How many Pistons do I have to ruin

[loganm]

Milford Lake? OK, I will see if I can get BKM to come too.

I'll have my brother along too on his 200x.

[Onetrackmind]

loganm

I'm sorry to post in your thread without having anything of value to offer, but I am having a really hard time understanding your purpose here. I joined this forum to gain real knowledge from a VERY knowledgeable group of VERY helpful, like-minded people who love to give out that knowledge free of charge.

At first, it seemed to me that was your reason to be here as well...now I don't think that it is. It's very confusing. You have asked for help and insight several times, yet when you receive the very thing you were asking for...you poo-poo on the very people you were asking. Why do that? If you already have the answers...why even ask the questions at all? People don't like that.

Please do me a favor (even though you don't know me). Don't ask for help anymore if you are just going to blatantly disregard the advice you get in return. That will only make it harder for guys like me who really WANT good advice to get it when we really need it.

I'm not trying to be a di_k at all... I'm just trying to make sure that you don't ruin this place for the rest of us.

[loganm]

loganm

I'm sorry to post in your thread without having anything of value to offer, but I am having a really hard time understanding your purpose here. I joined this forum to gain real knowledge from a VERY knowledgeable group of VERY helpful, like-minded people who love to give out that knowledge free of charge.

At first, it seemed to me that was your reason to be here as well...now I don't think that it is. It's very confusing. You have asked for help and insight several times, yet when you receive the very thing you were asking for...you poo-poo on the very people you were asking. Why do that? If you already have the answers...why even ask the questions at all? People don't like that.

Please do me a favor (even though you don't know me). Don't ask for help anymore if you are just going to blatantly disregard the advice you get in return. That will only make it harder for guys like me who really WANT good advice to get it when we really need it.

I'm not trying to be a di_k at all... I'm just trying to make sure that you don't ruin this place for the rest of us.

Because I'm trying to explore all options. But when the general consensus goes against what my personal experience and insight of professional engine builders I'm going to go with what makes the most sense to me.

Don't ever overlook the small things. Something as simple as a jetting change can fix all your problems. Remember I bought this in a non-running state, with an oversized piston. I have no idea what top end was on it and how it ran before.

[JesseA420]

air leak is an air leak. that means there goes your af ratio. simple as that.

so it seized? i assumed since the only reference to the damage done was ruined pistons, is that u were burning holes in them.
what the hell make and model bike is this anyway? what does the seizure look like?

how are you going to go ride next month when u cant keep this basket case together long than 10 minutes each time? this thread really is all over the place.

if you eventually get your ducks in a row u should swing up to genoa for the jamboree. you are only a short drive. its a great place to ride.

[loganm]

air leak is an air leak. that means there goes your af ratio. simple as that.

so it seized? i assumed since the only reference to the damage done was ruined pistons, is that u were burning holes in them.
what the hell make and model bike is this anyway? what does the seizure look like?

how are you going to go ride next month when u cant keep this basket case together long than 10 minutes each time? this thread really is all over the place.

if you eventually get your ducks in a row u should swing up to genoa for the jamboree. your are only a short drive. its a great place to ride.

Look at the first or second post, pics are there. Think about this, with the engine turning 4500 RPM, there is a very large volume of air flow, a 1psi/HR air leak is not going to throw it off to the point it's seizing the piston unless I'm already running right on the edge of seizure.

I've posted this thread over at s.com too, since the site is dedicated to the 1st and 2nd gen 250rs with these engines.

[JesseA420]

lol. ok i thought about it. but your logic is so goofy im not even going to comment.
how does a pic of a carboned up head and piston top show anything in regards to diagnosing a seizures root cause?
im sure you will poo poo their comments on that forum just like u have everyones here.


at this point i think u are merely trying to troll. good day sir.

[loganm]

lol. ok i thought about it. but your logic is so goofy im not even going to comment.
how does a pic of a carboned up head and piston top show anything in regards to diagnosing a seizures root cause?
im sure you will poo poo their comments on that forum just like u have everyones here.


at this point i think u are merely trying to troll. good day sir.

So a professional engine builder backing me up isn't enough? Do you have any actual experience with tuning engines or are you just repeating what everyone else has said?

Running lean WILL CAUSE THE PISTON TO SIEZE IN THE TOP END, whether the bore is tight or not. It is running lean at ~1/3 throttle, I know that for a fact, so instead of taking the top end somewhere else so they can do the same thing, I'm going to make adjustments to the jetting. PM me if you have some actual data or experience to share, otherwise, you can go away, thanks.

[AK47KID]

Abilene-ish

Hey, my grandpa lived there before he passed away last summer. Curran was his last name, you at any chance knew him? He lived there pretty much his whole life and worked at the grey hound race track

Sent from my SM-G935V using Tapatalk

[loganm]

Can someone tell me what kind of acid I need to dissolve aluminum off the cylinder walls?

