I'm going to start logging how the bike is doing during my tuning and if anyone has any advice that would be great,
I purchased the max performance kit for my vt1100 spirit. I installed the backdraft exhaust and velocity stacks. Initially I put in the biggest main jet and pilot with no extra shimming of the needle. It had one on it already. I believe it was a 200 main jet and 50 pilot.
I replaced the exhaust gaskets and carb boots. I also replaced the fuel filter and fuel pump with oem parts.
i got the bike idling and reving great at 2.5 turns out on the fuel mixture screw. So I rode it, it was doing great while I was going slow. I got on the highway and as I reached 50 mph the bike lost all power and started sputtering and back firing, as I slowed back down it still wanted to do that a little. Then would slowly get better.
i pulled the carbs again and shimmed the needle up. I put the two extra shims on both needles. So a total of three for each needle, looking back now I think that is too much. Put the bike back together. Adjusted the fuel mixture screw until it idled and revved the best. This time it was set to 1/4 turn out. Rode it for a very short distance and it seems to be a little better but still doing it.
my next step is to check the float height
New update. I rode the bike again today. I can accelerate through all years, but once I get up to cruising speed and just try to maintain that speed. Having the throttle only open slightly it starts stuttering and popping at the end of the exhaust. Rolling onto the throttle at this point the bike picks up and accelerates like it's supposed to
@Jesse Williams you need these to help you in your tuning quest! - file:///C:/Users/xfuel/AppData/Local/Microsoft/Windows/INetCache/IE/M9D63G14/Performance%20Tuning%20Secrets[1].pdf
https://shoptjbc.com/pages/performance-tuning-secrets-the-course?utm_source=Klaviyo&utm_medium=email&utm_campaign=Post%20Purchase%20%28Performance%20Tuning%20Secrets%20Course%29&utm_id=WXf7UV&_kx=3qrPUqJNER6EIjdbMWbpiQ.JWFNV5
Thanks I have those, but for some reason I still can't get it right. Hopefully I fixed it today but the next time I'm able to ride will really show if it's fixed.
the float bowl was at 11.9mm. So I adjusted it to spec 9.2mm. And lowered the needle back down to one shim.
so the current carb setup is 200 main, 50 pilot, and 1 shim on needle. The fuel mixture screw is 3 turns out.
i will update as soon as I'm able to ride it again
@Jesse Williams I have the same problem on my bike ! Did the one shim on the needle solve the problem?
@Jesse Williams did you ever fix this? im having the same problem
@Jesse Williams several things could be happening
- There are two bowl vents in the center area of the carbs, they are joined by a T. Put about 8-10 inches of hose ont his and route it towards the rear of the bike.
- If some of the vacuum ports are left open this will cause a lean condition.
- a leak in the slide diaphragm. if the slide diaphragm is punctured, or if there is not a complete seal at the slide cover then once that slide starts to rise, the leak will prevent it from actually lifting to allow more fuel/air mix through the needle jet. ( thats the little brass nubbin sticking up into the venturi.)
- the intake boots arent sealing, they're too old or they've been cut or ripped. I've done this myself a few times so dont feel bad! i use some grease or wd40 to help the carbs slip into place.
- was the bike running before you did the upgrade?
- is the tank venting properly?
- is the petcock or petcock filter full of crud and restricting fuel flow?
- is a fuel line pinched?
- are you still running the fuel pump or are you running straight to carb? i ended up running from tank to carb, not using the fuel pump.
after addressing the entire fuel system, you can check for spark. are the coil connections clean? not corroded?
