750 swinging arm options

S

smlav

Senior member
Location
Shropshire UK
A bit of play in GTL 750 swinging arm, so need to take it apart and fit new bushes or bearings. what are my options? I’ve had a look through forum and found some old info, but nothing recent. I don’t mind fitting needles, but what are the gotcha’s with that?

I read that bushes are preferred, but new axle is unlikely to be found.

Sean
 
smlav said:
A bit of play in GTL 750 swinging arm, so need to take it apart and fit new bushes or bearings. what are my options? I’ve had a look through forum and found some old info, but nothing recent. I don’t mind fitting needles, but what are the gotcha’s with that?

I read that bushes are preferred, but new axle is unlikely to be found.

Sean
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None really, other that they won't be quite as durable as the bronze bushes. Even if they are regularly lubed (seldom the case!), they will wear rather quickly because of the tiny pressure points the needles place on the races. But "quickly" is a bit relative. While the bushes can last decades, you should be able to get about 6-7 seasons out of a set of needle bearings before they're truely knackered. I devised a conversion for myself incorporating a proper oil seal instead of having to rely on the standard plastic washer, this has held up nicely for over 10 years now.

piet
 
sfcpiet said:
I devised a conversion for myself incorporating a proper oil seal instead of having to rely on the standard plastic washer, this has held up nicely for over 10 years now.

piet
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I don't think the problem is a poor seal allowing grime in, Piet. If you loosen the axle and pump the grease in until it squelches out, then retighten the axle, you are highly unlikely to get contamination. So not sure you'd increase the lifespan of the bearings by fitting seals - but definitely preferable to have them there as insurance anyway. I'll be happy if I get 7 or 8 seasons out of mine.
 
All no great problem if the bike never sees rain. The stock washers cannot stop water ingress, add some sloppy maintenance, ie, not enough grease inside, the bearings quickly rot out. Must be a reason why it's always the drive side that's the worse of the two. Wear is always exaggerated and if a bearing is rusty, it will be the drive side.

Adding proper seals makes initial greasing quite difficult, they seal to such a degree that grease guns hardly manage to fill the swing arm pivot, using lots of grease during assembly is very necessary. Gets better after a couple of months of use.

I removed my swing arm after about 6 years of service to clean out the bearings for fresh lube. Waste of time and effort, all nice and clean with only the slightest witness marks of bearing movement, a far cry from what I'm used to finding there. I've modded the 3C and wifeys' 500 to accept the seals as well, very happy with the results.

piet
 
Interestingly, my GTL arm has no grease nipple, but my SF1 does. With GTL being a few years younger I wonder why no grease nipple was used. Same on rear brake, GTL non, SF1 yes.
 
smlav said:
Interestingly, my GTL arm has no grease nipple, but my SF1 does. With GTL being a few years younger I wonder why no grease nipple was used. Same on rear brake, GTL non, SF1 yes.
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Some 750's have rubber swing arm bushings, so don't need a grease nipple.
 
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smlav said:
Interestingly, my GTL arm has no grease nipple, but my SF1 does. With GTL being a few years younger I wonder why no grease nipple was used. Same on rear brake, GTL non, SF1 yes.
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Grease nipple on brake? Possibly retro-fitted.

I've added grease nipples to the rear brake lever pivot and the speedo drive housing on my forever bike. I've considered installing them on the brake pivots but haven't yet worked out anything I'd be OK with.

My GTL is one of the very earliest, VIN fits in the SF2 range, came with knackered bronze bushes and dried out grease nipple. Being ex-Kuwait Police Force, I've no reason to suspect it to have been non-original.

piet
 
Def agree about the need for full grease filling - with swingarm out I bolted the axle in place and pumped the grease in until it was worming out of every available air space around the needle rollers. The Honda swingarm on the SFQ didn't have a grease nipple, so I fitted one. It also interestingly had a cartridge ball bearing on the non-drive side and a needle roller on the drive side and a smaller axle that the Laverda. I modded it to take the std Laverda needle rollers and axle.

I'd be interested to see your seal design, Piet. It can be a tricky space to keep things in place when fitting.
 
Pretty simple Quentin.

Instead of the one long bearing bush, I use 2 shorter ones that leave enough space for a very narrow(3mm?) oil seal. This seals on the inner race and actually holds it all nicely together when fitting. The plastic thrust washers are still needed to keep the swingarm in line, because they hardly recieve any grease they get a drop of oil every now and then.

