OzVMX Forum
Clubroom => Tech Talk => Topic started by: oldfart on December 22, 2009, 10:31:04 pm
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This is why I always sand blast my frames prior to painting .
Rm 400 T front down tube @ tank mount bolt hole ??? I've put it down to abuse ::)
(http://i72.photobucket.com/albums/i180/mutchoo/RmT400build005.jpg)
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you must be just plain lucky Stew :P in all the bikes I've built and owned the only 1 to have a cracked frame is my little XR/YZ80 and it was cracked when I bought it. I hand sand all my frames back to bare metal so it's not as though I've missed anything. Maybe it's more the '79 and onwards models as all mine are '78 C's and earlier and the biggest problem I've found with these is the lower frame rails under the engine can rust out, boring a small ventilation/drain hole on the lowest part of the cradle on both sides fixes this problem :-\
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I was at the Suzuki factory car today, we were discussing their quality policy compared to Toyota, interesting given that Suzuki are cruising with a 20% share selling to VW for 2.8 BUSD and Toyota are having their pants sued off at the moment/
I think the welding on the frame may tell you why it cracked. Recently I modified C frame and there wasn't much metal under those shock mounts but a lot of MIG filler. Not sure you could butcher it any more than the factory did.
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Not the nicest weld in the world, wonder how much is actually attached to parent metal. Are all their frames that badly done back then or is that a one off?
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This frame in particular, weleding was sub standard and standard and should of been binned.
Most of welds are cold ::) see below as I have re-done all main craddle welds as a safe gurad.
(http://i72.photobucket.com/albums/i180/mutchoo/Rm250Trearrailrepairs009.jpg)
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Not the nicest weld in the world, wonder how much is actually attached to parent metal. Are all their frames that badly done back then or is that a one off?
I was going to take some photos of the 125C frame I blasted and painted, welds were appalling, like I said they had gunned in a heap of filler from the MIG to fill any holes. Also the weld area around the swingarm bolt looked like a Parrot with dysentery had laid it down.
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This frame in particular, welding was sub standard and standard and should of been binned.
Most Japanese factories work on zero defect policies. Suzuki doesn't, its is very much about price and they accept a few rejects. Still it is Toyota getting their ass sued off in states at the moment.
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Those 400 and 250T frames use to crack at the bottom rear of the cradle, weld a brace underneath Stu.
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hey stu that was welded by a friday robot about 4.25 pm. but no problem for you mate a man of your genius it will be better then new when your finnished. and have a great chrismas
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I hand sand all my frames back to bare metal
Jeez Doc,hand sanding!, talk about dedication to duty and masochism! In the 30 odd vintage bikes I've restored or rebuilt over the years, I only ever hand sanded one....the first, my 350 Maico. Since then my friendly media blasting guy gets the gig.
I was going to take some photos of the 125C frame I blasted and painted, welds were appalling
Now I don't intend to insult Suzuki owners but I have to agree with Marc, of all of the frames I've seen over the years Suzuki takes the "birdshit welding" honours by a country mile. I've seen Suzuki welds that totall missed the butt and many of the welds look like they were squeezed out of a tube. The steering head snapped chean out of our old '76TS250 that became the donor for the TM/TS $100 project bike. It's always been a wonder to me that more didn't break.
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I agree the welding looks bloody woefull on many Japanese bikes from the 70's and 80's but, you have to remember any defects that you are finding now are showing up 30 odd years of misuse and abuse after the fact. In the case of the competition bikes they were only basically designed to run a season or 2 at most and then be ditched in favour of the next generation items. Many were and are still race bikes today. Considering the amount of bikes produced in this era compared to the amount of problems I've actually witnessed in 30 years of said production I'd say the dud or failure ratio is extremely low. These days you get your arse sued off if things fail so the birdshit welds should be a thing of the past..hopefully. Bottom line is yes, the welds on most early jap stuff are nothing short of hideous! :o
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I wouldn't complain about a 30+ year old frame when you get a 1-2 year old MX frame doing this.
Known to happen 06+ and 07+ yzf/wr aluminium frames at the steering head
(http://i199.photobucket.com/albums/aa250/hjcoupe/framecrack.jpg)
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Ah so he or she has quit thier job with Suzuki and started up with Yamaha.
Yes I must agree that most of the Rm and Pe around 1980 - 81 have bird shit welds, at steering head gusset
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my 125 yz done the same at peg mounts and head stem aswell...
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I wouldn't complain about a 30+ year old frame when you get a 1-2 year old MX frame doing this.
