BruceSki
Formerly Motoman25
- Location
- Long Island
So I didn't even ask. How did the wrist pin bearings look? How about the surface of the rods where the bearing rides?
Metal through an 865
- Thread starter shawn_NJ
- Start date
All I'm saying is either water or a super rich condition is gonna wash the piston an domes. I'm by no means saying that's what happened, just a hunch. Water will instantly knock all carbon off a piston/dome. And those look awfully clean. The detonation signs is what throws a wrench into the mix. Good catch on finding it early tho.
Thrust washers still intact on the crank?
Thrust washers still intact on the crank?
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- Location
- New Jersey 732
Both wrist pin's looked perfect, wrist pin bearing on the front cylinder ( not the one that has pitting ) had a little evidence of what looked to be surface rust on the outer edge of the cage. I checked each needle in the bearings for pitting etc and found nothing. As for the inside of the rods where the wrist pins ride they looked perfect also not a hint of moisture, rust or wear. ( All checked with magnifying glass not the naked eye )
BruceSki
Formerly Motoman25
- Location
- Long Island
Nice. Made out better than I did. That's for sure. I think I had more hours on mine than I estimated. I do a lot of wot too.
- Location
- New Jersey 732
Completely agree with you, just wanted to verify that water leak was ruled out. Minus the pitting on the piston and dome this motor looks like it was put together last week. The cross hatch in the cylinder is still perfect, and there is virtually no wear on either piston skirts.
Thrust washers are still intact, Lower rod bearings do not have excessive play and look great, no signs of heat on them either.
- Location
- Colorado
if you can't find any thing i'm saying a little air leak on the back cylinder lean it out causing deto but running rich to over compensate on the low end, so it's not letting it to build up carbon, but on the the top end it leaning out so bad to deto leaving the scare due to the piston heating up under a lean condition and then the pin holes on the top of the piston and head, lean is hot and rich is cool. if any other engine builders have any thing else chime in, thats what i think, or i know.
Superjetjim
X-
I'd say the qty of carbon on your pistons is also down to the oil your running..
If it were my engine I'd be tearing it right down to find the source of that peice of debris - could be a read cage part, crank shell, epoxy, carb butterfly screw etc etc - either way it shouldn't be there and could be a sign of worse to come.
Just my opinion..
If it were my engine I'd be tearing it right down to find the source of that peice of debris - could be a read cage part, crank shell, epoxy, carb butterfly screw etc etc - either way it shouldn't be there and could be a sign of worse to come.
Just my opinion..
I dont think that is caused by debris . Looks like deto .
Freakrider
X247
- Location
- Tampa Bay area
running one screen allows it to vibrate and possibly come apart...IMO run no screens, I do...
- Location
- Cruising Around
Kind of a stretch here, but any chance of air getting to that carb under wot or high rpm brapps? Been known to happen, and cause scoring along with detonation.
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
Its not from DETO, the smash marks matched up on the on dome, and you can follow the path it took out the transfer port, up the cylinder, and sid eof piston. Only mark on the piston or cylinder. We checked everything over as good as possible, then cleaned the piston and dome up. Reassembled everything, and I will be water testing this weekend. Going to keep the WOT blasts to a minimum this season, incase the piston marks cause DETO down the road. Motor will be getting complete overhaul after daytona this year. New OEM crank, topend, ect.
Also going to bore scope it after a ride and make sure no new marks appear. Running 3 screens in the FA now.
Also going to bore scope it after a ride and make sure no new marks appear. Running 3 screens in the FA now.
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BruceSki
Formerly Motoman25
- Location
- Long Island
You may notice a difference in throttle response with 3 screens. I tried this at the beginning of this season before I toasted my motor.
Went from open style F/A (Prok) to two OEM 61X guys. It didn't run right until I pulled two screens out of it. Three screens is pretty restrictive compared to the open F/A or one screen and changes the carb signal. It dumps loads more fuel due to the low popoff pressure those carbs are set at.
Give it a shot though, but i have a feeling its not going to respond as well as it used to. W
Went from open style F/A (Prok) to two OEM 61X guys. It didn't run right until I pulled two screens out of it. Three screens is pretty restrictive compared to the open F/A or one screen and changes the carb signal. It dumps loads more fuel due to the low popoff pressure those carbs are set at.
Give it a shot though, but i have a feeling its not going to respond as well as it used to. W
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
Thanks for the info. I was expecting it to hurt response some, but if there is a chance it can stop something from going through the motor I'll give it a try. If it totally sucks will have to reevaluate.
BruceSki
Formerly Motoman25
- Location
- Long Island
you may need to adjust the carbs slightly. I went the easy way and went down to 1 screen. Although now I'm thinking about no screens.
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
I had been running one before this.
BruceSki
Formerly Motoman25
- Location
- Long Island
I know, just saying 3 screens might make it load up and feel blubbery. Thats what happened to mine when I tried 3. Ran great when I dropped back to 1.
Sorry if I was unclear in the earlier posts.
Let me know how it works out for ya.
Sorry if I was unclear in the earlier posts.
Let me know how it works out for ya.
shawn_NJ
Chasing waves.
- Location
- Daytona Beach
Didnt know if I posted it in this thread. Def appreciate the feedback being you tried it out already. Also thinking of shop vacing the inside of the hull after every ride...lol
You'd need to raise the popoff.
BruceSki
Formerly Motoman25
- Location
- Long Island
I concur. However it was easier to pull two screens for me.