TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: trx250scar on September 29, 2013, 08:35:44 PM
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ok let me give some history.i spent so much on parts i didnt trust myself to assemble it as i am not a pro but have done rebuilds on my other trx250r so am not a complete idiot. i sent it off to another builder in rancho cucomondo cali. i know he is not the favorite here so please save the bashing and if you can limit the commets only to helpfull ones. 2001 cr250 ignition. i ordered a new esr 330 pv cylinder with pump gas dome and trx9 porting, esr cases that the deck hieght was set up for 4 mil stroker crank which i ordered new from ebay and sent to crankworks to have balanced and welded. cylinder was supposed to be also set up for 4 mil stroker. i ordered the esr parts directly from them and told tom when he was there to have eddie set it up for the 4 mil. i also ordered a brand new trx5 pipe with a type 2 silencer. also new esr 38mm air stryker. dgh needle 60 pilot 182 main 2nd clip from bottom. i ran wot plug chops and 185 bobbled a little like was rich so went 182 it had a nice tan color. now i have never been able to get it to idle. does anybody run a larger pilot? i have an oversize pwk radiator which i tried another oem known to work radiator so it is not clogged up. flow is good when checked with the radiator cap off. in line temp gauge(ESR) on the top hose opposite of the pipe. this thing runs very strong however builds heat very quickly and continues to peg the temp gauge in just two minutes of riding after it has reached the warm up temp of 150. do i have a timing issue? poor cylinder casting? was the cylinder improperly set up? was the crank not a stroker? stroke not matching the ports? maybe wrong dome as i did not see it with my eyes before it was installed? i dont think it is lean as the plug at wot looked good and ran clean no popping and what not. i was thinking lean in the mid since wot was good so i even went back to a 185 and lifted the needle to top clip. still overheating. hoping maybe rsss396 will read this and chime in as he seems to be knowledgable about the timing tho all opinions are valuable. thanks in advance for the help.
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Pump gas dome with stroker crank?? I was told by Tom not to use pump gas or pump gas dome with my 350pv +4 stroker. He originally told me I could mix 50/50 but then called me back to tell me not to mix. told me to use 100% race gas. Just a thought.
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i dont have a solution for your issue but i know if your pegging the gauge then you have a serious problem somewhere. personally i wouldnt keep riding it until you get it sorted out.
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well i dont continue riding it at high temps to prevent damage but do need to try different jets needle position etc
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Pump gas dome with stroker crank?? I was told by Tom not to use pump gas or pump gas dome with my 350pv +4 stroker. He originally told me I could mix 50/50 but then called me back to tell me not to mix. told me to use 100% race gas. Just a thought.
What octane Did they recommend for your application.
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i think you have more than a jetting problem. is your timing set correct ? a couple more things come to mind, recently i seen a issue with esr pipes holding alot of heat in the cylinder and the cylinder front water jacket not being up to par
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advanced timing will add some heat to the motors cooling system but I would say not enough to cause overheating issues.
are you sure you do not have a blown head gasket? only 2 min of riding after reaching 150 seam a little extreme, I would not expect that quickly even on a 90+ degree day, I forget how high do the ESR gages read? is it puking antifreeze out of the radiator?
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esr gauge is 250*. ya timing doesnt seem like the issue plus it would probly run like crap if it was very far off. if head gasket was blown it would either go to the outside which he would see or into the chamber but he claimed its was running strong so i dont think its going inside
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It will start puking but I am unsure at what temp. ESR gauge reads 250 max. Running 100% distilled water now.Did start with antifreeze mix.
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maybe they really screwed up your head dome ? put a call into jerry hall tomorow and ask if the pipe stinger issue along with the water jacket could cause your problem.
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Who is Jerry hall
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halls precison machine i think in glendal AZ. pretty smart feller. forgot as much as carlos knows
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if you blow the inner oring it will over pressurize the cooling system and add heat but you normally start having a hard time starting it because it will want to leak back in the cylinder and water level will drop in the system from puking out and the cylinder burning some.
nothing can be wrong with the cylinders to put to much heat in the cooling system, porting not going to cause this either.
