POS 250R blows up again

[Blown 331]

Well last night I went up the bar and there were a few guys riding 4 wheelers so I decided to go get mine. When I got home I figured the ATC250R would get some good reactions compared to the 450R so I rode it up there. Well I got about 1/4 mile from the bar and it lost power and died. I pushed it up there it would kick over then stop. And a lot of people did look at it, everyone said how fast they are and how nice it was and you gotta have balls to ride one of those. lol. Too bad it was blown up! I pulled the head and there was melted metal on top of the piston. I pulled the jug and the piston looks fine, I have no idea where it came from. The rod is discolored at the crank but it is tignt and the bearing seems good. I have no idea what happened or why it happened. My top end only had 3 tanks of gas ran through it and now the Wiseco is pretty beat up from the alluminum bouncing around, along with the head. I've had this thing since November and it's the 2nd time it blew up. The piston shattered and blew the crank case halfs out about 3 weeks after I got it. I bought a different motor, put it in, the pulled the top end, the piston had 3 huge cracks so I put a new top end on it. Now it's blown up again. I think I'm done with 2-strokes, nothing but problems. Every one I've had or that anyone I know has had. That's why every one I know rides 4 strokes. You can beat the **** out of them for 30 years and they like it.

I have 2 blown up motors I think I'm going to put on ebay. Then I'm not sure what to do with the money. Buy a complete big bore power valve motor off ebay so I can finally hang with the 450's until I blow up a $1000 top end (it will happen). I also thought about just parting it out and puting the money into my 450R. I really like 3-wheelers but I'm sick of 2-stroke problems. I also thought about finding a 350X roller and put a CRF450R motor in it. In my opinion that is the ultimate 3-wheeler. I guess I could try to fix the motor I have, I think it may need a new rod based on the color but it seems fine and I'm sure it will just blow up any way.

Just had to vent, I'm totally pissed as you can imagine, any one else have there problems? Any idea what happened? I was running 110 octane leaded gas with 32 to 1 ratio Honda synthetic oil. I'll post some pictures tomorrow when I'm at work.

[bigredhead]

The rad and cooling system in good shape ? That's just wrong .......

Sorry to hear. Get and SX and don't look back.

[MTS]

, when you say melted metal on the top of the piston, like the crown is melted or something is imbeded in it? coulda you lost a circlip, see if there both in there still, or half of one,dose the head and piston look like its got sand blasted? small lilttle dings....from it boucing around in there? also check the pins in the piston, make sure they didnt push in for some ungodly reason (seen it before) and let the rings turn....is the rod discolour'd blue? jetting could be at fault here...

[250rAL]

Might be jetting... two different motors with the same carb, I assume?

[resto250r]

I would have to agree with both either circlip came out or even the rod bearing (did you replace with the piston?) How do the piston skirts look?

[TeamGeek6]

The melted aluminum is melted piston crown. Nothing to do with the bottom end, especially if the rod big end is tight. The oil premix is right on, I usually ran 50:1 and beat it hard racing and Im still on stock bore and stroke after way too many hours. (86 250R water cooled).

It shouldnt need 110 octane fuel, that may be contributing to overheating because high octane gasolines burn very slowly. I run 86 octane always.

This kind of failure is typical for 2 stroke thats out of tune, excess fuel and weak ignition will do it every time.

The Keihin PJ (read - "piece of crap") carb runs extremely rich from the factory, I have more work in modifying the carb on mine than the entire engine rebuild / massage. Jetting wouldnt fix it.

Then add a wimpy ignition system and misfire from a bad CDI plug and the piston gets the blow torch treatment and melts.

Mine used to run hot till I modified the carb and ignition and thats been solved. The pipe goes about 170 - 250 degrees on idle and 500 when running hard. Plus it makes so much torque that first and second gears are useless even with a 14-36 sprocket combo.

