hole bigger