Check the manual it shows a diagram of the belt routing. If you don't have your manual you can get it here: http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0805481.pdf
You can find a diagram for the Craftsman model 917270840 deck belt on the official Craftsman website, often in the support or parts section. Additionally, you can check online retailers like eBay or Amazon, which sometimes provide diagrams in their product listings. Another useful resource is lawn mower repair forums or websites specializing in lawn equipment repair, where users may share diagrams and guides.
Gates
The drive belt is a Craftsman #140294 The deck belts are Craftman #'s 180808 & 174368
You can go to www.searspartsdirect.com and put your model number in the box on the right side of the screen. It will give you a listing for you mower and a parts breakdown with pictures. Try the link and choose the EHP decks.
1980
There could be anywhere from 2 to 6 depending on the model of the mower.
917.276360
make a drawing of how the old one is on it before replacing it,
I have a Craftsman DYS 4500 and there is a nut under the left rear fender next to the tire that adjusts level. I'm still having trouble getting the deck tuned again despite my best effort with a bubble level, but that nut is definitely adjusted it.
The Craftsman model 917257621 typically uses a 42-inch cutting deck, which generally requires three blades. The specific blade size for this model is usually 21 inches in length. It's always advisable to check the user manual or the manufacturer's specifications for the most accurate information.
I just relaced the same belt on the same model number tractor yesterday and it was an 88"x1/2".
You can get a basic idea by the picture see the link below: