W.A.T. Posted August 12, 2012 Share Posted August 12, 2012 Background: At cold engine startup I noticed that the engine would backfire slightly and run ruff until it warmed up. I did not think much about it, just thought it was normal for a cold engine. (I now believe it was running too lean due to slightly clogged idle jets) (Jet kit now ready to be installed) Note: If yours does this don't put it off. A bad day about a year ago: I started the engine and shortly after it started (it was running) it backfired (I think) so hard that is sounded just like someone took a sledge hammer and hit the bottom of my engine as hard as they could. The engine stalled and was completely locked up. I tried to restart it but it was completely locked. I went inside and cried for a bit then returned. It still would not turn over at all with the starter. I put it in second gear and started rocking it back an forth, then I hit the starter and it started running. I was glad that it sounded fairly normal but was very concerned that it could have internal damage. Today: It has been about 200 miles since that happened but now I have noticed a loud knocking noise coming for the transmission area. It is most noticeable rolling up just before I come to a stop. I put it on the center stand and turned the wheel by hand and there is something definitely wrong. All of the gears shifts fine and everything else seem OK. Not sure what has happened. Any advice would be appreciated. Thanks, W.A.T. Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted August 12, 2012 Share Posted August 12, 2012 Maybe a stuck link on the chain, or a very worn or dirty countershaft sprocket? How many miles on your chain? Did the bike sit out for a while with all this rain? Work has been running me late most nights, but I would be glad to come down and give a listen. Your area code. Two zero six 1 seven zero nine. I just came through Moultrie a hour ago. Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 13, 2012 Author Share Posted August 13, 2012 Maybe a stuck link on the chain, or a very worn or dirty countershaft sprocket? How many miles on your chain? Did the bike sit out for a while with all this rain? Work has been running me late most nights, but I would be glad to come down and give a listen. Your area code. Two zero six 1 seven zero nine. I just came through Moultrie a hour ago. Thanks Redxxrdr for your offer... Well the chain and sprockets are almost new maybe only 500 miles, oil changed at that time also. I did notice while adjusting the new chain that the chain gets tighter and looser as I turn the back wheel. Not sure if the new DID chain would do that or if it could be something else. Today I drained the oil expecting to see the tail tale signs of gray aluminum power ground up in the oil but it looked clean and normal. Tomorrow I will pull the filter and cut it open and check for metal. I'm thinking that the bearing near the drive sprocket is going bad. Only 14,000 mile since new and always stored indoors. How hard is it to get to the transmission bearings? I normally work on small airplanes and have a FAA A&P/IA mechanics license but, this is my baby. Not looking forward to this at all and I know this is no airplane. Quote Link to comment Share on other sites More sharing options...
rockmeupto125 Posted August 13, 2012 Share Posted August 13, 2012 This sounds drastic, but don't approach it in a panic. Its easy to pull the sprocket cover and investigate. Check the sprocket teeth, the condition of the chain, play in the shaft and look for fresh oil around it, and looseness of sprocket on the shaft. Run the bike on the centerstand. Block the front wheel and take it through the gears. Listen for the noise and watch the chain and sprockets for any snatch or wobbles. If you can, activate your rear brake to place a load on the system. If you get any noises, loosen the rear wheel and drop the chain off the front sprocket to repeat the test. All this is diagnostic, and can help you not pull the engine if not needed, or know what you're getting into if that's the case. Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted August 15, 2012 Share Posted August 15, 2012 I do have a hard copy of the FI year manual. I suspect the mechanicals are the same as the Carb setup. Your welcome to use it if you want. Are you working out of Spence field? For Maule or someone else? I really need to get a life and pull my 11AC out of the rafters of my barn. Craig Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 15, 2012 Author Share Posted August 15, 2012 I have a XX Manual, just need to get out in the shop and get started looking into the problem. Thanks for you offer to use yours that's cool. I onced owned a Cheif as well (great little plane). I sold it and bought a L-16 Aeronca "Military Champ". It needs to be restored as well. Spent 8 years working with Maule Engineering but left them to try to catch up at home. Still trying to catch up after 9 years. www.wrightaircrafttechnology.com Quote Link to comment Share on other sites More sharing options...
