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'04 Honda 919, Candy apple red met., 16/44t sprockets,f-16 windscreen,delkevic ss exhaust,Tharbars,givi engine bars, billet alum. led turns w/ running lights,red adj.levers from china, bar end mirrors,grip heaters
I can't tell from the pics, what broke exactly? I'm guessing you broke a piston rod but please confirm.
When you were talking about 4th gear throttle-on wheelies, I thought it might be too much power for the stock internals.
If everything but the rod survived, it might be time for some beefy rods if you can find them. Of course, you may find another weak link but if you keep at it, we'll all learn how to build a bulletproog turboed 919
Sorry to hear about the failure. Good luck with it.
A 919 is almost an 11:1 Static Compression Ratio engine. How much boost did you set up with ? (What's the Wastegate set at ?) Do you have boost gauge ? If so, what kind of numbers were you seeing. Generally, the more Boost Pressure, the less Static Ratio is used. How many heat ranges were the spark plugs dropped down from stock ? Are the factory injectors capable of enough flow to provide proper A/F ratio under all boost conditions ? Interesting looking failure. It appears that it's a peripheral piston crown failure from above the top ring land near an intake valve, which is generally the cooler place. Looking at the head, the other chamber looks to show carbon and soot, meanwhile your failed cylinder shows a chamber that appears to have run real hot, especially the exhaust valves. What kind of fuel were you running ? Any visual indication of detonation (knock) or pre-ignition (hot spotting ignition) ?
I'd say with only 5 psi and only 10 miles untill a piston failure it seems obviouse that there was a tune problem. Or someone screwed up the 1st rebuild.
Hone it and toss a set of forged pistons in. The cyclinders are not coated there is steel sleeves.
5psi with a good tune should run fine. With only ten miles it had to have been a bad tune or maybe your airbox tweaked the injector manifold causing uneven fuel injection. You had to have heard some pre-ignition before that happened. JE has plans for a 10.5:1 forged piston (I have 4 of them in my bike)
Forged pistons would not have prevented such a failure nor prevent it in the future. The variation in the chamber and piston top pictures say so. Forged and Cast Piston give the same "read" on the piston top and chamber - aside from cooler running displays on thick headed forged pistons.
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Quote:
Originally Posted by woodyeee
Oh well it was fun while it lasted...all of two rides and no more than 10 miles
I had a little misfire and when i pulled a plug it had closed completly...not good i thought
Who said honda's are bullet proof
Ouch.
The lack of damage to the combustion chamber points toward something I have seen before. Either the piston was sloppily installed (misdirected driver blow), dropped, or damaged in shipping and installed regardless. The impact deflects the crown down into the upper ring land, slightly stretching the metal across the least well supported area, in this case between the ring land and the valve pocket. It will spring back to nearly it's original position, but this leaves a stress line in the crown. Under ordinary conditions it could last the life of the engine, but bumping it's power by 50%, with the obligatory dyno run of course, promptly puts the damaged piston to a brutal test, and it failed. Damn.
The upside is there is little apparent damage past the piston, and depending on the condition of the bore a fine hone and thorough washing of same is all you would need to do, and frankly if it was mine that's exactly what I would do. If I'm going to find out how well the completely stock motor does when a turbocharger is fitted it must, of course, remain as stock as possible.
Infinitely adjustable, made of the finest materials available, and completely sourced from local suppliers -- gotta support the local economy! Order today and know handlebar Nirvana.
Gotta laugh.
I have in my hand one of life's prizes. A piston out of the 1972 Petersen & Fitz Top Fuel dragster. Herm Petersen gave it to me at the Popular Hot Rod Meet at Kalamazoo US 131 that year. Donovan 417 with Arias Thermodome piston. Like Herm said " we smoked the left bank" . It was a hot stick and shows the very same break out that your piston shows, aside from yours oddly being on the intake side. I'd love to see a side shot of your piston !
The valve pockets are a bit larger on the intake side. Looks like the deepest part of the pocket is right above the back of the ring groove. Looks like probably the weakest spot on the crown.
Could be that was simply the weak link.
I'm sure my advice is just more noise but if I put that kind of money into my 919 and had that kind of failure, I'd be thinkin seriously about some turbo spec pistons and some beefy rods. Might be all you need to make that puppy bulletproof. I'm sure there might be a couple other tweaks to really tie up the details.
CG - good call. Lower static CR and revisit boost setting, proper pistons and proper rods. Cooling system likely needs bigger rad. Spark plug heat range needs to be dropped, as in select colder plug.
Maybe water injection also, for full boost runs. Just like the Germans did with their Ju88 Night Fighters that were assigned to hunt Path Finder Mosquitoes at altitudes above the Ju88s limit. First they tried N02 injection on top of the already forced induction engines, but found they needed water injection to keep them in one piece when in "Ha Ha" mode.
5psi with a good tune should run fine. With only ten miles it had to have been a bad tune or maybe your airbox tweaked the injector manifold causing uneven fuel injection. You had to have heard some pre-ignition before that happened. JE has plans for a 10.5:1 forged piston (I have 4 of them in my bike)
Can you please tell me who/where you ordered your pistons from?
Are they oversize or standard?
I think i will put some forged pistons in while the engine is apart if i can get them.
I'am not to sure of the root cause of the failiure at present but i will try and investigate further once the engine is out the bike and stripped.
There are to many questions for me to answer at this time but i will post some answers later.
Thanks guys.
Maybe water injection also, for full boost runs. Just like the Germans did with their Ju88 Night Fighters that were assigned to hunt Path Finder Mosquitoes at altitudes above the Ju88s limit. First they tried N02 injection on top of the already forced induction engines, but found they needed water injection to keep them in one piece when in "Ha Ha" mode.
i have no idea what you just said young man... but you touched my heart....
Good catch UJM. For sure the piece trapped there was thicker than the squish height at that point. You're bang on calling for a very close look at the rod bearing and crank journal. I assume you meant the big end. I'd be looking at the wrist pin and little end too.
Man this really sucks! Something just didn't sound right to me though when I read the the third and fourth gear wheelies. I'm running about 7lbs and I come no where close to that kind of performance. I've also got over 3000 miles on my motor sense I turbo'd it without a hitch. It sure seems to me that if you're running 140 to 150 hp you'd have to be pumping more than just 5psi?
Ok just to answer a few questions
Ive fired off a few emails and will get the forged pistons from wave.
I have also spoke and sent the pictures to the guy who i got the turbo off, he also set it up on his dyno.
This is the reply i got.......THAT IS DETONATION DAMAGE MOTOR MUST BE SEEING OVER 6lb OF BOOST TO DO THAT
The cnut told me it was set at 6-7lb when i bought it and when it was on his dyno he said its only at about 5lb and i could run more boost.
I didnt have a boost gauge fitted as i was going to fit one when it was all up and running ok.
I was running on super unleaded fuel which is about 98 ron i think.
I will check the rest of the motor when it gets stripped down.
Ah ha! I have a feeling you may have been actually running more like 10lbs of boost. I also wonder what happens if you have maybe a 10 degree drop in temperature after you've tuned it? I think this could cause you to run lean. Maybe I'm wrong but the way you were describing the performance of that thing just sounded more like a 1000cc bike turbo charged or much more boost on a 919, which can happen with a lot more changes like high pressure fuel pump bigger injectors ect.
well, hopefully rebuild #2 will go a little better for ya 
. Hope you figure out what happened.
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