Swingarm question

For what it is worth, I just received and installed the bronze bushings from Mikes in my 77 this weekend. No problems at all with the fitment.
As a side note, when I wanted to order one of those infamous starter gear kits, Mikes let me know that they rejected a batch because of a quality problem. Getting a new bach in a few weeks.

Posted via Mobile
 
60 grit sanding wheel did the trick. I can now put in the cylinder by hand with no hammer or mallet.

full
 
Folks, we have two issues here. First: inner bushing (AKA pivot tube) fitment in the outer bushing. Sometimes a little touch-up is needed after installation; it's seldom anything that a light touch with a paper roll won't cure. Second: outer bushing clearance from the thrust covers (AKA grease seals). The swingarm axle is a pinch bolt, and it pulls the frame and thrust covers tight against the inner bushing. If there's not a bit of side clearance between the thrust covers and the outer bushings the outer bushings will be pinched as well. Too many guys tighten the swingarm axle nut until action of the swingarm starts to get stiff, then apply the lock washer and call it good; but if the swingarm axle nut isn't torqued down firmly (latest manual spec is 47 footpounds), frame flex will result. And yeah, I know about the needle bearing kits with the thrust bearings that won't take more than 30 footpounds--that's why I don't use them anymore.

Bear in mind that tolerances at the factory were so loosey-goosey that some swingarms were produced with so much side play that shims had to be installed at the factory to bring side play under the max limit of .020", so sometimes you'll get a swingarm that will allow adequate end clearance for the inner bushing after bronze outer bushings are installed, and sometimes not (inner bushing end clearance=side play). The best way to know what's going to happen is to measure before installing the outer bushings in the swingarm--add flange thicknesses to swingarm pivot width and compare to the length of the inner bushing.
 
Great info. I'll check this. I'm really close to just hardtailing this bike lol

Folks, we have two issues here. First: inner bushing (AKA pivot tube) fitment in the outer bushing. Sometimes a little touch-up is needed after installation; it's seldom anything that a light touch with a paper roll won't cure. Second: outer bushing clearance from the thrust covers (AKA grease seals). The swingarm axle is a pinch bolt, and it pulls the frame and thrust covers tight against the inner bushing. If there's not a bit of side clearance between the thrust covers and the outer bushings the outer bushings will be pinched as well. Too many guys tighten the swingarm axle nut until action of the swingarm starts to get stiff, then apply the lock washer and call it good; but if the swingarm axle nut isn't torqued down firmly (latest manual spec is 47 footpounds), frame flex will result. And yeah, I know about the needle bearing kits with the thrust bearings that won't take more than 30 footpounds--that's why I don't use them anymore.

Bear in mind that tolerances at the factory were so loosey-goosey that some swingarms were produced with so much side play that shims had to be installed at the factory to bring side play under the max limit of .020", so sometimes you'll get a swingarm that will allow adequate end clearance for the inner bushing after bronze outer bushings are installed, and sometimes not (inner bushing end clearance=side play). The best way to know what's going to happen is to measure before installing the outer bushings in the swingarm--add flange thicknesses to swingarm pivot width and compare to the length of the inner bushing.
 
Can you use a small hoan(sorry for the spelling) I have a small 3 stone that I use on old ford wheel cylinders. I chuck it up in my hand drill and then use a bit of oil. This takes a bit of time but it might be worth a try.
 
That would work too. I ended up Using a 60 grit flap wheel attachment. Worked perfectly.

Can you use a small hoan(sorry for the spelling) I have a small 3 stone that I use on old ford wheel cylinders. I chuck it up in my hand drill and then use a bit of oil. This takes a bit of time but it might be worth a try.
 
Ground down bushing so pivot tube is out slightly. All greased up and ready to go

full


Folks, we have two issues here. First: inner bushing (AKA pivot tube) fitment in the outer bushing. Sometimes a little touch-up is needed after installation; it's seldom anything that a light touch with a paper roll won't cure. Second: outer bushing clearance from the thrust covers (AKA grease seals). The swingarm axle is a pinch bolt, and it pulls the frame and thrust covers tight against the inner bushing. If there's not a bit of side clearance between the thrust covers and the outer bushings the outer bushings will be pinched as well. Too many guys tighten the swingarm axle nut until action of the swingarm starts to get stiff, then apply the lock washer and call it good; but if the swingarm axle nut isn't torqued down firmly (latest manual spec is 47 footpounds), frame flex will result. And yeah, I know about the needle bearing kits with the thrust bearings that won't take more than 30 footpounds--that's why I don't use them anymore.

