Need help with 1983 Yamaha tri moto yt175j

[Madmike420]

I recently bought a tri moto that didn't run. previous owner claimed it was just a carb problem
Took the carb off cleaned it nothing. Opened the engine up found a no good piston. Rings melted into one side basically. And both gaskets toast head and base so I got new ones of those and also a piston. So it ran then all of a sudden I have no compression actually 30psi I just finally got a tester today. My cylinder is 67mm and my piston is 65.5mm is that the issue? I know my Reed's r worn out and I found a decent used one online which I am waiting for. I spray carb cleaner in the carb and all that happens is it starts as far as the cleaner takes it so one stroke probably.

[fabiodriven]

I understand why it would be embarrassing to you if you got the wrong size piston, but it still would have been your best bet to continue your old thread. I'm thinking you'd want somewhere between .050-.100 piston clearance, and you're 50% over that (guessed) maximum.


Are you certain you got the right size piston? Rings installed correctly? Piston facing the correct direction?


Yes

You seemed so certain, so convincing. I never would have guessed that you'd never actually measured it.

http://www.3wheelerworld.com/showthread.php/187545-Tried-moto-yt175

[Madmike420]

Why did the engine run when I first put the new piston in if it's to small?

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

You're beyond help.

[Madmike420]

You're beyond help.What's trailprotrailpro problem man? I'm just trying to learn.

Sent from my LM-X510WM using Tapatalk

[Madmike420]

What's your problem?

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

What's trailprotrailpro problem man? I'm just trying to learn.

Sent from my LM-X510WM using Tapatalk

You're not trying to learn at all actually, that's my problem. Myself and others here enjoy helping others and the biggest hinderenc by far in your original thread was you.

Now this is coming from a pot head, but whenever you're ready to put the bong away, perform some diagnostics, and take some measurements, then you might start getting some helpful replies (again). You got helpful replies before but you didn't want to pay attention to what anyone was saying.

So now are you ready to learn and partake in your own thread?

[Madmike420]

You're not trying to learn at all actually, that's my problem. Myself and others here enjoy helping others and the biggest hinderenc by far in your original thread was you.

Now this is coming from a pot head, but whenever you're ready to put the bong away, perform some diagnostics, and take some measurements, then you might start getting some helpful replies (again). You got helpful replies before but you didn't want to pay attention to what anyone was saying.

So now are you ready to learn and partake in your own thread?When did I ever say I smoke weed? What cuz I like trailer park boys and used Ricky as a pic

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

If I were you I'd just stick with the premise it's a substance related issue.

[Madmike420]

I just recently bought a digital caliper and compression tester and a flywheel puller . Gotta start somewhere. Sorry I'm not understanding trailprotrailpro sarcastic replies.

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

Good man. Now your first step is to figure out if you've got the correct piston or not by measuring the piston and the bore. There is an actual number you'll be able to find as far as what kind of piston to cylinder clearance is acceptable. Do not go by the numbers I guessed at above, that was a total guess.

[ironchop]

When did I ever say I smoke weed? What cuz I like trailer park boys and used Ricky as a pic

Sent from my LM-X510WM using TapatalkLol

I would guess it had something to do with your username. More specifically the numbers at the end of your username.

I have no idea what the trailer park boys are, but I do know what 420 means around here.

I guess I shouldn't assume things. It could simply be that your birthday is April 20th or something like that?

We can be a bit trigger happy around here because every few months or so, we get a new member who will spend six pages of thread getting the best advice you can find but will refuse to heed the advice or do any of their own work to help us help them. They don't stop asking questions either, they are just waiting to hear the answer they want to hear (which is usually some f**ked up attempt at a shortcut or "do nothing, keep riding") and they are willing to keep stringing everyone along until they get that answer.

So since you bought tools for the job, I'd say it's safe to say that you want to fix it correctly......

So where are you at right now? Is the cylinder off the trike?

It would help if you post some pics of the cylinder and the sides and top of the piston and also pics of the bore in the cylinder. There are people here who can diagnose a helluva lot of things just by the visual appearance of the piston. You should be able to get some initial measurements with the calipers. Post those up along with those pics. We can't assume anything to help you until we see some measurements and some pics.







