So this off season, I had my cylinders ported and I reassembled everything myself with new gaskets from jetmaniac. It passed a 10 psi leak down test by a mile. After 45 minutes it didn't drop at all, and that was with a season old(6 gallons of oil through it last year) rebuilt motor. I installed the carb with two new greased gaskets and made sure those nuts were plenty tight since I couldn't leak down test that.
My setup is an ada girdled head with 35 cc domes, b pipe, 44mm carb and all of the other necessary mods. I wound up starting with 150 main, 125 pilot with a 95 g spring and 1.5 n/s. I was spot on with the jetting and at 1.5 turns out on each it ripped from bottom to top, no hesitations or bogs. I probably could have leaned it out some,but I was satisfied.
Took it out for about an hour and a half with a couple very very short WOT passes(going 2\3 throttle for like 15 seconds, and full throttle for like 3) and it was perfectly fine. Only thing I noticed is that I made my coupler too long for my internal fill setup and if I had the nose up, a half of tank would suck a little bit of air after a trick. But on plane I could go for a while yet. After that good ride I torqued the girdle nuts to 32 ft pounds(they didn't loosen up at all, so it was pretty much just checking the torque). I left the head bolts as is with the stock torque specs and blue loctite.
So Friday I had it at the dell's Freeride and probably put close to a tank on it. A couple people rode it and can verify that it rips hard for a square. Did plenty of 3/4 runs at least 10 seconds long with short bursts of WOT too. Everything was great.
Saturday we took a little longer cruise around, and I would be varying it from 1/2 to 2/3 throttle for a few minutes with a few short WOT bursts every now and then. Otherwise I rode it as normal and at least 4 other people were riding my ski and it was perfectly fine. And before I knew it I noticed it running low on fuel again.
On the way back I was varying from 1/2 to 2/3-3/4 throttle with not many WOT bursts for a few minutes to get back to the shore a couple miles away. It was a little choppy and I didn't notice my fuel pickup sucking air at all. Then all of a sudden I went to give it more gas and it kinda hesitated and then died, then was a pain to start back up, then did the same thing.
It started up and was fine, and I rode it probably another mile or so and it still has a decent amount of power, but it was somewhat hard to tell due to the chop.
Right away I thought it was my fuel pickup not being long enough and maybe it was running low on fuel, but the pickup still went into the fuel a couple inches. Put my hand on the rear cylinder and I couldn't hold it for longer than 5 seconds without my hand hurting, and my front cylinder was nice and warm and I could put my hand on it all day. I'm also running dual cooling with two lines going into the exhaust mani so lack of cooling was ruled out.
Pulled the plugs, and one was extremely dark and the other one was very lightly colored. The light colored one is the rear cylinder.
Turns out Zack at PHP was walking right by and I showed him my plugs and he was like "you're running a single carb so there's no way your carb is what's causing you to be that lean. There's definitely an air leak going on".
Checked the compression, 185 on the front and 25 on the rear. Still had a whole day of the Freeride to ride and my ski was toast. Damn.
Pulled the head, and there was a decent amount of metal transfer but not really any deep scores. Only one mark that was semi deep. If I can clean that aluminum off I most likely can get away with just a hone, piston, and rings. Also, the oil on the rear cylinder dome was really concentrated and thick(probably because it wasn't getting fully ignited) , while the other some seemed normal to me.
I know that was long but I feel like the details always help. If anything what I'm about to type is what matters:
Since I was back at home, I decided to put the head back on, get it running, and see if I could spray some carb cleaner or starting fluid at the rear crank seals, base gasket, and carb gaskets to check for leaks. Nope, with the ski running nothing leaked enough for spraying fluid to make it Rev up.
Hooked up my leak down test setup, and it held 10 psi with zero change after 15 minutes. So a leak was completely ruled out.
Took the cylinder off, and my piston looks like so :
Completely stuck a ring Haha.
Anyways, the only thing I noticed was that the gasket surface on the front of the cases was perfectly clean and the gasket surface on the rear of the cases was oily.
(ignore the wierd look of the piston, it actually looks perfect in person. No deto, no nothing. I'm extremely cautious and run 1.5 gallons or race gas with 3.5 gallons of premium and 45:1 klotz.
Also, the base gasket looks like so:
Left side is the rear piston.
To me, it looks like the only possibility was that base gasket leaking. But what confuses the hell out of me is that it never leaked during tuning and it has ran great and no runaways, no nothing. And it's always passed a leak down test.
Honestly there's only one way I could be at fault, and that's if it was due to improper torqueing the girdle bolts. I went to retorque them after the first tank and they all pretty much stayed the same, so for two more tanks I didn't retorque them again. But when I went to take the cylinders off the girdle nuts were still super tight. I have a hard time believing they came loose and caused a leak..
But when I got it running again today, I reinstalled and retorque every head bolt and girdle nut.
