TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: F-Red on April 29, 2015, 10:08:04 AM
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I've come to the realization, maybe I'm not to own one of this fine machines. All my life, I wanted to own the infamous TRX250R. At the age of 46, my dream came true. Found a nice clean machine in Maryland. Brought her home and for a year was Happy! Happy! Then I started to purchase aftermarket cylinders, and the trouble begins. The first 330 had overheating issues. 3 pistons, until I found the water passages around the exhaust side, were tiny little slivers. Fixed that and away I go. Now comes to the current 350. Three nice heat cycles and two short little trips up and down the road, I have this galling building up already. So now we buy more pistons until I find, what the FUK happen this time? It's getting old and expensive. My 450R is a blessing! No problems like this POS. I'm on the ledge! I don't know if I'm coming back in. :upset:
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/27C78F3B-2E91-4E90-8AF7-CF315F4D9BC2.jpg)
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[video=youtube;6SYR1THGEE4]https://www.youtube.com/watch?v=6SYR1THGEE4[/video]
Its too tight
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You have the same problem as my buddy. Hes the only local friend i have that has a 250r and cant get it running right. When i met him he had a ESR 310 and now i hooked him up with a ESR 370 and still cant figure it out. Hes payed shops to tune it with no luck and they still take his money. Hes gone through a couple pistons and still keeps riding it all messed up. I think he worst part is he lets people ride it that dont even know how to ride. I keep telling him to let me have it for a while so i can play with it but he always has an excuse not to bring it over. Hes so frustrated he just wants to sell everything. Hopefully hell change his mind when he gets a chance to ride mine.
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I've come to the realization, maybe I'm not to own one of this fine machines. All my life, I wanted to own the infamous TRX250R. At the age of 46, my dream came true. Found a nice clean machine in Maryland. Brought her home and for a year was Happy! Happy! Then I started to purchase aftermarket cylinders, and the trouble begins. The first 330 had overheating issues. 3 pistons, until I found the water passages around the exhaust side, were tiny little slivers. Fixed that and away I go. Now comes to the current 350. Three nice heat cycles and two short little trips up and down the road, I have this galling building up already. So now we buy more pistons until I find, what the FUK happen this time? It's getting old and expensive. My 450R is a blessing! No problems like this POS. I'm on the ledge! I don't know if I'm coming back in. :upset:
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/27C78F3B-2E91-4E90-8AF7-CF315F4D9BC2.jpg)
Are there seize marks on the carburetor side of the cylinder?
What was the piston clearance set at?
What pipe and silencer are you using?
What type load had been on the engine the last 15 seconds or so before the seizure?
Heat cycles are a waste of time, especially if your heat cycles are low temperature heat cycles like your piston crown shows. The stress relieving should be done during the manufacturing of the piston just before the final machining is done. If the low temperature heat cycles actually relieved stress within the piston to be benificial, the rings would not fit in grooves. The wrist pin would not rotate in the piston. The skirts of the piston would not have the proper shape.
Break_in is the period of time while the piston and cylinder wares to the minimum operating clearance necessary for reliable engine operation. The piston clearance can be set to the minimum operating clearance when we bore a cylinder but as soon as the peaks wear off the tool marks on the piston skirts, the piston clearance will be excessive. Wearing the peaks of the tool marks typically takes from 20 min when using the controlled environment on the dyno or sometimes a couple of hours riding using very brief periods of full throttle initially (2 to 3 seconds) and increasing the periods of full throttle as the break-in period accumulates more and more time.
We have to set the piston clearance on drag engines to the minimum operating clearance when we bore the cylinders. The pistons do not usually have enough time on them before they are put under full load to wear the piston to provide the minimum operating clearance.
If we bore a cylinder and set the piston clearance "tight", more break-in time is required to ware the piston to the same minimum operating clearance that is required in a drag engine. The advantage of setting up a bore tight is when the minimum operating clearance is finally achieved, more of the tool mark peaks are worn off and the piston wares more slowly from that point forward.
I do not see what I call "proper port chamfers". Improper port chamfers will not not cause seized pistons but proper chamfers will make your new piston and rings last longer
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Seems there is a whole group of 250r guys running 350 cylinders with 250 pipes. They start blaming the pipe. A larger stinger diameter will let the pipe cool your motor down.
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It looks like the piston to bore clearance may have been too tight. Like Jerry asked, do you have similar markings on the carb side? What was your piston clearance set at?
