OzVMX Forum
Marque Remarks => Suzuki => Topic started by: maxi81 on May 04, 2016, 06:30:39 pm
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I recently replaced the thrust washers and the dust covers on the swingarm. I looked the parts diagram on the alpha sports and got the parts from suzuki. I noticed when I put the swingarm back on there is a gap betwen the dust cover and the frame. Its like there needs to be another washer either side to close the gap. Have I missed something?
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How big is the gap?
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Maybe 3-5mm.
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3mm is typical suzuki sloppy tolerances, i have seen it before, 1.5mm each side is non unheard of, 5mm i think is a lot to ask to clamp up to. Personally i aim for less than .5mm fitting clearance each side, for custom apps anyway. I would check the length of the inner spacer tubes. I suspect they are worn but they are a hard item and i would not expect mm of wear off those either..... Was this swingarm all loose and sloppy when you got the bike? If it had been neglected maybe the sides of the frame have worn a bit?. Also check the press in bushes in the swingarm. Flange should be 3mm thick on those. I have seen horrible stuff. I was recently sold a swingarm that has been in use and the needle bearings and pivot tube were trashed. Totally dry and rusted Never seen grease since 1978 it looked like, with deep roller marks on the tube. And people ride around like this ::)
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Have you got thrust washers insde of dust deals ...if dust seals are replaced you need to do the shims also.
Common mistake
1mm would be acceptable , anything more and l would be looking at whats not right.l
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The bike was my dad's and he bought it brand new. I have been slowly restoring it over the past 6 years. I suspect that the swingarm bearing/bushes etc are still original so I will get those all replaced and see how it looks then. Anyone recommend anyone in Brisbane to replace swingarm bearings?
Thanks for the replies.
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Sorry to deviate off topic a bit but still swing arm related. Has anyone had experience in welding an 81 (or similar vintage) swing arm up near the front bushing area? Looking at it from side on its cracked across the outer surface facing the engine where the front bushes go in.
Any suggestions ?
Thanks
JS
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Yes the suzuki swinger extrusions split at the front facing the engine in the thin area of the extrusion.
Can be welded and line bored. I think I recall reading in VMX mag that Anthony Gunter had this prob with the RM400N he restored and I have also found the same issue on PE250/400 T.
Definitely a known prob and can be fixed by competent skilled welder/machinist.
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Thanks rocketfrog and excuse my ignorance but what is line boring? Do you mean having the centres re drilled/bored after the welding process?
Cheers
JS
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Lineboring is where something is clamped down & all holes that are in line with each other a bored to size in 1 pass, it makes sure that there is no misalignment. Commonly used in crankcase which are then marked as a pair, over head cam cylinder heads as 2 examples
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With CNC machine centres the same thing can be done with them, using a rotary table or if the cutter head rotates. What is probably better than welding up the original pivot tube is cutting it out and getting a new larger diameter one weld in and then machined. That way you could also investigate roller bearings instead of bronze bushes.
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Thanks guys.
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They use needle roller bearings as standard fitment already.
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With CNC machine centres the same thing can be done with them, using a rotary table or if the cutter head rotates. What is probably better than welding up the original pivot tube is cutting it out and getting a new larger diameter one weld in and then machined. That way you could also investigate roller bearings instead of bronze bushes.
This maybe a silly qestion but do you have to reheatreat the swing arm after a major repair like this? I had one for rm 125 repaired. Just one weld(about 50mm long) was worn off by dropped chain and I am allways bit worried that the swing arm may break where it was repaired since it was not heat treated after repair. The weld was done profesionaly(TIG) and is probably beter than original MIG weld.
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We repair them by cutting off the old tubing and welding a bigger new one in place. Welding the old one never seems to last and distorts the bearing hole.
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I am a believer in getting stuff like this T6 heat treated after welding. I will be getting it done to several of mine.
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Yes it should be heat treated, as its the (pivot point ) taking all the movement at load.