I'm so confused. There were no tell tale signs at all. Is it possible for that base gasket to only leak when it's running? Or something else to leak only when running? The only difference this season was that last season I was running an OEM base gasket and this season I was using a gasket from jetmaniac(so I doubt the gasket is the issue.)
Everything in this post is pretty much every detail about the situation that I can think of. I'm lost right now. Any insight is appreciated!
My setup is an ada girdled head with 35 cc domes, b pipe, 44mm carb and all of the other necessary mods. I wound up starting with 150 main, 125 pilot with a 95 g spring and 1.5 n/s. I was spot on with the jetting and at 1.5 turns out on each it ripped from bottom to top, no hesitations or bogs. I probably could have leaned it out some,but I was satisfied.
Took it out for about an hour and a half with a couple very very short WOT passes(going 2\3 throttle for like 15 seconds, and full throttle for like 3) and it was perfectly fine. Only thing I noticed is that I made my coupler too long for my internal fill setup and if I had the nose up, a half of tank would suck a little bit of air after a trick. But on plane I could go for a while yet. After that good ride I torqued the girdle nuts to 32 ft pounds(they didn't loosen up at all, so it was pretty much just checking the torque). I left the head bolts as is with the stock torque specs and blue loctite.
So Friday I had it at the dell's Freeride and probably put close to a tank on it. A couple people rode it and can verify that it rips hard for a square. Did plenty of 3/4 runs at least 10 seconds long with short bursts of WOT too. Everything was great.
Saturday we took a little longer cruise around, and I would be varying it from 1/2 to 2/3 throttle for a few minutes with a few short WOT bursts every now and then. Otherwise I rode it as normal and at least 4 other people were riding my ski and it was perfectly fine. And before I knew it I noticed it running low on fuel again.
On the way back I was varying from 1/2 to 2/3-3/4 throttle with not many WOT bursts for a few minutes to get back to the shore a couple miles away. It was a little choppy and I didn't notice my fuel pickup sucking air at all. Then all of a sudden I went to give it more gas and it kinda hesitated and then died, then was a pain to start back up, then did the same thing.
It started up and was fine, and I rode it probably another mile or so and it still has a decent amount of power, but it was somewhat hard to tell due to the chop.
Right away I thought it was my fuel pickup not being long enough and maybe it was running low on fuel, but the pickup still went into the fuel a couple inches. Put my hand on the rear cylinder and I couldn't hold it for longer than 5 seconds without my hand hurting, and my front cylinder was nice and warm and I could put my hand on it all day. I'm also running dual cooling with two lines going into the exhaust mani so lack of cooling was ruled out.
Pulled the plugs, and one was extremely dark and the other one was very lightly colored. The light colored one is the rear cylinder.
Turns out Zack at PHP was walking right by and I showed him my plugs and he was like "you're running a single carb so there's no way your carb is what's causing you to be that lean. There's definitely an air leak going on".
Checked the compression, 185 on the front and 25 on the rear. Still had a whole day of the Freeride to ride and my ski was toast. Damn.
Pulled the head, and there was a decent amount of metal transfer but not really any deep scores. Only one mark that was semi deep. If I can clean that aluminum off I most likely can get away with just a hone, piston, and rings. Also, the oil on the rear cylinder dome was really concentrated and thick(probably because it wasn't getting fully ignited) , while the other some seemed normal to me.
I know that was long but I feel like the details always help. If anything what I'm about to type is what matters:
Since I was back at home, I decided to put the head back on, get it running, and see if I could spray some carb cleaner or starting fluid at the rear crank seals, base gasket, and carb gaskets to check for leaks. Nope, with the ski running nothing leaked enough for spraying fluid to make it Rev up.
Hooked up my leak down test setup, and it held 10 psi with zero change after 15 minutes. So a leak was completely ruled out.
Took the cylinder off, and my piston looks like so :
Anyways, the only thing I noticed was that the gasket surface on the front of the cases was perfectly clean and the gasket surface on the rear of the cases was oily.
Also, the base gasket looks like so:
Left side is the rear piston.
To me, it looks like the only possibility was that base gasket leaking. But what confuses the hell out of me is that it never leaked during tuning and it has ran great and no runaways, no nothing. And it's always passed a leak down test.
Honestly there's only one way I could be at fault, and that's if it was due to improper torqueing the girdle bolts. I went to retorque them after the first tank and they all pretty much stayed the same, so for two more tanks I didn't retorque them again. But when I went to take the cylinders off the girdle nuts were still super tight. I have a hard time believing they came loose and caused a leak..
But when I got it running again today, I reinstalled and retorque every head bolt and girdle nut.
I'm so confused. There were no tell tale signs at all. Is it possible for that base gasket to only leak when it's running? Or something else to leak only when running? The only difference this season was that last season I was running an OEM base gasket and this season I was using a gasket from jetmaniac(so I doubt the gasket is the issue.)
Everything in this post is pretty much every detail about the situation that I can think of. I'm lost right now. Any insight is appreciated!