A too small of a stinger is not going to create issues unless you are holding wide open for longer periods of time.
sure seams like a water flow issue, even running pretty darn lean should not make it climb like crazy in such a short time. sorry dont have any more for you.
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said he swaped rads and still the same thing ? if the pump was broke the engine would be hot as a mutha but it wouldnt push water to the gauge so it would read alot lower i would think. ya im stumped good luck dude
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I think you need to contact Eddie @ ESR and find out if you have one of the cylinders that needs the water jacket modified towards the front of the cylinder by the exhaust port.
Also, you sure the gauge is working correctly? Maybe find another alternative to measuring your temperature to rule this out. Thermometer in your rad with the cap off? Lol just a thought (although you did say it was puking out the overflow)
Don't worry about the exhaust. The stinger diameter wouldn't raise temps that high, that fast. No way.
Set your timing it is not advanced nor retarded. Just to rule that out.
Do a leak down test...
Is this an o-ring head? If it is, then pop the head off and inspect the o-rings. I put a little bit of white lithium grease on them to help seal.
It would run like crap if it wasn't setup correctly for the +4mm stroke.
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Make sure the inner o-ring is not leaking. Any scratches on the head can cause the o-ring to fail. Run only race gas. Detonation can cause o-ring failure.
Do a pressure test to make sure you have no air leaks.
A one inch id tail pipe will cause it to overheat at full throttle. If you are lean around 3/4 throttle opening it is because you are using a DGH needle. Change the pilot jet to a 50, try a DEJ needle in the 4th from top clip position and start with a 182 main jet. a 182 should be plenty rich. We usually end up with a 178 main jet.
It has been my experience (only about 30 years) that the combination of pump gas, DGH needle and a 1" tail pipe would give you exactly the result you are experiencing.
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sounds like an air leak. wont idle and overheats rather quickly.
john
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What octane Did they recommend for your application.
When I asked Tom for a pump gas dome with my +4 stroker he recomended against it. He said "you dont want to run pump gas" He originally told me that I could mix 50/50 (pump gas with race fuel) but then called me back about an hour later and told me that I needed 100% race fuel. Now when I got my kit I seen they put a race dome in my head. Tom recomended the vp110 or the c12 fuel. I run the vp110 and run around 200-205 degrees. Takes about 2-3 minutes (warmup before ride) to get to 150 and then SLOWLY climbs to the 200 degree mark. After checking your o-rings as mentioned above I would get yourself some race fuel. Even if you mix 50/50, if in fact it is a pump fuel dome you have, it may make a difference.
Also I thought the water jacket issue was more on the non-powervalve engines because of the extra alluminum that was not hollowed out in that area. At least thats what I had read somewhere about that. The small stinger issue is not an issue IMO.
Becarefull when you put the o-rings on your cylinder deck. Do not roll them into the groove they need to be set into the groove. Dont want them twisted sitting in there. If you tried all thats suggested and nothing works I would definitely call Eddie. My guess is he would want the oppurtunity to make it right than have bigger problems down the road like a p.o. customer.
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OK guys Thanks for all the great info and response on this. I work a lot during the week so this weekend i will be tryingpthese suggested fixes this weekend. Will give updates as I eliminate potential problems. .
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Make sure the inner o-ring is not leaking. Any scratches on the head can cause the o-ring to fail. Run only race gas. Detonation can cause o-ring failure.
Do a pressure test to make sure you have no air leaks.
A one inch id tail pipe will cause it to overheat at full throttle. If you are lean around 3/4 throttle opening it is because you are using a DGH needle. Change the pilot jet to a 50, try a DEJ needle in the 4th from top clip position and start with a 182 main jet. a 182 should be plenty rich. We usually end up with a 178 main jet.
