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Post by GrumpyUnk on Sept 1, 2021 9:31:01 GMT -5
Maybe I missed the boat somewhere. If the piston is damaged, it will not slide in the cylinder properly, or will rock back and forth if it is worn. Is the piston damaged? Or was it the rings not seating, causing low compression? You can get a set of rings for $3 if you shop. The cylinder may or may not need 'glaze breaking' as that procedure has come into question. A set of new rings might be just all you need, along with at least a new head gasket. Steel head gaskets do not seem to handle more than one tigntening and may not seal the second time through. You really don't need to fill the intake or exhaust ports with fluid. It doesn't take much to find out if the valves are seated and sealing properly. If they are not, a replacement or doing some work on the seats and valves using valve grinding compound can make them work again. The procedure is called 'lapping the valves'. You likely can find 3,266 videos on the topic at utube. If you run an engine without oil in the sump, you can ruin it pretty quickly. Given these engines have ball bearings on the crankshaft, the first thing damaged, expectedly, would be the rings. No splash of lube as the crankshaft spins, slinging oil all over the place, and the rings run dry. The inside of an engine is like a hurricane once the engine starts. That too may be views on the web if you wish. Anyway, the rings get HOT real quick with no lube splash. They then rub against the cylinder and either get hot and lose their tension, and no longer push much against the cylinder wall, OR the edge of the ring starts to melt, and no longer seals. Take your pick. You do want in any case to inspect the cylinder wall for scoring or other damage before deciding on what to do. You can get cylinder/ring/gasket/piston kits on the web for various prices. I would select someone who has been selling for a while if you go that way. I have bought from aliexpress and had pretty good luck. Some are better than others. You will have to wait for them. Don't over tighten the head stud nuts. About 14-15ft/lb is all it takes. I lubricate the piston, cylinder and rings liberally with motor oil before/during assembly. Others may do it differently, but auto/truck ring makers I have used have ALL suggested liberal application of motor oil to the parts before assembly. I have followed those instructions for 40+ years and had decent luck. tom
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Post by scooter7878 on Sept 1, 2021 10:24:06 GMT -5
Maybe I missed the boat somewhere. If the piston is damaged, it will not slide in the cylinder properly, or will rock back and forth if it is worn. Is the piston damaged? Or was it the rings not seating, causing low compression? You can get a set of rings for $3 if you shop. The cylinder may or may not need 'glaze breaking' as that procedure has come into question. A set of new rings might be just all you need, along with at least a new head gasket. Steel head gaskets do not seem to handle more than one tigntening and may not seal the second time through. You really don't need to fill the intake or exhaust ports with fluid. It doesn't take much to find out if the valves are seated and sealing properly. If they are not, a replacement or doing some work on the seats and valves using valve grinding compound can make them work again. The procedure is called 'lapping the valves'. You likely can find 3,266 videos on the topic at utube. If you run an engine without oil in the sump, you can ruin it pretty quickly. Given these engines have ball bearings on the crankshaft, the first thing damaged, expectedly, would be the rings. No splash of lube as the crankshaft spins, slinging oil all over the place, and the rings run dry. The inside of an engine is like a hurricane once the engine starts. That too may be views on the web if you wish. Anyway, the rings get HOT real quick with no lube splash. They then rub against the cylinder and either get hot and lose their tension, and no longer push much against the cylinder wall, OR the edge of the ring starts to melt, and no longer seals. Take your pick. You do want in any case to inspect the cylinder wall for scoring or other damage before deciding on what to do. You can get cylinder/ring/gasket/piston kits on the web for various prices. I would select someone who has been selling for a while if you go that way. I have bought from aliexpress and had pretty good luck. Some are better than others. You will have to wait for them. Don't over tighten the head stud nuts. About 14-15ft/lb is all it takes. I lubricate the piston, cylinder and rings liberally with motor oil before/during assembly. Others may do it differently, but auto/truck ring makers I have used have ALL suggested liberal application of motor oil to the parts before assembly. I have followed those instructions for 40+ years and had decent luck. tom . I just can't see only putting rings on without a cylinder even at 100 for a good cylinder set but u can get complete cylinder and piston kit on Amazon or eBay for 30 to 50 bucks he's been after this for a long time and may not be able to tell if the cylinder is no good. He spent 10 on a piston another 20 and he could get a chepe kit to me it doesn't make sense. And also now if he just puts piston in and it doesn't fix it he's gonna be there wondering if that was issue or not and he's still gonna be left dicking around trying to fix it over 20 bucks if he puts even a cheap cylinder and piston at least he knows either it fixed it or that wasent his issue I could understand doing that if u were talking Abt 200 for a cylinder or trying a piston for 10 but idk just my opinion
