Sorry to see that!
When the crown eats away on the exhaust side like that, its from excessive heat from too lean of jetting, poor fuel, air leak, ignition too far advanced.
In this case[because more then one piston is involved] I would suggest its probably from too lean of jetting combined with todays fuel.
Hopefully you caught it early enough that it has not damaged the cylinders.
What main jets, needle postion, pilots was this sled running?
Gutted Airbox?
Cold air kit?
Ignition advance key?
Heads cut?
Premium fuel?
When the crown eats away on the exhaust side like that, its from excessive heat from too lean of jetting, poor fuel, air leak, ignition too far advanced.
In this case[because more then one piston is involved] I would suggest its probably from too lean of jetting combined with todays fuel.
Hopefully you caught it early enough that it has not damaged the cylinders.
What main jets, needle postion, pilots was this sled running?
Gutted Airbox?
Cold air kit?
Ignition advance key?
Heads cut?
Premium fuel?
donkeypunch
New member
Cylinders look nice and clean, no scratching at all.
Mains/needle/pilot = assuming factory stock. We'd have to look and learn how to tell.
Gutted air box = his air box is just a big black empty box with a small 1/2-3/4" foam on top.
cold air kit = no
Ignition advance key = huh? haha
Heads cut = not that we know of
Premium fuel = always.
One thing is, his sled ALWAYS ran hot. Always. Within a few seconds of sitting on the side of a trail his sled was hot. In low snow conditions it would always run hot. It did a LOT of idling while the temp gauge was flashing or solid.
My buddy is still afraid we did this when the engine flooded, but I'm saying it probably had nothing to do with it other than the engine running like crap and we tore into it after a compression test and found the problems...
Next question is...rebuilding. Must we check the crank or can we get away with a quick top-end rebuild? I see people doing top-ends all the time with no mention of checking the crank. The sled has around 5k'ish miles if I remember correctly.
Mains/needle/pilot = assuming factory stock. We'd have to look and learn how to tell.
Gutted air box = his air box is just a big black empty box with a small 1/2-3/4" foam on top.
cold air kit = no
Ignition advance key = huh? haha
Heads cut = not that we know of
Premium fuel = always.
One thing is, his sled ALWAYS ran hot. Always. Within a few seconds of sitting on the side of a trail his sled was hot. In low snow conditions it would always run hot. It did a LOT of idling while the temp gauge was flashing or solid.
My buddy is still afraid we did this when the engine flooded, but I'm saying it probably had nothing to do with it other than the engine running like crap and we tore into it after a compression test and found the problems...
Next question is...rebuilding. Must we check the crank or can we get away with a quick top-end rebuild? I see people doing top-ends all the time with no mention of checking the crank. The sled has around 5k'ish miles if I remember correctly.
sounds like another gutted air box lean situation....................
donkeypunch
New member
I will go snap a picture of the air box real quick...hold the phone!
if its gutted and u run the stock jetting and its pretty cold i'm sure it was runnnig lean ...............
donkeypunch
New member
Thats what you call a gutted airbox, the top also has extra holes in it as well.
The top of my airbox looks like that, I have the cold air kit, but I run the shelf inside that has the horns in it.
I don't notice any performance difference having the shelf in or out, but it is quieter with the shelf in.
JM.02c
The top of my airbox looks like that, I have the cold air kit, but I run the shelf inside that has the horns in it.
I don't notice any performance difference having the shelf in or out, but it is quieter with the shelf in.
JM.02c
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donkeypunch
New member
What is the cold air kit? There was a funnel that attaches to the side of the air box, but it looked like it served no purpose as it had no inlet into the air box?
Wow those are really large cut outs in that box... I would invest in another stock box.... Was probably running lean,,,, Especially if temp light was coming on,,... Srx does not normally run hot even in low snow conditions...
Bender supplied the Cold Air kit.
It contains an added air intake on the dash right in front of the speedo + tach facing the handle bars + an angled peace of foam that seals to an added cutout in the hood.
That vent on the side of the airbox is stock and directs cold air from an opening in the hood to the brake/chaincase area.
The cold air kit has an effect on your jetting and requires bigger main jets.
It contains an added air intake on the dash right in front of the speedo + tach facing the handle bars + an angled peace of foam that seals to an added cutout in the hood.
That vent on the side of the airbox is stock and directs cold air from an opening in the hood to the brake/chaincase area.
The cold air kit has an effect on your jetting and requires bigger main jets.
donkeypunch
New member
Looking at the power valves, the powervalve on cyl #3 is a little roughed up on the edge. Is that an issue? Need to be replaced?
Is it roughed up... or has it collected some of the melting aluminum off the piston?
In any case if it looks bad or damaged + you can't clean it up... replace it with a good used one or new if you have to.[they are pretty expensive new]
In any case if it looks bad or damaged + you can't clean it up... replace it with a good used one or new if you have to.[they are pretty expensive new]
donkeypunch
New member
It looks like maybe some of the piston melted to it, can't really tell yet. Need to clean it real good and have a look. We are trying to look for powervalves on ebay and haven't found any. Got a line on them?
donkeypunch said:
Maybe YA*MA*HEAD ?
donkeypunch
New member
donkeypunch said:Found a goober inside a cylinder. Verdict?
Either get that fixed[replated], find a good used cylinder, or exchange it at a company like Milennium...to much damage to reuse.
donkeypunch
New member
Sorry I need lamens terms. Replated?
donkeypunch said:
The cylinders are cast alluminum, plated with a nicasil coating[looks like chrome but isn't] There are companies that will strip and replate the cylinders.
Some companies:
-US Chrome[Fondulac Wisconson]
-Milllenium[has an exchange program]
I have experience with both and they do excellent work
donkeypunch
New member
Thanks for that. Hmm... i have a feeling my friend will end up looking for a new head. $150ish sound about right??
donkeypunch
New member
Looking at the powervalve port, there is a pin in one of the ports. Only one cylinder is like this...why?