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if im not mistaken didnt you buy this complete from eddie? or did you assemble yourself
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sometimes its difficult to pin point exactly what went wrong. check your clearances, see if the jet size was in the ballpark, plugged silencer, cooling system working good etc etc.
its a good idea to do everything possible to provide as much lube as you can to the moving parts. might try some type of oil holes in the piston. it certainly couldnt hurt. never hurts to have plenty of oil in the gas either. 32:1 is bare minimum imo. honestly i would even recomend more oil than that but i dont want to start a pissing match
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Seems there is a whole group of 250r guys running 350 cylinders with 250 pipes. They start blaming the pipe. A larger stinger diameter will let the pipe cool your motor down.
I see this every week. Guys need to wait until they have the money to do it "right". You will usually have problems if you are trying to upgrade to a big bore cylinder and running mismatched components until you have the money to purchase the rest of the necessary components
My experience has been that putting a larger stinger and muffler core on a 250 pipe that was developed for the OEM cylinders is often a band aid . Less restriction on the outlet of the pipe will help keep the piston temperature reasonable on hard pulls but will often not make the power that a pipe that was specifically designed and tested for the big bore cylinders and porting being used.
Even though the same basic molds appear to be used on the Pro X 310s, 330s, 350s, and ESR family of big bore castings, the scavenging ports effective discharge angles and areas change when a given casting is machined for a different bore size. Cylinders that scavenge differently and have different displacements need different pipes to match the unique scavenging patters of the different groups of displacements.
Old pipe formulas and pipe software used one size of stinger for 125cc engines, another size stinger for 250s and so on without regard to how much power the engines made. The amount of exhaust being pushed through a given diameter stinger is a function of the power being made. If your big bore cylinder makes significantly more power than a good running 250, the 250 pipe is more than likely going to be two restrictive and piston overheating WILL occur.
I think that it is the engine builders/parts supplier DUTY to inform the customer as to what pipe, porting, head, carb, reeds etc. and starting point on jetting they should be using for a given engine package. If the engine builder cannot furnish this information you need to go to builder or supplier that can. This knowledge only comes from expensive testing on the engine builders part. If you are following all of your builders recommendations for engine package components and tuning specifications and are still having problems....you need a builders that has done the necessary testing and development. A customer should not have to go through a handful of $150.00 pistons to work out the bugs that was in a engine package that was supposed to be already developed.
Customers often shoot themselves in the foot trying to select their engine package components themselves rather than finding a builder and following his recommendations to a "T". I have some customers that do not listen to my recommendations and use the wrong pipe, porting, head etc.because they do not want to spend the money for the tried and tested components and do not understand the importance of using components that compliment one another.
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F-RED.....Did you use a WISECO Piston ? My buddy had the exact same issue....it seems a lot of people are having issues with the Wiseco's expanding too much.Not sure if they changed their chemical makeup in the Aluminum....something has changed.
Switch over to a WOSSNER....And your Problem will be solved....they don't expand as much as the Wiseco's
Keep us posted...and Never give up on the R.
:)
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i dont think we can blame wiseco as a whole. ive used their pistons for years in numerous engines, plated and iron sleeved... never a problem. i did hear something the other day, whether its true or not is hard to say , as i havent personally seen it happen but supposedly wiseco has in the past mislabeled some piston boxes and the clearance stated on the box was wrong. maybe its something to look into ?
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F-RED.....Did you use a WISECO Piston ? My buddy had the exact same issue....it seems a lot of people are having issues with the Wiseco's expanding too much.Not sure if they changed their chemical makeup in the Aluminum....something has changed.
Switch over to a WOSSNER....And your Problem will be solved....they don't expand as much as the Wiseco's
Keep us posted...and Never give up on the R.
:)
Did Wossner ever get the weight down to an acceptable level , They used to be so heavy that I was afraid to use them in our healthy big Bore builds that turned a lot of RPM.
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F-RED.....Did you use a WISECO Piston ? My buddy had the exact same issue....it seems a lot of people are having issues with the Wiseco's expanding too much.Not sure if they changed their chemical makeup in the Aluminum....something has changed.
Switch over to a WOSSNER....And your Problem will be solved....they don't expand as much as the Wiseco's
Keep us posted...and Never give up on the R.
:)
What clearance does Wossner currently recommend for their Honda big bore pistons?
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F-RED.....Did you use a WISECO Piston ? My buddy had the exact same issue....it seems a lot of people are having issues with the Wiseco's expanding too much.Not sure if they changed their chemical makeup in the Aluminum....something has changed.
Switch over to a WOSSNER....And your Problem will be solved....they don't expand as much as the Wiseco's
Keep us posted...and Never give up on the R.
:)
Thermal expansion is not really an issue. You just have to account for it in your piston to bore clearance, just like you would any other piston, Wossner, Prox, etc. You should always match your clearance to the equipment you are using.
