johnjsy Posted September 2, 2014 Report Share Posted September 2, 2014 Hi again Tripp,the seals I get from Simply Bearings in Lancashire,U.K. & phone number is --01942-269-837-- you may have to a country code from where you are,I think it is 44 ,best check that. They are pricey at £9.11 each!! I would also like to mention that I now always use C3 bearings on a crankshaft when re-assembling. This is a greater clearance bearing & I think worth having. The last ones I used were SKF Explorer 6205/C3 ,they are only a few pennies more than standard ones. Now back to your problem.I have been turning over a few ideas in my mind over the week end & think to try something a little different.With the motor assembled to try pressurising it! Not too difficult,a well known way of finding any leakage.Ready? Piston at B D C to uncover all ports,spark plug in & tighten down. Next, cut a piece of steel or alloy about 3/16 thick to cover the exhaust port with a good gasket. There must be no leaks here to get meaningful readings. Next,do the same for the inlet manifold but drill a hole to fit in a Schrader valve from an old inner tube . Also you need to connect here a low pressure gauge ( from an old compressor) ? To monitor the pressure in the motor. Now put in about 6 or 7 LBS of pressure,no more than that as the seals would let go. The pressure should hold for several minutes, if it goes down too quickly,you need to see where from. If the pressure holds,it must be a carb: issue. I hope this helps, & apologies for a rather long reply, John. So Quote Link to comment Share on other sites More sharing options...
johnjsy Posted September 3, 2014 Report Share Posted September 3, 2014 Hi again Tripp,apologies & correction to what I wrote yesterday. The Schrader valve & take off for a pressure gauge needs to go onto the exhaust blank plate. With the piston down the inlet is effectively closed ! You could make the pressure inlet through an old spark plug,break out the ceramic centre & weld in a piece of tube then a top piece to make a T piece. Air in on one side,pressure gauge on the other. I have to stop here, evening meal is on the table. John. Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 4, 2014 Author Report Share Posted September 4, 2014 Johnjsy Thanks for the information. That seems to be my best option for finding my problem. I will try to give it a shot this weekend and report back. Quote Link to comment Share on other sites More sharing options...
guys Posted September 4, 2014 Report Share Posted September 4, 2014 (edited) I think I might split the engine of my 159 this winter too, and replace all the bearing and seals, big and small end bearing and piston if necessary. Something to look forward to. Edited September 4, 2014 by guys Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 5, 2014 Author Report Share Posted September 5, 2014 Thanks everyone for your help. I finally seem to be getting somewhere. I built a pressure tester and block off plate for the exhaust and it worked great. Loosing air at the base of the cylinder at the case seams. I hope to work on it some today. Thanks again Tripp 2 Quote Link to comment Share on other sites More sharing options...
johnjsy Posted September 5, 2014 Report Share Posted September 5, 2014 Aha! Well done Tripp. When you consider that air pressure is (I think) around 14 LBS per SQ inch at sea level, plus as the piston rises the crankcases have suction & even with a tiny gap the amount of air getting in would be quite a lot. A quick question,when joining the centre cases is it best to ---1 use a gasket sealer or 2 leave the gasket dry or 3 rub lithium grease onto the gasket? Different publications recommend each of these 3. Many years back I worked at a Ford & Renault sub dealer & we always used a gasket cement avaiable at that time called Osotite. The Foreman was not happy with grease saying that when a motor gets hot the grease will melt,drip away,& then an oil leak. Your thoughts on that? Regards John. Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 5, 2014 Author Report Share Posted September 5, 2014 Pulled the cylinder and put a little permatex moto seal on the case seams under the base gasket. The engine is holding pressure for a few minutes. Still leaking slightly at the rear seam. Getting a little leakage from the head also. Will try again tomorrow. Johnjsy, I put grease on my center case gasket. My Bultaco manual specifies grease. Tripp Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 8, 2014 Author Report Share Posted September 8, 2014 Got the bottom end buttoned up. She holds pressure when cold. After warming up the head leaks terribly. This is a non gasket head. Re torqued multiple times. Throttle is still hanging. Guess it's getting air from the head. Any suggestions. Thanks, Tripp Quote Link to comment Share on other sites More sharing options...
bullylover Posted September 8, 2014 Report Share Posted September 8, 2014 Hello Tripp. What I have done in the past is take the head and barrel off and just lap the head onto the barrel with valve grinding paste. Start with coarse and end with the fine stuff. You will see where it is not meeting the barrel correctly. Graham. Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 8, 2014 Author Report Share Posted September 8, 2014 Bullylover Thanks for the tip. Will give it a try today. Tripp Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 9, 2014 Author Report Share Posted September 9, 2014 Lapped the head multiple times. Guess I have had the head and barrel off and on six times today. Cannot get it to seal. Wow, quite an education this motor has been. She pulls like a freight train but will not behave. Have a trial in a couple of weeks, then Barber, and another. Time to put this one aside for awhile. Tripp Quote Link to comment Share on other sites More sharing options...
johnjsy Posted September 9, 2014 Report Share Posted September 9, 2014 Oh heck Tripp,this has been a teaser all the way ! Not a hairline crack in the liner right at the top,on the flange,causing this? When cold it is fine,but with some heat the crack opens up quite a bit. If this has happened,some oily residue should be visible,I would think. I will keep checking to see when you post your next entry. Regards,John. 1 Quote Link to comment Share on other sites More sharing options...
lbhbul Posted September 12, 2014 Report Share Posted September 12, 2014 Saw Miller, I think I can be of help with your woes. I am in the proximity of your location. Please E mail me. Larry Quote Link to comment Share on other sites More sharing options...
smelling123 Posted September 13, 2014 Report Share Posted September 13, 2014 No harm in using a little silicone automotive sealant on the head, lapping it should provide a good fit but if not,try a rub of silicone (permatex or similar) 1 Quote Link to comment Share on other sites More sharing options...
saw miller Posted September 13, 2014 Author Report Share Posted September 13, 2014 Tried lapping again also used a little copper seal. Still leaking. I am beginning to think it is leaking around the liner. Going to try a another head next to make sure. Ibhbul, Where do I find your address. Tripp Quote Link to comment Share on other sites More sharing options...
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