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The trouble with heat treating Al alloys is there is a specific ramp up, soak and aging process for each different type of alloy. You need to know exactly what the composition of the Alloy is to effectively restore full hardness. You might assume 6000 series and you would be right, but is it 6060 6106 or 6061? all of these lend themselves niceley to extruded forms and are easily welded but the ultimate strength achieved by tempering is very different and the process used varies as stated. (I would like to think Al 6061 is used, but I dont know for a fact).
The only way to know for sure is to use a machine such as a Scanning Electron Microscope or SEM to analyse the alloy material and compare the percentages of the various alloys detected against known alloy composition.
Karl Landrus will only build a swing arm from known mill certified materials to ensure that the finished temper will be true to specification.
What does all this mean? You might as well have the welding and or machining done by a competent professional and omit the heat treating unless you can verify the actual alloy Suzuki used in 1980.
Post rework NDT (Non Destructive Testing) is a good idea to check for cracks and flaws associated with welding and machining.
On going safety by inspection is good practice to include in your regular maintenance regime.
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Let say the swing arm is most commonly used 6061 aluminium. Can anyone recomend a place that would be happy to do the heat treatment? It may be hard to find a place that is happy to do a small jobs like this. Also I am not sure about cost of such service.
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Tomas, contact GMC on this site. Geoff uses heat treaters for his frame work and would have a friendly company on his books for sure.
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Well i know my aftermarket ones are 6061. Not sure what suzuki used
Here is a bit mentioned on the japanese material
http://www.vitalmx.com/forums/Old-School-Moto,22/Vintage-Aluminum-Swingarm-Question,1122127
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Dont get me wrong, I am all for heat treating and understand the importance of optimum strength in components such as frames and swingers. I have read through that blog before and was a little disturbed to hear the engineers reply to the enquiry on heat treating, obviously this bloke did not understand the concept of post weld heat treating.
I really would like to know what the material spec is for 1980 RM swingarms is, I have done conductivity and hardness testing to get an idea of what material is used in an RM125T arm.
I spot faced the extrusion and the axle plate to remove a small area of anodising to get a true reading but the test is not conclusive. This test just narrows it down to a handful of likely materials, although 6061 T6 is probable being that the physical properties of 6061 tick the boxes for a structural component which is both extruded and welded and can be heat treated to achieve the best strength for the 6000 series alloys.
I doubt anyone would disagree that that 6061 would be the best choice for the application, but what were the Japs thinking in 1980? Build to last or build to a price?
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Karl Landrus will only build a swing arm from known mill certified materials to ensure that the finished temper will be true to specification.
Who is Karl Landrus?
Is it likely he would build me a Supermoto swing arm?
How do I contact him?
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Well in my opinion the 79/80 RM's were not built to last more than a couple seasons. It appears they were trying to cut weight everywhere where they could but keep production and final cost for the consumer realistic. And this continued even more into the early 80's as well with alloy screws and drilled out axle spacers. The hex nuts they made as thin and small as possible, swingarm spacers drilled out, reduced rear axle down to 15mm on 250/400 when they were 17mm 77/78. 79 RM's had thin alloy axle nuts, they must of had some issues with these as they went back to steel in 80. I might have a junk 1980 PE swingarm i could possibly sacrifice for some material if someone wants to find out what they are made from.
Who is Karl Landrus?
Is it likely he would build me a Supermoto swing arm?
How do I contact him?
http://www.klpracing.com
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Karl Landrus will only build a swing arm from known mill certified materials to ensure that the finished temper will be true to specification.
Who is Karl Landrus?
Is it likely he would build me a Supermoto swing arm?
How do I contact him?
karl builds after market swingarms in the states trick stuff not cheap but you pay for what you get goggle him , he has his own site
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If you are considering buying an aftermarket swingarm, make sure it is an exact replica of a swing arm made back in the day.
Some of the swingarms available are not and can run into eligibility problems.
One easy way to check is what the chain adjusters are like. If they are the more modern style with an alloy block chances are they are not a true replica.