What upgrades are available for Tri-Moto 175s? Engine swaps?

[VenomRS4]

So I just picked up another tri-moto 175 for $180 tonight. Its in pretty good mechanical shape but needs some tlc...especially in the cosmetics department The plus side is my other tri-moto (which I thought was a 175 but turned out to be a 125 with 175 plastics) is in great cosmetic shape so I can swap stuff over. But now that I can see the difference in performance between the 2 (175 def has more spunk)...Im hungry for more. What kind of upgrades are available. Ive heard of swingarm rear suspension conversions, pipes, big carbs, etc. Whats available?

Also, are there any other motors that swap in somewhat easily? Since its a 175, does that mean its based off of, say, and old IT175?

Thanks

[Vealmonkey]

The engines don't swap directly over, the transmission shafts are too short and the front sprocket and rear sprockets won't line up. You can mix and match parts. You can run the it175 top end, recommended, you can switch over to manual clutch. You can switch over to kick start. the 175 has a decent front end, but if you want better, get a yt200 front end and swap the steering stems over for better suspension. Of course there are exhaust pipes, and you can port and polish the cylinders. Better clutches if you go with a manual clutch. There are suspension kits, if you can find them and they have a tendency to be pricey and incomplete. That pretty much covers it in a nutshell. Oh, and most people bypass the auto lube system and premix.

[VenomRS4]

Yep, you just covered all the bases. What is involved in the process of switching over to a manual clutch? And if I put an it175 top end on it, do I have to machine the cases?

edit: I was just on ebay. I see bassani pipes for yt125s but none for 175s. Is a pipe something i will need to have custom made?

[Vealmonkey]

The IT175 is a drop in, but you will need the cylinder and piston and head. The piston is way different than the yt175, mx175 or the dt175. For manual clutch, you will need the manual clutch parts from a mx175,dt175 in the 77-78 year range. I don't think any earlier or any later will work. I also thing the it175 engine lower end is too different to work. Also, you just use the yt175 trans gears and you should be ok. Yt175 pipes come and go on ebay. The Bassani uses a different pipe between the yt125 and the yt175. Some other pipes, DG and PK Racing, can use the same pipe on either engine. I'm in the process of sending a board member alot of yt125 and yt175 parts. A custom made pipe would be expensive and you would probably have to have your trike in the persons posession so they could fit the pipe, but it would probably make more power than the old exhausts did. Also, I managed to find a DG gold head for my IT175 top end, so that's an option as well. DG had a mod for an it top end in their old catalogs and they also had some performance parts as well. There were several other places that had yt performance parts, but they are super scarce. Good luck with your project.

[RubberSalt]

The IT cylinder has way better porting to start with, but the YT cylinder can match and surpase it in performance with the help of porting.

I'm currently fitting a blaster reed cage into the 175 intake. Shaved down the sides of the cage and opening the intake up to fit it in, A space will be needed. This will let you get some nice flow through the intake.. finaly. If you are still on the stock cylinder, then some por twork will go a looong way, more than a pipe alone.

For the porting;
Tools; Rotory tool(dremel)+ highspeed cutting bits and tungston bits + other kinds
Small files - smooth out small areas
Depth guage - Measure heights of ports with this
Sharpie - Mark things
Sand Paper - smooth things


Exhaust Port
If you raise the transfers then raise the exhaust port 7.5-7.8mm, This will give you a duration of 190-192 degrees. If you DO NOT Raise the transfers, then you'll only want to raise the exhaust between 180-182 degrees. This is 5.16-5.6mm
Place the exhaust gasket in the exhaust port and remove all the metal until it meets up with the gasket.
Widen the exhuast port by 3mm on the left and right sides, then square it out similar to the transfers, with rounded edges. Chamfer the exhaust, NO!! sharp edges!

Use sand paper to make a mirror finish on the exhaust - helps keep carbon from building up.

Raise the transfer ports 1.1-1.3mm, this will you give a duration of 124-125 degrees. Only do this if you raise the exhaust Port by 7.5mm
Looking at the transfers through the base of the cylinder; smooth the metal casting down against the cylinder, if you can catch your fingernail, it needs smoothed down.

Raise the top intake port near reed cage by 1.3-1.5mm, giving you a duration of 125-126 degrees.
Widen this port 4mm on each side.

When looking through the intake, you will see what i call a wall, smooth that down to a nice curve, this allows the fuel/air to actualy flow instead of hitting a wall.
The 2 big ports through the intake you'll want ro raise them 2mm and remove the lip going into the cylinder. Make the gap smaller between these.