Hey, my grandpa lived there before he passed away last summer. Curran was his last name, you at any chance knew that? He lived there pretty much his whole life and worked at the grey hound race track

Sent from my SM-G935V using Tapatalk

Doesn't sound familiar, sorry

[AK47KID]

Can someone tell me what kind of acid I need to dissolve aluminum off the cylinder walls?



Doesn't sound familiar, sorry

Oh, okay just had to ask. Never know lol

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[JesseA420]

u dont have to tell me twice, everyone else already bailed on trying to help you. clearly is a lost cause.

its obviously not meant to be if i were you i would just go back to a 4 stroke. u built a 2 stroke engine multiple times and didnt even know what a leakdown test is.

seriously get it together and swing up to genoa. bring your buddies its a great place to ride.

[loganm]

u dont have to tell me twice, everyone else already bailed on trying to help you. clearly is a lost cause.

its obviously not meant to be if i were you i would just go back to a 4 stroke. u built a 2 stroke engine multiple times and didnt even know what a leakdown test is.

seriously get it together and swing up to genoa. bring your buddies its a great place to ride.

So, you've ran an engine with a minuscule air leak on a dyno, then ran the same engine with no air leak on the same dyno, with the same jetting on both engines, and compared hp and cylinder temps and EGTs? Because if not you're talking out your ass.

A modern 4 stroke has an engine and carburetor that are vastly more complicated to build and tune. I gave up on them for a reason: cost.

[NeverLift]

Can someone tell me what kind of acid I need to dissolve aluminum off the cylinder walls?

http://www.menards.com/main/paint/so...4444212919.htm

Muriatic Acid. Dip a Q tip in it and rub it on the aluminum spot let sit for 5 to 10 minutes, wipe clean and repeat until all the aluminum is off the sleeve.

[Red Rider]

I just got off the phone with John at JSR. He said to take acid to the cylinder walls to get the aluminum out, and to go over the piston lightly where it seized.

Can someone tell me what kind of acid I need to dissolve aluminum off the cylinder walls?

Uh, John might know. I would have asked him that when I had him on the phone.

[Dirtcrasher]

I have feeler gauges I can measure the piston clearance with

Those long feeler gauges are only for a rough estimate. And building motors well, that don't leak and trying to jet at the same time isn't real easy for allot of guys. Just go to any machine shop and it might cost you 25$ but they will measure it in many different places; A feeler gauge cannot do that.

Don't get ready to jump off a bridge, try to learn from all this and you have gained more than you had.

Always start with a rich jet if it blew up and a pressure test for an air leak. Thats rule #1 for a DOA.

If it were a motor that was tired and had low compression, you just send out the new piston/cylinder and they bore and hone to fit the correct clearance and those intake and exhaust ports should also be deburred.

A feeler gauge only gives you a rough estimate. If I had a .008 feeler gauge that fit in the piston and cylinder wall, I know it needs to be bored .020 over, because .010 is too close to .008 and .010 may not clear it all up properly. Hand the piston and cylinder to a shop and read whats in the box of your new piston if it's a Wiseco. It will tell your "bore shop" what the ideal clearances are; Wiseco might be .003, just read it or search the net. Cast and forged pistons also have different clearances. Liquid cooled versus water cooled may also require a different clearance amount.

As far as premix, read the bottle. Many people are hesitant to use such little oil, but this is 2016 and 30+ years have created new oils with new properties for lubrication. Lots of the ATC250R owners on here run what would seem to be super lean. But if you pull the head off their motor, it'll be pretty clean in there and no scoring.

And here's another one for ya; If you use more or less premix oil, it either takes away more fuel or adds more fuel. I'll be extreme here, but if you had plain 95% gas and 5% oil or 75% gas with 25% oil, there is less gas for the air/fuel mixture in the carb, and that means it would require rejetting to either more or less fuel due to less fuel from the carburetor and from your gas tank.

Lots of easy tests I do are taking the airbox lid on or off and seeing how it run. Lid off is more air and lid on is less, you gotta see how it runs under load and check the sparkplug based on plug chops, once it's gently broke in, because you can't use WOT on a fresh motor.

Most anyone can take apart a motor and do a so called "COMPLETE REBUILD" but that doesn't mean it was done right. As an example, if a guy wings it, a liquid cooled 250R left crank seal is not pressed in flush, it's either 4 or 5mm past flush or inner portion of that seal is still on the crank taper and will end up being an air leak. Just look how many idiots have red RTV all around the valve cover on a thumper. It tells me that I do not want that motor!

And you've proved you can put a piston in; Some guys don't even know how to do that. But when I had an RM250 at 16y.o., I thought "cleaning my carb was getting the outside spotless, I didn't know anything about jets. But I started leaving repair manuals in front of me to remind me to read them. And the way a 4 stroke works and why or a 2 stroke were learned.....