1996 GTX Top End Rebuild

[ahm2kewl]

First time doing this. Been building engines for bikes and cars for decades. It was running great then all of a sudden it wouldn’t start after I stopped the engine. Front piston is at 150 psi and rear is at 60 psi.
Ordered the WSM platinum top end kit and a sleeve. Will see how this goes after I get all of the parts and get that rear cylinder bored out after I install the new sleeve.
Any good advices are always welcome.
Here are some pics.

 

[POPPS]

Do you need a new sleeve?..the 800 sleeves can be rebored to .75mm over.

 

[ahm2kewl]

Yeah. Definitely need a new sleeve. Thought about that at first but decided to get a new sleeve. I’m just getting it bored out to stock 82mm. Pulled one sleeve out already by putting it in the oven at 425 degrees.

 

[GGuillot]

I wouldn't rush with it, dig a little deeper and see if you can figure the 'why' part, otherwise you'll be doing it again. I'd double check the oil pump and the carbs, something caused it is all I'm saying.

I'm faced with the same situation on my 96' GSX, a few weeks ago I lost power dropping the rear PTO cylinder, thought it was a fouled plug at first, 60 psi on it when I got home. Right now I'm thinking I didn't have the fuel on all the way. I removed the seat at the launch and bumped the selector knob putting it back on. I lost the little rubber center cap when left the idle zone and didn't think much about it, 20 minutes later I had a power loss problem and noted the fuel wasn't all the way on. It was too late.

I'm actually sending off for one cylinder resleeve/bore since my MAG piston/cylinder appears to be fine, but I had them both at std 82mm bore with WISECO pistons. It's either that or have both overbored, but that would require a new set of pistons.

 

[ahm2kewl]

Thanks for the advice. I bought this Jetski used for $600. Compression on the rear cylinder was around 125 psi. I had to rebuild the jet pump, the carbs and the carbon ring and boot. Also replaced the rectifier.
I should’ve known when I cleaned out the rave valve that it was on it’s last leg.
just got my new sleeve and piston rebuild kit. I will start working on it tomorrow and the weekend so I can take it out to the lake next week.

 

[Lothsahn]

I wouldn't rush with it, dig a little deeper and see if you can figure the 'why' part, otherwise you'll be doing it again. I'd double check the oil pump and the carbs, something caused it is all I'm saying.

I'm faced with the same situation on my 96' GSX, a few weeks ago I lost power dropping the rear PTO cylinder, thought it was a fouled plug at first, 60 psi on it when I got home. Right now I'm thinking I didn't have the fuel on all the way. I removed the seat at the launch and bumped the selector knob putting it back on. I lost the little rubber center cap when left the idle zone and didn't think much about it, 20 minutes later I had a power loss problem and noted the fuel wasn't all the way on. It was too late.

I'm actually sending off for one cylinder resleeve/bore since my MAG piston/cylinder appears to be fine, but I had them both at std 82mm bore with WISECO pistons. It's either that or have both overbored, but that would require a new set of pistons.

Wait, so if there's a restriction in fuel flow through the valve, it'll cause the engine to run lean and destroy itself?

 

[mikidymac]

Wait, so if there's a restriction in fuel flow through the valve, it'll cause the engine to run lean and destroy itself?

Absolutely.