The shorter bearings also have the advantage that the needles are less prone to skewing while rotating under pressure, therefore resulting in smoother action and longer life.

piet
 
I am keen to add grease fitting to my rear set pivot points, I have had then szeaze twice over the years sticking in high enough gears to make getting home a pain in the arse. Last weekend's ride had it sticking down and needing to be lifted with my foot to upchange. I stopped washing my bike so often just for this type of stuff. I did wash it for the first time in at least a year, and it's back to stripping the rear sets for a regrease again. I was surprised to see zero grease nipples on my Atlas, even with its Single shock and linked suspension, very odd. And then I read this, designed to use water as a lube. Apparently, it didnt catch on.

  • Rear suspension and wheel​

  • Rear wheels bearings​

    Get high quality bearings from INA, SKF, etc. In particular for a big trail like the Atlas, always look for high quality bearings. The rear bearings are originally open, use only the closed version as given here in the list!
    • rear wheel bearing: 2x 3203 2RS
    • rear sprocket-holder: 2x 6204A 2RS
    • seals: 2x 25x40x7

    • Swingingarm and shock bearings​

      Quite unusually, Laverda used maintenancefree Permaglide type P10bushes from Schaeffler-INA for the entire rear suspension. These bushes are a composite of four layers (from inner to outer):
      • a "running-in"-layer of teflon and lead.
      • the gliding layer: a sintered bronzematrix with embedded teflon and lead.
      • a steel housing
      • an zinn anticorrosion-layer
        During the running-in, a sliding and sealing layer of teflon and lead is build between the bush and the steel axis. As long as there is no play, water does not pass through this layer, as a consequence, the bearings must not be DEMOUNTED, CLEANED or even GREASED! Demounting/cleaing will destroy the sealing layer, adding grease will build an abbrasive paste, resulting in abnormal wear [Reference: Permaglide datasheets, Schaeffler Group].
      From this, two problems do result:
      • how to replace an endless (closed) secondary chain without getting out the swinging arm?
      • how to examine the bushes and steel axis when you must not separate them?
      • how to protect the steel axis from incoming water and corrosion?
        The answer: it's simply not possible! Disassembling the rear suspension system will damage its bearings.
      The problem with our bikes is, that nearly every Atlas has been "forgotten" for a while, leant over (to the right side...) on its side stand with bearings a little bit worn out ... during the years, water passed (maybe pushed in with a Kercher???) and stayed in the right side bearings, particulary on the long bolt on the "bone", doing its corrosive work...
      So what to do when the bearings are used or rusted away?
      • replace them with the original P10 and hope that you do not need to disassemble the system for the next 50.000 miles
      • replace them with the "Permaglide-P20". The P20 are equally made out of a comparable multi-layer compound - but (must) work with grease, as a consequence diassembling is no problem any more. Like normal needle-bearings, the P20 have to be periodically relubrificated.
      • if the "running-in" layer of the original P10 bearings is gone but mecanical wear is more or less within the tolerances, we made good experience with greasing the P10 like normal bearings Put new seals and grease regulary (e.g. every 7 tsd miles)
        Notes:
      • The types P10 and P20 are replaced by the lead-free P14 and P24.
      • P10/P20 product information / specs : Schaeffler/Ina Permaglide
      • Order information: type: PAP ddll Pnm (e.g.: PAP 2025 P10), with:
        • dd = (inner)-diameter = diameter of the axis (in mm)
        • ll = length (in mm)
        • Pnm = type (P10, P14, P20...)
 
smlav said:
On the rear brake lever pivot, looks standard.
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It's not... ;)

Apparently, quite a few owners over the years have decided a couple of grease nipples here and there would be a good idea! Rear brake lever pivot is just one of the many lube points that is constantly neglected by most.

piet
 
"Some 750's have rubber swing arm bushings, so don't need a grease nipple."

it is my undrstanding and personal experiance that all pre '72 twins had rubber silentblocks in the swing arm and hence no bushes, they usually last longer than the bronze top hat bushes ('72 on) and hence no grease nipple.
CLEM
 
Now that I have an SF1 alongside the GTL I’m noticing subtle differences. I know the GTL as it’s owned from new. On brake side of rear wheel, between brake and swinging arm there is a washer-spacer next to brake then a long space. On the SF1 it’s just a long spacer. I thought maybe SF1 had gotten its spaces mixed up, but measuring them the gap they fill is 51mm on both bikes, SF1 long spacer being a bit longer than GTL.
 
smlav said:
Now that I have an SF1 alongside the GTL I’m noticing subtle differences. I know the GTL as it’s owned from new. On brake side of rear wheel, between brake and swinging arm there is a washer-spacer next to brake then a long space. On the SF1 it’s just a long spacer. I thought maybe SF1 had gotten its spaces mixed up, but measuring them the gap they fill is 51mm on both bikes, SF1 long spacer being a bit longer than GTL.
Click to expand...
I sometimes wonder if suppliers of spacers to Moto Laverda didn't have their off days.
Paul
 
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