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Well figured I WOULD SHARE MY MISTAKE WITH OTHER RIDERS. I have a 98 GSXR 750 with a power commander back in the day it was actually putting out 192HP to rear wheel. Well as of lately it had alot of power loss so in my wisdom i decided to do a compression test! What I found out i was running about 70-75 pounds of compression on cylinders 2-4 and on #1 85 pounds, so i decided to do rings after waiting a long two weeks due to being special order cause of my bike being so old they arrived. The tear down went good along with re-assembly. Pistons looked good and the head no leaks did few test turns to make sure rings seated before head placement and then the start. Wow i got power back she piced up front wheel by power instead of clutch up
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all was going well then the death knock happened. To make it quick and short i blew apart @2 piston to a million pieces and the connecting rod went threw the front wall and the remainder pieces traveled to #1 and punched the head and snapped the jug walls. Lesson learned as old as my bike is if your gonna do the rings do the pistons and connecting rod shafts with new clips. In short if you have the original pistons upgrade those with the rigs she couldn't handle the new compression on old pistons. SEE PICTURES ATTACHED!!!
 

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Discussion Starter #3
10 psi difference?? That could've been from the measuring instrument.

If I were you I'd leave it alone.
the rings were over 10 mil out of spec beyond the normal spec parameters. I should have had at least 150 per cylinder.
 

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Oooof. That should be labelled NSFW for those of us that don't like excessive gore.
I am waiting on my new engine now going to put a 99 in her and port and polish head with new pistons and rings. Also going with steal valves instead of titanium.
 

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Discussion Starter #7
I have been restoring her I got her with 5000 on the odometer now she at 57000 but that also due to my gearing. Plus the guy I sold her to wrecked a week after having her then got bike impounded and I got her back now just trying to make her pretty again.
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OK, either there's something else that we don't know, or I'm calling Total BS on many things in this post.

Sorry you blew your engine.

First off- 192RWHP from a '98 750? Do you work for Yoshimura? Is this/was this a full on race bike motor at one time?
I quick search had the best RWHP with light mods @ 128RWHP. They were usually under 120RWHP though.

Second, you're thinking you shattered a piston, because you put new rings on it?
Then I would have blown up many motors in my day.

Something was wrong with it, you fixed it you thought, now it blew up.

Welcome to the 'R'
 

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Discussion Starter #9
OK, either there's something else that we don't know, or I'm calling Total BS on many things in this post.

Sorry you blew your engine.

First off- 192RWHP from a '98 750? Do you work for Yoshimura? Is this/was this a full on race bike motor at one time?
I quick search had the best RWHP with light mods @ 128RWHP. They were usually under 120RWHP though.

Second, you're thinking you shattered a piston, because you put new rings on it?
Then I would have blown up many motors in my day.

Something was wrong with it, you fixed it you thought, now it blew up.

Welcome to the 'R'
Yes on sumo it put out 192 and yes is a track bike made street legal again with the power commander wide open no rev limit. And the pistons were the factory original and were cracked I did not notice until I pulled it back down and looked closer also I had all the work done by j Jeremy toye at Lee’s cycle in San Diego ca. Who if you look up has raced the isle of Mann along with numerous other events.
 

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OK, a 750 with over 200HP at the crank. OK
 

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Is that with pump gas or race gas?

My 04 750 only puts out a measly 133 hp at the wheel.

A BMW 1000 rr only puts out ~190 hp at the wheels.
 

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Discussion Starter #12
With a race fuel blend thank god or it did when we set it up we went threw two rear tires brand new on the Dyno running it out. In total on dyne and running alone cost me over $3500.
 

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Discussion Starter #13
OK, a 750 with over 200HP at the crank. OK
Did I say 200 no so take your sarcasm somewhere else cause I’m the one that had to pay for all the parts mods and running along with Dyno runs to make it pull 192 with documented print out from a maintained synopsis machine with all current certificates.
 

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Hmmm. Strange story.

My guess is that the engine was over revved big time and the valve head(s) failed due to floating and piston contact. A failed piston does not break off valve heads like that..

As far as the damage on #1, the pieces from #2 can't "travel to" it. Not possible. Again, it looks like valve head failure.

And 192 hp at the real wheel out of a 750? Interesting. I know BMW was able to get over 1000hp out of a 1.5L engine for their F1 cars but it was heavily boosted.
 

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Did I say 200 no so take your sarcasm somewhere else cause I’m the one that had to pay for all the parts mods and running along with Dyno runs to make it pull 192 with documented print out from a maintained synopsis machine with all current certificates.
Mr. Spyzel,

Hello? 192 at the REAR wheel, is definitely over 200 at the crank! You have heard of parasitic losses, etc.?
You didn't say that, I did.
I posted my last dyno run, of a basically stock motor.
Could you please upload yours? With the $3500 dyno tune? I'm glad you have money like that.
My last dyno- no tuning involved- was $59.
 

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Yeah. I can't buy that either. $3500 into a 750, even WELL spent isn't going to get you that many ponies. Ported, polished with over sized valves on stock displacement, will barely give you 150 at the crank. Those are impossible numbers without boost or spray. And even with that it's hard to believe. It is, however, easy to believe you did that to a stock engine trying to SPRAY your way to 190+ HP. In fact I have seen it. Just never saw a piston completely disintegrate like that. I have built a lot of engines. Learned many things the hard (and expensive) way. This engine did not blow for the reasons you think it did, or doing what you thought you were, LOL. You came to the wrong place to try and spread THAT kind of bullshit...
 
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