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1997 Honda Shadow Spirit vt1100c
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Discussion Starter #1
I bought a 1997 Honda shadow 1100 a while back. I removed the stock intake and installed a cyclonic K&N air filter, cobra jet kit and cobra slash cut exhaust. I am having problems getting the carbs tuned correctly. I followed the instructions that came with the cobra jet kit but my bike sounds like it is starving for fuel when ridding and I give it a lot of throttle it also has a lot of popping when decelerating. Could anyone help me with this? Or does anyone have any thoughts on what I could do to help?
 

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1983 Honda vt750 Shadow
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13,422 Posts
Putting it all back to stock will really help. But probably not you want to do.
When you change the intake system a lot you learn a great deal about carb tuning. These CV carbs are very sensitive to air flow so that is what is causing the problem. Now you need to go back in and add fuel . Maybe bigger main jet, different needle position, etc.

 

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2007 VT750DCA7 Spirit - NHB01 Black
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472 Posts
Carb tuning instructions are about as useful as instructions on how to get a bullseye in darts. Yeah, it gives you the idea and concept but the reality is the likelihood of one-shotting a carb jet change and it being perfect after mods is about as good as one-shot hitting a bullseye and you haven’t played darts before.

What a lot of carb tuning is, is understanding what you’re hearing and what the issue is based on what you changed. Don’t fret, because it’s 100% possible to get excellent running carbs with any number of mods, it just takes the right skill in listening, adjusting, tuning and patience when you have to remove the carbs for the sixth time in a day to change something back to how it was.

Unless you’re comfortable diving back into the carbs half a dozen times, take it to a qualified shop. Sounds like you have some main jet and needle height issues to me, but that’s mostly a shot in the dark without seeing/hearing the bike running.
 

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1983 Honda vt750 Shadow
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13,422 Posts
Make an adjustment, take a ride, check the spark plug colors,
Make an adjustment, take a ride, check the spark plug colors,
Make an adjustment, take a ride, check the spark plug colors ,etc.
 

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1999 Shadow 750 ACE VT750CD3
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2,215 Posts
You were probably OK with the Cobra jetting kit with just the exhaust, but as soon as you swapped out the air intake you would have been way too lean in the main jet sizing, off the top of my head maybe 10 numbers.

Honda tunes the Shadows using the whole intake tract to configure the air flow, that has been lost and now you are learning carb tuning.

The Factory Pro method is IMO the best approach.
Sometimes it feels like you need to rent a track for a day, but for proper jetting success it is imperative to get the main jets right first.
Everything in the fuel delivery profile is effected by the sizing of the main jet.

@swifty2014's plug checks will let you know when you are getting close, but the fine tuning can only come from the seat of the pants testing or some dynometer time.

Welcome to the game.
 

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1997 Honda Shadow Spirit vt1100c
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5 Posts
Discussion Starter #7
When you say that you removed the stock intake, what exactly did you do?
I removed the filter and filter box that goes to the tubing in the frame and installed a 3” 45 degree bend and a cyclonic k&n air filter.
 

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1997 Honda Shadow Spirit vt1100c
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5 Posts
Discussion Starter #8
You were probably OK with the Cobra jetting kit with just the exhaust, but as soon as you swapped out the air intake you would have been way too lean in the main jet sizing, off the top of my head maybe 10 numbers.

Honda tunes the Shadows using the whole intake tract to configure the air flow, that has been lost and now you are learning carb tuning.

The Factory Pro method is IMO the best approach.
Sometimes it feels like you need to rent a track for a day, but for proper jetting success it is imperative to get the main jets right first.
Everything in the fuel delivery profile is effected by the sizing of the main jet.

@swifty2014's plug checks will let you know when you are getting close, but the fine tuning can only come from the seat of the pants testing or some dynometer time.

Welcome to the game.
Thank you I will have to set a day or two aside to try and get this tuning correct. Or reinstall the factory air box and go from there which may be the best option.
 

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1997 Honda Shadow Spirit vt1100c
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5 Posts
Discussion Starter #9
I reinstalled all the factory air box filter and other components that I removed going to see how it runs now.
 

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1999 Shadow 750 ACE VT750CD3
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2,215 Posts
I reinstalled all the factory air box filter and other components that I removed going to see how it runs now.
That should do it I think.
It will at least give you a stable running base point to work from if/when you want to pursue the air intake mods.
 

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1997 Honda Shadow Spirit vt1100c
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Discussion Starter #11
That should do it I think.
It will at least give you a stable running base point to work from if/when you want to pursue the air intake mods.
I the air intake mod was just something that i saw and wanted to try. It was not something that i had to do I just thought it might would help not hurt. so back to factory with that and see how it does and what gas mileage I get.
 

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1999 Shadow 750 ACE VT750CD3
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2,215 Posts
There are some cool sounds and probably some power to be gained with the intake mod, it will just be a bunch of trial and error to get it sorted out.
Jets are fairly cheap, but one can easily waste a few prime riding days working getting things dialed back in.
 

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VT 1100c 1994
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183 Posts
What's your current setup, which needle groove/position, which main jets, which pilot jets? AFAIK eliminating the airbox makes things more complicated, but on the other hand it's a question of needle type, main- and pilot-jets and needle position, something you can solve. Just takes some patience, and after a couple of times taking the carbs out and in takes about 10 mins. each. I rejetted and I am happy that I did it. The cobra set is made by Dynojet, too.
 

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I bought a 1997 Honda shadow 1100 a while back. I removed the stock intake and installed a cyclonic K&N air filter, cobra jet kit and cobra slash cut exhaust. I am having problems getting the carbs tuned correctly. I followed the instructions that came with the cobra jet kit but my bike sounds like it is starving for fuel when ridding and I give it a lot of throttle it also has a lot of popping when decelerating. Could anyone help me with this? Or does anyone have any thoughts on what I could do to help?
I agree with the make adj. Take a ride method, but I would start with removing the cyclone. See if that 1 thing makes a difference. That may answer which way to go on carb tuning.
 
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