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I've come to the realization, maybe I'm not to own one of this fine machines. All my life, I wanted to own the infamous TRX250R. At the age of 46, my dream came true. Found a nice clean machine in Maryland. Brought her home and for a year was Happy! Happy! Then I started to purchase aftermarket cylinders, and the trouble begins. The first 330 had overheating issues. 3 pistons, until I found the water passages around the exhaust side, were tiny little slivers. Fixed that and away I go. Now comes to the current 350. Three nice heat cycles and two short little trips up and down the road, I have this galling building up already. So now we buy more pistons until I find, what the FUK happen this time? It's getting old and expensive. My 450R is a blessing! No problems like this POS. I'm on the ledge! I don't know if I'm coming back in. :upset:
I had this same feeling when I got my engine together and exploded the cases because I didn't put loctite on 2 tiny bolts.......I almost threw in the towel and parted the whole thing out to buy a 450.
Once you take your time and do everything the right way it all works fine.
Nothing against ESR (I know people have had plenty of success with them), but I would have the ESR kit sent to a reputable builder before assembling it. Just to make sure everything is good to go
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F-Red:
Make a list of the components and specifications of you engine package. If you do not know all of these specs. call you engine builder...he should be able to supply the info.
Piston clearance when the engine was assembled.
Piston to head clearance at the squish OD and at the squish ID
Volume on top of the piston at TDC.
Mfg. of Pipe and silencer, stinger ID and muffler ID where it exits to the atmosphere
Carb Mfg. size and jetting
Brand of fuel and octane of the fuel you were using
Ignition timing.
spark plug Mfg. and heat range
Port timings
reed valve
intake system and air filter
Radiator Mfg. and are there any inline temp guages or inline coolers?
Fuel to oil ratio
The above specification and components are what we call an engine package. All of the above should have been engineered and tested to work together. If any one of the above specs or components were not tested as part of the package, it could result in the failure you experienced!!!
What was the approximate outside air temp and cylinder temp when the failure occurred?
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how many times was it starved out of fuel do to your float level being to low? the post in the carb section with pics the floats were way off.
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Did Wossner ever get the weight down to an acceptable level , They used to be so heavy that I was afraid to use them in our healthy big Bore builds that turned a lot of RPM.
78.5mm Big-Bore Piston wights:
Wiseco - 296 grams
Wossner - 307 grams
BOTH Pistons have the "NEW" design features of the extra material beside the Piston pin Area towards the exhaust side to eliminate the cross linking issue.
:)
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78.5mm Big-Bore Piston wights:
Wiseco - 296 grams
Wossner - 307 grams
BOTH Pistons have the "NEW" design features of the extra material beside the Piston pin Area towards the exhaust side to eliminate the cross linking issue.
:)
It is good to see the Wossner pistons went on a diet. When LA sleeve first started selling the Wossner big bore pistons, I bought one. The Wossner piston felt heavy when I when I held it in one hand and the old Wiseco on the other. I got the scales out and they were over 50 grams heavier. I sent it back and started using the ESR Wiseco pistons because I was afraid that the Wossner pistons would break the con-rod on that high revving 330 engine.
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A lot is discussed regarding the piston lifecycle, but is it possible these relatively new ESR cylinders have a design flaws that are causing otherwise good pistons to interfere with the bore?
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I viewed a discussion on this a few weeks ago and one builder mentioned ring gap being to tight and heat transfer from piston to cylinder via the rings.Jerry can you elaborate on this .
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I viewed a discussion on this a few weeks ago and one builder mentioned ring gap being to tight and heat transfer from piston to cylinder via the rings.Jerry can you elaborate on this .
Can you rephrase the question? I am not sure what you are asking.
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i agree with the comment about waiting until you have the money to do it All and do it Right the first time. i bought a R with a used ESR 310 pv complete kit last fall. the bore was worn out. so i took it to my machinist for a new bore. i bought the specific ESR Wiseco piston and he followed all the Wiseco/ESR specifications that i got right from Eddie. even down to the clearance on the PV to the .000th. spark plug type, inital jetting, torque spec, break in......on and on. i have been riding it like it since early this spring and i am far from nice to it. point being, do it RIGHT and do it once! 2 strokes are easy! if you are having this many problems with a 2 stroke then there has to be something that your missing. maybe its not your fault. not trying to be mean to you my any means! but these bikes are so so so easy to work on and build. maybe the machinist your using doesnt know what hes doing. maybe there was some suggestion that you were givin that you misunderstood. DONT GIVE UP ON THE R!!! do some extra research this time. call Eddie, (hes hard to get ahold of but keep trying. hes such a wealth of knowledge and likes to help!) talk to your machinist/engin builder to make sure hes following the correct specs, double check EVERYTHING on your next build. dont give up dude! theres plenty of people that have been in your same situation and now have a good reliable R because they were able to learn from their mistakes and diddnt give up. knowledge is power but nobody is born with it!
