old trials fanatic Posted October 18, 2004 Report Share Posted October 18, 2004 For my sins i decided its about time i got the old Ossa back up and running. Its been sitting in the corner of the garage for the last 10 years while other projects have been soaking up funds (sound familiar?) Now i've never stripped an Ossa before. Plenty of Bultaco's and Montesa but not the Ossa. Anybody know of anything or any special tools i will need? also parts seem almost like the "Holy Grail" always promised but never actually there. One last cycle part i need is an origional airbox. I know i could get one fabricated but would like to restore to origional. Anybody got one holding the shed door open?? So any advice and or location of parts will be greatfully received. Jeff Bungay tries and is a really nice bloke but even he struggles with obtaining parts. Had a seat cover on order for nearly a year now. So Please, Please guys help me out if you can. Quote Link to comment Share on other sites More sharing options...
congus Posted October 18, 2004 Report Share Posted October 18, 2004 Buy your Gripper seat cover from ccedesign@fastwebnet.it Gripper airbox replica can be bought from www.trialclasico.com Good luck! Conny Gustafsson, Sweden Quote Link to comment Share on other sites More sharing options...
woody Posted October 18, 2004 Report Share Posted October 18, 2004 The things to watch when splitting the Ossa crankcases are the shims. The crank will have shims on it and the gearbox mainshaft, layshaft, selector drum and kickstart shaft will probably all have shims on them, possibly at each end. When you split the cases, the crank and gear train will remain in the right hand case, do it slowly so that nothing falls out, that way you can note exactly where the shims are in order to put them back in the same place on reassembly. Some of the gear shims are paper thin and can stick to the bearings when you split cases rather than stay on the shaft, so check that also. There is also a shim, approx 1mm thick from memory, which sits behind the outside gear cog on the clutch side of the mainshaft. Watch you don't lose this as that gear can slide off the shaft when cases are split and the shim can go with it. Then again, don't be surprised to find only one or two or no shims in the entire engine, depends on how it was shimmed at the factory or by whoever last had it apart. If it ran ok last time you used it and the gears selected ok I'd just put it back together with the shims exactly as they are now. To shim an Ossa engine from scratch is a time consuming nightmare. It's easy to see why a lot have just been put back together without being shimmed. If the shimming is out though you may have gear selection problems. Some seem more fussy than others. The only special tool you may need is to remove a tapered fit sleeve on the clutch side of the crankshaft. Can't remember if the Gripper has this. The MAR does as it is for the cush drive. Grippers didn't have the cush drive, but not sure about the sleeve. Best to speak to Jeff on this. Have an impact driver ready to remove the crankcase screws. If they've been in for a long time chances are they'll be stubborn. The heads are soft and can chew easily, especially if the screwdriver is not a good fit. Best loosen them with a driver but watch not to smash the cases by getting over enthusiastic. Also remove the selecter drum spring and housing before splitting cases. This is a large screw, say 1.5cm diameter, in the right hand case somewhere under the final drive sprocket. Removing this takes the tension off the drum and will stop the gear train being pushed out of the right hand casing when you split them due to the tension of this spring on the drum. Just makes retaining the gear train in one lump easier when the cases come apart. Get a manual from Sammy Miller as it covers most of this. Although it isn't for the Gripper the MAR engine is identical in terms of disassembly and assembly, apart from maybe that sleeve on the crank. There is also a good website, can't remember the actual address but it is run by a Swedish guy called Mats Nyberg. If you search under his name you'll find it. Loads of links to various suppliers and you may also be able to download a manual. You may have to look the States for Piston and Con-rod kit if you need them and Jeff or Miller can't help. The parts situation in the UK is not good for Ossas, especially Grippers and the various breakers have nothing left. Bearings and seals though can be had from local bearing company so no problem there, including the O-rings that seal the gearshaft and the Kickstart shaft (in the right hand crankase for the gearshaft and the clutch case for the kickstart and gear shaft) Worth replacing these as if the one in the right hand crankcase leaks after you reassemble it is another strip-down to replace it. Can't think of anything else at the moment other than to say good luck as they can be a bitch to work on.... Just getting the engine out of a Gripper frame is a trial of patience. Whoever designed that layout must have been on drugs and you may need a few yourself after an hour or so's wrestling Quote Link to comment Share on other sites More sharing options...