Sent from my Z958 using Tapatalk

[Madmike420]

One piston was new and one was in it when I got it.i also sanded the inside of the cylinder I need to get it honed.https://uploads.tapatalk-cdn.com/20190129/c4a8e658a013fbca85c23f3c9d56d258.jpghttps://uploads.tapatalk-cdn.com/20190129/f8436949ecd317fb0d33a716fd3d5e14.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

I'll have to take more pics when I get home from workhttps://uploads.tapatalk-cdn.com/20190129/b43777269490f1a20b3f50b9912ecc33.jpghttps://uploads.tapatalk-cdn.com/20190129/f70667e71cd016d5593115607f918069.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

Piston that came with the trikehttps://uploads.tapatalk-cdn.com/20190129/09e57e33c6b8e033c6d50e45948ea06a.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

That's all for now till I get homehttps://uploads.tapatalk-cdn.com/20190129/5742662f08d332bf9fe1a53f634da951.jpghttps://uploads.tapatalk-cdn.com/20190129/5c26901e1961ee0ec109bcfb63f17aa4.jpg

Sent from my LM-X510WM using Tapatalk

[stoshu]

If you are ready to do it right this time, you can use that new piston as an ashtray. Pull the engine out, remove the cylinder and take it all to Ray at Associated Crankshaft. He is just North of Winnipeg and does rebores for most dealers in town. He can get the piston you need and bore your cylinder to the proper size. You could also try Gord at Main Motorsports, but be prepared to leave him a deposit for the work you need done if he doesn't know you. Way to many customers drop stuff off and then cant/won't pay the bill.

[fabiodriven]

I agree with stoshu unless you have the means to measure and hone that cylinder correctly, assuming it doesn't wind up needing a bore. The only way you'll be able to mic the entire jug is with ID snap gauges. I'm going to go ahead and guess this might all be a bit more than you're capable of handling at home.

[Madmike420]

About how much does that cost ?

Sent from my LM-X510WM using Tapatalk

[stoshu]

Probably $60 for a bore, plus piston, plus gaskets.

[Madmike420]

The new piston .https://uploads.tapatalk-cdn.com/20190130/65bbb672c228ad76809fa28a804c1d69.jpghttps://uploads.tapatalk-cdn.com/20190130/1222cba679514d20282c6b57ad4d0771.jpghttps://uploads.tapatalk-cdn.com/20190130/c5cfb55b66cd051666f06aacadc782bd.jpghttps://uploads.tapatalk-cdn.com/20190130/cab2b073de4405272c05b9c1125809a0.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

No good?https://uploads.tapatalk-cdn.com/20190130/ba7e24c1f4c5977bcf820707b9ec6815.jpghttps://uploads.tapatalk-cdn.com/20190130/634a883c5025aedfa658d69bb26c9de4.jpg

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

Pictures do help sometimes but what you have to do is actually find out what numbers you need.

Find out what piston size you have, then find out what bore size that piston requires. WRITE THOSE DOWN

Bore needs to be measured in multiple places, not just at the top and bottom. Measure the cylinder and get your numbers. WRITE THOSE DOWN

Compare the numbers of what cylinder size would be correct for your piston with the actual numbers you have measured your cylinder out to be. Assuming your bore is good and usable, and it measures within spec for the piston you have there, then hone it.

Look up the numbers for what your ring end gap should be. WRITE THAT DOWN

Take your rings and use the piston to slide them gently into your bore. Then measure your ring end gap. WRITE THAT DOWN

Then compare those two numbers and see if your rings are within spec.

Your piston rings can most likely only be installed one way. If your rings are directional, be sure you do not put them in upside-down.

You have some tools there, you can do some stuff. Don't expect this machine to run right if you cut corners and don't bother concerning yourself with "why it won't run right with the wrong piston". It won't run right with the wrong piston because it's the wrong piston, what more do you want to know? Fix it and you'll find out why.

[fabiodriven]

And as I said, measure your piston clearance as well.

[ironchop]

Ok Mike...

So you know pistons are made tapered, right? The skirt will be the widest part of the piston because the skirt is what stabilizes the piston in the cylinder bore. You ALWAYS measure piston-to-cylinder clearance at the skirt and feeler guages are not a good way to measure it. Feelers will contact at the edges of the feeler instead of the center where the radius of the cylinder wall will be farthest from the piston skirt. I use a guage pin set. Most guys don't have that kind of metrology equipment laying around which is why most guys just outsource the bore job to a shop with the correct measuring equipment. Sometimes a used cylinder will be tapered or out-of-round, so just honing won't cut it. You must measure the cylinder at several points inside to get an accurate idea

You MUST have the new piston present in order to bore the cylinder to fit the piston, not the other way around.

In your case, the calipers are good enough for me to say that I can tell you that your piston skirt looks to be almost 1mm too small for that bore (0.0393 inches is definitely too much clearance)

Sent from my Z958 using Tapatalk

[ironchop]

Just to add to what I said above

What happens with a piston too small, is that the piston will tilt in the bore. Upstroke will tilt the piston one direction, and the downstroke will make it tilt the other way.

