My tuning journey


  • 8/23/26  My current ride is an 07 Spirit vt750c2. I picked her up last summer. Right now she has between 17k and 18k miles. I absolutely love riding this bike. Decided Im going to customize her to my liking. As of today I haven't riden her in almost 4 weeks and to be honest, its starting to bother me. Anyway, I have installed open exhaust and v stack. Couple other shiny cosmetics that dont apply to this. 

    Took the carb off, took it apart and cleaned it, used the performance kit from tjbc. Started with the 50 pilot jet and 148 main. Double shim on the needle. Reinstall carb and she'll only idle with the enrichment value pulled out. Running lean, cool. 

    Today I have time to work on it. Switch out the 50 pilot for the 55. Still will only idle with enrichment valve pulled out. So now im going to take the carb off again, clean everything again, and check the float height this time. When I get paid Thursday I'll probably buy some new spark plugs just to have them.

    Anyway, thats where im at right now. If anyone has any suggestions im open to them. Ill post on here again and hopefully she'll be idling properly.

     

    **UPDATE ** 8/29/26

    I finally got the bitch running today and I am over joyed! Pulled the carb, took it apart, and gave all the pieces a good soak for about 30 minutes in a big ass can of carb cleaner. Then took my time with a brass brush, spray can carb cleaner, and canned air i cleaned everything up and sprayed all the holes and crevices out. Reassembled everything. Started the 50 pilot and 148 main. Float height is JUST below 18.5 mm. Used my stock gas line. (Originally I had used new line I cut longer because the stock is a bitch to get on.)

    Forgot about the choke and she fired right up and idled. After fucking with the air/fuel screw and idle screw for a couple minutes I got idle is sit around 1200. (Bought a cheap tach that wraps around the plug wire.) Little bit of black smoke out the exhaust and possible afterfire. Partial throttle seemed good to go.  Was getting dark so im done for the day. Tomorrow going back at her. Might be a little rich at idle. 

    **note** vstack, exhaust, and performance kit are all tjbc. I did Originally replace the carb boot. I did remove and install exhaust gaskets**



  • 8/30/26

    Turned the air/fuel screw IN to about 2 1/4 turns out and again to about 2 turns out. She's idling fine, quarter throttle sounds fine. At idle there is still a little black smoke coming out the exhaust. Doesn't seem to be any smoke when the throttle is applied. Any advice or words of encouragement are appreciated.  Im going to take her out on the road and see how she does 


  • 8/30/26

    Turned the air/fuel in to about 1 3/4, she starts and idles great. Apply throttle still good to go. If there's any black smoke coming out the exhaust its very hard to see. Turn bike off. Remove the  tachometer, attach the speedo to the tank, attach the seat. Go to start up, won't start. Rock the bike there's fuel in the tank, feels low. Switch to reserve, try again,  nothing. Use the choke, still nothing.

     

    So now im stumped. I dont have time to today but at some point this week imma check the plugs. Is there anything else anyone can think of?


  • @Dr.Phatpants check the clutch safety switch, neutral safety switch, and the kickstand safety switch, also, try leaving speedo unplugged before you try to start. you did something between your testing and your reasembly. 


  • @TJ really?? Ok, I'll check those out. Ive cleaned 2 of the 4 spark plugs. Covered in soot. Been waiting on payday to buy a 6 inch extension to pull the other 2. 

     

    Thanks for the advice! 


  • Finally got all 4 spark plugs pulled and cleaned. Bike fired right up! Still running a little rich. Turn the mix screw in a quarter turn at a time. White smoke is coming out. Must be lean now. Bike idles low and then dies. I had/have the idle screw turned all the way in. Gonna turn it out a little bit, see if I can get her to behave properly. Seems to be an extremely fine line between too much and too little air/fuel. 

    **edit** air/fuel is 1 turn out


  • I seem to be stuck now. Im making very small turns (⅛ to 1/16 turns)  in and out on both the air/fuel and idle screws. Keeps jumping between slightly lean and slightly rich. Low to right idle speed. I can hear the carb over the exhaust.... maybe a vacuum leak???

    Ill figure it out eventually 


  • Really dont know what's wrong. When I have time I'll take the carb off and check if the diaphragm is seated properly. Might clean the carb again. If that doesn't work, I'll haul it over to my mechanic who works on bikes for a living. Because, by then, I will be completely tired of fucking with it.


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