mudyman Posted June 24, 2012 Report Share Posted June 24, 2012 Hi all !! My 350 Gripper (that I got about a year ago but havent done much with) has a loud engine. The noise seems to be coming mainly from inside the clutch cover but its difficult to say exactly. I opend up this side and have found that the primary chain is quite sloppy. I´m not sure if I could change this my self or if it´s to difficult. Maybe a chain tensioner for In motion would be the right choice as it hasn´t got one ? The othe thing that I noticed is that inside the clutch cover casing there are some very light score marks where the weight on the end of the crank has been rubbing on the cover. I investigated this and have fond that the crank has play in it from left to right (but not up and down). Would this be normal or is something badly worn and if so what ? Thanks in advance !! Quote Link to comment Share on other sites More sharing options...
woody Posted June 25, 2012 Report Share Posted June 25, 2012 The noise could be anything, primary chain, weight catching the casing, main bearing, big end, piston… Your movement on the crank could be a loose weight as they can work loose. Take off the ignition cover and see if you can detect any play from that side. You should definitely detect play up and down if there is any in the main bearings. If the weight is loose and is catching on the cover, just re-tighten it and try again. The weight is held on by a type of allen bolt (odd size but can’t remember what – 9mm maybe) You can shove a thick rag inbetween the chain and sprocket to jam the clutch in order to re-tighten the bolt. It should have a lock washer under it so may be worth removing it to check first. You will have to replace the casing to start the engine as if you don’t there is nothing to support the shaft and you may bend it with the compression the 350 Gripper has, but anyway, without the casing fitted you won’t know if it is catching. If the chain is worn, it will have to be replaced, there is no tensioner on the Ossa. If it is very badly worn it will score the casing with the excess movement it has. Replacement is fairly easy and involves removal of the complete clutch as you have to fit the chain to the sprocket and basket and fit onto the shafts together. As above use a thick rag inbetween the chain and sprocket to jam the clutch to undo the weight’s allen bolt. To undo the nut that holds the basket put the bike in gear and lock the back wheel which will stop the gearbox shaft turning when you try and undo the nut. The weight just slides of its splined shaft. When you remove the weight there are two semi-circular thrust washers behind it and these will fall out. Use grease to hold them when you refit it (can be fiddly) Once the weight is off you can slide off the crankshaft sprocket but it must be done together with the chain and basket/hub. The hub may be a tight fit on its shaft and need a bit of persuasion. If you don’t have suitable pullers, you can use tyre levers to lever behind the basket which will bring the hub with it but obviously be very careful what you lever against to avoid damage. It shouldn't need excessive effort. The basket sits on a sleeve with a thrust washer and spacer behind it – these should remain on the shaft but make sure they don’t get dragged off with the basket. Refitting with the new chain is a reversal of the above. If you still have noise then you’re going to have to look further at other components such as piston, mains etc. Check that the bashplate isn’t touching the engine underneath as the vibration this causes can make noises that sound like worn components. I once had this on a Bultaco and all that was happening was that the engine was vibrating against the bashplate. It sounded like the engine was falling apart… Quote Link to comment Share on other sites More sharing options...
mudyman Posted June 26, 2012 Author Report Share Posted June 26, 2012 Thanks a lot Woody I´ll do all as instructed and see what I can find. Don´t think its the weight because I had the bike on the side and could see the crankshaft moving as I pulled and pushed it. What do you think about the after market chain tensioner that In motion have (to be fitted by drilling a hole in the casing) ? The Gripper is a loud bike in comparison to all my other bikes (3 xSWM & 2 x Montesa) this makes it more difficult to decide where the noise really comes from. The primary chain is definatly worn and quite slack so I wanted to get it chagned. As it´s loud at tickover I thought this could probably be the cause. Just botherd because I saw the rubbing marks inside and want to be sure before I order things (international postage). The sump guard was missing when I got the bike and it was loud then. I´ve got a new one and fitted it some weeks ago so I don´t really need to look there. Quote Link to comment Share on other sites More sharing options...
jojotut Posted July 4, 2012 Report Share Posted July 4, 2012 Hi do you have an engine strip down for one of these? I have looked all over the place, people are saying that there is not one. I can get an exploded view but by the time you try and make it bigger you cannot make anything out. Its a bit a problem when you buy a bike when you have had a drink and the guy says "Its all there mate! all you need to do is put it back together?" You take the bike home the engine looks like your 6 year old has given up on it, your wife looks at you and with that I told you so smile and you reach for the cans again. O why do we do it. Sorry about that, someone help Quote Link to comment Share on other sites More sharing options...
woody Posted July 4, 2012 Report Share Posted July 4, 2012 It's the same as a MAR engine so the Clymer manual will cover it. The only difference is the MAR has a cushdrive on the clutch whereas the Gripper doesn't, it has a counter weight. Gearbox sprocket nut is left hand thread. The ignition flywheel may also be left hand thread, some are left, some are right - can never remember if it is the early Ossas that had left hand thread on this or the later ones - it changed around 1974. Clymer may mention it. Quote Link to comment Share on other sites More sharing options...
jojotut Posted July 5, 2012 Report Share Posted July 5, 2012 Thanks for that Woody, sorry did not mean to take over this posting mudyman, anyone know know how to date the 350 Gripper and is there a site I can get a Clymer from. My head is starting to clear a bit now and the smile is coming back. Thanks to everyone Quote Link to comment Share on other sites More sharing options...