If you want help resurrecting it, email me.

http://gl1200harness.tripod.com/2stroke.html

[1984kxtTECATE]

Should have got a tecate, lmao

[BIGCRIP28]

that sucks.
when i first saw the title i was thinking, didnt he just get a new engine in it?
maybe you just have bad luck. :D

[Blown 331]

The first motor had the stock 34mm round slide carb, it blew because it was 20 years old and had the stock piston. Lots of piston slap cracked the skirts off. The second motor had a 36mm PJ flat slide. I had a 175 main and it was running rich. I'm only using one thin layer of the head gasket is why I had 110 in it. When it went I was running at about 1/2 to 3/4 throttle for about 3 minutes. The crank end of the rod is tight but it is discolored, not blue though, it almost looks gray, I will post a pic tomorrow. It had new wrist pin and bearing, the piston pins and circlips are fine. There was melted alluminum on top of the piston but the piston is not melted any where. It almost looks like I could clean the alluminum up, put it back together and run it. Yes the piston and head have small dings in them, the head was perfect before that. I don't get it. I'm probably gonna put it back together to keep all the parts in order and I think it's gonna sit for at least a year if not longer. I'm sick of wasting money on this thing. Might even sell it. Sell my 2 blown up motor, the ESR pipe then the rolling chasis. I think it's time for an ATC450R.

[bigredhead]

The plug tip was intact ?

[TeamGeek6]

" I had a 175 main and it was running rich. I'm only using one thin layer of the head gasket is why I had 110 in it."

175!!! Thats only about 50 sizes too large. IM at about 132 and turnign a clean plug. Thin head gasket is no reason to run 110 octane.

[Blown 331]

My air box lid is off too, I think a 165 would have been about right. I'm guessing you have your air box lid on. 110 is more forgiving when tuning too and I had just got this motor together. I just looked at the plug, it's totally fine, looks just like it has about 3 tanks of gas on it, oh wait that's because it does.
I also checked out the rod some more. It is tight but I started rotating the engine and it starts to bind. It may be because some alluminum in in the bearing but I'm thinking the rod failed. I'm still not sure where this melted alluminum is from though. Beater.

[TeamGeek6]

it has nothing to do with airbox lid, that will only make a fractional change in main jst (or needle) . If the crank is tight, then theres debris or scoring, wear would make it loose. Probably aluminum down in the bottom end. Yukkkk :(

[Dynofox]

Had you done any mid rpm plug checks to see if your needle was set correctly? If you burnt it down going 1/2 to 3/4 throttle you may have been lean on your needle clip position.

[KASEY]

175!!! Thats only about 50 sizes too large. IM at about 132 and turnign a clean plug. Thin head gasket is no reason to run 110 octane.

actually higher compression is a good reason to run higher octane,,,, also your jetting is for YOUR trike, not his,, i have several 250r's and they all run different i have main jets from 142 to 180 ,, it just depends on mods,,, so if he says thats what he is running why would it be 50 sizes to big??? BESIDES there are NOT50 sizes between what he is running and what your running,,,, :rolleyes: :rolleyes: :rolleyes: :rolleyes:

[OldSchoolin86]

actually higher compression is a good reason to run higher octane,,,, also your jetting is for YOUR trike, not his,, i have several 250r's and they all run different i have main jets from 142 to 180 ,, it just depends on mods,,, so if he says thats what he is running why would it be 50 sizes to big??? BESIDES there are NOT50 sizes between what he is running and what your running,,,, :rolleyes: :rolleyes: :rolleyes: :rolleyes:
Well said KASEY! ;)

[Dammit!]

IM at about 132 and turnign a clean plug.

132? In Ohio with a water cooled R? Every bike is gonna be a little different but man that sounds weird to me. I ran a 160 when I lived there. Stock carb, airbox lid on. Motor was modded but still. Wow. Big difference.

[Blown 331]

Here are some pics. Camera phone again so the pics suck but you can see the rod is discolored.
I think I'm gonna go ahead and fix it one more time, it's just too much fun!
I think the rod bearing is what failed. You can see it's discolored plus now that I rotated the motor over some it is starting to bind. I'm still not sure where the melted aluminum came from. You can see it on top of the piston.
Could improper jetting make your rod bearing fail? I didn't think so. The piston is not damaged at all other than being beat up. I'm still not sure what to do about a top end. I guess I wont do anything to expensive just incase it goes again. I would really like to do a 310 kit.

EDIT: Just noticed this, does anyone think the opening on the lower end of the rod looks larger than normal? Maybe the metal on top of the piston wasn't aluminum? I'm just gonna take the bottom end to Honda and tell them to put bearings in it. I hope the lower cases aren't melted at all. I still have my old cases that are cracked but they did say they could fix them for less than $100.

[TeamGeek6]

I run thin head gasket (cut down CR gasket) with 86 octane with no problems, no overheating and no detonation even when I beat on it full throttle. Yeah, its not "sizes," its numbers, sorry about the goof. Thats 13 sizes too large from stock.

