Engine Build Threads

[Balduccimoto]

Does anyone have any good engine build threads they bookmarked? I did my own porting this year and it turned out well. I did alot of reading on porting 2 stroke engines beforehand and it was very interesting. I'd like to find some more articles, builds etc. definately something with stroking a crankshaft and whats involved.

The pricetags on a stroker crankshaft are alot, kinda curious what is actually involved in stroking a crankshaft besides a longer rod. Just slapping on +4mm rod would mean that it would only travel 4mm higher in the stroke. To counter that im guessing the webs of the crank where the crank pin is inserted needs to be elongated and welded? At that point perhaps there would need to be some trenching of bottom of the cases to clearance the rod at BDC?

 

[Schmidty721]

Length of the Rod has nothing to do with the stroke of the crank.
If you wanted a +4mm stroker crank, the crank pin has to be moved out +2mm from the center line of the crank.
Stock webs can accommodate a +4mm stroke.

 

[Balduccimoto]

Length of the Rod has nothing to do with the stroke of the crank.
If you wanted a +4mm stroker crank, the crank pin has to be moved out +2mm from the center line of the crank.
Stock webs can accommodate a +4mm stroke.

Thanks I never thought of it this way. This explains why larger strokes require the billet webs. I tried to find a correlation between bore/stroke ratios of the different motors and combos we run. Just trying to figure out if there is a correlation of bore/stroke to the low end torque everyone is looking for. All the motors are a little oversquare (more bore than stroke). The dasa 850 stock stroke is the most oversquare (1.31:1 rounded to nearest hundredth) while a DASA 16mil 1100 is 1.09:1

I guess regardless of bore/stroke ratio, displacement and the depth of the wallet take the most consideration. Just throwing ideas around in my head, its amazing how much in depth is the designing of a motor.

Still, has anyone ever made their own stroker motor and documented it here?