Super Jet Sj 1200

['kotajoe]

Ive done this in an 08 sj. I reduced the exhaust to the sj size straight after the fx140 hose. Had alot of tuning issues due to too much back pressure. A buddy did the same conversion and we altered his exhaust sizing all the way through the hull and it was awesome.

This is what I heard and is why im converting my entire exhaust system to 3"

 

[mybad]

This is what I heard and is why im converting my entire exhaust system to 3"

3" exhaust is a great upgrade. That will work. Im going to run the OEM and see how it responds.

 

[mybad]

Yamaha909. Quick questions to help me decide. Stock or modified motor? What chamber 1100 or 1200? Carbs? Prop? Pump? Thanks bro. All input is very helpful.

 

[227]

Subscribed

 

[mybad]

I removed the excess plastic from the bottom of the battery box and reinforced the sides with angle aluminum to create clearance for the OEM battery. Used button head allens to minimize height of fasteners. As you can see I now have room to fit a full size OEM battery. Might need that extra weight to balance out the exhaust.
Mounted the mid shaft into housing and set back 20mm. Put a thin coating of regular silicone on the rear of the housing then fastened in place and added grease. Done.

 

[Yami-Rider]

lookin good. where did you get those 90 degree black hose fittings for the exhaust over the battery?

 

[mybad]

Those are from the stock SJ exhaust tubing that runs from the chamber to water box.

 

[yamaha909]

I had a 1100 motor,case porting,mild exhaust porting,1100 chamber,1200 electrics,pro tec modded cdi,Bored out 38's and was running a 140 set back mag pump with a 16/21 prop. It went pretty good,but definitely was on and off with the tuning side of things. I removed the waterbox totally to try it without the restriction,still not great.
Didn't want to enlarge the entire exhaust system so ended up putting it into a blaster with a 3 inch exhaust system. Ran great and needed alot more fuel than it ever needed in the sj.

 

[mybad]

Fresh paint on modified bed plate.

 

[mybad]

 

[mybad]

Delete

 

[mybad]

View attachment 205152View attachment 205153Installed the modified dash with breather holes. Installed the drilled out fuel selector. Installed the oil injector blockoff. Installed electrical box and most of the wiring. Need to order new crank, weisco piston kit, seals and gaskets. Need someone local to bore these cylinders.

 

[#ZERO]

Need to order new crank, weisco piston kit, seals and gaskets. Need someone local to bore these cylinders.

Be sure to have the exhaust manifold torqued on when having someone bore the cylinders to eliminate distortion on the 1100 & 1200 engines and use the 1100 63M exhaust gasket because it has larger cooling passages.

 

[mybad]

Back to my build after several months off. Winter sucks so I installed a shop heater and some tunes. Trial and error is all I have. I made a few changes and was lucky enough to get top secret advice from a member here. I will be using the stock pump with a Solas 16/23 -5mm hooked up to a jet dynamics top loader and oem ride plate.

 

[MADMAT]

Damn I didn't know you could go -5! Cool! I can't wait to ride this thing!!!

 

[mybad]

delete

 

[mybad]

delete

 

[mybad]

Matt - Thanks to Dave at Impros. He knows his pumps. Otherwise I would have went -3. A little extra is always nice.

 

[mybad]

View attachment 212567View attachment 212568
I needed to remove the liner because the GP chamber is so tall. I used a putty knife, mallet and cutters.

 

[MADMAT]

Matt - Thanks to Dave at Impros. He knows his pumps. Otherwise I would have went -3. A little extra is always nice.

That guy is great! Someone told me he keeps a book of riders weights and "hit" preferences and the props they ultimately choose to love.....I believe it because he has been spot on for me and many others around here over the years...