It has been my experience (only about 30 years) that the combination of pump gas, DGH needle and a 1" tail pipe would give you exactly the result you are experiencing.
should i perform pressure test with exhaust off and plugged there and carb off with the gauge at the intake boot? i also forgot to mention in first post i am running br9es and castor 927 32:1. i will pull the head inspect dome for any markings indicating pump or race fuel. either way i will try some race fuel. i currently use only ethonal free 93 but will try some 110. also will go ahead and order some o rings in case they r damaged when i get in there. any suggestions on were to pick up a dej needle? also was thinking how would i know if the pv was not opening properly while the rpm increases? could this be an issue?
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You must plug the exhaust, the power valve and the spark plug hole. You can pressurize though the intake to 12 psi. I should hold pressure for 15 minutes with little or no loss of pressure.
If you have a good compression tester you can check cranking compression. I need to be a good gauge, I prefer Snap-on compression testers. With the engine cold, hold the throttle wide open and kick until the gauge needle stops going up in pressure. Anything over 180 psi should be straight race gas. many of the engines like yours have the piston coming out of the top of the cylinder, because the cylinder is made for a 72mm stroke and is to short. This give a very poor combustion chamber. I think good fuel is important even if the compression is not high on that type of engine.
We stock DEJ, DEK, DEL needles.
If the power valve is not raising the engine will not have much top end power, or rev out.
You may want to call me so I can better explain how to proceed in trouble shooting this issue.
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You say you've got the Clip in the top groove in the Needle ? That's the LEANEST setting.....move it down to the 3rd or 4th position
And Like Arlen & Jon Suggests.....do a Leak-down test....if you can't hold 12 psi for 15 min then you've got an air leak and that will make you run LEAN - and raise your operating temps.
Good luck & keep us posted
:)
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Make sure the inner o-ring is not leaking. Any scratches on the head can cause the o-ring to fail. Run only race gas. Detonation can cause o-ring failure.
Do a pressure test to make sure you have no air leaks.
A one inch id tail pipe will cause it to overheat at full throttle. If you are lean around 3/4 throttle opening it is because you are using a DGH needle. Change the pilot jet to a 50, try a DEJ needle in the 4th from top clip position and start with a 182 main jet. a 182 should be plenty rich. We usually end up with a 178 main jet.
It has been my experience (only about 30 years) that the combination of pump gas, DGH needle and a 1" tail pipe would give you exactly the result you are experiencing.
I dont think this thread will spin off in the wrong direction as some do on .net, but I would like to point out to all of you, just above where Arlan states (only about 30 years) that means we all need to take note of what he has to say, because in those years of working on 2 strokes & TRX250R engines, a man can learn a lot & more than likely hes speaking from what his hands have touched & not what is read from a book.
The only other person that I would put up beside Arlan when it comes to knowing a TRX250R engine, Allen at CT Racing, both those men are like 250R Gods in my book. If I just knew 1/2 of what they have forgot over the years, I would be pleased to no end.
So, lets take notes what he replys, cause you can trust it works.
Neil
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Thank you Neil for the vote of confidence. Means a lot coming from a man of your experience.
There is more than one way to build an engine. I am sharing what I have learned doing it my way, and what I have done to solve problems I have seen. Hope my advise helps.
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Allen - very smart but would lie to u in a heartbeat. I have zero respect for him. Just my .02
Arlan- straight up guy and always willing to talk.
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thanks for all the input guys
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Allen - very smart but would lie to u in a heartbeat. I have zero respect for him. Just my .02
Arlan- straight up guy and always willing to talk.
I know thats right about Allen, but Allen needs to be understood, like when you call its like if you cuss at him everything goes smooth. I never did cuss & still got good help from him like we were on the same wave link.
Now miss Roxann, Allens wife, heck with Allen, just let me talk to her every time cause shes just as good as he is at answering questions.
Thank you Arlan for what you add, but far as my experience, well, all I know is from hard knocks trying this or that to know what worked & what didnt & really climbing into everything I touched, but being poor, most of the time I had to take nothing & then use that to make something out of it.
Thank you as well for the AMA/ATVA EDT sponsorship at Busco Beach. Was good to see a quad with L.E.D grafics on it competing this season, so hope you'll be back next year.
Neil