pmk Posted November 5, 2016 Report Share Posted November 5, 2016 My 1973 MAR has some corrosion on the flywheel and stator. With care, I have cleaned up the poles of the stator. To clean the corrosion from the flywheel I used abrasive cloth and cleaned the magnets and interior. I also used the abrasive cloth to clean the flywheel exterior. Removing the corrosion also removed whatever protective coating was there, so I ask, does anyone know what the oem finish was and what color a new flywheel would be. Quote Link to comment Share on other sites More sharing options...
woody Posted November 5, 2016 Report Share Posted November 5, 2016 I'm no electronics man but not sure the flywheel has a protective coating? Sometimes, flywheels are skimmed to improve engine pick up and if they are, the original finish of the surface is skimmed away. I've done a couple myself and they don't corrode. Still shiny in fact. I wouldn't worry about it but I guess you could always use engine lacquer on it 1 Quote Link to comment Share on other sites More sharing options...
bondy Posted November 5, 2016 Report Share Posted November 5, 2016 I cleaned a flywheel off 1 off my bikes years ago still looks the same as Woody says don't worry about it I be more worried about if the bike. Runs. Quote Link to comment Share on other sites More sharing options...
pmk Posted November 6, 2016 Author Report Share Posted November 6, 2016 When I got this machine, It had been sitting outdoors for a while. The tires were flat and the thing looks rough. The engine would not spin via turning by hand using the kickstarter initially. After a couple light attempts to just have it turn a little, it did come loose. My first thought was a stuck piston, but later turning the flywheel by hand, the engine is smooth. So I suspected and confirmed after removing the ignition side cover there had been some water inside it from sitting outside. Enough water to partially submerge the lower magnets and stator poles. These rusted and made the motor stuck. Fast forward, bike is home, pulled the flywheel and it certainly is not bare steel. There was very little reddish rust, mostly the white powder almost as if it was zinc or silver cadmium plated. Removing the corrosion, removed the coating. Currently, the flywheel is bare steel and coated with an oil to keep it from rusting. I had a look at various photos on the net after my initial post and most flywheels had a grayish color. Assuming the Motoplat fires the plug and the ignition is usable, I will probably have the flywheel and other various bits of hardware cad plated. Thanks for the replies. Still not disappointed, just some effort so far. Want to get it fired and ensure it runs compiling a list of needed items. Then pull the engine and chassis apart assuming it is viable to fix up vs part out. Quote Link to comment Share on other sites More sharing options...
pmk Posted November 6, 2016 Author Report Share Posted November 6, 2016 Photo before corrosion was removed and after removed. Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted November 6, 2016 Report Share Posted November 6, 2016 How feasible is it to plate the flywheel without affecting the threads or the taper? I would leave it but do what we did in the day and put a breather in the top of the case. Quote Link to comment Share on other sites More sharing options...
pmk Posted November 6, 2016 Author Report Share Posted November 6, 2016 How feasible is it to plate the flywheel without affecting the threads or the taper? I would leave it but do what we did in the day and put a breather in the top of the case. Agree, the taper must not be abrasive blasted or cad plated. I considered this before removing corrosion. It will be possible to install a bolt through a washer, then through a rubber washer, through the flywheel taper, then a rubber washer followed by a washer and nut. This once tightened will seal the taper from abrasive grit blasting and the liquid cadmium bath. Previously I worked in an aircraft propeller repair shop. I will use them to replate the items needed and should be minimal cost if any. So I think plating it should be done, especially since where I live, here in Florida the humidity is high any everything rusts. As for the added vent, I had read about people doing this. Since the previous owner had some type of failure that cracked / broke the side cover top to bottom just aft of the clutch actuator, the case will be repaired and is a viable candidate to be modified after welding. Quote Link to comment Share on other sites More sharing options...
bondy Posted November 6, 2016 Report Share Posted November 6, 2016 The breather Goss on the front I will put a photo on latter also the ignition wires get moved from the bottom to the top. Quote Link to comment Share on other sites More sharing options...
bondy Posted November 6, 2016 Report Share Posted November 6, 2016 (edited) hears my ignition breather pipe the clear pipe right on the front and my wires comming from top rather then the bottom. Edited November 6, 2016 by bondy Quote Link to comment Share on other sites More sharing options...
lotus54 Posted November 6, 2016 Report Share Posted November 6, 2016 Did you check your crank seals when it was apart? I've had a couple of old OSSAs with bad crank seals, especially the dry side. Mark Quote Link to comment Share on other sites More sharing options...
pmk Posted November 6, 2016 Author Report Share Posted November 6, 2016 Did you check your crank seals when it was apart? I've had a couple of old OSSAs with bad crank seals, especially the dry side. Mark Mark, I had plans to do a case leakage test, but held off for the moment. When I removed the flywheel and stator, I noticed the crank seal sitting a bit proud. I did not mess with it at the time, simply went about cleaning the yuck from that area before placing the stator and flywheel back on. Curious, beyond the simply mark the stator to reinstall it, and wanting to read how the timing is set I browsed through the manuals, both my Clymer and the online version. As I read, I payed close attention to the photos that showed the seal and the text read the seal should be flush with the case. Not sure if the original owner installed a thicker seal or what, I did not want to set it flush. Rather I grabbed the seal with my super short finger nails and it pulled right out. Basically, the stator backing plate retained the seal from completely coming out. I cleaned the seal and for the initial test run, reinstalled it flush. I am not sure why the seal was sitting proud. Possibly the bike was sunk and water filled the bottom end, popping the seal out. Maybe, since the flywheel and stator had been removed previously, the seal was replaced and never seated. I honestly don't know. My friend I got the bike from told me as we loaded it up, she probably needs rings or a top end since it was down on power last time he rode it. Maybe the seal was leaking and it was one of those lean enough to need jetting but not lean enough to quit running. Again I don't know. At this point, once I know the ignition is good, carb is ok, and it at least fires up, It will come back apart, changing those seals and others at a minimum but probably split the cases and do more. Simply time will tell, it all adds up. Tires, cables, shocks, fork seals, paint work, fuel tank(?), chain tensioner stuff and maybe more. Best part is the parts are out there. Still have not gotten my 81 KTM 495 back together yet. Some of it on parts availability, some on simply refusing to pay far more than fair market value from dealers and private sellers. Quote Link to comment Share on other sites More sharing options...
pmk Posted November 9, 2016 Author Report Share Posted November 9, 2016 The Motoplat, even after the abuse of sitting and corroding, cleaned up and fired the spark plug allowing it to run. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.