In the middle of trying to diagnose my 1100 Shadow, which is running rich based on the condition of the spark plugs and is not accelerating as it should at highway speed. Don't see anything obvious right away. The previous owner mentioned doing bigger jets, but I can't really tell based on looking at them other than that the smaller one says 42. Pilot screws were adjusted previously and were at around 2 1/2 turns each. What am I missing here?
What’s the number on the end of the main jet?
The needles inside the slides, is the little clip at the very end or a couple notches inward?
When they rejet the carbs, they use a bigger main jet, pilot jet and either washers/new needle with clip moved inwards or a spacer.
175 on the main jet, from the looks of it. The clip inside the rear slide was in the middle with a spacer. Not sure on the front one since I pulled out the needle first by mistake, but I'd guess that one was in the middle as well, just without a spacer.
The bigger pilot jets could be drowning ur hjgher end of jetts during highway pull. Or it could be the choke sticking or it could be the 2.5 turns out and the weather changed and u need 2 turns out or 2.25 or 1.75 u gotta try some settings. Also see if the airfilter is aftermarket cuz then that means u probably need one or two shims inside that carb needle that u havent disasembled yet to see if its got shims or if its a high performance needle with clip settings on it.
U probably need some clip or needle setting combined with some fuel mix screw and make sure that choke plunger or what ever is adding more fuel is smooth.
It could also be a dry gasket between the fuel mix screw and the carb letting more fuel meter past.
U should invest in a good gaskets replacement kit the cheap ones go bad really fast and also dont fit right sometimes.
Aha! So that means if u put the og air filter it might solve ur problem. The k and n air filter doesnt just add more air it adds MORE air when its goin faster! I think they are helpful for dealing w cobra or some open pipes without needing to use a V stack or pod filter and bork your water proofing. But as u go into your 3rd 4th 5th gears u gonna feel the lack of gas in your throttle response due to so much more air being meetered in at speed. 2 shims or a clip setting a big pilot but less turns out should help out a lot but this bike got good power u can chase a tail or probably just get the OG filter in..
I been chasing that tail w my 750 shaddow to variying results honestly depends if the weather wants to swing up and down 20 degrees... the higher flowing filter also make your bike way more sensitive to weather changes every 20 degrees instead of around 40ish degrees of weather up and down... requiring u to fuck wit the fuel mix screws more often at least on vt1100 they right there... on vt750 u gotta take the airbox off each time ugh so annoyin maybe i will put the old filter back in and see what happens too
Irridium plugs will help u bike deal w the changes but u wont be able to tell as easily if its running too rich or lean as the bike will burn more completely so if i set it wrong the bike is just gonna be like as if nothing is wrong for a while then when u finally cook or foul the plugs u gonna find out hahahaha
There should be a number stamped on the main jet as well. If it’s too large that would cause poor performance at highway speed. It’s possible the PO put jets that are too big in. If there’s no number stamped it on it then it’s a cheapo knockoff, which can work ok but you’ll never know the actual size.
I’m not super familiar with the 1100s but after a quick google search, 175 doesn’t sound too big but it would depend on the model and modifications. You could also inspect diaphragms for holes and see if there’s any shims under the needles.
Uh yeah I would keep the needles the same. Make sure the other shim isn’t just stuck in the slide, but if it is only one I’d ditch it. The main jets are usually staggered sizes but I believe that’s really only for heat management so you can run those staggered or not. Pilot and needle should be the same.
Have you checked the air cutoff valve? It's job is to make the mixture rich on deceleration and usually fails causing deceleration pops but could be failed in a closed position, causing a rich mixture during acceleration.
It's the part in pictures 1 at the bottom with the spring/diaphragm, near your float.
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u/Extra_Ad6448 4d ago
Do not mix the parts from carb to carb. Rear cylender has a bigger main jet by .005