Running out on the lake yesterday, ran about 30 miles on 9lbs no problem, racing got started, switched to 12 lbs, and after 4-5 runs the sled started pushing oil out the breather and smoking out the exhaust.
This was on 93 octane pump fuel with 135 mains, 2 head gaskets. My first thought obviously was detonation, but when I pulled it down this morning only 1 cylinder was damaged, I thought detonation from too low of octane would have showed up in every cylinder, but there is no obvious visible damage to the other three pistons/cylinders. Three plugs were cardboard brown except for the cylinder that went down was pretty white and the ground strap was green (coolant?). The ground strap on #1 cylinder spark plug was also slightly green.
The third picture is of cyl #1, in the pic I know it looks damaged but it is very hard to see anything wrong with it in person other than maybe it is slightly cleaner on the intake edge than the others.
So what do you guys think, just too low of octane or maybe an air leak? The sled was runnin sweet, no popping or overheating they say. I wasn't riding it at the time so I can't say for sure.
Also, whats the best route gonna be to fix this thing, you can see from the pictures that there is monster chunk taken out of #2 cylinder. New block, or is it cheaper to find a used motor and start over? Any way to have this one repaired?
Any advice or opinions at this point are welcome, or if you have a lead on any parts please let me know.
This was on 93 octane pump fuel with 135 mains, 2 head gaskets. My first thought obviously was detonation, but when I pulled it down this morning only 1 cylinder was damaged, I thought detonation from too low of octane would have showed up in every cylinder, but there is no obvious visible damage to the other three pistons/cylinders. Three plugs were cardboard brown except for the cylinder that went down was pretty white and the ground strap was green (coolant?). The ground strap on #1 cylinder spark plug was also slightly green.
The third picture is of cyl #1, in the pic I know it looks damaged but it is very hard to see anything wrong with it in person other than maybe it is slightly cleaner on the intake edge than the others.
So what do you guys think, just too low of octane or maybe an air leak? The sled was runnin sweet, no popping or overheating they say. I wasn't riding it at the time so I can't say for sure.
Also, whats the best route gonna be to fix this thing, you can see from the pictures that there is monster chunk taken out of #2 cylinder. New block, or is it cheaper to find a used motor and start over? Any way to have this one repaired?
Any advice or opinions at this point are welcome, or if you have a lead on any parts please let me know.
peteracing
Expert
DETO!!!!!!!!!!!!!!!!!!. Is that carb. clean? blocked jets?...
If it ran lean on only one cyl... Investigate carburation...
If it ran lean on only one cyl... Investigate carburation...
givemeaboost
TY 4 Stroke Junkie
- Joined
- Dec 5, 2003
- Messages
- 689
- Location
- Great Falls, MT.
- Country
- USA
- Snowmobile
- 03 Rx1 Turbo
- LOCATION
- Great Falls,MT
I'd say it's from detonation and from the looks of that other piston it was about ready to go too. When mine went it only took one piston and was hardly noticeable except for one little spot on the intake side. When I tore it down I found that it got just hot enough to let the ring land expand and when the ring started rocking it screwed up the cylinder at the top of the stroke but not near as bad as what you have. I ran mine on pump gas at 8000 ft and had problems so you guys at 1000 ft better run a little better fuel or there's going to be a shortage of good used rx1 engines, Ken.
I would say find a new block or used engine to start.
Too low of octane for the boost you were running. Since you now have to rebuild put in LC pistons.
Man that sucks!! How long do you think they were wide open?? What turbo you running? Man i would look close at that carb. Looks like that cyl was leaner than the rest.
Skydog
Skydog
Where did you get the gas from?? Mobil??
I would say they were running about 800 ft. Gas was from a Marathon station.
I agree that the cyl looked lean. No obvious problems with the carb yet. Jets weren't clogged, everything seems to still be sealed up but I will investigate it closer tommorrow.
I agree that the cyl looked lean. No obvious problems with the carb yet. Jets weren't clogged, everything seems to still be sealed up but I will investigate it closer tommorrow.
Its pretty common to have a catastrophic failure of 1 cyl while the others look good
There are many reasons
1 being manufacturing tolerances on everything from the carb to the header
2 being once detonation starts it does not want to stop, that damage happened in a matter of seconds not minutes
What I hear is 10lbs with 3 head gaskets on pump gas so I think you were running too much boost
There are many reasons
1 being manufacturing tolerances on everything from the carb to the header
2 being once detonation starts it does not want to stop, that damage happened in a matter of seconds not minutes
What I hear is 10lbs with 3 head gaskets on pump gas so I think you were running too much boost
Man i have run 12psi for 1,200 miles with 2 gaskets on pump.
Why is that plug white? And the other 3 right on? I feel you where lean on that cyl and the intercooler was heat soaked fuel was a little weak and then detonation took over. What kind of load you put on the motor? What RPM you spinning at?
Skydog
Why is that plug white? And the other 3 right on? I feel you where lean on that cyl and the intercooler was heat soaked fuel was a little weak and then detonation took over. What kind of load you put on the motor? What RPM you spinning at?
Skydog
No Sighs of detonation on any of the plugs? Is your boost gage right on? What brand? Where are you reading boost from? I was reading back a week or so you where going to turn up the boost to like 13psi? You think you where closer to 13-14 than 12?
Skydog
Skydog
- Joined
- Apr 17, 2003
- Messages
- 5,366
- Location
- Menno, SD
- Website
- www.ulmerracing.com
- Country
- USA
- Snowmobile
- 2014 Yamaha SR Viper LTX, 2014 Yamaha SR Viper RTX SE, 2015 Yamaha SR Viper MTX SE 162 (turbo), 2015 Yamaha SR Viper MTX SE 153
- LOCATION
- Menno, SD
- WEBSITE
- www.ulmerracing.com
Call Millenium Technologies, they can fix that cylinder and have it as good as new. You're probably looking at around $800 for a cost to fix just the block though.
Turbomania
Veteran
Man, sorry to hear the bad news.
Was it Houghton Lake and were you running in front of the Best Western????
Was it Houghton Lake and were you running in front of the Best Western????
Mountaintech
TY 4 Stroke God
Am I right in guessing that you're running a front mount??
