Super Jet Jetting on 62 T from Waveventure

[sj650bp]

I put a 62T out of a WaveVenture in my 93SJ. What my question is I put a RIVA non-girdled head with gas domes on it with a set of WestCoast Velocity Stacks. The motor has been bored to 82.5mm. Will I need to do any rejetting on this? I am running a stock 701 superjet exhaust. Attached is a picture of the engine. I started the engine yesterday and it seems to run fine on the stand and idles good. I just don't want to lean it out when Spring gets here when I put it in the water. I have not done any adjustments to the carbs other than cleaning out the jet side. I completely tore the motor down put new seals, gaskets and pressure checked.

 

[tor*p*do]

bumping compression doesn't significantly change mixture needs
those a/f will require you to rich it up a little
BUT they look like great water snorkels in a SJ

 

[sj650bp]

Any suggestions on jetting? I know I am a little worried about taking water in with them. I am not much of a carb guy so any suggestion would be appreciated. I can tear 'em down and clean them, replace parts etc. Thanks

 

[piratelife]

It will run rich if anything because the venture pipe works alot better then the stock superjet pipe.

 

[piratelife]

Nice job on the motor looks good but i would run the stock air box instead of those f/a. those will act like funnels if water comes through the hood.

 

[kevbo]

You will have to get a tach or just power tune it on the trailer sunk as deep as possible.

 

[sj650bp]

Thanks for the suggestions. I noticed on the horsepower rating for the Waveventure vs. the SJ and it rated the Waveventure higher so the only thing I could assume is like piratelife said that the pipe works better on the venture. I guess what I could do is check what jets are in a stock SJ and what is in a stock Venture set of 38's. This might tell me something?

 

[kevbo]

Thanks for the suggestions. I noticed on the horsepower rating for the Waveventure vs. the SJ and it rated the Waveventure higher so the only thing I could assume is like piratelife said that the pipe works better on the venture. I guess what I could do is check what jets are in a stock SJ and what is in a stock Venture set of 38's. This might tell me something?

Not really because the port timing is different. The venture carbs wiil probably be OK in the pilot/popoff but too rich at full throttle with the stock SJ pipe. The easiest thing to do is to tie it down to a trailer, sink it deep, and power tune the top screw on the carbs. A tach is ideal but the rpm change is audible enough to tune by.

 

[sj650bp]

So do you think the F/A's will make up for the richness? I looked up the difference in the jets. It shows that the WV has a 120 main jet in #1 carb and 130 in #2. The superjet shows 130 for both. The WV shows 67.5 on the pilot jet and the SJ shows 70. Everything else is the same except for the recommended Low Speed screw turns and the High speed screw setting. The WV shows 5/8 +/- 1/4 for low speed and the SJ shows 7/8 +/- 1/4. For the high speed the WV shows 5/8 front and 1-1/8 rear +/-1/4 rear and the SJ shows 1-1/8 Front and 1-1/2 rear +/-1/4. Like I said I can tear just about anything down and put it back together, but I am not the best at jetting numbers. I can only assume that the larger the jet number the larger the hole which means more gas flow? I appreciate your help kevbo. I have a friend who was talking about the same trailer tuning. I just want to make sure that while the ice is on the lake I get as much wrenching in as possible before it thaws. So you think I will be able to keep the carbs as is and just tune on the trailer with the high speed screw?

 

[piratelife]

The trailer trick will get u close but dont rely on that completely it will change once you ride it. there is a diffrent load on the motor which changes the jetting a little bit

 

[sj650bp]

Thanks, I was just hoping there might be an answer such as put the same size jets in as the SJ shows and set the high and low speed the same, but it appears with the different port timing for the 62T and the different f/a's that would not be possible. I still might put stock f/a's on and then tune in the spring when I can get it in the water. The problem I have is that this is my first stand up and I need to learn how to ride and tune the thing.

 

[piratelife]

I never stagger the jetting in a superjet i would run the main jets both at 125 and set the screws at one turn and then go from there. Good luck bro and it looks like your in the right direction for your first stand up! I have a sn also with the same motor but im running a factory pipe with a raider chamber. I decided to run that chamber because it was designed for the 62t cylinder. i havent got it in the water yet but i will let u know how it runs.