OzVMX Forum
Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: YUMASTEPSIDE on April 10, 2010, 02:32:41 pm
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..........as in the KTM thread, I also picked up a '73 SDR 250 Ossa, needs a big end bearing, but basically complete....
(http://i727.photobucket.com/albums/ww272/yumastepside/sdrossa.jpg)
Roger
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Nice pick up Rodger :). Looks very complete and original.
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Good pickup just proves there is still some complete and rare projects out and about to be brought
SDR ossa are a rare bird with all the hard to find parts attached
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.......had a bit of a look over it yesterday, only appears to be missing one rear grab handle, headlight lens, front number plate, headlight switch and front guard.
Roger
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Nice find it's in a lot better state than mine was when I got it. I'm pretty sure they only had the grab handle on the left side.
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I think you're right John.......one less thing to look for ;D
Roger
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I know of another SDR, same thing though, needs a big end but probably in similar condition unless its the same one! ;)
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My mate has two identical OSSA SDRs, one pristine, the other only slightly less and both running. He got them as part of a package deal with a '76 Phantom. I've had dibs on one of them for a Vinduro mount but I grew tired of waiting for him to cut the deal so bought an IT175 instead.
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Monte , wasn't down at 'wang was it ??
Roger
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Monte , wasn't down at 'wang was it ??
These bikes wouldn't have come out of Ron Merricks shed would they Roger? If so, it's amazing you got them out of one of our sports more eccentric Harold Steptoe hoarders. :D
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...............don't ask me how or why, but I seem to have a rapport with these blokes.......these from Ronny, matador from Anthony.........I must be just a marvelous bloke ;D ;D ;D (vomit) ;D ;D ;D
Roger
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Yes, Ron from 'wang it was. He would be a good source of parts to suit most makes and models especially Montesas, but he would be one of the more eccentric blokes you would ever meet. I haven't seen him for a while, you have to hope it's a good day when you give him a call ;)
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Between Anthony and Ron they've hoarded just about every available bike west of Leura and east of Dubbo! I like 'em both though. The sports a bit duller without them. I really can't understand why Anthony turned his back on the sport. His reason that VMX is biased against Bultacos is as much bullshit as the claims from another bloke that the mag's biased against Victoria and Victorians.
I only hope that either Anthony comes back to the fold or that he's releases some of the hundred odd Bultacos back onto the market to give someone else a go. The same with Ron. I like him a lot but the way he drags bikes into that cave of a shed of his, dismantles them and then scatters the parts all over the place annoys me no end. I bought a RZ Honda roller from him a few years ago and it took him over a year to find all the bits! ;D
You're indeed a lucky bugger to get anything out of either of them, let alone unmolested bikes with all parts intact from Ron.
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From memory, Ron never laid a glove on the SDR, maybe it was because it was a black sheep in the fold. Speaking of which, he is the only person I've seen walk over his bikes in the shed like a sheepdog travels across the tightly packed sheep in a pen :o Not too bad for someone of his age and fitness either!
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they have a weak big end there is a modification
you can do to fix it
maybe a ossa person can come on and explain ;)
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Most hard reving racing ossas models Phantom etc :-\ will need the yamaha rod kit fitted all of the US dealers stock early/late model crankpin sizes crank flywheels need to machined
SDR with std porting and used for fun enduro work std ossa rod should be OK
Cheers
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.........so, whats the lowdown on this yamaha rod conversion ?? ??? ??? ???
Roger
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Try www.ossaplanet.com I'm sure they will have everything you need. www.ossaworld.com is another one that might comes in handy.
For a bike company that that folded 30 years ago parts are quite easy and reasonably inexpensive.
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Anyone know what Yamaha rod is used in this conversion ??
Roger
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I'm told that the supply of that particular Yamaha rod has dried up. Ossa workshops in the ' States now use a heavier rod and crankpin manufactured for their use and based on the original Yamaha parts. Rod kit alone was around $150 US, and an exchange flywheel from Ossa Planet ,which includes the rod kit and all of the re machining and fitting was $300 US in mid 2009.
When I was buying stuff a couple of years ago Ossa World had a good range of parts at a good price and their service was excellent.
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I think it's the Yamaha 250 J rod Roger but don't take my word. I think that's the one we use on 250 Maicos and something in my subconcious tells me that it's the same. Whichever Yamaha rod it is, it's the one off model that varied from the 214 rod for a year or so.....the Yamaha blokes will know.
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The conrod mod for the Phsntoms was a YB125 Yamaha road bike rod, where avaliable through pro-x.
Each crank half needs machining as the bigend of the Yamaha rod is slightly wider than the ossa's. May not be a necessary mod for a sdr but it's up to you.
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The info' I got from Ron Bors and Keith Lynas is that the rods are no longer available (except through them) hopefully I can get enough information from them to buy a minimum amount of goods from the states and be able to buy the majority of it locally.
I can machine the crank halves here in my workshop, the details are supplied on the OSSA-World website and I can machine the stepped pin also.
Roger.
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Roger,
the Yam rod hasn't been available in US for yonks. It still was available here a few years ago both from Yam sources & Pro-X so it'd be worth checking Oz suppliers. YA or YB 125 IIRC.
