Superjet motor swap from hell

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BenjiBlowsion

Location
Seattle
So I recently purchased a rebuilt motor with a 61x crank and cylinder and an 62 t head from SBT. When putting it in i replaced the fuel lines, rebuilt the carbs (dual 38) I just got a new factory b limited and it has carbon fiber reeds and dual exhaust. Nothing too fancy. On my 1st test run I was having a Pretty bad issue with bogging After quarter throttle The for I got to wide-open throttle but I was able to feather it through the mid range to get to wide-open throttle if I did it just right . So I took it out of the water and Came to the conclusion that it was running rich so I put bigger pilot and main jets in Factory pipe recommended a 135 in a 70 to start with so after the boggish you I put a 140 mean and a 70 pilot. This did pretty much nothing. It then turned into an investigation taking the carbs off 3 more times To Go down to half sizes of jets in then adjust pop off pressure from 55PSI down to 30PSI. Here's where it gets exciting I finally got great results from lowering the pop off pressure significantly So I put it in the water and went for a ride in the road very well with only a very very minimal amount of bog on the bottom-end. Then I was at quarter throttle for a long period and it started To feel like it was running on one cylinder like I had fouled a spark plug. I then changed the plugs and had the same slow sluggish ski. Then changed the coil.... same slow ski. I'm starting to think that it must be some kind of electrical issue because I finally got Running with Virtually no bargaining at all-and then all the sudden the symptoms significantly changed when I went for that one ride. I'm really hoping you guys can put your heads together and see if you can come-up with something else for me to try because I'm quite literally a dead and and have no idea what else to do with this money pit that I love so much lol . Let me know if you want pics or more info. I tried to be thorough but I know I'm not very descriptive
 
khaos

khaos

Party in a can!
Site Supporter
Location
Tidewater, VA
Get an eyeball in the cylinders make sure it looks OK. No slime or chunks. Hand turning the crank and listening is an indication of jug health. Its fresh so it will be slightly more 'scrapey' than a broke in one. I would get a pressure reading front and back too. If you have a block off you can pressure check the block and esp the seals for air leaks. #GOHAWKS

If anyone has other ideas I hope they chime in.
 
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BenjiBlowsion

Location
Seattle
Thanks for the reply. I'll try to see what condition the jug and pistons are in I guess I overlooked a compression test considering that it was a newly rebuilt motor But I guess running it well having bug in tuning issues could toast it pretty fast
 
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BenjiBlowsion

Location
Seattle
khaos said:
Get an eyeball in the cylinders make sure it looks OK. No slime or chunks. Hand turning the crank and listening is an indication of jug health. Its fresh so it will be slightly more 'scrapey' than a broke in one. I would get a pressure reading front and back too. If you have a block off you can pressure check the block and esp the seals for air leaks. #GOHAWKS

If anyone has other ideas I hope they chime in.
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Hey khaos I Get a compression test and everything is still fine when cylinders at 150 PSI in one is at 145. I looked in with the spark plugs off in the cylinder head looked black and a little gunky. The spark plugs were also very black like dry sooty black. What does the gunky cylinder head mean?
 
khaos

khaos

Party in a can!
Site Supporter
Location
Tidewater, VA
150/145 might be OK cold. Try again later after shes warmed up from running a minute.
The soot might be crap oil/too much or crap gas or way too much oil. Breaking a new build in I would think 40:1 at the thinnest. Also, at 150psi you might have issues on low test. You might want to try a midgrade. You are prolly in need of someone in person. I'm no SBT fan but its seems brand new maybe their local guy can put an ear/eye on it. Search the X for Seattle riders. Someone knows whats up and can hook it up. I'm not trying to blow you off at all but Armchair mechanic-ing is far from perfect science. I don't want you to miss any ride time because I didn't know the answer :)
 
Muggs

Muggs

Location
Oregon
you said that you were running to rich, then went up on your jetting, but I think you wanted to go down. I would go back to factory pipe jetting ,and air adjustments. they are pretty close for stock motor. I'm only running 140/75 in 38's on a ported 735 with 185 compression
 
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BenjiBlowsion

Location
Seattle
Muggs said:
you said that you were running to rich, then went up on your jetting, but I think you wanted to go down. I would go back to factory pipe jetting ,and air adjustments. they are pretty close for stock motor. I'm only running 140/75 in 38's on a ported 735 with 185 compression
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so the pilots are at 70 which is what factory recommends and the main is 140 (5 above recommendation) When I try playing with the adjuster screws that seems to like it when they are 2 and a 1/2 to 3 turns out. Does not have to mean that I'm running lean?
 
Citizen

Citizen

Location
Coeur D' Alene, ID
2.5 to 3 turns out is about max adjustment on screws, so in theory your jetting is too small? Someone correct me if i am wrong. I would bump the jetting up and get your screws in the .5 to 1.5 turns range.
 
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BenjiBlowsion

Location
Seattle
Then you guys I didn't realize that the manual was so thorough as far is tuning procedures and trouble shooting of a world of help. I do have a weird update So low jecky won't start now won't turn over nothing happens when I hit the start button are there any electrical problems it can cause it to feel like it's running on one cylinder and then digress to not even turning over
 
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BenjiBlowsion

Location
Seattle
Found out the problem!! So the stator threaded itself loose somehow and eventually broke off the mounting bolts. Once it broke off, the flywheel caught the wires and hence it wouldn't start. Magnets on flywheel got destroyed by a broken bolt head too. So new stator and flywheel on the way and hopefully my ski will be ridden more than once!!!
 
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