This project was made possible by the cooperation of the VI mailing Listers, and is a great example that nothing is impossible, if you've got someone willing to do a job + a bunch of people willing to support it by finding the information needed & providing feedback on what they want in a new product.
Lyle, who has a page about his other castings here on the VI site, had been looking into making a set of '38 Sport Scout cases into patterns for casting new ones in his garage foundry. Quickly the focus centered on which improvements should be incorporated in new cases, and quite naturally the factory 648 "Big Base" cases came up. As most of us know these were made for the 1948 Daytona racer in small quantities (Jerry Hatfield quotes various sources for the number of 50 sets in his books), incorporating many improvements over the earlier versions.
But where could a set of these mythical beasts be found?
Enter "Fasst" Jim Wall, winner of the 1999 Davenport Vintage races on his 1928 "Boardtracker". Jim is very much into racing Scouts (in fact there will shortly be pages on this website, chronicling his building of 2 hot Sport Scout racers!), and he had not only a set of Big Base cases, but also copies of most of the original factory blueprints for them...
The stage is set for the following to happen over the winter/spring:
Lyle will make patterns for a set of cases, being not true BB replicas, but incorporating the best design features of them into the format of the "ordinary" Sport Scout cases. Most of these new cases would be used for street bikes, and facilities for this should be considered. Lyle is busy with other things until after December, so please don't expect the cases right away! (Lyle, being a cautious man, tells me "that the cases are just a RUMOR until he'll have something to show", but having seen some of Lyle's other work, I betcha he's going to pull this one off too. Moen). Still, this is a great start.
The cases will leave Lyle's garage in unmachined form, and machining up a prototype set for testing before they go on sale is important, but the idea of a "central" machining deal could be considered. Setting up tooling for the machining of crankcases is a time consuming and costly affair, and we could probably all save money by having only one (or a few) places doing this, rather than each having our "pet machinist" do it in a hundred localities around the world. While Lyle would certainly expect to be paid for his work, and while there is no way (I think?) that we can get the machining done for free, this could still mean new, stronger cases for your Scout project (-you have one, don't you? There are too many Chiefs out there! :-) Moen) at affordable cost. Stay tuned for this angle.
OK, what's so special
about Big Base cases? Here's a bunch of pictures from Jim to whet your
appetites. Click on the small pictures to see full size versions, and
click on the big pictures to return here (or use your browser's "back"
button). In all modesty, this is kind of a (-nother! there goes the
modesty...) scoop for the VI website, as all most of us have ever seen
of these cases, is one picture in Jerry Hatfield's fine books. Thanks again
to Jim for the pictures! Moen.
|Big Base case to the left, Sport Scout right. Note fat main bearing boss.||Another view. Note that the major difference in the mounting points seems to be just the lower rear boss; new rear engine plates will solve this.|
|Close up; BB drive side main bearing boss.||Sport Scout main bearing boss.|
|Rear view; BB on the left. Look at at that fat snout for the d/s bearing... Note also shallower cam case on the BB.||Again BB left; look at the way the lift cavity is moved inwards, and the beefed up mainbearing area (not partially cut away like the stock cases, right).|
|Close up of the BB cam area. Lift cavity moved inwards making cam case shallower.||Same view of the stock cases.|
|Drive side cases, BB left. Note sump and flywheel scraper (and beefy bearing boss).||Cam side view. BB left.|
|Interior view of BB cam side case. Note how nice & fat things are.||Same view of stock cases. This is what the factory gave us to play with instead of what you see to the left of here....|