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I viewed a discussion on this a few weeks ago and one builder mentioned ring gap being to tight and heat transfer from piston to cylinder via the rings.Jerry can you elaborate on this .
I wish I had seen this thread earlier. My first thought was the obvious seizure, but seeing the vertical lines extending all the way to the top of the cylinder, my SECOND thought was the ring gap.
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I also noticed the scoring streak from the top piston ring. When the ring gap is too tight there will usually be many lines around the whole circumference of the bore, but the lines are not usually as wide as the "ring streak" pictured.
I frequently see the rings put steaks in the bores directly above the center bridge in a bridged exhaust port when the bridge has not been relieved and guys are not running enough oil in the fuel for their type of riding. The center bridge in an exhaust port runs much hotter than any other part of the cylinder wall. The excessive heat oftens kills the oils ability to lubricate, causing the rings to gauld where the ring is making contact with the dry unlubricated bridge. The gaulding damages the ring and the ring damages any other part of the cylinder wall where it makes contact.
I think that the same phenomena mentioned above occurred on the bridge of the pictured cylinder between the main and auxiliary exhaust port. There was aluminium transferred to the bore in this same bridged area. This means that there was a time when the surface temperature of the piston skirt was over 1100 deg. F. I do not know of any lubricant that can provide lubrication when it is 1100 deg F. The lubrication has to fail before aluminum can be transferred to the cylinder wall even though the piston was a press fit a few strokes before the seizure.
The friction from the press fit of the piston in the bore is what generates the excessive heat that causes the surface of the piston skirt to melt and transfer aluminum to the bore.
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To continue Jerry's thought just a little further, castor oil is about the best you could hope for in a seizure/overheating application. It has excellent shear strength (meaning it doesn't get scraped off quite as easily as other oils), and if/when it DOES overheat and burn, it leaves behind a waxy substance that still has lubricating properties.
Now, that doesn't mean Castor is the "best", it burns dirty, gummy, and leaves behind a lot of residue. But it generally IS the best in preventing a seizure if something goes wrong inside your engine.
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..............Now, that doesn't mean Castor is the "best", it burns dirty, gummy, and leaves behind a lot of residue. But it generally IS the best in preventing a seizure if something goes wrong inside your engine.
For me, castor oil has some very desirable characteristics that mineral and synthetics oils do not possess. This unique quality does not show up in the conventional (falex test, 3 and 4 ball test, timkin test, etc.), laboratory oil test where the parts are swimming in oil.
There are many oils and additives that will carry more load in the above lab tests than castor but they do not burn well and many that do burn well produce an abrasive ash when they burn. Oils that produce an abrasive ash when burned can be eliminated as candidates as being used as base stock in a two stroke oil. The manufactures of the two stroke oils that show high load carrying capability in the above test that do not burn well usually recommend that "best performance" is obtained at ratios in the 32:1 to 100:1 fuel to oil ratios. Make note of the words "best performance" which means best power not best lubrication is obtained at those ratios. Oils that do not burn well do so because these oil molecules get in the way and slow the chain reaction in the combustion process.
The gummy brown waxy residue from castor oil becomes a high temperature lubricant at temperatures where most mineral and synthetics have turned to ash. This is what I like about castor oils. The gummy brown residue from castor oil does not form on a part that is running cool. A part that is running cool does not need a very good or more lubricant.
The things I look for in a two stroke oil that will be subjected to the most extreme engine component heat and load condition are:
1. The oil must mix well with the fuel at the temperatures the fuel will be at while supplying the engine with fuel.
2. The oil must provide high load carrying capability at extreme temperatures.
3. The oil must burn easily even at ratios of 15:1. Remember that oil is a fuel and if it burns easily it makes the fuel a better fuel
An oil that burns clean is not a high priority for me on an all out racing oil, but an oil that can be run at low ratios is desirable. An engine that is running on a low fuel to oil ratios (around 20:1) provides a little more "wetting" of the parts. A part that has more wetting will have a wider contact patch for heat to pass from the hot parts to it's cooler heat sink.
Intuition and physical test says a cylinder wall that has more oil on it provides a better ring seal and yields higher cranking pressure on a compression gauge. I do not think that this is a valid point on a high RPM engine for running more oil in the fuel. A cylinder wall that has more oil on it provides more surface area for heat to flow from the hot piston skirts and rings to the cooler cylinder wall.
