@@kimberlyclimbs i had totally forgotten about this video. . . That came out sideways!!! Glad you enjoyed it. He loves biking and dirt biking. We ride every day.

you are correct about the high pressure airstream through molten glass. but there are a few different ways of creating the glass fibers depending on what their intended use is. fiberglass insulation is created in the way you describe in a system that is very similar to how cotton candy is made. fiberglass used for fiber optics is a single extruded and coated strand of glass in a highly controlled process. I’m no expert, just provided a few basic examples of common fiberglass manufacturing techniques. thanks for watching!

I’m glad you liked it! I worked really hard on it!

Thanks! It’s till running strong despite the concerning noise so I’m going to just tell myself it’s normal and hope she continues to perform. I love this mower! The noise just sounds so wrong!

dwjw1 interesting. When do you plan to make the repair? Please let me know how it goes!

@@n8ander Yes, I have. When I pulled the cover off I could see that the top of the flywheel was able to move a significant amount. When I pulled the flywheel, it was evident that it was hitting the magneto tips that stick out as pickups for the spark. I didn't think that it could be the cause of the noise, but I think it was. In any event the upper bearing was enlarged by about 0.033" which allows the flywheel too much motion. So I took the engine apart (expecting to find more damage inside - there was none). I measured the crank and inspected all of the parts but the only thing that I found was the upper bearing was shot. It is part of the shell which is basically unavailable but if you can find one it would be around $70 - 100. So I decided to try boring the thing out to insert a sleeve bearing. I found an oil impregnated bronze bushing with a flange on the top that was 1" bore and 1-1/4" OD with the flange which is larger. All about 1" long. This appeared to fit the bill so I ordered it for about $15. I used a step drill bit that I bought from Harbor Freight ($18 for two sizes) which included a 1-3/8" cut. I ground off the edge of the 1-3/8" cut on the bit so that all of the 1-1/4" cut was left. By mounting the step drill in the chuck of my drill press and clamping the upper shell of the engine to the drill plate, I was able to drill the hole out to 1-14" very nicely. I had tested the cut on a smaller piece of aluminum and the hole had drilled out to just shy of 1-1/4" so I hoped that I would get a tight interference fit. But the 1-1/4" OD sleeve fit into the hole almost perfectly. So when I was ready, I set it in there with red locktite. I found out that the top of the new bearing was too high and the bottom was too low. I ended up having to use the step drill to open the bearing at the top so that the seal would seat correctly. I drilled it in two steps down to a little more than the thickness of the seal, which is less than the thickness of the flange on the bearing. And I had to remove the amount of material that was below the inside of the engine shell surface because when it stuck out that much, the crank was prevented from being positioned to install the connecting rod. I had to shave of about 1/8" from the bottom of the bearing. I had hoped that it would be able to act as an upper stop, but there was not enough end play - much tighter than I had thought. So both of these cuts need to be made before the bearing is installed. In fact, I would suggest using a bearing without the flange at all. Insert it flush with the lower (inner) edge of the shell and grind the top off flush. I highly recommend the loctite red though - it will hold that sleeve in there tight. Just give it a couple of days to set hard. (When you install it, coat both surfaces and slide the sleave in until it is flush with the bottom of the hole surface. In a few seconds you won't be able to move it.) Of course use new seals top and bottom - they were cheap. I did not find that the bottom bearing was very badly damaged. The upper one even when dressed down and polished was only a couple of ten thousandths undersized. But the sleeve bearing was slightly undersized, too, so when I put them together, it was rather tight. It took only a little operation (turning) to loosen things up enough to spin it with the starter. I left the spark plug out and turned it with an electric drill - it loosened right up. When I put the thing back together, I found that the engine wouldn't start. I thought that I had set the gap between the magneto and the flywheel properly but it was far away. I set it again a little closer, but it wouldn't turn around because the magneto was catching on the flywheel. So I set it with a thin piece of cardboard. Now it turned alright but when I tried to start it the engine backfired and it made that clunking noise again. I double-checked the timing and couldn't see anything except that when I turned the flywheel to the point where the engine was supposed to be ready to receive spark, the flywheel was way off. I pulled the flywheel and found that the flywheel had somehow slipped - the key was partially stripped and the flywheel was off considerable amount. So I flipped the key over and reinstalled the fly wheel and voila - it started - runs relatively quietly and everything was good. I haven't used it to mow anything, but after getting the idle speed properly set, it seems to have plenty of power to run the mower and the wheels. BTW if you take off the cover for the cam and lifters, don't reseal it with make-a-gasket silicone. I made a paper gasket and used pliable gasket sealer so that I can take it off many times. Be sure to get the material of the cover straightened out if you damaged it while removing it or it will probably leak no matter how you try to seal it. I am pretty certain that the noise is caused either by the flywheel wobbling enough to hit the magneto or by the flywheel being dislocated from its proper position. You can try adjusting the magneto using a small piece of cardboard until it does not touch the flywheel as you turn it. When you do that, you might lose the spark because when it starts, the flywheel makes it spin more true so the spark might be too weak to keep it running. If it is caused by the flywheel, you just have to get it back into position. Mine had the noise after I fixed the bearing but the flywheel was off. I fixed the flywheel and now it is quiet.

dwjw1 wow!!!! Interesting work. Would have been cool to have that documented with photos/video. I have a few dirtbikes taking up my time at the moment but will pull the mower out and see what the flywheel looks like under the cover.