Anyone ever speed up a 48" IH deck?

[ken6x6]

got a center pulley on the way, now i got to figure out the size i need to go down to. OEM is 5" im thinking maybe a 4"?

[olds45512]

Originally Posted by ken6x6

got a center pulley on the way, now i got to figure out the size i need to go down to. OEM is 5" im thinking maybe a 4"?

If the engine is running at 3600 and you know what size the current pulleys are you can figure out the rpm of the deck, from there it wouldn't to hard to mess with the numbers to get the rpm your looking for.

[ken6x6]

its been a while since i updated this thread. so, i got the OEM center pulley. threw it on the lathe and split the two sections. i had found a web site that lets you put in pulley sizes, belt length, drive rpm, and the desired final rpm and it will give you the pulley size you need. i checked the blade tip speed and it actually matches the engine speed at any rpm. WOT is 3600. i figured upping the speed to 4500 would be good. that would mean i needed a 4'' pulley, and that's what i got. only thing i had to do was open up the key way from 3/16 to 1/4. then i went and welded the two pulleys together. had to use stick since the space between the two pulleys is only a half inch. once that was all done it was time to install. went on with ease just had to replace the grease bolt with a longer one. put the deck back on and that's when i realized i needed a shorter belt. duhh . it looks like 2'' shorter should do it. ill be heading to NAPA to see if i cant match one up. i also have been re making the baffles on the deck, im extending them down to mach the bottom of the deck which also matches the blade height. im hoping this will help with the lift. the one pic shows the old vs new.

[mjsoldcub]

when i did my 50" i used a weld a pulley that was 4.5" and cut the top one off with a hole saw and fried on the new one...works great but the 12 hp doesnt like the initial start up as much as the juiced 16hp... but it cuts!!

[riesedesperado6170]

you can also put a peace of steel on the bent up part to make a higher wing i ad 1/2" to my blades and they are the high throw blades. Know even when it wet it throws great.

[ken6x6]

well napa proved to be useless, so ill have to order a belt.

i got the baffles all done just waiting for the paint to dry.

i have heard of welding a piece of steel to the blades for more lift. ill give that a try if the new baffles and speed up pulley don't work out.

[ken6x6]

finally got the belt and threw the deck on today for the final leaf clean up (i know its almost January) and WOW! that deck sounds like there was a tornado under me. i ran the throttle about 3/4 for a few minutes just to make sure it wasn't going to explode. then i let er' rip, WOT!! it now sucks up everything from the lawn and launches it out the shoot 8' feet away. the little 12hp seems to do ok with it. i defiantly have to slow down in the heavy leafs or shes starts to struggle. i haven't checked the blade tip speed yet but ill update with that info soon.

[jaynjeep]

Nice looking work! You are very talented Ken!