When the rings aren't square to the bore (as in the case of a tilted piston), they won't seal correctly and will leak compression. The more they tilt, the bigger the leak. The piston skirt is meant to help keep the piston straight and the rings square to the bore

Sent from my Z958 using Tapatalk

[Madmike420]

Yea it leans that's what caught my attention. Pretty sure it's to late for that piston cuz there r marks on it now. My crankcase doesn't line up properly. I'm gonna try get a pic where u can see it.

Sent from my LM-X510WM using Tapatalk

[Madmike420]

I'm starting to get really frustrated. I bought a harmonic puller to get the flywheel off so I can take the crankcase apart and see why it isn't lined up but it's not working the bolts that came r to big and my tap and die set isn't cooperating. https://uploads.tapatalk-cdn.com/20190130/7dcece382b42c3f89245f016b4fc2433.jpghttps://uploads.tapatalk-cdn.com/20190130/10d78d9f8e63d7aac55b498b3e1f310e.jpghttps://uploads.tapatalk-cdn.com/20190130/8eeae6a16cc3df4da2226252fa46ebab.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

I know maybe I should get a bong and some weed and some BBQ chips I think someone said lol to help chill me out. I've spent hours and hours and hours working on this trike.

Sent from my LM-X510WM using Tapatalk

[ironchop]

Don't worry about that case mismatch inside there.

The only place it would matter is above where those two studs are coming out.... That's the deck where the cylinder mates to the cases and is where you should have no mismatch... on that deck and between the two studs where the case seam runs, the cases should be perfectly flush on that gasket surface

Sent from my Z958 using Tapatalk

[Madmike420]

It isn't. I had to sand some of it down . When I tried to get the crankcase open one of the screws was bent. I'm starting to feel like picking up small engine mechanic for a hobby wasn't a wise idea. Maybe I'm just over reacting. It's all started with my custom built bicycle that I built with a 66cc 2stroke engine.

Sent from my LM-X510WM using Tapatalk

[Madmike420]

I brought that trike back to life once already I'm sure I can do it again.

Sent from my LM-X510WM using Tapatalk

[ironchop]

And if you had a case mismatch there, you'd have known it pretty darn quick because it would have leaned out that motor and probably run away on you (pegged the throttle on its own). Since you didn't mention a runaway their when it was running, I'm going to assume that it's ok.

So if you get a bong and some chips, bring enough for the whole class [emoji16]

So... personal question so that we can guage exactly how much help you need... Have you ever rebuilt small engines before? And what kind? I ask because a two stroke engine is a little more temperamental than four strokes and there are also some other critical things that you'll need to know to deal with rebuilding a two stroke. Even with you outsourcing the bore, re-assembly of a two stroke has special requirements which we'll get to later when you get to that point

Sent from my Z958 using Tapatalk

[ironchop]

It isn't. I had to sand some of it down...

Sent from my LM-X510WM using Tapatalk

Not good. The only way to get that deck perfectly flat, square to the crank, and flush at the seams is to machine the deck if the cases are mismatched



Sent from my Z958 using Tapatalk

[Madmike420]

I actually just started messing around with engines seriously last Oct I think. It all started with me buying a 49cc motorized bicycle. Something happened to the engine and I had no idea what was wrong. Guy who sold it to me pretty much told me to bad fix it or get it fixed. No one really wanted to work on it. So I had no choice but to try and figure it out. I didn't yet lol I bought a 66cc that looks exactly like a 49 unless u break out a caliper or something lol. Anyways I learned I enjoyed working on engines. I built a motorized bicycle with the 66cc engine by combining a beach cruiser and a gt Harley Davidson bicycle only 1000 of those made. So now I have the only Harley Davidson motorized bicycle. It actually dawned on me tonight that after all trailprotrailpro teaching bout piston and rings and cylinders that the 49 cc probably has a trailprotrailprotrailprotrailprotrailprotrailpro piston but at the time I didn't know enough and was scared to take the engine to much apart. I'm gonna open that trailprotrailprotrailprotrailprotrailpro up next time I go to my shop and probably laugh at myself cuz I was so nieve

Sent from my LM-X510WM using Tapatalk

[Madmike420]

2018 custom Harley Davidson motorized bicyclehttps://uploads.tapatalk-cdn.com/20190131/ef19bf5954f1e59b933ffa179dfe1bc3.jpg

Sent from my LM-X510WM using Tapatalk

[Madmike420]

This is a custom gt Harley Davidson bicycle. The bike I took all the parts from. It was made in the 90s . Bike goes for 2 grand I picked it up for 35o and stripped it lolhttps://uploads.tapatalk-cdn.com/20190131/1c677b03ef8a35e7e8dc5ab5d41ff9f4.jpghttps://uploads.tapatalk-cdn.com/20190131/b14241ced95a54e5f8411939d640be0a.jpghttps://uploads.tapatalk-cdn.com/20190131/84079d37ccff47f572431c9f2b46914a.jpg

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

Cool story bro. Bicyclists are the bane of the modern roadway, I can't stand bicycles.