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Post by scooter7878 on Sept 1, 2021 10:31:10 GMT -5
And besides that weather cylinder is glazed or true or not u still need the cross hatch to help with ring break in they act as kinda a file on the rings to wear them in correctly and also work to hold a oil film in the cylinder walls during crucial break in period. It may work without a cylinder but it will never make the same compression as a fresh cylinder and piston properly broke in and will probably burn some oil
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vacationer
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Post by vacationer on Sept 1, 2021 14:56:28 GMT -5
I'll get the cylinder if that'll save me from having to understand all of what you just said about honing and such. I'd love to sit and learn about all of it but I'm spending $15-20 a day taking uber to and from work. Just returned an impact driver to amazon but I'm sure by the time I get that $100 back I'll be $100 in the hole from uber again.
This isn't actually my scooter. My roommate's letting me borrow it, so I can't complain. But I wish he hadn't bought it drunk. Might have spent that $1000 on something more reliable, like a $1000 walking stick.
As for the head... As I was screwing back on yesterday with a torque wrench, one bolt was turning a suspiciously long time without causing the wrench to click. Eventually, the screw snapped and I replaced it. Wrench didn't click with that one either so I stopped when it felt like I was going too far again. Might be the reason for low compression. Starting to think what this thing needs is a stick of dynamite.
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Post by scooter7878 on Sept 1, 2021 16:20:42 GMT -5
I believe with a new cylinder and piston u will be on road driving good as long as u get everything together correctly. As for the broken bolt are u referring to the 4 studs under valve cover or the two on the side not under cover? And as for the cylinder issue there's a proper way to do it professional way to do it and there's what we as professional mechanics call the back yard mechanic way. I'm not putting anyone down but u not being a mechanic really don't have the knowledge or tools to correctly check the cylinder properly or hone it. That being said buying a cylinder is the sure way to do it correctly. I have the knowledge and tools to check it and I don't even bother I just always get a cylinder and piston it's not worth my time or effort to correctly check it and than hone it over 60 bucks. Any time a piston and rings are replaced the cylinder needs to be checked and honed to get proper ring seal to achieve the best compression and not burn oil. Doing it any other way is a gamble it might work good it might work ok but use oil or it might run but never make good compression and burn a ton of oil. As for checking the valves with carb cleaner while the head is off it literally takes less than 3 min and a 4 dollar can of carb cleaner to be sure u have good valve seal it's the next best way to check valve seal besides a machine shop dye testing the head for cracks and valve seal I can't see not doing it over 3 min to be sure. I do that and a visual inspection of the valves and head. And in that broken bolt if u are toque it to right spec and it's breaking before u reach spec that needs to be addressed before the assembly of new cylinder. Let me know what bolt u are talking about and a few things need be sure if if the hole it screws into is a blind hole meaning it has a bottom it's not open at the bottom end of threads if there is any oil or other fluid down the threads the bolt will hydro lock if what ever fluid is at bottom of hole can not compress as u screw bolt in the bolt will never torque and can possibly break. Also different oils/grease /antifreeze affects how a bolt torques down for instance if u put anti seize in studs for lug nuts the studs will break before u ever reach the torque spec. Every live will affect differently so be sure there's no fluid down hole and the threads if hole and bolt are dry when u put bolt in
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Post by scooter7878 on Sept 1, 2021 16:25:10 GMT -5
If u have time Google engine piston ring break in there's plenty of articles that will probably explain better than I have u will understand more if how important it really is to have proper ring sealing and why I was recommending u get a cylinder
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vacationer
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Post by vacationer on Sept 1, 2021 19:13:55 GMT -5
I'll definitely get a cylinder then.
