Guys, I am really sorry to post a negative review such as this, on this great piece of engineering work, but reading this might save you a lot of both wasted time & money. I started printing this engine with the larger parts first, that was the Pistons, Piston Rods & Full Head Assemblies.
The Outer Diameter of the 2 Pistons is 4” Inches. The designer of this model stated; “(Plexiglass Tube: 2-1/4 ODx 2" ID x11-7/8 1Pc from ebay)”. I’m not sure what to do with this & makes NO logical sense. Most all of the Plexiglass Tubes that I could fine on E-Bay have a 4” Inch OD & a 3 & ¾” Inch ID, so the Pistons will Never Fit into the Plexiglass Tubes.
But now the real Problem with this 51 Piece Model, is the (Lack of any Assembly Instructions). Also the Bill of Material (BOM) for this model is really poor. As an engineer, I am really surprised & disappointed in this excellent piece of work having 51 pieces & most of them are all Gears, but I’m not going to spend months trying to figure out which (Gear goes Where).
Now I just found this model by accident, & it was just what I was looking for. The BMW R90/S Motorcycle Engine Model from Franzis model #504185 is a Working Twin Cylinder with a Transmission, ½ scale with LEDs & Sound. This is a German Co. & not a Chinese Co., so you know that the model will be of High Quality. I ordered my model today from www.grooves-inc.com for $194.81 with free shipping & NO tax. This was cheaper than both E-Bay & Amazon; which by the way, will each charge you Tax.
Build Time for this Model is about 3 or more hours & it does come with very Detailed Assembly Instructions. This is a Screw-In & Snap-On Model & there are tons of Videos on YouTube regarding this Model. Here are two really Good Step-by-Step Videos of the Full Assembly Process & you can see & hear the finished model.
Each Gear is numbered & is assembled together in numerical order. There are 102 Parts to this model & what a gorgeous & precise working model it truly is. You can build this in a lot less time & money, than you can trying to print & build one on your printer.