woody Posted October 19, 2004 Report Share Posted October 19, 2004 Ossa website address; http://hem.passagen.se/ossa/ Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted October 19, 2004 Author Report Share Posted October 19, 2004 (edited) Thanks guys. Will give the two web addresses a try. Thanks Conny. Bit nervous about buying abroad but if its the only way have to give it a go. I know i'm just a bit old fashioned. Well Woody thats a comprehensive bit of advice. Not too sure now if i should start pulling it apart or put it on e bay? Sounds a lot more complicated than the old sherpa. Still the Bultaco's are about as basic as you can get this side of a Villiers 37A and that is basic. Is anybody out there running a Gripper in trials? Most of the local guys are all running Bultaco or C15,B40 Cub. Seems that the only Spanish bike with any kind of spares resource is Bultaco via Dave Renham. So as for competition might have to stick with the 340 Sherpa. Seems a shame to leave the old Ossa to gather dust though. Edited October 19, 2004 by Old trials fanatic Quote Link to comment Share on other sites More sharing options...
woody Posted October 19, 2004 Report Share Posted October 19, 2004 If you know Chris Slack, who is from around your area - I think he runs or assists with the running of the Peak Classic club - speak to him. He rebuilt a 350 Gripper not too long ago and made a superb job of it, looked like new. Not sure what condition it was in before he started the rebuild so maybe it didn't need many parts, but he may be able to help. They have one trial left this year at Mick Andrew's place. Not sure of the date but it will be in TMX. Maybe worth going along to see if you can find him. He rides a Majesty now. There are some Grippers in use down south in classic trials, and Steve Bisby from Sheffield runs one in the ACU Classic series, so there are a few out there. If you are prepared to hunt, you probably will find most mechanical parts - piston and con-rod should be no problem in the states - but if you do order one make sure it is an Ossa one. The Yanks also fit modified Yamaha rod kits to Ossas, mainly Phantoms as they are much stronger than the Ossa one, but these require the crank webs machined to take the larger big-end bearing so they aren't a simple replacement fit. There are some reputable US traders listed on Mats' site. The main problems with parts start if you are missing anything other than the airbox such as exhaust, tank, side-panels, sliencer etc. These can be very hard to come by. Don't give up on it. The engine isn't as bad as I've probably made it sound to work on. The Bult is without doubt a piece of cake by comparison but really you just need to watch the shims and be patient. If you trust it to anyone else make sure they know Ossas. Quote Link to comment Share on other sites More sharing options...
mick annick Posted October 21, 2004 Report Share Posted October 21, 2004 Jeff Nolen at VMX in the States got me a really good seat cover for my MAR, not cheap but he delivered on his promise. Can't remember his website but mail me back if you can't find it and I'll track him down. Bob Stanley at Sammy Miller rebuilt my engine for me which has been trouble free for three years now, albeit not ridden that regularly. Mick Quote Link to comment Share on other sites More sharing options...
scotty Posted October 17, 2006 Report Share Posted October 17, 2006 had an gripper 250 a few years ago! loved it apart when you needed to get the amal carb off for a strip down! if i remember rightly rear mudgaurd/side panels/seat/air box i think, what a bloody nightmare!!! so god knows what the the engine would be like? but no doubt worth it, think about it ossa engine's are bullet proof!!! so well worth spending money on, i had a MAR 26 yrs old still working well engine never been stripped!!! fab bikes to ride and i think look gorgeous esp,350 yellow ones!!! Quote Link to comment Share on other sites More sharing options...
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