Anyhow! You bought a trike, which was a good move. You picked the perfect machine. Cheap, simple, not super desirable, but big and fast enough to be a lot of fun (if you can get it running). You've already figured out that you have to be a bit more careful about your measurements and just tossing things together doesn't work. You're lucky more things didn't get damaged. If this is something you're going to get into, this is a simple, easy way to start. If this bike turns you off, it doesn't get much easier. You'll have to go back to your fat girl. I mean bicycle.

[stoshu]

I actually just started messing around with engines seriously last Oct I think. It all started with me buying a 49cc motorized bicycle. Something happened to the engine and I had no idea what was wrong. Guy who sold it to me pretty much told me to bad fix it or get it fixed. No one really wanted to work on it. So I had no choice but to try and figure it out. I didn't yet lol I bought a 66cc that looks exactly like a 49 unless u break out a caliper or something lol. Anyways I learned I enjoyed working on engines. I built a motorized bicycle with the 66cc engine by combining a beach cruiser and a gt Harley Davidson bicycle only 1000 of those made. So now I have the only Harley Davidson motorized bicycle. It actually dawned on me tonight that after all trailprotrailpro teaching bout piston and rings and cylinders that the 49 cc probably has a trailprotrailprotrailprotrailprotrailprotrailpro piston but at the time I didn't know enough and was scared to take the engine to much apart. I'm gonna open that trailprotrailprotrailprotrailprotrailpro up next time I go to my shop and probably laugh at myself cuz I was so nieve

Sent from my LM-X510WM using Tapatalk

Not a Harley

[Madmike420]

Not a HarleyNot a hater. Lol

Sent from my LM-X510WM using Tapatalk

[Madmike420]

Who is the administrator for this forum ? I keep getting a message saying to contact them .I try to ask questions and it won't let me. I wanna know if a blaster piston will work In my tri moto.

Sent from my LM-X510WM using Tapatalk

[fabiodriven]

You're getting error messages because you're trying to post multiple times inside of one minute. This forum is set up so snot nosed kids with two second attention spans can't type out ten half thoughts in 15 seconds. People text me that way, I'm sure that's what you do. You send ten text messages which are a half of a sentence long in five seconds instead of just sending your entire thought.

This is where you would ask about your piston, in your thread. You can do a Google search and a forum search and look for results that way, but this is the place to ask about your piston. We've been talking about your pistons and your bikes in your threads for weeks now. You already started a new thread because you were embarrassed about not listening to us in your old thread, and here we are still trying to help you for some ridiculous reason. Why I have no idea.

No need to start a new thread, no new magic answers are going to be found that way. I bet more people would reply to you if you weren't quite so helpless.

[fabiodriven]

Have you or anyone else been able to measure your entire cylinder yet like we told you? That's your next step so... Waiting on you.

[Quintin]

You have a 66mm piston in a 67mm hole. That is 1mm piston clearance. I'm amazed it even started. At this point your best bet is to get a 67.5mm Wiseco piston kit #471M06750 and have it bored to fit, probably around .05mm piston clearance. I am currently doing an 82 YT175 that was brought to me in a box, actually 3 boxes and 2 cans.

[Black_Widow]

Who is the administrator for this forum ? I keep getting a message saying to contact them .I try to ask questions and it won't let me. I wanna know if a blaster piston will work In my tri moto.

Sent from my LM-X510WM using Tapatalk


Yes! Do the blaster piston! :beer

[nmarciano19]

You're getting error messages because you're trying to post multiple times inside of one minute. This forum is set up so snot nosed kids with two second attention spans can't type out ten half thoughts in 15 seconds. People text me that way, I'm sure that's what you do. You send ten text messages which are a half of a sentence long in five seconds instead of just sending your entire thought.

This is where you would ask about your piston, in your thread. You can do a Google search and a forum search and look for results that way, but this is the place to ask about your piston. We've been talking about your pistons and your bikes in your threads for weeks now. You already started a new thread because you were embarrassed about not listening to us in your old thread, and here we are still trying to help you for some ridiculous reason. Why I have no idea.

No need to start a new thread, no new magic answers are going to be found that way. I bet more people would reply to you if you weren't quite so helpless.Lol calm down.

Sent from my SM-J727U using Tapatalk

[fabiodriven]

Lol calm down.

Sent from my SM-J727U using Tapatalk

Frig off.......

[nmarciano19]

Frig off.......Haha, ok

Sent from my SM-J727U using Tapatalk