just put a smaller pulley on the tranny. I put a 4 inch on the tranny and left the front one stock and she goes 20 kph but i didnt want to go fast because it s a muddin tractor.
Chunk Established Member
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A 1:1 gear ratio is pretty good, use large diamter pulleys though so you get more belt grip.
Mine was the same, stock pulley upfront with a 4 inch on the rear, did about 10-15mph, better than stock, but not by much. Didn't work very well in the mud though.
dangeroustoys56 Veteran Member
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My ex mod murray used to go unofficially well above 30mph - it was REALLY fast- a scarey fast for a nearly stock tractor. I have a video of it actually on YT ( id have to take it off private) . I debated on modding it more severely , but decided to build a whole ' nother tractor- a 69 wheelhorse body on a 03 bolens chassis- rat rod style- which i can mod out to handle better and safer ( i was always afraid of crashing on the murray - it was extremely unstable at higher speeds)- my whole goal was to build a tractor that could do 45 plus MPH with a governed, mostly stock 18.5HP twin opposed - the murray i never had WOT /high gear( 6th) - it was far to unstable. The wheelhorse should do that or more since itll be properly built this time- low to the ground, direct steer, disc brake , 5 speed peerless and straight rear axle.
a current project ( mild mod MTD thread posted here) is also an experemental tractor on how fast a vari drive drivetrain could go- so far, not that fast. Probably does like 10 mph or so- same as my stock 97 mastercut ( its fast for a stock tractor- also have a vid of that) - i doubt itll get much faster even with some more tweeks , shorter rear tires , 5 1/2 front , 4 rear , stock vari drive.
another future project is a wizard with a 5HP horizontal honda to a straight rear axle , go kart clutch, chain drive- itll be lowered and have direct steer, 6" wheels , custom spindles.
The MTD and wizard are just fun projects to goof with - the wheelhorse will be the real project.
Chunk Established Member
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As a general rule, a 1:1 gear ratio will get you doing about 20mph I think, dont quote me on that! A futre project of mine is a 6hp (1968) Briggs with a manual belt clutch, to a jackshaft with sprockets to a straight axle. Just for messing aroun on really, nothing serious, that will hopefully do 25mph
dangeroustoys56 Veteran Member
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The theory ive herd is the larger the engine pulley ( the engine has to work less but puts out more ) and the smaller the trans pulley = a fast tractor IF the trans will hold up to that many rpms. A smaller engine pulley would spin it lots faster but tax the motor more- another issue with a larger motor pulley could be a lil bit of lag while it spools up. I noticed that with my murray- took a second to gain speed, but when it did- it flew.
A foot/hand throttle would add a crisper throttle response then the stock throttle setup as well. I liked my murray for the fact that it had the shift on the go trans- meaning no clutching to shift or slowing down- im sorta wondering how well that peerless will work on the wheelhorse......wonder if i could adapt that shift on the fly......
Mississippi1313 Member
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23MPH I got a smaller transaxle pulley (don't remember size Bigger front pulley don't remember what size either 18HP Vanguard V Twin 22x12-8 Kenda Bear Claws Pretty good setup,it's pretty fast but it will still sling some mud =D
Ok I measured pulleys. 5.5" on back 4.5" on front
I'm going to be going bigger up front,for a little more speed. Probably a 1:1 ratio
Last edited by Mississippi1313 on Tue 27 Apr 2010, 7:54 pm; edited 1 time in total
Chunk Established Member
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23MPH Pretty good setup,it's pretty fast but it will still sling some mud =D
That's really the speed Im after too! Let me know what sizes you're running, I got a 6 up front, still not got one for the rear end though. Cant wait to see more of your machine man!
my 1989 craftsman, 12 hp, with a 6 in. drive pulley and a 3 in. rear pulley will do 26 mph. but its super scary when going that fast. i'm considering slowing it down to make it safer and better for offroad.
Chunk Established Member
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The hood really made a difference? thats crazy. I thought these were geared so low that they would top at the same speed with any weight on them.
Im gonna check the speed of my mudder with my GPS. Im thinking about 15/20mph. Plenty fast for off road. IF it went any faster, I would loose crawling speed in 1st!!!!
dangeroustoys56 Veteran Member
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Chunk: I know on my murrays 6 speed even with the 6/3 inch pulleys - 1st and 2nd are nearly stock ( y saw my vid of that ) 3rd and up are eye openers..... was never that fast with the 14.5 and stock wheels - the golf kart front wheels and larger 'stock' rear tires ( almost as big as the ones on the Alko) along with tapered front wheel berings made it faster.
Thats another reason i want to put it back together- but ill use smaller tires this time to lower it- just like the mild mod MTD.
Chunk Established Member
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Yeah, with 20" tall tyres, a lifted tranny and stock seat height, this thing is a little scary. I think Ive decided against seat suspenion, too much hassle. Just going to make it as long to the frame as I can It'll be even worse once I get my Kenda bearclaws, there're gonna raise it by another inch.
MSteele323 Member
Age : 50 Join date : 2010-04-09 Points : 5697 Posts : 267 Location : Little Rock Arkansas
The Murrat goes 7.4 M.P.H. according to my wifes Garmin nuvi. if i mash on the foot throttle. and yeah the carb is still messed up. I will post a vid later of it.
MSteele323 Member
Age : 50 Join date : 2010-04-09 Points : 5697 Posts : 267 Location : Little Rock Arkansas
Its actually sort of a rush going real fast on a tractor- i know my murray wouldve probably hit 50 mph in 6th ( darn close to it) i never cranked it up past 4th. Was just too unstable with it being nearly stock . I plan on rebuilding it sometime.
Years ago when i found out about modded tractors ( and did a D'oh when i could built em when i was younger yet) - i had intentions to build a 'correct' and safe tractor to easily do 50- 60mph WITH a basically stock AND governed motor - i believe its still feasable ( specially after i found out how fast my murray went) . After reading thru racing tractor web sites and see how many problems they have with total custom built motors ( and cost included) - which is why it should be reletively easy with a stock motor ( it wont over rev the governed motor, so the cast flywheel should be okay as well) .
The problem with larger front pulleys is it does go faster, but its laggy in initial accelleration , once it winds up tho...itll fly- even with the 6" is lagged a bit.
Im thinking of a 7 or 8" on the wheelhorse's 18.5 twin engine and a 4 on the 5 speed 700 peerless trans , not sure what sprocket on the trans to use or on the axle yet. It should move pretty good .
Believe it or not- smaller then 3" on the back wouldnt work - belt couldnt stay on that small of pulley. Chain drive would work, BUT the trans probably would fly apart unless heavily modified with stronger gears.
Faster doesnt always work when driving thru mud - unless its a straight shot . Not good for going thru rough woods either ..... itd work for going to the site and back ( if its still running- LOL!) - i wanted to power up the agway some to get down to the swamp up north- 3 gears takes forever....
All of the rally tractors we run will do around 35-40MPH road speed. Don't have a video posted of full speed on the road, but this race video from last fall will give you a bit of an idea. The guy in the lead is Stretch44875. He shows you how much driving skill affects amateur racing... https://www.youtube.com/watch?v=nsnDZ7gzvIQ
Subject: 
Wed 17 Mar 2010, 7:54 am
thats crazy. I thought these were geared so low that they would top at the same speed with any weight on them.
. I need to do a pulley swap soon, I am itching to do double digits on one of these things lol.
