Steve Best
Well-Known Member
It was a generic picture off the internet with me colouring it in with PAINT program because I have misplaced my camera and didn't get pictures. The actual 66cc engine I did it to has no name on it and is not a late model Grubee for sure, very small ports.
The 40mm OD bearings are 6203-c3 which also means 17mm crank vs 15mm for the 6202-c3 bearings.
It also means some scooter cranks with longer strokes could be used too, since most of them are 6203 bearings.
The shaft ends would have to be dressed to match the magnet and gear, and a woodruff keyseat cut but 45mm stroke is possible.
I have a Grubee 48cc engine as well and noticed all the differences from the 66cc also.
They look similar but very different. I don't know if the cranks are interchangeable or not.
I like the way the transfer troughs do not extend deeper than the crank on this case you picture:
The groove by the bearing seat is to allow oil flow through the bearing.
My stuffed case did not have that and I could see baked oil in there.
I drilled from the transfer trough down to this location and grooved it like shown in your picture.
This allows a free flow of oil and air to lubricate and cool the bearing.
I went for a long ride on the little black stuffer yesterday.
I have it jetting so it won't start cold without choke but starts and warms up quick.
It only does about 45 kph but will hold it well and does hills quite well.
With stock new Grubee catalyst muffler it is quiet and smooth. Very enjoyable.
Raining today, who knows what I might do?
Steve
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