Hi all! I managed to get the OEM motor that came with the MB200 back together; start it and not blow it or myself up! :smile:
The inductive pickup tach registered a max RPM around 6000; that was at wide open throttle with the throttle linkage pegged to wot. It didn't seem like it could rev higher, but such is probably expected since I didn't do any valve or carb upgrades.
During the assembly this afternoon, before I connected gas tank, air filter housing, etc; I wanted to fill the crankcase with oil and give the engine a few turns by hand to get oil to all critical surfaces. To my horror, about 3 minutes after manually spinning the engine, I noticed oil leaking out around the base of the side cover!!!!
I drained the oil out and pulled off the side cover; it was then that I saw where the leaking may have been coming from: See the image below of a motor that might be a 6.5hp, but nonetheless if it isn't, it looks very close to it. (I got the image from the web and modified it). What the photo is pointing out is the internal cylindrical pocket and the fact that the gasket I used (which I ordered 3 from an online minibike parts vendor; not OldMiniBikes warehouse) just overlapped that area and did not have a small semicircular cut out for it....
I thought at first that I lost one of the guide pins, but looking at the photo it shows only 2 guide pins and i only recall there being 2 such pins as well. What may not have helped the situation is that my side cover came from the factory with a 3mm wide or so ledge above the rest of the gasket surface all the way around. There is no such pocket slot on the crankcase gasket surface. Thus I believe that having such ledge on the side cover doesn't lend itself to good sealing....
Anyway, what I did to that cylindrical pocket was to swab it out, ensure there was no oil there and then fill it flush to the case gasket sealing surface using black RTV. I then put TWO side cover gaskets on, torqued down the cover bolts, filled it with fresh oil and ran it for about 10-15 minutes.... No leaks!!!
Am I potentially damaging anything using 2 side cover gaskets in this manner???? The crank endplay seems to be about 10 thou... I am not sure if that is too much...
As always, thanks for the helpful advice and info and I certainly learned a lot through this process!
The inductive pickup tach registered a max RPM around 6000; that was at wide open throttle with the throttle linkage pegged to wot. It didn't seem like it could rev higher, but such is probably expected since I didn't do any valve or carb upgrades.
During the assembly this afternoon, before I connected gas tank, air filter housing, etc; I wanted to fill the crankcase with oil and give the engine a few turns by hand to get oil to all critical surfaces. To my horror, about 3 minutes after manually spinning the engine, I noticed oil leaking out around the base of the side cover!!!!
I drained the oil out and pulled off the side cover; it was then that I saw where the leaking may have been coming from: See the image below of a motor that might be a 6.5hp, but nonetheless if it isn't, it looks very close to it. (I got the image from the web and modified it). What the photo is pointing out is the internal cylindrical pocket and the fact that the gasket I used (which I ordered 3 from an online minibike parts vendor; not OldMiniBikes warehouse) just overlapped that area and did not have a small semicircular cut out for it....
I thought at first that I lost one of the guide pins, but looking at the photo it shows only 2 guide pins and i only recall there being 2 such pins as well. What may not have helped the situation is that my side cover came from the factory with a 3mm wide or so ledge above the rest of the gasket surface all the way around. There is no such pocket slot on the crankcase gasket surface. Thus I believe that having such ledge on the side cover doesn't lend itself to good sealing....
Anyway, what I did to that cylindrical pocket was to swab it out, ensure there was no oil there and then fill it flush to the case gasket sealing surface using black RTV. I then put TWO side cover gaskets on, torqued down the cover bolts, filled it with fresh oil and ran it for about 10-15 minutes.... No leaks!!!
Am I potentially damaging anything using 2 side cover gaskets in this manner???? The crank endplay seems to be about 10 thou... I am not sure if that is too much...
As always, thanks for the helpful advice and info and I certainly learned a lot through this process!
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