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Discussion Starter #1
Just would like some input if running my r out of gas at pretty high rpm could cause this? I have a 330 esr 38mm a/s 52 pilot and 180 main. stock cdi and coil. br8es, ERS trx 9 pipe. Race dome running vp110 with 927 mix. Do yall think that caused it or do i need to look for other problems? Oh yea i pressure checked it less than 5 hrs ride time. it was good. It has just been rebuilt with new everything crank and bearings and all new seals. It burnt a hole and melted the top of the piston down to top ring on the exhaust side of the piston. Thanks any input would be appreciated .
 

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When running out of fuel you are leaning out your engine. So theoretically speaking, I believe that you could burn a piston. If you were on a long full throttle pull at high rpm I bet it would increase the odds. Far more often piston meltdown occurs when you have an air leak or you don't have your carb jetting correct. High rpm runs are when you need to be spot on in regards to your main jet. Your fuel choice is not the issue for sure. I have a 391R and 310R both at 15.5-1 compression and I use sonoco 110. My son's R's are at 13.5-1 and they run on non ethanol 92 octane. After you rebuild your 330 be sure you have zero air leakage! Do a proper break in and then do a leakdown test again. Also be cognizant of your fuel level!
Loren
 

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Just would like some input if running my r out of gas at pretty high rpm could cause this? I have a 330 esr 38mm a/s 52 pilot and 180 main. stock cdi and coil. br8es, ERS trx 9 pipe. Race dome running vp110 with 927 mix. Do yall think that caused it or do i need to look for other problems? Oh yea i pressure checked it less than 5 hrs ride time. it was good. It has just been rebuilt with new everything crank and bearings and all new seals. It burnt a hole and melted the top of the piston down to top ring on the exhaust side of the piston. Thanks any input would be appreciated .
Piston failure as the picture shows normally does not occur instantly, not a failure caused by "running out of gas". IMO this was an ongoing negative condition, leading to failure. Some of the causes listed from the most likely to least:

Air Leak...severe, usually on stator side.
Faulty IGN, Advanced Timing, Bad CDI box.
Lean carburetor jetting...
High Compression vs Low Octane...UCCR is high
Spark Plug to Hot

Perform a full leak down, inspect all electronics to Honda OEM specs, what does the bottom inside of the piston look like?

Carlos
 

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Discussion Starter #5
Everything on the inside of the engine was a grey chalky color. It looked like it went very lean for sure. Got everything to put it back together but i want to be sure everything is right before i do. The carburetor is almost new from esr less than 5or10 hrs at the most. 180 main. Done some chops when i put the engine in it was fine at that time.
 

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I would start at 190 and work down.
 

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Everything on the inside of the engine was a grey chalky color. It looked like it went very lean for sure. Got everything to put it back together but i want to be sure everything is right before i do. The carburetor is almost new from esr less than 5or10 hrs at the most. 180 main. Done some chops when i put the engine in it was fine at that time.

First....
Check list:
Full leak down test.
Check Reed Pedals
Check all Electronics to OEM specs. Specially keep an eye-test on CDI
Make sure pipe, Carburetor & Intake are fully sealed; NO leaks
Set squish at .055"-.065"...important on ESR 330's
Perform a full UCCR...a must IMO

" I have a 330 esr 38mm a/s 52 pilot and 180 main. stock cdi and coil. br8es"...that is good jetting for a 330 on 110 Race Fuel, except I would go B9ES or BR9ES and not an '8' series. Set your Needle (DGH preferred) to 4th clip from top, set AS to 1 1/2 turns out. If you want to up the Main, go to 185 max, 330's don't need Main jetting usually above 180, and 185 is plenty Rich on Top. If it runs lean, you have other engine-carb-intake-pipe issues; refer to top check list.

Carlos
 

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Discussion Starter #9
Thanks Carlos i am on it. I will see what i can find and let yall know. I am thinking about putting the pump gas dome back in it for now. What do i need to look out for if something wrong with cdi. It cranks easy once it warms up. A little hard to start when cold. No kickback at all. I want to check the timing too. This is the first time i have run this pipe also. Its a esr trx9r. Dont know much about these pipes at all. Is this pipe a good choice for my setup? I know is was running real strong with it. Mid to upper range.
 

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If it's an OEM CDI, and it starts fine, idles, and pulls strong....then likely the CDI is "OK"...unfortunately checking CDI's can't be don with an OHM meter. You can check Timing with a DC Timing Light to the OEM Flywheel timing marks.

The TRX9R is a decent-good off the shelf pipe.

Carlos
 

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Discussion Starter #11
Ok going to get it back together this week and run down the check list. Thanks for the help..
 
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