Yamaha YT 175 aftermarket 2 stroke exhaust

[RubberSalt]

I want a new pipe on my trbike pretty bad, but i have limited money like the rest of us. I can try my hand at making 1, but that is time consuming and difficult. I can save up for ever and try to buy an aftermarket pipe designed for this trike, but few exist.

So, I came to the conclusion that i could buy a pipe, and "make" it fit with my welder and such. Now my question is, What pipe to get?

This is the stock pipe. Its the best pics i could find in 40 seconds

This is a pipe I'm thinking about modding

I figure the 125 of dirt bike would probley flow better than my 175 and still act as a pipe. The bends in the pipe are what make it a difficult choice.

[the great gazoo]

I'm pretty sure the older 2 stroke expansion chambers were shaped a lot less like the newer ones are because of the porting,and older type pipe is what you should start with. Your best bet is to do your research on here, check out the thread "protec 175 the beginning", it will tell you what you need to know. Also look into an early IT175 cylinder, the ports are way bigger.

[RubberSalt]

My ports are way bigger

I've got a 2nd cylinder which i've ported (mimiced flotek's blaster porting). Added some boost ports and a couple small exhaust ports for a triple port exhaust. I've also removed that massive chunk of metal restriction in the exhaust. It runs WAY better than stock, but i need a pipe. The older pipes probley wont compare to a nice bladder pipe for it. Building a pipe is difficult without proper metal bending machines. I've also made carbon fiber reeds and added a 34mm mikuni carb. Still need a pipe, just a pipe.

If i could get access to a way to machine metal, I'd make ome awesome pipes, probley miss on the first few but i'd get a design down for it.

[Vealmonkey]

I would think that without tons of trial and error, that a restrictive stock pipe would do better than a cobbled up pipe with bad flow characteristics would do. I would also think in the long run, that you would end up spending more for your trial and error pipes than you would just stepping up and buying an existing exhaust. And your blaster ported cylinder, well that's good for a blaster with it's newer exhaust, but you don't have a blaster or a blaster pipe. The requirements for your cylinder and machine are different than a blaster. You could buy yourself a program to help you come up with an exhaust, but it will be way more than buying an exhaust itself. Then it's still alot of time and effort to come up with a pipe, and cutting the metal, and rolling the metal for the pipe sections and welding the metal and then putting the sections together for a working pipe. Not saying it can't be done, but it won't be done soon. Nos pipes are available, I've got several for the yt175 and one sllightly used yt125 exhaust and even one super clean stock pipe. Personally I'm not a porting guy. I liked the idea of the stock it175 piston and cylinder being way better than the yt175 stock piston and cylinder. How much more performance do you want out of your hardtail? I think improving your trikes suspension would go more to performance abilities. Find yourself a nice rear suspension kit. If you want a sport trike, then get yourself a tri z or something like that. Even with a rear suspension kit, your trike would never equal a sport trikes suspension or performance. I dig the effort you are putting into your trike, but I think you are losing sight of what your trike is. Not trying to bring you down or discourage you from your task, but keep in mind what you are dealing with here. And one way or another, you have to and are going to be paying hard earned dough ray mi. There is just no other way about it. You can ask anyone on here with a trike that they have upped the performance. And being that you aren't even starting with a sport trike with disc brakes and suspension, your task will be just that much more. I wish you all the luck in the world, it just pains me to see you banging your head in the wall like this.

[RubberSalt]

The stock pipe sucks very bad, not as bad as the 125. I've got all my math done, I just don't have a way to work metal.. yet. So a starting on another pipe i can mod is a much easier option.

This isn't just something i'm trying to make go fast, this is something i'm want to learn to do, make pipes.

Yes there will be trial and error, yes it will be pain staking, yes, i will have something that steps on the stock pipe.

If you want to see a restrictive pipe, look at the yt125, that things practicaly straight pipe with some wierd plumbing on the side lol.

[Vealmonkey]

Here are 2 aftermarket yt175 pipes that I have.

[Yamaha_Rules69]

I used to have a Bassani, just like the one vealmonkey posted in the last pic - mounted on my YT175 , and with power reeds, it made it a whole new machine, and everything else was stock! I loved that pipe, it made more power everywhere, and sounded MUCH better than the factory POS. I agree with you 100%, what the heck were they thinking when they made the factory 125 and 175 pipes? Worst pipe design ever. On this other YT175 "project" of mine, I have what I believe to be a PK performance pipe, like veal posted in the first pic. It is a major improvement over the stocker, but still not a bassani. Keep an eye on ebay, once in a while you will see a pipe - for cheap, then BAM its gone.

[RubberSalt]

The bigger carb + home brew reeds gave me a ton more bottom end and some top end. Don't know how much yet, I pulled out my triple ported cylinder, might extend the port up or down , gonna set my degree wheel up tonight and see where its at.

The bassani pipe looks simple to replicate, very simple. And heres some, what I'm going to base my designs off of. I've got a few books on pipes, this is 1 of the pages.

[RubberSalt]

I just got my Port durations, exhaust opens at 90degrees, closes at 114.5 - for a durations of 155.5 degrees
All the intakes are the same, open at 117 degrees and close at 125.5 - open for a duration 117.5 degrees

I going to map out the ports later today and get a few more measurements - con rod, exact bore, ect.

I've got a complete spare engine to get my numbers off of :-p to bad the crank/rod is shot. Good for getting numbers without tearing mine down at the moment right?

[RubberSalt]

Conrod length is 106.2mm center-center
Head gasket is .5squish
Bore is 66mm (66.5 on the bored over)
Stroke is 50mm
Compression is 5.2 :1 book says so

Wounder what other info i need besides the port windows(size)

Better double check the books

[RubberSalt]

Port window is roughly 765 square mm for stock and 1087mm for my triple port

[Dirtcrasher]

Geez, that looks like allot of work and math. You may wanna just buy a Tri-Z

Hope it works out for you!

[RubberSalt]

Would if i had a job:-p

BUT if it does work out, and work out well - I'll make more pipes and have a job:-p

According to this web site http://www.mh-aerotools.de/airfoils/javapipe_en.htm, I wont have to do math:-p I've actualy done alot of some already and it matches up fairly well with the exceptions of a few variables.

What I entered as information:
Velocity of rotation: 7000 RPM
Exhaust port angle:156
Transferport angle: 118
exhaust port area:1087
Exhaust temp: 800K
Select gasoline

I understand the IT175 makes roughly 15hp at 7500RPM - dunno how high the YT can rev but 7000RPM should be plenty safe.

Also, does anyone have pictures of an IT175 cylinder's port work? I've found images off an 82/83 and they are different, lot more intake than mine, about the same amount of exhaust minus the triple porting

[RubberSalt]

After looking into the pipe some more and taking measurements, a double or triple stage diffuser will be needed on my pipe:\

I also raised the aux. exhaust port another degree, 1 degree higher than the main port.

I need to bring that bike back home so i can study it more.