mudyman Posted July 8, 2012 Author Report Share Posted July 8, 2012 Hi jojotut have a look at this http://hem.spray.es/manyb it covers the 5 speed engine and should help. Haven´t had any time for the Gripper recently as theres too much work and it´s to hot for me to take it apart in the sun (a Garage or workshop would be good). Quote Link to comment Share on other sites More sharing options...
woody Posted July 8, 2012 Report Share Posted July 8, 2012 You can't really date a Gripper as they all have frame/engine numbers beginning 73 (76 for 250) The 350 was built from late 79 - 82/3 so the higher the frame number the later the bike, that's about as close as you can get. There is an on-line manual here, at the bottom of the page, although it may be the same one as the link in the post above http://hem.passagen.se/ossa/ Quote Link to comment Share on other sites More sharing options...
jojotut Posted July 11, 2012 Report Share Posted July 11, 2012 Thanks for the web addresses the one posted by mudyman did not open but the other one did. Talked(via email) to a guy who sells original stuff for theses bikes in Spain and he says that there is a book for the TR80 model and wanted over $100 for it?? Think I will make do with the company’s printer. All the very best to everyone Quote Link to comment Share on other sites More sharing options...
mudyman Posted July 14, 2012 Author Report Share Posted July 14, 2012 (edited) Sorry jojotut, I made the mistake to put es (for spain it should be http://hem.spray.se/manyb/ ! You should then come to the workshop manual for 5 speed engines. Edited July 14, 2012 by mudyman Quote Link to comment Share on other sites More sharing options...
mudyman Posted July 14, 2012 Author Report Share Posted July 14, 2012 Thanks again for youre advice on this subject Woody, Ive now at last got around to having another look and after removing the Ignition side cover as you suggested its possible to say that the crank has the same movement on this side about 3 mm left to right if you push and pull it. It also has some up and down movement but less (about 1 or 2 mm). What do you think could be the cause for this (maybe a worn crankshaft or main bearings). Is this a job that most people can do ? I have had top ends off and clutch things etc. but never opend an engine completely up and I´m rather concernd taht I might not get all the bits back together again. Quote Link to comment Share on other sites More sharing options...
woody Posted July 17, 2012 Report Share Posted July 17, 2012 (edited) First, I'm not a mechanic so I'd never try and give specific advice on how what's wrong or how to repair an engine, as I wouldn't want to mislead someone if I got something wrong However, from what you say, it does sound as though the main bearings are pretty worn, so yes the engine will need to come apart. Whilst it is apart the condition of the big end and piston/bore can also be checked. If you have no experience with this you are going to need a competent mechanic to check them for you. Stripping the engine is fiddly because you have to remove the sleeve from the crankshaft that the clutch weight sits on. It's a tapered fit and can be very difficult to remove as they can be a very tight fit. You need a special puller to get this off and the only place I have seen one for sale is Keith Lynas in USA (Ossa Planet website) Someone clever may be able to make you something that will do the job. You also have to remember the left hand thread on the gearbox sprocket and the ignition flywheel. Once you have the crankcases split you have to watch out for the shims. They can be on both ends of every shaft in the gearbox including selector drum and kickstart and they need to go back in exactly the same places - Or, you can carry out the extemely time consuming job of trying to re-shim the shafts (crankshaft should have shims too) from scratch when you reassemble. Or there could be none in there, but unlikely. if you've never done an engine before they can be a bit fiddly, so it may be better to find someone who can help and watch them do it, or do it under their supervision. If you get the shims wrong in the gearbox, you could end up with the shafts not turning, no gear selection or stiff gear selection. That's why, when you split the engine, do it gently and make sure all the gear cluster sits in the right hand side (ignition side) crankcase. Any shims will stay on the end of the shafts or be stuck onto the bearings with oil. When you remove the gear cluster from the right side crankcase, the same applies, watch for shims staying on the shaft or sticking to the bearings. There can be more than one shim on the end of each shaft. There is generally a big shim behind the final drive gear which is usually left in the gearbox when the cluster is removed. It's the same size as the crankshaft shims. When you get replacement crank bearings, make sure they are 6205 C3. If you get normal 6205 and not C3, they will most likely melt - they did in a Bultaco I rebuilt years ago. Forgot to check I'd been given C3 - I hadn't. They must be C3. Edited July 18, 2012 by woody 1 Quote Link to comment Share on other sites More sharing options...
bisby Posted July 18, 2012 Report Share Posted July 18, 2012 Woodys advise is very good, but i have rebuilt my motor two or three times over the years. I bought the ossa clymer manual for the MAR and followed that (even tells you what gas mark for the oven to get the bearings out of the crank cases) clean the cases up first though cos the kitchen will smell bad!!!!! take your time and photos can help. i bought a set of cheap pullers and modified the ends to get the sleeve off the end of the crank, works well but they are always tight. good luck have a go you can always ask for help. steve. Quote Link to comment Share on other sites More sharing options...
mudyman Posted July 18, 2012 Author Report Share Posted July 18, 2012 Hi Woody, I realise that you are only giving me general advice and not specific instructions. Thats just what I need at present. I certainly wont be starting anything without finding someone that can help if it gets tricky or maybe does all. Maybe I can find someone in my area as I would like to get a bit more experience in rebuilding and this seems to be necessary. Thanks again for the very useful help ! Quote Link to comment Share on other sites More sharing options...
mudyman Posted July 18, 2012 Author Report Share Posted July 18, 2012 Hi again I have Just read the posting from bisby (steve). Is this a book just for the Ossa (ossa clymer manual) or a general book for different makes (I seem to remember seeing one like this at amazon that if I remember right was for Bultaco, Montesa and Ossa etc.) Quote Link to comment Share on other sites More sharing options...
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