94 gtx rebuild

[dakota1205]

Been working on rebuilding the engine on my 94 gtx model 5862 with a 657x engine. I bought it used, ran it several times and then it burned a piston. I am running PREMIX by the way. Not exactly sure if this is the original engine, but I can tell it has been rebuilt before, it had 1.0M pistons in them. My question is, when I went to install the rotary valve, manual says it's a 147, but this engine had a 159 in it, so i set it up at 149 deg opening, 65 deg closing, which happens to be for the XP model 5854. Is something wrong here, could this be a engine swapped from an XP or what? Will this rotary valve setting work in the GTX?
Thanks for any advise in advance.

 

[mikidymac]

Does the tag on the engine say 657 or 657X?

 

[Seadoo timebomb]

`94 model is supposed to have a standard 657 with 147 valve. If it has been changed out to a 657X then takes the 159 valve.

 

[AKnarrowback]

Agreed, big red flag on the "X" designation. My two machines, because my wife stole my 97 gtx, are a 94 XP and her old 94 GTX, two different motors.

I would strongly suggest two things.

1- You verify if you have the 657 or 657X motor by the black metal tag on the mag flywheel housing.

2 - If you EVER get a 110hp gtx given to you, that you love to ride, NEVER let your wife drive it or she'll keep it. Not saying a 657 GTX is a bad thing but HP is HP and the more the better.