The bolt hold should have been totally dry. Not sure what could have gotten in but I'l make sure it's dry next time I take it out. It's the one on the bottom left of the square formation of bolts. So not the two shorter bolts holding that u-shaped piece of metal on but the one just to the right of those. I think that's the one you're referring to.
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Post by scooter7878 on Sept 1, 2021 21:32:52 GMT -5
Ur not talking Abt the valve cover ? The bolt ur talking Abt holds the cylinder and head on that one on the timing chain side? So there's 4 long studs under the cover the 4 nuts hold the cylinder in than not under valve cover on the timing chain side there's two fairly long 8mm bolts that also hold the head on ?
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Post by GrumpyUnk on Sept 2, 2021 8:41:10 GMT -5
Seekling a bit of clarity. When you say 'get a cylinder', I figure that means "get a piston/wrist pint clips/rings/cylinder/gasket' combination, not just a cylinder by itself. The studs(4 in a square pattern, under the rocker arm cover) compress the cylinder head gasket and the base gasket, clamping both cylinder and head in place to the engine block. There are MANY torque specs published for the 4 nuts. As 78 stated, you want clean dry threads, and all blind holes empty of everything except air. You can probe them using a clean dry piece of shop towel/paper towel/?? with a small screwdriver to insure there is no liquid residing. Generally, the studs are screwed into the block and are not removed unless they need replacement. There should be two sets of 'ferrules' that are used to guide and place the cylinder and the cylinder head that fit into enlarged bores on two of the studs. I think the chosen studs are in different places for the cylinder>block alignment and the head>cylinder alignment. In addition there is an oil supply passage on the outer surface of the block. Do NOT get anything in there such as gasket crumbs or sealer. You should be able to get oil to pump up and flow out the hole by cranking the engine. If you do, using the starter, be sure to hang onto the connecting rod so it doesn't fly around and ruin something. An oil flow check would insure you don't have bits'n'pieces down the hole. You can give the studs an 'adjustment' if they don't align properly and won't go readily into the 4 holes. Slight bending is allowed as they will eventually get where you'd bend them as they are pushed into place and the 4 nuts tightened. It just makes assembly easier if they are aligned properly, AND allows you to feel things fall into place as you set the cylinder. It is especially nice when you are fitting the piston & rings into the cylinder to NOT have binding studs affecting placement and friction. Whenever I have done this sort of thing, I have had the CVT cover removed. That allows for positioning of the crankshaft at TDC by using the variator as a handle. You can also check the validity of your TDC indicator on the flywheel by positioning the connecting rod/crankshaft at TDC(you can pull on the rod to do this), and checking that the T mark is aligned properly on the flywheel. It likely is fine, but it can't hurt to take a look as some have reported the mark being incorrectly made on the outer surface of the flywheel. tom
FWIW, I have gotten Glixal big bore(47mm) from the web and it was adequate. It worked fine, and I had no problems. Do be sure to check ring end gap before installation. I think I have had to do a bit of filing on almost all compression ring sets. There is information in the 'tech' section on-site. tom
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vacationer
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Post by vacationer on Sept 2, 2021 18:23:55 GMT -5
This is the bolt I'm talking about. I might have gotten my terminology wrong. The one you see there is the replacement bolt. I was torquing to 10 ft-lb since that's what I see for most nuts and that's the lowest my torque wrench goes but I guess I should be actually check. I'm also now seeing that the valve specs in the manual are smaller than what Brent and other videos have recommended for the gaps. Which should I be following?
