Troy Bilt MTD Unexperienced offroader

I am new to this mud mower stuff not new to mowers. Any suggestion for a new size front pully and what belt size i need to run its a 17.5hp engine and pedal drive varidrive im going to tsc later so if anyone knows the pully and corrisponding bekt size please let me know. I will go get pictures of all the belts and stuff

How fast do you want to go, and what ratio do you have now? If you want to go 20 from 5 then you will need a pulley ratio that is 4x higher than stock, so 1/2 the size of the rear pulley and twice the size of the front pulley as an example. Hope this helps.

Did i blow the head gasket??? It was running fine as it should and all the sudden is started stuttering and coughing while i had it chsrging its battery and idle and i shut it off when it did that and it was spewing oil on the muffler 

Also i just wanna go a little faster its stock at the moment fast enough to get places but not dangerous fast like 20mph or 15

For the head gasket check your PCV valve. If there is oil in the air filter housing then you have most likely blown a head gasket. There also may be a slim chance that you dropped a valve or valve seat but I would doubt that. As far as pulleys go (unpopular opinion here, so be wary of trying this) you can flip the front pulley stack, drill a hole across the crankshaft and put a bolt with a lock nut (might want a lock washer too for peace of mind here) so the deck drive pulley becomes the transaxle drive pulley. Again, this is not the best idea but it will get you to around 8-10 mph, or you can simply just put a 6” pulley on the front and delete the pulley stack. If you have any junk belts take one cut it and measure the distance you will need because other wise it becomes trial and error. Also Amazon has good quality Kevlar belts from around half the price, I’ve bought one and it seems well made.

Head gaskets not blown i started it back up it was just running weird i guess ill still check the pcv valve and it made a really loud backfire when i shut it back off

So if i increase the pully size by a certain amount how much do i increase the belt size like if i put a 5 inch front pully how much would i increase the belt size

You just have to either guesstimate or try and get an approximate size with a string, route the string around the belt’s path keeping it tight and cut and measure it and you’ll get an approximate size.

Im gonna do the math on it so i dont have to guess i just wanna get the right size the first time

Also heres a few pics, my other mtd doesnt have that bump on the transmission what might that be? Also i added in led lights to replace the lightbulbs 

Good luck with estimating the belt length - I did the same thing (and I'm very good with math & physics), and the best I could manage with the math was +/- 1 or 2 inches of the correct belt size.  You'll really need to use trial and error, so buy your belts someplace where you can return the ones that don't fit.  That's what I did.

Of course, you'll only have to do it once because once you know your proper belt length you're golden.

I did the front pulley flip, but didn't like the idea of cross-drilling the crankshaft, so I used my lathe to cut off the deck pulley & drive pulley and weld the deck one one the tube where the drive pulley used to be.  Of course, I also replaced my 9" rear pulley with a 3", so now I can do about 30 mph.  That major change in belt size meant a bit more trial and error than you'll have to do if you don't want to go that fast.  For me, 5.7 mph was waaaay too slow!

I know two people with lathes ill ask if i can use one of them to change pully size

That's definitely the best way to do it.  Once mine was welded up, it's way stronger than the original setup.  Due to space restrictions, I ended up having to hack up the 3 1/2" original drive pulley to get access to the 5 1/2" one on the lathe.  I did the cut on the bigger one VERY carefully, to try to leave it as tight a fit to the original mount cylinder as possible.  It did work, and when I spun the final result up on the lathe, it ran extremely true, with no runout or wobble.

If your pulley stack is anything like my Craftsman one, the original cylinder core mount MUST be used.  It has an embedded step, plus a pressed-in locating key, which would be very hard to recreate.  I also had to shorten the bottom end of the core quite a bit to be able to use the original securing bolt, which I also had to shorten.

I have a lot of work otherwise, I am thinking that tractor supply might be the was to go but I don't know what I am going to do yet because I'm gonna be doing a whole bunch of weight reduction to the chassis and I might start today it requires removing he whole body.

What type of weight reduction? If you're referring to deck parts that should be fine but I wouldn't take much more off. Those MTD frames are pretty flimsy from stock so I wouldn't take too much off. You could start having strength issues depending on how you ride it if you take more than just deck related parts off.

just deck parts, im going to weld in cross braces if i can find more tubing or square stock. first objectives are pully swap, weight reduction, front bumper/crash bar, rear rack, exhaust, tires. and if while im at pully swapping it i see it being flimsy ill add some bracing but the deck parts gotta go i cant change the rear pully because the bar being in the way

i tested it pretty thouroughly yesterday crawled it almost rolled it, its terribly slow but has all the torque, its decent at mudding for a stock mower. goes right through some sticky mud it spins a little but does fine. and it goes right over snow piles while my john deere wont for some reason

anybody got any tips for making a good back storage rack i dont want it breaking and i mostlu have anle iron

Brace it down to the frame at an angle, and it should hold up. Extreme cases you may need to go through the fenders directly to the frame rails. How much weight do you intend to add to this rack, and what size is your angle iron?

Just tools gas spares etc

You’ll be fine with just a couple 45 braces going down to the frame then, I think you won’t have more than 120 lbs on there.

its old steel bedframe

starter died yesterday swapped it for brandused starter with a metal gear and it fires off so easy needs valve adjustment and a new valve cover gasket. still havent did a rack. hood fell off broke a tensoner spring fixed it then blew the valve cover gasket lost a bunch of oil, not enough to hurt anything. im gonna work on the hitch and rack possibly if its nice after school. bumper is bent brush guard broke off and ive got too many projects on my plate

*UPDATE* custom exhaust, bumper hitch (needs reinforced), hood side supports (because im tired of putting the side pannels back on), valve cover sealed, valves adjusted. Now it fires right up immediately no outside help needed. Came in clutch my brother wrecked his bicycle over railroad tracks landed face first (hes ok just roadrash), i Had drove my youngest brother on my trailer to a bday party we where all at and it fired right up and i took the wrecked one home.