Blown 331, before you deep six it, come on down and Ill show you my setup, maybe I can make a 2 stroke addict out of you??

The tops of the cases are even black, thats serious overheating. Heres what happened.

Its jetted extremely rich on a carb that has an extremely rich float setting from factory. The cylinder can't burn off that excess fuel so the fuel loads up in the cylinder walls and rings and washes the oil off, creating a hugeamount of friction, which makes a huge amount of heat. Since the rod is connected directly to the piston, that heat is transferred to the rod and cooks it.

The slot in the rod big end is normal width from what I can see in the picture, its supposed to be slotted out.

This will take an entire top end rebuild (bore, hone, chamfer, both decks checked and milled if warped) and complete crank rebuild. Wiseco makes a nice Hot Rod kit but it doesnt include the crank pin, which may be toast now. Id put new main bearings in also as the excess heat has probably cooked the oil and damaged them.

[Blown 331]

I am planning a trip to Ohio to pick up an XR650R for my buddy so I'll see if I can make an extra stop. The cases are black because it's a 1985. I know the piston looks black in the pictures but in person it's really not that dark. Your over heating theory doesn't make sense to me.

[TeamGeek6]

Understood, but its not a theory, it takes ~ 1100* F (depending on the aluminum alloy) to melt that piston crown and more to melt the head because its a harder alloy and water cooled. Heat can only come from 2 sources, combustion and friction. In this case, its probably both. Look at the rings under a magnifying glass or microscope, may find some interesting damage on them.

Its good that the cases were black, that means the heat wasnt bad enough to warp the case halves. It may not be that hard to rebuild.

[Dammit!]

His piston isn't melted. That was some sort of debris sitting on top of the piston. In the second pic the piston looks fine other than being dark and dinged up.

[Hornetpowerspor]

The melted aluminum is melted piston crown. Nothing to do with the bottom end, especially if the rod big end is tight. The oil premix is right on, I usually ran 50:1 and beat it hard racing and Im still on stock bore and stroke after way too many hours. (86 250R water cooled).

It shouldnt need 110 octane fuel, that may be contributing to overheating because high octane gasolines burn very slowly. I run 86 octane always.

This kind of failure is typical for 2 stroke thats out of tune, excess fuel and weak ignition will do it every time.

The Keihin PJ (read - "piece of crap") carb runs extremely rich from the factory, I have more work in modifying the carb on mine than the entire engine rebuild / massage. Jetting wouldnt fix it.

Then add a wimpy ignition system and misfire from a bad CDI plug and the piston gets the blow torch treatment and melts.


Mine used to run hot till I modified the carb and ignition and thats been solved. The pipe goes about 170 - 250 degrees on idle and 500 when running hard. Plus it makes so much torque that first and second gears are useless even with a 14-36 sprocket combo.

If you want help resurrecting it, email me.

http://gl1200harness.tripod.com/2stroke.html

First off, higher octane fuel is required for higher compression motors to keep it from detonation. 2nd higher octane does burn slower but burns cooler NOT hotter. I have 6 250Rs with pj carbs on them and they are fine carbs for a stock or slightly modified motor, they are not a piece of crap. And a weak spark or wimpy ign system will not cause debris in the motor, or cause it to overheat. A faulty CDI, maybe.

[OldSchoolin86]

Don't fear gentlemen, I'm getting the John Boat ready for this thread. ;)

[TeamGeek6]

132? In Ohio with a water cooled R? Every bike is gonna be a little different but man that sounds weird to me. I ran a 160 when I lived there. Stock carb, airbox lid on. Motor was modded but still. Wow. Big difference.

Yep, 132 main, 1st needle clip (lean), main jet tube and float modified to go even leaner. 35 slow jet. Plus some other extreme dirty tricks :twisted: I wont mention to make it even leaner. Its a factory bore and stroke and makes enough torque to unscrew the rear axle carrier. I get a couple full throttle trips around the yard and have to tighten the chain again. No, theres nothing wrong with the rear axle carrier, its totally rebuilt.

And it sits there and idles with no coolant water flow because the 140* F thermostat is closed. Pipe = 240F, side of the jug = 120*F. I have to turn the coolant off on idle or it will not warm up.

All the things the "crowd" says cant be done...

Its not about fuel, its all about electrical engineering[/*]. :cool:

[Blown 331]

That's some weird stuff right there. If we make the trip to Ohio I have to see this.