Known to happen 06+ and 07+ yzf/wr aluminium frames at the steering head
(http://i199.photobucket.com/albums/aa250/hjcoupe/framecrack.jpg)
That can't be good. Weld looks ok. Maybe poor engineering if a few are doing it? What do you do once that happens? ???
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(http://i199.photobucket.com/albums/aa250/hjcoupe/framecrack.jpg)
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If you have a close look that frame has been welded in that area twice at the factory, possibly had a defect in the first place.
Don`t be too hard on the welders doing the frames, you need to remember they only have 50% vision in the first place. ;D
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I am yet to be convinced that MXers gained anything from alloy frames. I am expecting them to reintroduce a new wonder material, chromoly steel.
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I agree, thank god the Euro's still use CR- moly. My opinion why they use alloy is because it's CHEAP!!!. I dont think it's lighter and it's definately not as strong -pound for pound. With all the money and resources the japs have they still carn't make a bike as light as the euros!!!!. It's funny you know, the japs are allways copying someone but I cannot think which euro DIRT- bike manufacturer has made an alloy framed bike and gone on with it? Shouldn't have said that, now somebody will make me eat meso soup -yuk!!
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Soup time,
TM have been making alloy framed bikes for a few years now without any problems? Aprillia as well.
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It's MISO and it's beautiful stuff it will put lots of lead in your pencil ;).
Frames are made from AL- U- forkING -MIN -I- UM because it's possible to cast up many sections with very intricate shapes and weld them all together very cheaply. You can also build in flex and rigidity easier in places you want it.Cr-Mo tubular frames are far more expensive to manufacture.KTM have an al-u-forking-min-i-um frame just parked in the garage to debut 'when the market demands it'
True that Al has not got the strength to weight ratio of Cr-Mo but it can dampen harmonics/natural frequencies in frames better than Cr-Mo.
Has a lot to do with company policy/market demands also, there is no right or wrong answer.
That IS a nasty crack though, could be from to quick cooling, certainly not from the quality of the welding.
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Havent they knocked the Aprilla on the head? -450's and 550's gonesky? and as far as TM goes there 7 bikes a year dont count!! ;D
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Don't be telling Josh Coppins that, he's signed to do MXGP on an Aprilia for 2010 ;)
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I agree, thank god the Euro's still use CR- moly. My opinion why they use alloy is because it's CHEAP!!!. I dont think it's lighter and it's definately not as strong -pound for pound. With all the money and resources the japs have they still carn't make a bike as light as the euros!!!!. It's funny you know, the japs are allways copying someone but I cannot think which euro DIRT- bike manufacturer has made an alloy framed bike and gone on with it? Shouldn't have said that, now somebody will make me eat meso soup -yuk!!
Hey Davey i hate to say it but the alloy framed Jap 450 mx'ers are lighter than the Euro ones.. especially the Husky.
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Coppins is riding a totaly different bike/engine combo. The original 450 and 550's are that worthless in the UK the only way they can sell is by wrecking them!!. Probably be collectors items one day, should be buying all the parts now if I was smart? The euro mxers all have electric start dont they? I know what I'd rather be starting.
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The husky went back to kick start in '06. The KTM has a nice little electric start on the 450.
I'd rather ride and own an alloy frame Jap bike any day..
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The KTM has a nice little electric start on the 450.
I'd rather ride and own an alloy frame Jap bike any day..
Ditto having been on the 2010 RM450, I have hopes for the new RMX.
Speaking of nice little electric starts have you seen where the BMW sited theirs, forms a crumple zone I guess. no wonder Knight ditched it and climbed back on to a Kawasaki to start winning again.
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KTM have an al-u-forking-min-i-um frame just parked in the garage to debut 'when the market demands it'
And a bloody linkage on the rear suspension >:( >:( >:( thank the yanks for that!
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(http://i199.photobucket.com/albums/aa250/hjcoupe/framecrack.jpg)
If you have a close look that frame has been welded in that area twice at the factory, possibly had a defect in the first place.
Don`t be too hard on the welders doing the frames, you need to remember they only have 50% vision in the first place. ;D
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Well spotted Billet, It's had a factory repair. When you hang shit on todays welders you have to remember you are hanging it on robots.
Robots are brilliant welders but only weld where they are told. If some part doesn't sit exactly right in the jig they can miss bits. That extra weld may have gone on cold when the deformity was discovered as it went through quality control.
The success of repairs depends on why they broke. When things break through exceptional circumstances (crash etc.) then they would repair okay until the next event.
The drama is when things break through normal wear & tear, then the problem will arise again unless extra precautions are taken (extra gussets etc.)
Lozza is right, the aluminium alloy frames are built for ease of manufacture as they require far less parts