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Post by scooter7878 on Sept 2, 2021 18:41:09 GMT -5
That bolt is a valve cover bolt it won't effect anything with compression. It will cause oil to leak from the valve cover. Idk what the specs are I hand tighten those but they do not need to be super tight just hand tight them in a Criss cross pattern do each one at first just barely tight like soon as u feel the rubber seal compress. Than go back over same criss pattern and snug them. Once they bottom out go a little more use a smaller ratchet u can feel what is happening better. I use a 1/4 inch ratchet on everything except like variator nuts and clutch nuts. Remove that emissions system if u have the ability to make some sort of block off plate for the port in the head. Easy way is u can cut that tube leave about 2 inches on side that bolts to the head remove the two bolts from flange on valve cover and take off tube. Than crush the tube off the head pinch the end tight so it's flat and than fold the edge over it's exhaust that flows through there so whatever u do be sure it can with stand some heat. That system is shit and u don't need it it's only emissions or u can make a plate to block off port on head which ever is easier for u but def remove that metal tube and whatever other hoses are connected with it
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Post by scooter7878 on Sept 2, 2021 18:51:06 GMT -5
I don't believe any oil will come out in the valve cover side u can pinch the tube there also if u want u can buy valve covers that don't have that but u don't have too. The only bolts I would use torque wrench on is the 4 nuts in cylinder stud and the two cylinder/head bolts on the chain side everything else use a 1/4 ratchet u can feel what going in much better than with a big ratchet or torque wrench. If u have any questions iin the piston install lmk but be sure to check the end gap and clock the rings in proper position. Also the break in period is very important the first 50 miles and also what oil u use for break in will make a big difference in getting the most compression and oil seal from the rings. I'm gonna message u my phn number if u would like a run down on how I do it u can message or call me. If we do it here it will usually start a war of comments bc every one has there own beliefs of how to do it. I know my way works I run 9500 rpm at 60 plus mph and make over 200 psi compression without using a drop of oil.
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Post by scooter7878 on Sept 2, 2021 18:57:35 GMT -5
Also when I install bbk kits I run a fatter ground wire and power wire from the battery to the starter solenoid and run a fatter ground from batt - to the frame it goes right in front of valve cover in the side with that tube. Than run a fatter wire from that frame spot instead of it going to the valve cover I go to the starter bolt. It eliminates the starter strain the bbk kit causes. Even with my high compression piston and stroker crank my starter doesn't even strain
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Post by GrumpyUnk on Sept 3, 2021 11:15:19 GMT -5
That U-shaped tube is the 'pulse-air' system that just injects a bit of fresh air into the exhaust gas stream, with the intention to dilute the gas, or to provide oxygen to burn anything that didn't burn inside the engine. I doubt it hurts anything to leave it on. It does not inject exhaust gas into the intake, so does not rob power that way, and the exhaust gas pulses it uses are created anyway, and do nothing. I do not know why people are so intent on removing bits and pieces that harm nothing. But, have at it if you want. If/when you decide to replace the piston/cylinder/etc, when you place the wrist pin clips, some suggest orienting them so that the opening between the ends of the clip is at the top or bottom of the wrist pin bore. That way, the clip will not have one end being subjected to the G forces at top/bottom of the stroke tending to pull on the unsupported end of the clip. Both ends will be against the outer diameter of the clip groove, and thus 'supported'. I really don't know if it makes a difference, but does not take much effort to orient them that way. tom
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Post by scooter7878 on Sept 3, 2021 15:24:24 GMT -5
That U-shaped tube is the 'pulse-air' system that just injects a bit of fresh air into the exhaust gas stream, with the intention to dilute the gas, or to provide oxygen to burn anything that didn't burn inside the engine. I doubt it hurts anything to leave it on. It does not inject exhaust gas into the intake, so does not rob power that way, and the exhaust gas pulses it uses are created anyway, and do nothing. I do not know why people are so intent on removing bits and pieces that harm nothing. But, have at it if you want. If/when you decide to replace the piston/cylinder/etc, when you place the wrist pin clips, some suggest orienting them so that the opening between the ends of the clip is at the top or bottom of the wrist pin bore. That way, the clip will not have one end being subjected to the G forces at top/bottom of the stroke tending to pull on the unsupported end of the clip. Both ends will be against the outer diameter of the clip groove, and thus 'supported'. I really don't know if it makes a difference, but does not take much effort to orient them that way. tom . That pair system causes decel backfiring on motors that have kits and performance exhaust I've had 4 of my friends bikes that had constant decel backfiring I removed that system without doing anything else and it was totally fine no more backfire at all. Jetting was all correct. Brent even says to remove it in a few of his videos
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