650sx rebuild

jordanh

jordanh

Location
Grand forks ND
Well just figured I would post my 650.
Picked up for $600 as you see here.
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Then I thrashed for two weeks to have it ready for Independence Day. I completely tore it down and cleaned everything, added a block off, painted, turfed, etc. Did a lot of the popular mods like a 44sbn carb, ride plate, intake..

This was my first turf job so I was a bit nervous but I think it turned out greatimage.jpg
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I was trying to find a cheap solution for under padding. I came across some large foam children's playroom puzzle pieces that were 7/16" thick. Came in a pack of 4 for $9. Worked out great.
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I rode it like that and enjoyed it for a few months. Then a couple weeks ago my bottom connecting rod bearing came apart. Only reasoning I can find behind that was a bad base gasket. So I decided my
Best solution was ordering a complete engine from SBT. So in the mean time I decided to build an aluminum handlepole. Here's where I'm at on that. I'll post more details in a bit.

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jordanh

jordanh

Location
Grand forks ND
Here's the carnage from the connecting rod bearing coming apart.

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Here's some more details of the handlepole I built. Currently in the process of laying up the chin pad. Should have that done in a few days.


Steering pivot machined from stainless
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I used my notcher that I made to do the slots, and the copes on the end of the tubes.
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Chinpad mold buck
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augustaf

augustaf

Location
central florida
Nice work you did! BTW , your engine failure was clearly caused by the (tired) crank failure. That can happen when they have lots of hours. Base gasket failure causes engine to run lean, possibly resulting in piston seizure.
I had a 650 SX once, put in a 750 engine- nice difference!
 
jordanh

jordanh

Location
Grand forks ND
augustaf said:
Nice work you did! BTW , your engine failure was clearly caused by the (tired) crank failure. That can happen when they have lots of hours. Base gasket failure causes engine to run lean, possibly resulting in piston seizure.
I had a 650 SX once, put in a 750 engine- nice difference!
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that makes sense. It was all caused by the lower connecting rod bearing. I was sort of leaning towards maybe the leaking base gasket was contaminating the bearing and drying it out. Here's what leads me to think that.

The day I was riding it I left shore and it had great power. Pissers were also flowing good water. I was riding for about 5min when it died. When I cranked it over it cranked fairly slow but did start. At that point it seemed to run alright but I did a quick check on my pissers and they were scalding hot. Which didn't make sense because that seemed like they were pushing decent water out. I have stock cooling except
For the stock pipe mod. I went back to shore and my cyl head was so hot I could maybe touch it for 1-2 sec. I pulled all my cooling lines and all was clear. So after awhile I started it to go for a quick test run. When I got on it I could tell the exhaust had a different note and then it died again. This time it cranked slow enough(from all the debris I would assume) that I couldn't get it restarted. When I pulled it apart nothing was siezed, just the damage from the bearing. The side that crapped out had a thick dark grayish slimy coating on everything. I could see a crap spot in the base gasket so that lead me to believe a small leak was causing the oil to not reach, or contaminate the connecting bearing and also cause my
Overhearing issue? Does that make sense or do you guys think I'm way off?

I can maybe wipe my finger and take a picture so you guys can see the color and consistency of the grayish oily coating. Seemed like an oil-water mix to me but its all over the exhaust ports and what not on the pto side that let go.
 
jordanh

jordanh

Location
Grand forks ND
augustaf said:
Overheating was likely caused by failure of headgasket
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Right, so is there any correlation between that and the connecting rod bearing that gave up... Other than dumb luck? I suppose everything in that engine was on its last breath. Compression was still 150 in each cylinder though when I checked it a few weeks prior to that. Bummer I didn't get more use out of it.
 
jordanh

jordanh

Location
Grand forks ND
yamanube said:
I am pretty sure I owned this ski at one time (probably 8 years ago) I remember that paint job.
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Today's your lucky day to
yamanube said:
I am pretty sure I owned this ski at one time (probably 8 years ago) I remember that paint job.
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todays your lucky day. You can now own a piece of yor past, with a new engine of course!
The paint job actually grew on my and I would have just left it had it not been so beat up.
 
jordanh

jordanh

Location
Grand forks ND
What's not working? Are you referring to the handling of the ski, or strictly just the left to right movement of the bars and the pump nozzle?

My steering worked as good as oem, and handling was far greater.
 
Fast_216

Fast_216

Co-Founder of TG Industries Custom Jetskis
Location
maquoketa iowa
jordanh said:
What's not working? Are you referring to the handling of the ski, or strictly just the left to right movement of the bars and the pump nozzle?

My steering worked as good as oem, and handling was far greater.
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It turns fine when the pole is all the way down but once I raise it up and try turning I barely get any movement from the pump nozzle
 
KawiKid

KawiKid

Location
SWFL
meaning, after you pulled the motor? just curious to see what it looks like under where your motor was. i think there is supposed to be a foam pad that is glued under the motor, but i dont have one. just curious if they all came with one and mine was removed, and if there is supposed to be one there, whats the purpose of it?
 
Fast_216

Fast_216

Co-Founder of TG Industries Custom Jetskis
Location
maquoketa iowa
jordanh said:
Is your cable housing solid mounted to the handlepole like you can see in this picture? You can see the bracket right as the cable goes into the tube.

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This is all I have on it. but now that you said that and I saw how yours is, it makes sense why mine wasn't working. Totally forgot about that when I made this new pole
 

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KawiKid

KawiKid

Location
SWFL
I know mine looks like jordanh 's too. I've never seen one that goes straight into the left tube of pole.
jordanh , will that cause an issue?
 
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