rms Posted May 29, 2019 Report Share Posted May 29, 2019 (edited) On 5/28/2019 at 2:44 PM, malcolm watt said: lovely bike mate I've just finished building my gripper 350 but having timing issues . there docent seem to be any timing marks could anyone shed any light on the matter It should be set 1,3mm to 1,8mm maximum BTDC. This is 14,5° to 17° BTDC. On my gripper, i have to turn the stator full clockwise (checked with timing lamp). Do you have to original cylinder head gasket ? Edited May 29, 2019 by rms Quote Link to comment Share on other sites More sharing options...
woody Posted May 29, 2019 Report Share Posted May 29, 2019 You say it should be between 1.3 and 1,8mm BTDC with the stator fully clockwise. That's fully retarded. If that is how you like it then that is ok but fully retarded isn't the Ossa recommendation for trials model which is usually 2.5 - 3mm before TDC Ultimately it's the owner's personal choice how they set it Quote Link to comment Share on other sites More sharing options...
rms Posted May 29, 2019 Report Share Posted May 29, 2019 The top engine of the TR80 is different from the MAR and TR77 (gaskets for the bottom engine can be used, but not for the top engine), they have a thin head gasket (copper, something like 0,6mm thickness). TR80 is not set up like other Ossa trials, and 1,3 - 1,8mm is the way it should be. Full clockwise is full retarded, this is what I meant ? Quote Link to comment Share on other sites More sharing options...
Triad Posted Monday at 07:33 PM Report Share Posted Monday at 07:33 PM Hello guys, sorry to resurrect an ancient thread... I have an Ossa engine requiring new crank seals as it's drinking gearbox oil. I'm kinda skeptical about doing the job myself as I never worked on such an old bike and I don't have the pullers. Is it hard? What kind of pullers do I need? The engine should be from a late 70s Pioneer, has the coarse teeth levers and runs, so the Motoplat rotor is good and has good compression. I'm in Italy, can't find a shop willing to tackle the job for me. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted Monday at 11:17 PM Report Share Posted Monday at 11:17 PM Triad, if the primary drive crankshaft sprocket has a cush drive, then it is an easy job to change the crankshaft seal, but you need to buy a special puller for the cush drive. These pullers are available from vintage OSSA parts suppliers in the UK and USA. Buy a primary drive cover gasket and crank seal holder gasket while you are at it. Quote Link to comment Share on other sites More sharing options...
Triad Posted yesterday at 12:52 AM Report Share Posted yesterday at 12:52 AM Uhm... gotta say the videos of guys pulling the cush drive with a handmade puller didn't really make me think it was easy. I tried to get in touch with a few mechanics here, specialized in old enduro bikes, but for now still no luck. Not really too excited at the idea of doing it myself, this bike is definitely way different from what I usually wrench on... Quote Link to comment Share on other sites More sharing options...
feetupfun Posted yesterday at 01:52 AM Report Share Posted yesterday at 01:52 AM 47 minutes ago, Triad said: Uhm... gotta say the videos of guys pulling the cush drive with a handmade puller didn't really make me think it was easy. I tried to get in touch with a few mechanics here, specialized in old enduro bikes, but for now still no luck. Not really too excited at the idea of doing it myself, this bike is definitely way different from what I usually wrench on... Yes it's not easy but are you saying you can't find where to buy the special puller from? Quote Link to comment Share on other sites More sharing options...
Triad Posted 17 hours ago Report Share Posted 17 hours ago Didn't really find it with my google search... I'm in Italy, BTW. I tried to find a mechanic willing to do it... some say they won't open the engine unless it's for a total check of all the parts. Another guy asked for €200, not sure how long it takes but seems a bit on the steep side, maybe? I should also take the engine out and pack it to ship it to his shop (and of course have it picked up after the job). Quote Link to comment Share on other sites More sharing options...
feetupfun Posted 16 hours ago Report Share Posted 16 hours ago 36 minutes ago, Triad said: Didn't really find it with my google search... I'm in Italy, BTW. I tried to find a mechanic willing to do it... some say they won't open the engine unless it's for a total check of all the parts. Another guy asked for €200, not sure how long it takes but seems a bit on the steep side, maybe? I should also take the engine out and pack it to ship it to his shop (and of course have it picked up after the job). 200 Euros labour plus parts sounds quite reasonable to me and even cheap if they have to source or make a special puller. Do they know what's involved? Quote Link to comment Share on other sites More sharing options...
Triad Posted 1 hour ago Report Share Posted 1 hour ago I guess they do, but they probably already have the puller? Is it absolutely impossible to get the cush drive out with a standard 3 arms puller? Quote Link to comment Share on other sites More sharing options...
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