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Noob engine help
So I have my motor out right now and before I do anything rash I thought I'd get some advice.
My motor ran, poorly(chewed oil and had oil on the plugs), but it ran. Obviously oil isn't staying where it needs to be and it really needs some love and tender touching after all these years of who knows what's happened to it. However, I've never "rebuilt" a motor before and this isn't exactly starting small. I have the manual, plenty of resources on the web, and even found a YouTube of someone replacing the rings. Is this something I can do on my own or am I barking up a big tree?
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80G |
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My thought is follow the disassembly process from a manual and go from there. Most likely the problem is in the rings or maybe valve guide seals.
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Howard ‘01 ZRX 1200, only bike in the garage. 2019 Rally Link: http://appleattic.net/XS2019/xs2019.htm |
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81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top. Last edited by motoman; 02-17-2017 at 01:07 PM. |
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I did compression test and it revealed 135/120/115/130.
The YouTube was Andy's Motorcycle Obsessions and he's posted an entire informative build series of some 50 videos of odds and ends for his xs11 and is on the XS11 Australian forums. He seems like he has done his research and isnt just "some youtube guy".
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80G |
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How long had the bike been sitting before you got it? how many miles did you put on it? How hard did you ride it?
These are three IMPORTANT questions to ask BEFORE doing anything with the XS11. A lot of these have sat for one to ten years, and show low compression even though they have only 20K or so miles on them. Running the bike for about a thousand miles will fix a lot of the problems with oil consumption. As the engine is out, pull the head and replace the valve seals. I would also flip it over and do the second gear fix, just because it's a known weak point. Rings are getting hard to find, but can be had. If you have a score or something in the bore, then it will be an overbore kit, and have a machine shop do work for you, about $250 for me local.
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Ray Matteis KE6NHG R1200RT Totaled 11-15-2016 XS1100 E '78 (winter project) XS1100 SF |
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Might I suggest looking for a donor engine? I have three or four just for that purpose, just in-case this guy goes on me.
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1979 XS1100F 2H9 Mod, Truck-Lite LED Headlight, TECHNA-FIT S/S Brake Lines, Rear Air Shocks, TKAT Fork Brace, Dyna DC-I Coils, TC Fuse Block, Barnett HD Clutch Springs, Superbike Handlebars, V-Star 650 ACCT, NGK Irridium Plugs, OEM Exhaust. CNC-Cut 2nd Gear Dogs; Ported/Milled Head; Modded Airbox: 8x8 Wix Panel Filter; #137.5 Main Jet, Viper Yellow Paint, Michelin Pilot Activ F/R, Interstate AGM Battery, 14MM MC, Maier Fairing, Cree LED Fog Lights. |
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What I would do
If the main bearing weren't making any knocking noise, then you should be satisfied to replace the rings and (lightly) lap the valves.
I would measure the cylinder walls first. They wear into an hourglass shape perpendicular to the wrist pins. If the cylinder dimensions are in spec, new STD rings are easy to find and inexpensive. You can use a ball hone easily, and replacing the rings is easy. If you find the cylinder walls are out of spec, then you have to find new pistons and new rings, so you are better off to find a kit. Like DiverRay said, most everyone would need to go to a machine shop to bore it out. Lapping the valves is easy, but you need a valve spring compressor to remove the valves. You can buy one for $35-50 US, or some folks have made them from a clamp and ratchet socket. You can search for posts. The valve seals are easy to find, and easy to replace once the valves are out. They only cost a few US dollars each. These items will get you back to stock compression and negligible oil consumption.
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-Mike _________ '79 XS1100SF 20k miles '80 XS1100SG 42k miles '81 XS1100H Venturer 35k miles '79 XS750SF 15k miles '84 Honda V65 Magna ? miles '84 Honda V65 Magna 48k miles (parts bike) '86 Yamaha VMAX 5k miles Previous '68 Motoguzzi 600cc '79 XS750SF 22k miles |
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80G |
#9
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Brant, I don't see how that can prevent oil loss. It would probably increase compression though.
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Skids (Sid Hansen) Down to two 1978 E's. Both stock air boxes with K&N filters, one with 81H pipes and carbs, One with Jardine 4-1 pipes. 8500 feet elevation. 03 Honda ST1300 ABS |
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Hey there Rex,
First, just want to ask how you did the compression test, because some folks don't know that you're supposed to have the throttle cracked wide open so there's no restriction of airflow into the engine. And so if you didn't have the throttle wide open, then your readings could be artificially low. But if you did do it correctly, then they are still not that bad. Stock is stated to be 142+/-10psi at sea level. And the 115 one is just a little more than 10% off from the 130 ones, so not that bad. As was stated, low comps is often just due to inactivity, gummed/stuck rings and such, and running the engine many hundred miles helps to loosen the rings and reseat them. Also, low comps can also be due to the valve clearances not set to spec. And what was stated about doing a good valve job, replacing the seals, and lapping the valves will stop oil from getting in from the valves and will help boost compression levels as well. SO....if you have the gauges, check the cylinders for oval wear, but if within specs, you may want to do a very light honing, OR...just put the head back on, and get it running, use a little Marvel Mystery Oil in the oil to help break up gum/varnish and loosen the rings, and then put several hundred miles on it, and then recheck the compression levels, and you'll probably find them back up close to stock and within 10% of each other. T.C. |
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81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top. |
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81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top. Last edited by motoman; 02-17-2017 at 08:43 PM. |
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Skids (Sid Hansen) Down to two 1978 E's. Both stock air boxes with K&N filters, one with 81H pipes and carbs, One with Jardine 4-1 pipes. 8500 feet elevation. 03 Honda ST1300 ABS |
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Should take about 8 hours max to get the valves done(if it's your first time), so not that much time as you can work in a garage, or even inside to pull apart and put together if you have someplace you can put down a bit of plywood to keep things from getting oiled up. Read through the repair sections here, and you will have a better idea of how easy it really is. Big thing is DO NOT INSTALL BOTH CAMS AT ONCE AND THEN TURN ONLY ONE!! The valves WILL bend if you do it wrong! IT's really not hard, but do read how so you understand the workings before you start.
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Ray Matteis KE6NHG R1200RT Totaled 11-15-2016 XS1100 E '78 (winter project) XS1100 SF |
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__________________
81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top. |
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engine, motor, rebuild, rings |
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