There was a guy in NSW who did the whole mod for $100 plus parts (he knows the part nos). Can't remember if his name was Michael Bevan or Michael Slater now (the latter I think) - yes, same as the cricketer but diff bloke. He could also recondition cranks w oversize bearings & proper heat treatment. He advertised in some of the early Club Bultaco newsletters which I could probable find if you wanted.
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Thanks John, that'd be great , anything I can get locally, in Oz, is preferable.
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Yamaha conrod
model ya6
Part number 137-11651-00 rod only
93310-42433 b/end bearing
90209-24073 thrust washers x2
crankpin 24mmx 58.2 straight late model style 74 upward
After market 137 kit the crank pin is to short Plus the SDR will have the stepped style crankpin
Better to just buy the correct rod kit from Ossaworld
Cheers
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Yep thats the nos. My notes show Yam b/end pin is only 48.75mm long. Maybe best doing as VMX60 says & buy thro Ossaworld
Bigend of Yam rod is 15mm wide whereas Ossa is only about 11mm, hence machining of flywheels is req'd, so presumeably the crank should be rebalanced too
I also have a brief article from 10/77 Cycle Guide about a mod AMA national #34 Darryl Hurst was doing for hi HP hi rpm Ossa engines fitting a TZ250 rod & b'end w silver plated bearing cage, which also req'd some machining of the flywheels.
The chap I mentioned above is Mark (not Michael) Slater at Coff's Harbour - "specializing in con-rod refurbishing... we can make it like new". It maybe an old mobile # by now that I have but PM me if y're interested
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Thanks John........Mark and I actually went to school together, so I'll give him a call.
Roger
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A mate of my says he has two old Ossas lying in his shed and though I tried to keep a straight face and ask him if I could meet him at the dump I think he twigged to what I was up to.
He reckons one has an elec issue and he's trying to fit a PEI unit to it, would this be a goer??
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A long way back you talked about grab rails at the back ,mine has two on it standard, the flywheel is same as the explorer so it doesn't rev fast like the phantoms.
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yeah.........not real sure about the grab handles, all the bikes I've seen either have none or one opposite the pipe and then you'll see a pic of one with the handle on the pipe side.......??... ???
It doesn't matter, but I think the norm is one handle ??? ???
Roger
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When new mine had 1 handle on left side only not on exhaust side.
Regards Rod.
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Mine has two, but it must have been a left one bent to fit it . The old yank mag i have here has one only.
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Ol mate years ago said " there is a blue Ossa in the old farm shed...do you want it??? cool as i could "nah i dont think so.... oh maybe we should have a look maybee ::)"
It was an SDR painted blue bugger it! and the lid was off, the shed was gone (Willy Willy got it) but it was complete.
i pulled it down and threw the shims in a bucket.... once i realized the significance of that stupidity (when i got the manual >:() and the price of the reco cranks.... i sold it for 100 bucks....
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Hi my name is Mick and I brought a n Ossa SDR twenty something years ago for fifty bucks . I have had it in a shed up until about 3 years ago when my father wanted to fix something . He has spent over a thousand on a new crank and big end and various other parts from the states . It ran but only had a poor spark and now has no spark at all . He thinks it needs a new stator . Although it is missing a lot of its original body work we would like to keep this one on the road and eventualy restore it with all parts available . Any advice ? Thanks Mick .
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I'd check that the wiring connections are all firm and correct including all earthed points.Sometimes a weak spark is caused by a bad earth.
If that all checks out try a new spark plug and ignition coil and a condenser.
I'm not see whether your bike has electronic ignition or a magneto / points set up.
Ossaworld and Ossa Planet in the USA may have parts for ignitions.
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Thanks for the advice , my father has pretty well checked all things and it is the motoplat electronic system and he is fairly sure the problem is in the stator . He has contacted keith lynus and ossa planet and didn't want to spend that much on a brand new one and was coping someone might have a working second hand one . I also wonder if anyone had used a another make like the Kawasaki system in the Maico early models ? Cheers and thanks for replying Mick .
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If its Motoplat black lead coil replace or try a later red lead coil which has the diode fitted inside also take the plug cap off and cut 5mm or so off the lead back to good wire plus a good earth wire to the top coil and remove the kill button wire from the coil just to check
cheers
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Motoplat ignitions can be rebuilt, sometimes at a lower cost than a good used one (that could fail at anytime)
Check this place out. http://www.uk-motoplat.com/home.html
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Small Coil Rewinds in Vic also does them if yr in Oz.
The motoplats sometimes get moisture in them. Sometimes (if its not too severe) some good pushing can get sufficient spark to get them started, then giving them a good long run dries them out & they're OK. But it only works if they're not too far gone in the first place.
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ive got a manual for the Ossa if anyone wants it, it would go for a dan murphys gift card I reckon for a bottle of Plonk! promised land is drinking well atm
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Thank you all for this advice and so quickly . This is what we wanted to know and we will try all options . My dad is 75 years old but still a very good mechanic and still understands " rebuilding stuff " over replacing stuff . Cheers Mick .