Super Jet I need some answers about my new superjet

[danaf99]

Ok, here's the whole story. . . Had a 91 superjet with 6m6 motor. Bought a pro-tec pipe in the classifieds on this site. Pipe was advertised as removed from a 6m6 motor and the seller assumed it was for a 6m6 but the manifold was port matched to a ported 6m6 motor. Compared to the 6m6 gasket the manifold exhaust ports definitely looked bigger. Installed on stock 6m6 motor anyway and it seemed to get some good mid and high gains. Recently bought a 2002 superjet with stock motor. Removed pipe from 91 and sold old ski. Was going to sell pipe separately. Now, due to my paranoia, I was concerned about the internals of the new superjet. Compression was 150 even both cylinders. Disassembled top end to inspect crank bearings. All internals are perfect with no corrosion. I noticed the crank shaft had 6M6 stamped on it. I looked at the case and it said 62T looked at the cylinders and they said 61X. I then looked at my pro-tec manifold and the casting marks are still on the inside indicating it has not been port matched or modified. I took my old exhaust gasket and the pro-tec manifold matched perfectly to the manifold gasket on my new motor. The questions: What motor do I really have in my 2002 superjet, 61x or 62t and what is the horsepower? The manufacture date on the motor is 08/01 (assuming july of 2001). Is my motor stock or has it been pieced together with different cases, cylinders and crank (all components are black in color except for the pipe and manifold, they are blue)? Finally, what motor is my pro-tec pipe for (see pict)? Lastly, If the pipe will fit on my motor what can I expect to see for performance gains?

 

[Boris]

You have a 62T cased 61X cylinder 701 which is what was stock in your SJ.
73 HP.
All bottom halves are 6m6 and that's what they are stamped as.
If the manifold matches your cylinder than run the pipe.

 

[chad]

yeah !

 

[tipafew]

yep, that is the stock motor. If the exh. ports line up run it. That is a good pipe for the money.

 

[danaf99]

Update, with more questions. I ran my 02 SJ motor completely stock all last year just to make sure there were no bugs, flawless ski. I installed the pipe this spring and contacted Pro-tec about carb settings, they suggested leaving everything stock except backing the low speed screws out to 1.5 turns (7/8 is stock) and the high speed screws to 2 ( 1-1/8 F and 1-1/2 R is stock). I rode this at lower temps (mid 70s air and mid 60s water temp) and it seemed to carburate fine. The water and air temp went up to mid 90s air and mid 80s water. I got a low to mid range bog that I could clean out of if I would bring the throttle on slowly. I contacted Pro-tec and they said the recommended carb settings were just a starting point and I need to tune it, which makes sense. I leaned out the low speed screw to 1 turn out and the bog is gone and the ski starts and runs much better now. My issue now is how to properly tune the high speed screw because it seems like there was no change in the top end. However, I am concerned that I will lean it out too much and burn down the motor. From what I read on the Mikuni tuning guide and Group Ks website I need a tach and I should set the high speed where ever I get the highest RPM. My questions: is there another way to tune the high-speed screw with out a tach? What are the signs that my high-speed screw is too lean? When the pipe was installed on my 650 I changed nothing on the carb and had no issues, rode it for one season. Should I set my carbs on the 701 back to stock and try that? Is there anyone out there familiar with my pipe (pictured in the first post) that knows about where my settings should be (elevation - 1000 ft above sea level)? Thanks.

 

[iangdesign]

Check your plugs after you run it (5 or 10 mins of ride time) and the engine heats up, if they start to white, you are running lean. Richen up the high speed screw maybe an 1/8 of a turn after each run until this goes away. If you are even lean. This is how I have tuned a couple carbs, and have been taught by others.

 

[MileHighJSC]

Put your screws back to stock. If your high speed screw is to lean, you will know about 5 to 10 seconds into a wide open run, ski will semm to fall flat and loose power. When it was cold out the air was more dense, now that the air is hot and thinner your motor is seeing to much fuel for the screw settings.