Metal through an 865

shawn_NJ

shawn_NJ

Chasing waves.
Location
Daytona Beach
Polish jet pilot said:
and the piting on the dome is deto - very light pitting, not as in a random piece of debris would hit and fall out through the exhaust....
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If there was not any damage to the cylinder above one of the transfer ports, going up the side of the piston I would agree 100% with you. Also I never said I do not have some type of DETO issue, just that something else was definetly going on as well. I am also removing my EPIC because this motor has had a few backfires on startup, blown the PV billows off many times, blown a waterbox up, ect. Carbs will be gone through as well.
 
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Flash-FX

Flash-FX

No Square..No Round..FX-1
Location
South Jersey Shore
The detonation that killed a piston on my 865, started around the piston top looking like some sandblasting around the outer edge, by the exhaust port. This piston looks real bad because I rode about 20 minutes on it to get back to the truck. This was the front cylinder.

A53D2048.jpg
 
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Flash-FX

Flash-FX

No Square..No Round..FX-1
Location
South Jersey Shore
Now at the same time, the rear piston got toasted because of the wrist pin bearing going away. The main reason it died was because of RUST. I had a big chunk of base gasket missing and every time I washed down the engine with fresh water, a little leaked into the crankcase....and started the rusting process.
A53D2049.jpg
 
Polish jet pilot

Polish jet pilot

4aces4aces4aces4aces4aces
Location
Warsaw, Poland
the scoring that the OP has could come from water ingestion also... and the pic above this post clearly show mechanical damage caused by a piece of metal, the OP's does not....

About EPIC: they are very good, but you might need to reflash yours and put in new SW - solves all problems with the CDI.
 
shawn_NJ

shawn_NJ

Chasing waves.
Location
Daytona Beach
MYTH BUSTED. Kenny and I tore the motor 100% down today. Crank has (2) bad bearings in it. The rear cylinder bearing cage has a constant TICK,TICK,TICK sound when you spin it. Def a bad spot somewhere on the bearing cage. Also the frontmost bearing on the crank is very noisy. Was a brandnew OEM crank last year, ski was never sunk or water in the motor that I know of. Thanks to everyone who pushed me to completely check the bottomend. New crank, and new topend going in. Gotta get it running asap. Summer is here!


Bobert540 said:
Where did you get one and how much was it? Seems like it would be a good tool to have and a piece of mind to go with it.
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Haven't picked it up yet but I am def getting one once I get the motor back together.
 
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Bobert540

Bobert540

Site Supporter
Location
Rockford,MI
Phew, I am sure you are glad that you saved yourself a few bucks in the long run!

Not trying to bash Xscream at all here but with all these bearing problems I am seeing in the 865 is this just a coincidence or something that could have been avoided?
 
shawn_NJ

shawn_NJ

Chasing waves.
Location
Daytona Beach
Bobert540 said:
Phew, I am sure you are glad that you saved yourself a few bucks in the long run!

Not trying to bash Xscream at all here but with all these bearing problems I am seeing in the 865 is this just a coincidence or something that could have been avoided?
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Most of the problems with the 865's that I heard of, have been with the wrist pin bearings. They were perfect on my motor.
 
Freakrider

Freakrider

X247
Location
Tampa Bay area
Are you going with a new OEM crank again ? Some people don't think they are worth the $600 to $700 investment, but to gamble a good motor with non OEM cranks is another story...just wondering. Yamahasportsplaza has them 30 % off...fyi.
 
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shawn_NJ

shawn_NJ

Chasing waves.
Location
Daytona Beach
Jump On It said:
Are you going with a new OEM crank again ? Some people don't think they are worth the $600 to $700 investment, but to gamble a good motor with non OEM cranks is another story...just wondering. Yamahasportsplaza has them 30 % off...fyi.
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I debated what to do with this....But looks like I'm going to buy another new OEM. I guess +100hours out of a motor that makes close to 2x the power of a stock 701 isnt that bad, but the cost is still tough amount to swallow. Dealer by me is about $100 more then YSP, but that only translates to few bucks more once you add rush shipping from west coast. I gotta get this thing back together ASAP.....Water is warm and weather is in the 80s! Horrible time to be doing a motor rebuild for the short northeast season. I see a spare motor in my future after this disaster.
 
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KTM434

KTM434

Jamie FN Hickey
Location
Palm Coast FL
Boreoscopes are much cheaper then they used to be. I bought one from Mac tools about 6 months ago and it was only like $185 or something. It includes a couple tips too, one that allows you to view straight down through the sparkplug hole and one that has a tiny mirror in the tip and allows you to see the cylinder walls and ports very easily. It's well worth the investment if you hear detonation or some shrapnel through you motor. Obviously you can't see the wristpin bearings on an 865 but you could see signs of bearing debris that passed through if you catch it early enough like Shawn did.
 
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