So i have a co-worker that got me a hook-up on a free 2006 John Deere D102.  I looked it up on John Deere's website and it says it has a Briggs 17hp.  I was wondering if it was a flat head or had an OHV.  the previous owner said the engine is seized up, but from what my buddy says, this guy isn't very smart when it comes to mechanical issues.  But if it is unsaleable, it's still a free mower i can find an engine for!

I started my build with a 1988 Rally lawn mower.  the frame is a U shape that is open at the top with a 1-2 inch lip at the top.  It seemed to be fairly sturdy when moving around(didn't seem to twist very much).  there was a spot for the battery that was countersunk about 1/2" lower than the rest of the frame.  This area was just forward of my 700 tranny and was getting in the way of the tranny pulley.  after cutting this piece out and welding in a new flat panel flush with the rest of the frame there now seems to be a lot of twisting in the frame now.  when i pick it up, it now flexes about 2-3" from one corner to the other.  I plan to put 1 1/2"x1 1/2" square tubing inside on both sides with cross members on the front and rear, and possibly somewhere in the middle.  is this common with this type of frame and would this be a good solution to remedy my current situation?

this is my first build so i'm not going to go too crazy at first.  there will be plenty of time to upgrade.  I was thinking of getting 5/8 spindles and running some 6x6 wheels with high speed bearings instead of 4x4 bolt pattern wheels and hubs.  is this acceptable?

what is ideal for the output shaft.  i have seen a few with large 8 spline output shafts and ones with finer higher count splines.  which is the preferred shaft and are there sprockets that will match up with either splines?

i was going to use my foote 4000 series trans axle until it blew up but when installing the tires the snap ring on one of the axles came loose and i figured if it happened on the install who's to say it wouldn't have came loose while riding it!  thankfully all i have spent on that tranny was $4 for some rtv to seal it up.

I am brand new to the lawn mower racing scene.  I just scored a 1988 rally riding mower.  I have torn it completely down to inspect it. i have taken the engine apart to inspect for wear and i see little to no wear, the engine still has good compression, and the transmission has no missing or broken teeth.  I plan on flipping my transaxle to get the mower lower in the rear and replace the front end completely as well as the steering.  i plan on taking the governor out of it but not pinning the throttle to decrease my chances of blowing the engine.

my real question is what size pully's do you all run on the engine and the tranny.  It was stock with a 3 1/2" eng pulley and a 7" transmission pulley. I was thinking about ordering a 5 3/4" pulley for the engine and a 4" pulley on the tranny.  would this be a good choice for some more speed without making it too sluggish? 

also, what do you all do for the clutch, ie. centrifugal?