Make sure no ports have sharp edges!! They catch rings and destroy cylinders, do not let ANY ports have sharp edges.

For some porting, you can try these, by they are a little more difficult:
Add triple ports on the exhaust. These will be right above the transfers and be just as high as the exhaust.
Add boost ports from the intake. These go from the intake down to the transfers. They never touch the cylinder.

Leave all intake and transfer ports rough.

I've included some pictures of a stock cylinder and a port job; There is still plenty of room for improvement, These pictures are not the finished product, but should give you an idea what to look for.


Stock 1983 cylinder



After Some porting


I've got more pictures, when it's finished, but i cant seem to find them >.<

Aso, if you looking at making your own pipe, then if got some tips for you, all the math figured out, and some very nice software - as well as porting software.

For a carburator, you can upgrade to a blaster, it's 28mm, stock is a 24. I'm not sure of the jetting, I've got a 34mm mikuni in mine, been to cold to go out and jet it. A better option would be to get a flat slide carb off a 125 dirt bike/snowmobile, anything between 30-34mm would be good. I'd recommend a 30mm, i just happen to have had a 34 laying around.

[Yamaha_Rules69]

I was going to ask how you knew how much to raise or lower the ports, but I see that you mentioned that you have the porting software. What if someone wants drag race porting vs mx porting, does the software allow you to choose different options? How/where did you find the software, and how much did it cost? Nice work so far, and will be interesting to see a video of this improved motor work!

[RubberSalt]

I bought some porting software a while back - honestly, it's not very useful lol. The porting information came from flotek, most of it anyways. The 192 exhaust and 124 transfers are what they give for an aggressive trail port. The triples and the boost ports are just from research, race cylinders seem to always have triple exhaust. I've tried and tested the porting.. and holy crap. Seems that when ever i get on the pipe, my wheel comes up I'm still using the stock pipe.

Once i get mine jetted right, ill have to get a video of it. I've got a video of it reving up, but not tuned worth anything.

I've also got 2 pipe designing programs and a ton a formulas, each seems to match up close to the other.

It seems the 175 engine became the yfs200 engine, extremely similar, yet not close enough to be the same. My blaster reeds fit:-D i just need a spacer.
Blaster pistons should work, both have a 66mm bore. Blaster sprockets fit the engine, they could be to fat and need slimmed down, dont have a yt sprocket infront of me atm.
Also been told you can use blaster or banshee hubs on these, get away from the odd 3 bolt holes.

Here are more pictures;
Stock reeds vs Blaster reeds - had to shave the sides of the blaster reed cage by 1.5mm roughly, then shave the inside of the intake out off the cylinder by maybe 3 mm on each side - i cheated, power tools, needs smoothed out.

This allows for boysen pro series reeds to be installed


YT vs blaster piston - Both are 66.5mm wiesco - the left is the 175 and the right is the blaster.


Am I the first to put a better red cage in 1 of these?

[RubberSalt]

I'm just goign to make a thread on porting the 175, at a minimum, it will atleast be a reference for me when i do this next cylinder with blaster reeds - I'm going to make this 1 better, i as mention, i have lots of room for improvement on the current job.

[bcredneck]

dosent the IT 175 have the wrong side drive like a 81 yz 125 remeber the drum inside the sprocket setup that made it hard to find back rims for those bikes

[RubberSalt]

The IT works, but you have to change the output shafter, the IT isn't long enough. Otherwise the sprockets don't line up, they bolt into each other from what i am told. Vealmonkey knows alot about this area on the clutching.

[200XMichigan]

You guys want the manual for the YT175? Got it in PDF and I can e-mail it to you.

[RubberSalt]

I've got my copy already

[pickup-truckin]

Sorry to bring up a dead old thread, but I just picked up a yt175. I'm trying to bring it back to life and I'd like to redo the engine. I see people say to use it175 and dt175 engines and parts, but this being my first two stroke, I'm not sure where to go from here. I have two stroke experience but small. Like 50-70cc. I've been looking at jugs and heads, but dt175 parts are a lot more available than it175s. Are there only certain years that the dt engines would fit? I've noticed vealmonkey has a lot of knowledge about these trikes

[TriMotoMan]

a yamaha blaster engine fits with a little work, uses the stock mounts, have to change the rear mount a little, then take the rear fender off to kick start

[jpbois/yt175]

With witch parts can you converse the 175 to kickstart?