Yeah I looked at that and was surprised by my popoff pressure when I checked it... And the gauge I'm using is accurate. It's possible for a spring to be off spec tho, isn't it?
This melt down just might have me stumped..
- Thread starter Roseand
- Start date
SXIPro
JM781 Big Bore
- Location
- Here on the 'X' mostly
A static leak test typically will not catch an air leak caused by a bad primer or a primer that is plumbed wrong. I was bitten by that issue a few years ago.
primer should be above the butterfly, and have no effect on the airflow into the carb.
edit: i think i get you were referring to air in the fuel line?
- Location
- Charlotte NC
very possible for the spring to be out of spec. When i sit down to do pop off i take a handful of springs cause it may take quite a few different ones before the correct pop off is achieved.
x2 no race gas needed. It will run worse with race gas if not needed for the timing and compression.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
Too many people believe that race gas can be used as a performance gain or used for "extra" protection....... Not always so.
Mark44
Katie's Boss
- Location
- 100% one place
But race gas and the back flip sponge now that is a recipe for some cool riding.
I ran straight 93 and then switched to 20% race gas, and I noticed zero difference in power. I've been told countless times that running at high speeds with premium gas is risky since the quality of it is never consistent. I talked to zack alot about this a while back, and he did tell me that running a little bit of race gas won't hurt anything. I'm running usually a 20% blend and have for over a season and haven't had any issues.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
at that mix, you are most likely ok. Race gas takes more heat to get it to fire off. that is why if you do not have the timing or compression for it, then you are actually hurting your performance. I have ran 35cc domes with 92/93 octane for years with no issues. Your porting is based around freestyle. Not racing. You would be fine with straight pump gas. Years ago on RIVA's site you could order cylinders with porting. They gave you 2 options. Pump Gas or Race Gas. The race gas ones showed the compression setup actually in the 170 range on one option. But with a note stating that you had to run 105+ octane.. Its all about the port timing.
SXIPro
JM781 Big Bore
- Location
- Here on the 'X' mostly
never seen that!
Ada heads need a lot of water because they dont use a gasket with flow control holes. All single carbs will have a hot and cold cylinder, tune the hot one. I went through this many years ago until I learned to start way too rich and slowly lean to a hesitation after a tank of run time, depending on starting piston clearance. I would start with a 170 and 2 turns using a stock F/A. AM F/As may need a larger main. Never hold 60-90% throttle, if you are going to cruise on the pipe keep it pinned.
looking back at that piston wash on the rear cylinder, it honestly just looks like a lean lock up. if your varying throttle style of riding leaves that kind of a mark, a WOT run will for sure sieze it. Explains the leak down test, the awesome power gains you saw and why it only lasted one ride. I bet it started transferring metal the first day. when you rebuild it start real rich, work your way down. 150m 125p with 1.5 turns out on both means you could have gone up in jetting. You probably rode right on the cusp of power/sieze, and the area that sees the least oil in the air was the first to go. And correct me if im wrong, cause its been a long day of coding, but a burnt plug means its also lean, and the white plug would have been from getting washed off riding it back while its not running on that cylinder. (race fuel is almost better than acetone)
Id rebuild, up the jetting on both by at least 10 and tune from there, cause i bet 150 wasnt enough.
Id rebuild, up the jetting on both by at least 10 and tune from there, cause i bet 150 wasnt enough.
That makes me positive that the white plug was the rear. It happened over a mile away from shore(was still running it for a few minutes after it cut out and apparently dropped a cylinder) and I still was on plane the whole way back, so that would have given my plug time to get washed clean and my other plug to darken up. It's starting to make more sense as just a lean condition but you can't judge it by the front plug since I ran it for a few minutes after the siezure.
BruceSki
Formerly Motoman25
- Location
- Long Island
Just to add to the octane posts here.
I run an 82mm 61x cylinder with 33cc Ada girdled head. Stock porting.
I will hold my motor wide open as long as my body will let me with no issues. It's all about the jetting. A large/cool fuel charge will keep the heat away from grenading a piston.
I run an 82mm 61x cylinder with 33cc Ada girdled head. Stock porting.
I will hold my motor wide open as long as my body will let me with no issues. It's all about the jetting. A large/cool fuel charge will keep the heat away from grenading a piston.
If you think your plugs got washed clean, take the dark one and see how clean you can get it in acetone and a tooth/wire brush and then think if it's possible to clean a plug that well inside of the motor when the walls and head were covered with that gray oil residue
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Blasting it with metal bits will clean it pretty well.
Regardless the rear cylinder was lean, especially where it locked the ring. Fatten up your jetting and try again!