rhubarbray Posted August 16, 2012 Share Posted August 16, 2012 Well the chain and sprockets are almost new maybe only 500 miles, oil changed at that time also. I did notice while adjusting the new chain that the chain gets tighter and looser as I turn the back wheel. You are supposed to adjust the chain tension at the tightest point of the chain so as not to overstress anything in the driveline. However you mentioned the chain getting tighter and looser. What I`ve seen occasionally is a rear sprocket being made eccentric by just a little bit. If the centre hole is only off by 1mm, you now have a 2mm high to low variance. I don`t think this will give you the knocking you`re talking about but it will give you a pulsing/shuddering/ or vibration directly related to whel speed. Are you getting a vibration? Ray Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 17, 2012 Author Share Posted August 17, 2012 Update: I cut open the oil filter and checked for metal, expecting to find lots. To my relief, the filter was as clean as any I have ever seen, as was the oil. Fresh oil and filter installed. Removed the front sprocket cover and while on the center stand put the bike in gear and watched the chain and sprocket. Problem found: The photo I attempted to attach explains the problem. One side of the sprocket shows extreme wear. On the same side of the sprocket, 180 degrease across there is no wear at all. The stupid thing is warped. The 18T front sprocket that I installed a while back was ordered from White Buffalo Racing, when it arrived it had no markings other than the number 18 stamped on it. No way for me to know who made it. (New rule for me, If they don't put their name on it, DO NOT USE IT.) Obviously the engine backfire is not related, crazy how my mind always assumes the worst. Who makes the best front sprocket, 18 tooth, that is willing to put their name on it? You guys are the greatest, thanks for your input and help. Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted August 17, 2012 Share Posted August 17, 2012 I'm glad it was simple. I have always ( twice) used the OEM sprocket. But isn't that a 17? At work and CRS. I would give the chain a good evaluation once you get the new sprocket. Replacing a low mileage chain would suck, but replacing a engine case would suck more. EDIT: I had time to mag that picture. I have never seen a sprocket wear like that. I assume that you have laid the sprocket on glass or a milled surface to see if it is laterally warped. And is it really round? Could the sprocket or chain be different than a 530? It's such an extreme wear pattern. I thought White Buffalo closed a year or so ago. Maybe some old stock? If not, the used to stand behind thier products. Good on you to find it. I can't remember. Was the L16 the one that had spoilers on the wings too? A buddy of mine, Don Green, had a observation plane with rear facing seat, green house rear canopy, and a Aeronca type nose bowl. It's been too many years to remember it's designation. But I remember that it was cool to face rearward as he did loops. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted August 17, 2012 Share Posted August 17, 2012 I started the engine and shortly after it started (it was running) it backfired (I think) so hard that is sounded just like someone took a sledge hammer and hit the bottom of my engine as hard as they could. The engine stalled and was completely locked up. I tried to restart it but it was completely locked. So why was the engine locked? BTW-great photo and something new to watch out for. Quote Link to comment Share on other sites More sharing options...
rockmeupto125 Posted August 17, 2012 Share Posted August 17, 2012 What is the wear pattern on the other side of that sprocket? Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 17, 2012 Author Share Posted August 17, 2012 As for the engine lockup...I have no clue. Thats why I posted that information here hoping one of the really fart smellers here would have a good answer. The engine seems to be fine with no strange noises so far. It still has the original CCT installed but I have a new one ready to install if it starts making chain noise. Do you think I should go ahead and install it now? Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 17, 2012 Author Share Posted August 17, 2012 What is the wear pattern on the other side of that sprocket? Well I knew someone would ask this question. It is obvious that the factory rear wheel alignment marks are off (at least on mine). Even with the chain misalignment the pulley still has a problem. It does wobble when rotating. Quote Link to comment Share on other sites More sharing options...
W.A.T. Posted August 17, 2012 Author Share Posted August 17, 2012 I can't remember. Was the L16 the one that had spoilers on the wings too? A buddy of mine, Don Green, had a observation plane with rear facing seat, green house rear canopy, and a Aeronca type nose bowl. It's been too many years to remember it's designation. But I remember that it was cool to face rearward as he did loops. The L-16 is a two seat tandem, both occupants sit forward, full glass roof, used by the Air force for observation. See photo...not mine but it does look correct for the original Air force paint scheme. Loops while sitting backwards...don't think I could stomach that, but I would love to try it. Quote Link to comment Share on other sites More sharing options...
rockmeupto125 Posted August 18, 2012 Share Posted August 18, 2012 Even with the chain misalignment the pulley still has a problem. It does wobble when rotating. Wow. So some object jammed the chain and sprocket hard enough to bend the sprocket, then fell loose and was never noted. Plausible? Did you check the shaft itself? I solo'd in something like that L-16. It was capable of inverted and had a full glass roof, fore/aft seating. Aeronca or Bellanca...can't remember. Quote Link to comment Share on other sites More sharing options...
redxxrdr Posted August 18, 2012 Share Posted August 18, 2012 Thinking about the L16 made me do a search. Don's was a Taylor Craft L2. Pressure bowl cowl, and 30 plus years made me remember it as a Aeronca. It did have spoilers, that were not supposed to be used, and a neat rotating seat. Those little L models are my type of flying. I also got to ride in a Luscombe T8F that was owned by a friend. A big rear bubble canopy that tended to limit rudder control in a spin. Joe, I bet you soloed a Citabria, or Airbatic for those of us who read backwards. They are a higher stressed version of the 11AC champ with a window in the floor. Neat planes. W.A.T. don't throw out that sprocket. I would really like to see it. My homemade laser chain alignment tool was recently dropped, and doesn't work any more. I also have a ProAligner, I think it was Speedygeezer who sells them. My bifocals argued with it too much for me, but you are welcome to give it a try. Quote Link to comment Share on other sites More sharing options...
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