Thread: Need some help guys
07-19-2009, 07:46 PM #1
Need some help guys
This is some pics of my engine that was being broken in this weekend and ate it about the 1 hour mark. I had done 30-40 minutes of 0-1/4 throttle....followed by 1.5 hour cool down then the old 0-1/2 throttle and the ski was mixed at 32:1 with full syn oil. I let it warm up for about 15 minutes before doing the variable throttle etc. I was at the end of this period when it happend as I was riding back to allow the 2nd cool down. Here are the pics. I pressure tested the engine prior to running it. It held 10psi for 1.5 hours before I pulled the plug and installed it. After it did this damage...I checked and it still help 13 psi for 1:20 before I took it apart. It was about 10 gallons of gas ran through it. I checked the carbs...all were completely clean and full of fuel...no creases in check valves etc. It was running 145 psi with fresh 93 octane with the Riva CDI set for MOD 1 Is this just a classic case of snagging a ring or? Another question was this happend before but it was on Cylinder #2. It's possible I switched the VF3's from the #2 to the #3 ...could this be an issue? If the reeds don't close all the way....would this not run lean or will the pulse from the engine push them shut? I'm lost here....trying to find out what happend. Engine mods
85.5 R&D flat top
Riva CDI at MOD 1
TJ ported Cylinders
Dan Lamey ported and expo cases
Again...when this happend I was working the thorttle between 1/4-1/2 ...
07-19-2009, 07:47 PM #2
Look at the wash...this thing was rich ....
07-19-2009, 07:48 PM #3
07-19-2009, 07:57 PM #4
Piston to wall clearance? We use .007 on the 1390s.. Anything less is just as you have there..
07-19-2009, 07:59 PM #5
Ross....the ski was running with
#1 & #2 = 8 thou
#3 = 11 thou
07-19-2009, 08:01 PM #6
The piston on your first post looks more black than the other two below... I would double check the carb that supplies that one.
07-19-2009, 08:02 PM #7
I did...while waiting for the leak down...spotless...and same jetting as others. No creases in valves....nada...looks brand new...all the orfices are free and clear. Pulse line was tight...needles were set even richer then 1 and 2
07-19-2009, 08:10 PM #8
That looks like heat...you did leak down? Carbs ok? Hmmmmm....also check the water lead into the exhaust manifold, sometimes sand can get in there and clogged it up.
Something got her hot real quick.
Call me if you need to buddy.
07-19-2009, 08:24 PM #9
No..these were the R&D pistons
Yes I did the leak down....held 10 psi before 1.5 hours and then after the issue checked and was still air tight for like 1:20
I pulled the manifold apart "exh" and made sure it was clean because I was setting this up for the dual cooling. It had a nice solid pisser the entire time and never felt even close to hot by the water coming out.
I need something.....$1200 down the drain...and I've yet to find out what is causing it. I still wonder if the reeds are not shutting and that's the reason it ate up #2 before this rebuild....? It's possible I put the reeds from 2 into 3....that would make it run lean...
Thoughts on that guys?
07-20-2009, 07:07 AM #10
Timining.... with the Riva CDI do this? I was running 93 and had it set for MOD 1 ...
Limited and MOD 2 call for race fuel
Running 145PSI compression..
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