Super Jet Superjet bogging! Help!

Ryan05

Ryan05

Location
Holland Michigan
Hello again, I've been having very bad luck with my superjet. After the engine gets hot, it starts to bog out after a quarter throttle, it continues to get worse and worse over time. At first it was acting like a carb issue but we rebuilt it and it did the same thing. When we went to check the reeds we found a broken intake manifold gasket, so we replaced it and still no solution. Took out the heat sensor and it did nothing. There is a factory pipe on it and that's the only non stock thing. Had the spark and coils checked and they are fine. The reeds look good also.
We cleaned out all of the pisser and gas lines and there was no blockage, What is going on?! The season is winding down and I want to be able to ride for another month but that won't happen unless I can find a solution


Also, compression went down 30 lbs since the problem started just from riding it to see if we fixed the problem

Anything answer is helpful, thanks
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
Ryan05 said:
Hello again, I've been having very bad luck with my superjet. After the engine gets hot, it starts to bog out after a quarter throttle, it continues to get worse and worse over time. At first it was acting like a carb issue but we rebuilt it and it did the same thing. When we went to check the reeds we found a broken intake manifold gasket, so we replaced it and still no solution. Took out the heat sensor and it did nothing. There is a factory pipe on it and that's the only non stock thing. Had the spark and coils checked and they are fine. The reeds look good also.
We cleaned out all of the pisser and gas lines and there was no blockage, What is going on?! The season is winding down and I want to be able to ride for another month but that won't happen unless I can find a solution


Also, compression went down 30 lbs since the problem started just from riding it to see if we fixed the problem

Anything answer is helpful, thanks
Click to expand...

Stock carbs? What is your jetting? Are you running dual coooking? Any vapor or steam when you splash water on it?
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL

You say correct jetting, but thst doesnt mean anything. Correct jetting was 135 mains with a b-pipe, but i stuck a piston. 4-point lean. I have 140 mains.
 
cookn

cookn

Kamikaze
Location
where you live
Loss of compression usually means rebuild time. My guess would be something is going on in the cylinder. Probably time to pull the head and see whats going on in there and go from there
 
Pro-pulsion

Pro-pulsion

Location
Ontario, Canada
Either a rebuild is in order or a head gasket finally let go. Sudden and sharp compression losses as you say happened pretty well require at least removing the head for further inspection.
 
M

maatthu

Location
Jacksonville, Fl
Hey Ryan. I know I'm late to the party but I was having the exact same problems and symptoms as you and I checked all of the same things. After checking everything I swapped plugs with another ski that was running fine and I had zero issues with my ski. Apparently the spark plugs act differently after they run for a while and get hot.

Also, I am by NO means a genius at this. My cousin basically diagnosed all of the issues for me and found the problem. Your story just sounded eerily familar so I thought I'd share.
 
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