[Mr. Sandman]

Blown331, I've seen quite a few blown 250R motors and have never seen one blow from the jetting being too rich, from using a stock carb, a weak ignition, or from running high octane fuel, although you are probably just throwing money away if you don't really need it. Rich jetting will cause it to run like crap and a weak ingnition will cause a weak spark and it'll run like crap if it runs at all. The piece of aluminum on top of your piston could possibly be part of the piston skirt or is debris sucked in through your intake
somehow/somewhere, but it's not a melted piston crown.

Have faith in the mighty R and do a complete top end rebuild, use some fresh 92 octane pump gas pre-mix and get a handful of fresh plugs. Because you don't list what other mods are on your R start your jetting rich and get busy with the plug chops and jet down as necessary. Don't jet via the internet or how someone else jets; jet according to your riding area, elevation/altitude, temperature, mods, etc. Also, keep in mind that your jetting can and will change from area to area or from one day to the next depending on altitude/temperature. Usually, it's not too drastic and won't require re-jetting, but it is possible that it would be necessary, just do a quick plug chop to play it safe.

[mad_max]

I also thought about finding a 350X roller and put a CRF450R motor in it. In my opinion that is the ultimate 3-wheeler.

Just a thought on that conversion... a friend of mine has a TRX250R (quad) chassis that he put a CRF450R into. He hates it. I've watched him ride it and IMO the first gear is way to tall and gear spacing is too close for a ATV.

[threewheelin-feelin]

hell yeah dude! get you a 350X....and put you a 452 kit on it....or the CRF450/350X conversion would be sweet!!!

[KASEY]

did the reed cage come apart?? where did those pieces come from?
did you tear it down from the last blow up ??? gotta figure bout where tjhose pieces came from,,,,,,

[KASEY]

And it sits there and idles with no coolant water flow because the 140* F thermostat is closed. Pipe = 240F, side of the jug = 120*F. I have to turn the coolant off on idle or it will not warm up.

if you have combustion you have heat,so i don't believe that, unless your talkin about the first 30 seconds,,,,,i don't care what you have done ,,, with a 132 main it wouldn't last an hour in the dunes,,, 2 tree shots and it would be seized solid,,,

[Jason Hall]

I wonder if there was something stuck in the reads, from the first time it blew up. Or maybe something stuck in a transfer port, sure seems weird. I have had 250-r's for years, & as long as they are jetted rite they are usually indestructable. The piston looks real black, sure looks like it was hot. I have been running pro-x pistons for a long time now, they are cast. If you melt a wiseco it will almost always trash the bore. With a cast piston the piston melts to the cylinder, & can be cleaned out with acid. Pro-x is also lighter & you will notice it will rev quicker. Please don't give up on the old girl. Get your self a wiseco crank, & give the cast piston a try. I have a 89 trx that is .010 over, ported, with a honda cast piston & it is the best running 250 that i have. A 36mm carb is probably the best size carb to run on a 250, for all around riding. Pj carb is a great carb, they have awesome adjustability. I would check your needle setting, & make sure the cdi is not screwing up, so you don't burn er down again. I have some other sweet tricks you can do to that 250 to make it run alot better. Contact me Blown331 If you are interested. Another thing, If there was a piece of the old piston skirt stuck in that groove in the big end of the crank that would not be good. Make sure the bottom of the case is not broke, to where it could suck air & lean it out. I had some reed screws come out & get stuck under the crank, & it broke both case halfs rite under the crank where the case gasket is. You should be somewhere around a 160-175, on the main depending on your pipe, & other mods.

[Jason Hall]

Here is something else to think about, I had a 250-r that would idle real high, & run hot when run wide open. I finally found that it was pulling air through the tranny, & burning trans oil. I pulled the oil filler cap with It running, & it revved to the moon. I wonder if the case was cracked betweem the trans & crank case?

[nimda78]

the crank end of that rod was dry! the grey color you mentioned is a clear indicator of dry heat. look for case leaks. keep us updated as to where the trash on top of the pistion came from.
i like thumpers!!!

[TeamGeek6]

,, with a 132 main it wouldn't last an hour in the dunes,,, 2 tree shots and it would be seized solid,,,


The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

its all about electronics, kids. :twisted:

Any y' kids ever seen a top fuel ignition on a 2 stroke LELE LALA LOL :naughty: :Bounce

Kiddies, just because YOU can't do it doesn't mean IT cant be done.

Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.

[bigyellow4x4]

The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

its all about electronics, kids. :twisted:

Any y' kids ever seen a top fuel ignition on a 2 stroke LELE LALA LOL :naughty: :Bounce

Kiddies, just because YOU can't do it doesn't mean IT cant be done.

Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.


i live about an hour from there and would love to see that and were running temp just under 100 out right now when could you show me that?

[Dammit!]

The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

its all about electronics, kids. :twisted:

Any y' kids ever seen a top fuel ignition on a 2 stroke LELE LALA LOL :naughty: :Bounce

Kiddies, just because YOU can't do it doesn't mean IT cant be done.

Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.

lol

You know, wether or not you're telling the truth, without backing up all the talk with some proof everyone here is gonna think you're full of BS. So you can either continue being a legend in your own mind or you can share this wealth of knowledge. :lol:

Personally, I don't buy it for a second. But if you've really done all you claim and it actually works, more power to you. :beer

[oddball3]

Did it blow up when you let off the throttle. you might have a to small of a pilot jet. When you let off your throttle all the way your running through the pilot. Maybe not enought fuel/cooling and lubrication.

Or you might have a midrange hot spot, change your needle,lower the clip, which will richen your mid and you might have to lower your main jet. My 2cents.

[KASEY]

The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

WHATEVER,, i have seen temps of 230 on several vmachines fresh out of the tree shots,,, and that is due to pulling very hard,,high revs and no airflow and that is where you will have a melt down ,,,, so if you have a miracle ignition that actually cools the motor and takes the place of fuel and oil to cool and lubricate lets see some pictures and an explaination :rolleyes: :rolleyes: :rolleyes:

[3Razors]

The Geek knows what he is talkin about! He is an electronics wizard that should probably be working for nasa. I've seen his projects on macdizzy dot com at it is a real deal.

[KASEY]

so where in phoenix do you live? i am here too,,,,44th street close to the airport,,,

[Troll 2]

The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

its all about electronics, kids. :twisted:

Any y' kids ever seen a top fuel ignition on a 2 stroke LELE LALA LOL :naughty: :Bounce

Kiddies, just because YOU can't do it doesn't mean IT cant be done.

Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.

Are you telling us you have a "top-fuel" ignition system on your R ?.................. :D

[Billy Golightly]

The Geekster did it in the high desert in Richland Washington, hammer down in 110*F ambient and 154*F on the sand. Rad water went to 190*F and stayed there.

its all about electronics, kids. :twisted:

Any y' kids ever seen a top fuel ignition on a 2 stroke LELE LALA LOL :naughty: :Bounce

Kiddies, just because YOU can't do it doesn't mean IT cant be done.

Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.


You might be a rocket scientist when it comes to electronics, but there is no reason to talk down to us "kids". You'll find no love here when the first thing you do is refer to your college book learning as a means of bragging and be-littling us because of your vast intelligence due to your "edukashen".

I'm sure there are many people here that can dwarf your "10 years of engine tuning". Check your ego and attitude at the door. You might try showing some proof of your design before you go bragging about how good it is and you'll receive a little better reception. Anyone can go on a forum and run off a bunch of numbers in their post. Few can backup their claims with real world application and use.

[OldSchoolin86]

Don't fear boys, I've got a boat that can get through the thickest of BS now! :lol:

http://www.silverdollarboats.com/airboatpics/airboats008.jpg

[Mr. Sandman]

Its about simple physics:

Its not about strength, its about brain power.

Its not about fuel, its all about electrical engineering
its all about electronics, kids. Go to school and get some edukashen Take a 4 year EE course then a ME then get about 10 years engine tuning and come back N tell o'l Geek what cant be done.

So what's it really all about Geekster? Simple physics, brain power, electrical engineering, or electronics? Feeble but inquiring minds would like to know. Please fill us "uneducated kids" in as we really need to know so we can keep our 20 year old machines running as well as yours obviously does.

[Fox250R]

I saw one of those on flipper once

[NOS_350X]

Geek, i think your a geek and thats it, you use physics to come up with this crap and have never tryed any of it.

A 132 main is WAY lean. My almost stock 350x runs a 185main, and most stock r's run a main higher than that.

Whast with listing every little thing about your trike on the bottom? Who cares if you have boysen reeds, theres nothing special about them there just an aftermarket replacement. Just part of general maintince on a 2 stroke.