A better oil or more oil in the fuel would not have prevented the seized piston shown at the beginning of this thread. This engine has some basic problems with the build, tuning, and or break-in procedure. A better oil or more oil in the fuel in this engine build would have only added another 1/2 second or less before the engine seized.
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I see this every week.
I think that it is the engine builders/parts supplier DUTY to inform the customer as to what pipe, porting, head, carb, reeds etc. and starting point on jetting they should be using for a given engine package. If the engine builder cannot furnish this information you need to go to builder or supplier that can. This knowledge only comes from expensive testing on the engine builders part. If you are following all of your builders recommendations for engine package components and tuning specifications and are still having problems....you need a builders that has done the necessary testing and development. A customer should not have to go through a handful of $150.00 pistons to work out the bugs that was in a engine package that was supposed to be already developed.
Customers often shoot themselves in the foot trying to select their engine package components themselves rather than finding a builder and following his recommendations to a "T". I have some customers that do not listen to my recommendations and use the wrong pipe, porting, head etc.because they do not want to spend the money for the tried and tested components and do not understand the importance of using components that compliment one another.
AMEN Jerry. Thanks God for knowledgable and experienced men like you. Thanks for all you share with this site. Your insight and wisdom is not taken for granted.
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And THAT is why we love Jerry. Good luck trying to find that kind of in-depth, technical explanation on Facebook...
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And THAT is why we love Jerry. Good luck trying to find that kind of in-depth, technical explanation on Facebook...
X2. Nice to see you around here Wilks! :cool:
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Might be seeing a bit more of me. Weather is getting nicer, my schedule is opening up, gonna be dusting off the sport quads soon. Last couple years I didn't ride them much, too busy, just some trail riding with the utility. But I think I need to get back to my roots, and wrenching and riding always makes me come in here.
They've been neglected a little. One needs a new carb (but I'm not sure which size I'm gonna run), I need to find a custom axis rear shock, and I need to find a way to get croat1 to part with his graphics kit...
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Best wait till he dies.
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how many times was it starved out of fuel do to your float level being to low? the post in the carb section with pics the floats were way off.
Bingo! The float level was way too low. Made the proper adjustment and she's running fine now.
Thanks for all the advice and concerns. You guys are surely the best. :encouragement:
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So you've had another melt down since the last time Fred ?.
What did you do this time, acid the bore to remove the aluminum or fit a new piston.
Neil
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I wouldn't jump to conclusions calling it a POS. Ive sent 2 cylinders back to Eddie. There maching department is or was mediocre (no offense just the facts). I checked a bore before instalment and it had over .011" taper in it,(Honda service manual spec is under .001") .011" taper is HUGE in ANY bore especially an engine cylinder. Also there was perosity in the bore.It was a painstaking process to even get ahold of esr. We were down for over 6 weeks.They do not care about the customer. Any motor, especially a high performance engine like this one, will not run right with sloppy machining. ESR offers the engine builder package because they got so much complaints about there machining and porting.
As stated there are NO port chamfers in that motor. You wants the rings to slide smoothly past the ports Not "click" when they drag past a sharp edge like that. I give ESR credit for admiting their flaws & offering the engine builder package. I know they just got a makino horizontal with new tooling. Hopefully this will improve their machining department. Glad your R is working out for you now.
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So you've had another melt down since the last time Fred ?.
What did you do this time, acid the bore to remove the aluminum or fit a new piston.
Neil
Hey Neil. Just the first piston, since you ported the cylinder. I had it bored and adjusted the float level. She's good now.
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Hey Neil. Just the first piston, since you ported the cylinder. I had it bored and adjusted the float level. She's good now.
Thank goodness, was getting kinda worried looking at that pic. I know the coolant area, was opened up more so cooling shouldnt have reared its head up. Those ports dont look chamfered enough, but I know they are cause my hands touched them. That pic just not showing it clearly.
I know what your saying about the boring Klotz, lot of bore shops just will not take the time to do a 2 stroke cylinder right. I use auto shops for quite a few years for my boring, until one cost me two championships one season. Got in a hurry, on two bores in the middle of the week before a race & didnt check behind them. One bit me in the butt in practice & the other in a heat race. Both jugs once I pulled them down, measured 0.004 at top & bottom & right in the middle under the ports measured 0.002
Bore man I have now, he only does 2 stroke cylinders, takes pride in his work & he does not have an option for doing a sloppy job, cause his base work is 2 stroke air craft engines. You do a messed up job with one of those & your work can take a life real quick, so I trust him on every one I send him.
No more auto shops for me, not cylinder boring.
Neil