Thread: Burnt Valve, Need Advice
09-05-2010, 08:58 PM #1
Burnt Valve, Need Advice
Where is the best place to send the head to have it repaired. While trying to tune the Rude controller I was running at 12.3 or so at 8600 but not for very long and dropped a cylinder. Checked compression 30-140-140. Any advice would be apreciated, I know I was lean at WOT causing the problem. Thing was running real rich before hooking up the Rude to pull some fuel, guess I was too agressive with the map, thould have slowly started pulling but elected to start out in the 8000 rpm range setting all cells at 9.5, 7500 at 9.6., 7000 at 9.7, 6500 at 9.8, and 6000 at 9.9. Afrs were 14s at idle, 13.5s through the mids, and 12.3 or so at WOT. I was about add more fuel then bang. Before the Rude I was around 10.2 at wot, couldnt pull enough with the Riva RRFPR, even at 40 psi I was at 10.2., was dumping fuel in the oil. If I unhooked the boost line off the regulator I couldnt increase the static pressure enough to get the fuel required on top end. The Riva 50s will lock up at about 62psi. All this running the 50s, Riva RRFPR, X-Pro Charger, Riva ECU, Rear Air, Rear Exaust and added the Rude Controller. Any advice on the head would be appreciated. Hope all this makes since, its been a long day!!!
09-05-2010, 09:13 PM #2
Some have sent their head to Erik at Speedfreeks and sounds like he does a good job.
09-06-2010, 07:41 PM #3
Worse than I thought, valves look ok, #3 piston gummed up in the cylinder wall. Spent Labor Day tearing it down to the block. Gonna get it machined and bored, will drop it off at the machine shop tomorrow to see where im at, will then order a new set of the Rivas. What all is required to beef up the bottom end other than a set of rods? Prob go with the Riva studs and head gasket. I know I'll need a new set of head, cam, and crank bolts. Hell this far in I guess i'll replace the crank bearings and oil pump. Might as well replace the cam with the Rotax and pop in a set of light weight valves and retainers. Damn, this is fixin to hurt.........
09-06-2010, 09:45 PM #4
Then once you leaned it up the rings went.
I cant see 12.3 being lean enough to cause issues. Sure for long periods of time but not just during tuning.
You got a pic of number 3?
Your bottom end may not be that bad, did your oil pressure ever come on?
As far as parts you named off pretty much what you need, i would replace all bearings while apart.
Your rods may be ok. OEM are fine, unless you want to lighten and balance the crank and counter shaft.
I just rebuilt with the Riva piston's and cant say enough good things about them.
09-07-2010, 07:37 AM #5
Sorry to heard about the trouble. I am betting its the piston ring issue again. Take a picture of the piston for us. I have been using LUCAS upper cylinder lube per Dean from Dean's Team.
The stock bottom end is very strong. Stock crank and rods are fine unless you are planning to get real crazy.
JMO here. I am still running my stock 08 cam with a RIVA valvetrain upgrade and stock valves. There may be some kind of gain using the ROTAX cam, etc., and lightweight valves. I just don't think its worth the money for a rec rider.
09-07-2010, 02:13 PM #6
09-07-2010, 02:25 PM #7
Lucas upper cylinder lubricant. Been using it myself. It's in a clear container and most places have it including wal mart.
09-07-2010, 02:48 PM #8
Never lost oil pressure Skoepp, when I lost the cylinder and was still dazed and trying to figure out WTF I did get a check engine alert and beep. Had just changed the oil before going out again. Prob only ran one full tank with it being rich but noticed about a half qt. increase in oil so I changed it. What I started out doing that morning was running the ski at idle and checking the AFRs while stopping each time to write it down, checked at say 2500, stopped and wrote it down, then 3000, 3500, 4000, and so on until I reached 8000. Then I tried the WOT at around 8620 (higher than I wanted) and ran maybe 5 seconds or so then bang, she went....
Looked at #1 and #2 and was able to see a slight, slight, slight bit of scaring. Could still see 99.9 % of the honeing marks still in the sleeves. #3 was gummed up on the intake side as the piston melted ever so slightly and stuck to the walls as it was being smeared up and down the sleeve. The valves and head even had piston spatter stuck and plastered to them. The spark plug had molten piston stuck between the electrods. I need to get this sorted out before I try to run this thing again. I did notice an oily gunk laying in the IC and tubing between the IC and TB, was defenitely oil and water (milky looking). Just had the charger completely rebuilt and upgraded by Jerry. Am still runnng the stock IC, no salt water, 100 hrs runtime. Impeller in the charger looked new so I dont think I've injested water through the rear air.
A person would think that if they bought the Riva ECU, Riva 50s, Valvetrain Upgrade, Pro Series Charger upgrade things would be great as recommended by Riva. Well I can tell you that if you do you'll sure as hell be lean at WOT. Add a Walbro and a RIva RRFPR set to run without the reference line attached and you can't increase the fuel pressure above 62psi without the injectors locking up. Hook up the reference line and you cant decrease the pressure low enough to lean it down at WOT. Only option is the Rude to pull fuel with the RRFPR reference line installed. Mess around and pull to much as I did while trying to figure out how to build the mapps and boom!!! Hell, is there anyone out there that has a decent map for this setup?
09-07-2010, 02:48 PM #9
09-07-2010, 02:55 PM #10
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