Bear in mind that tolerances at the factory were so loosey-goosey that some swingarms were produced with so much side play that shims had to be installed at the factory to bring side play under the max limit of .020", so sometimes you'll get a swingarm that will allow adequate end clearance for the inner bushing after bronze outer bushings are installed, and sometimes not (inner bushing end clearance=side play). The best way to know what's going to happen is to measure before installing the outer bushings in the swingarm--add flange thicknesses to swingarm pivot width and compare to the length of the inner bushing.
 
There's one more step you should take to insure proper and easier lubing of the new bushings. The originals were designed to receive their supply of grease from the side, about halfway down the length of the bushing. The pivot tube and the bolt w/ grease fittings on the ends was designed to deliver the grease in this manner. Your new bushings probably have swirl grease grooves on their I.D.s running from top to bottom (or front to back). They were designed to get their grease supply from the rear. There are a couple ways you can implement this. First is to simply add another grease fitting to the center bottom of the swingarm pivot area .....

SwingarmGreaseNipple2.jpg


Second is to add two additional holes (red arrows below) to the pivot tube at the center. This will allow grease pumped into the original bolt end grease nipples to exit here and enter the new bushings from the rear .....

PivotTube.jpg
 
Excellent tip! Good thing I didn't install it yet! Going to get this done

There's one more step you should take to insure proper and easier lubing of the new bushings. The originals were designed to receive their supply of grease from the side, about halfway down the length of the bushing. The pivot tube and the bolt w/ grease fittings on the ends was designed to deliver the grease in this manner. Your new bushings probably have swirl grease grooves on their I.D.s running from top to bottom (or front to back). They were designed to get their grease supply from the rear. There are a couple ways you can implement this. First is to simply add another grease fitting to the center bottom of the swingarm pivot area .....

SwingarmGreaseNipple2.jpg


Second is to add two additional holes (red arrows below) to the pivot tube at the center. This will allow grease pumped into the original bolt end grease nipples to exit here and enter the new bushings from the rear .....

PivotTube.jpg
 
Note that the added grease nipple goes through the edge of the gusset plate. You want the added thickness the plate provides so the threads of the grease nipple don't protrude into the arm and rub on the pivot tube. That could also block the end and impede the grease flow.
 
Got it. Thanks.

Note that the added grease nipple goes through the edge of the gusset plate. You want the added thickness the plate provides so the threads of the grease nipple don't protrude into the arm and rub on the pivot tube. That could also block the end and impede the grease flow.
 
Note that the added grease nipple goes through the edge of the gusset plate. You want the added thickness the plate provides so the threads of the grease nipple don't protrude into the arm and rub on the pivot tube. That could also block the end and impede the grease flow.

thanks, saved me from making a mistake :doh:
 
Just a thought here but when I had a Ducati 900 some years ago and fitted new bronze bushes I found that the spindle would be fine when pushed in from either side but would tighten up solid when it pssed through both bushes. It turned out that the two bushes were slightly out of line, a common problem on the Ducati GTS, and what I needed to do was get hold of an expanding reamer long enough to cut both bushes at once and slowly increase the bore sizes until the spindle turned freely. I wonder if it's the same issue here?
 
Bushings were on straight. Even Before sanding the bushings down, I could not even get the cylinder through even one bushing. I could before it was in the swingarm. It compressed that much.

Just a thought here but when I had a Ducati 900 some years ago and fitted new bronze bushes I found that the spindle would be fine when pushed in from either side but would tighten up solid when it pssed through both bushes. It turned out that the two bushes were slightly out of line, a common problem on the Ducati GTS, and what I needed to do was get hold of an expanding reamer long enough to cut both bushes at once and slowly increase the bore sizes until the spindle turned freely. I wonder if it's the same issue here?
 
Back
Top