FUEL SYSTEM PROBLEM, CARB. SPUTTERS AT HIGHWAY CRUISING SPEED. NEW STAGE 1 INTAKE. V&H EXHAUST. REJET OR OTHER PROBLEM?

[QMChief]

Good test run before the rain today. Burped in 3rd, 4th gear while accelerating 50-60mph, intermittent burping once a minute or so at 75 highway cruising. Idled well. Here are my plugs, need help deciding to rejet intermediate or not. Is it better to run a little rich rather than lean?
LEFT IS FRONT RIGHT IS REAR CYLINDER FRONT LOOKS A SHADE DARKER. THANKS FOR HELPING GUYS!

 

[HMAN]

A little rich is better than a little lean.

 

[mleach72]

Good test run before the rain today. Burped in 3rd, 4th gear while accelerating 50-60mph, intermittent burping once a minute or so at 75 highway cruising. Idled well. Here are my plugs, need help deciding to rejet intermediate or not. Is it better to run a little rich rather than lean?
LEFT IS FRONT RIGHT IS REAR CYLINDER FRONT LOOKS A SHADE DARKER. THANKS FOR HELPING GUYS!
View attachment 125763

It doesn't look like you are running lean. If anything, those plugs look a little dark. Generally, you want a tan color. That's what doesn't make sense. You shouldn't be running rich with a 31 intermediate. It makes me wonder if there is a problem somewhere else. Did you check for intake leaks around the manifold? If you are using your new air cleaner, did you remove the plug? Is the enrichner able to close completely? Is there a check valve in the rear head breather hose?

 

[QMChief]

I'll check for leaks but I'm using the stock teardrop with a K&N. Afterwards I'll change plugs and test ride her again and post the plugs again. I'm going to make sure I'm dialed in with the s&s carb tuning guide too. I'm getting more backfiring too but I was told that's because of the V&H exhaust.

 

[QMChief]

No leaks. Dialed in the S&S tuning, took her for a ride. Need opinions on plug color (both are the same color). If this is on the lean side, should I go 1 up on the intermediate and dial it down with the tuning? Better to run rich than lean correct?

 

[HMAN]

No leaks. Dialed in the S&S tuning, took her for a ride. Need opinions on plug color (both are the same color). If this is on the lean side, should I go 1 up on the intermediate and dial it down with the tuning? Better to run rich than lean correct?
View attachment 125797

Tan is the color you are looking for. You are correct, better rich than lean.

 

[QMChief]

Well this posting is so long people have given up. I'm thinking I'm running in the good to lean range.

I appreciate the help from all who replied!

 

[Mikeinjersey]

Well this posting is so long people have given up. I'm thinking I'm running in the good to lean range.

I appreciate the help from all who replied!

If your getting "burping" it's not running right. Just wondering , How far out is your idle mixture screw?

 

[QMChief]

I adjusted everything to the s&s specs and tuned it before the last ride. I did get one burp (sputter/cough) but that was it. The idle mixture is pretty close to specs 1 1/4 out. I adjusted it a bit during tuning but didn't turn it too far from that. I have no leaks in the carb throat. I feel like I'm close to good but it needs something I'm just not sure what it is. It runs good except for that burp and a lot of backfire.

 

[Mikeinjersey]

Your description would indicate possible lean condition. Open up the idle mix screw a little more and see if it helps. You can do that while driving if you want. If your running no baffles you may not be able to get things perfect. Coughing is not acceptable though . You need to continue adjusting / jetting until you find the answer. Decel pop is less important.

 

[QMChief]

I'm going to install a stage 1 filter so I guess I'll rejet to the next higher intermediate which should be 032 and tune it. It does pop only on deceleration but it's loud and often. My plugs are OEM but a chart I found showed they are a cold plug by the color of the "strap" that might have something to do with it. Apparently you want the strap and bottom rim of the plug to all be the same color.

 

[john sachs]

I'm going to install a stage 1 filter so I guess I'll rejet to the next higher intermediate which should be 032 and tune it. It does pop only on deceleration but it's loud and often. My plugs are OEM but a chart I found showed they are a cold plug by the color of the "strap" that might have something to do with it. Apparently you want the strap and bottom rim of the plug to all be the same color.

DECEL pop, is usually an exhaust leak, or no baffels in the pipes (straight pipes). How many rings of heat (threads) are the pl;ugs showing ?
John

 

[Mickmorris]

Definitely looks like those plugs are on the lean side to me. Try the .032 like you mentioned that’s what I’m running in all my S&S Super G carbs. Might be the ticket!

 

[QMChief]

DECEL pop, is usually an exhaust leak, or no baffels in the pipes (straight pipes). How many rings of heat (threads) are the pl;ugs showing ?
John

I just tightened those suckers up too. I didn't like the nuts that came with the exhaust kit though so I'll change them out and see if that gets them tighter and stops the leak. The nuts are rounded off and my socket kept slipping off.

 

[QMChief]

DECEL pop, is usually an exhaust leak, or no baffels in the pipes (straight pipes). How many rings of heat (threads) are the pl;ugs showing ?
John

I'm only seeing color on the very bottom John. Is it possible the OEM plugs are too cold? I'm using the Champion RA8HC plugs recommended by BD. That's for a stock 117 engine though. How do I find the next hotter plug or should I stick with the OEM?

 

[john sachs]

I'm only seeing color on the very bottom John. Is it possible the OEM plugs are too cold? I'm using the Champion RA8HC plugs recommended by BD. That's for a stock 117 engine though. How do I find the next hotter plug or should I stick with the OEM?

You should stay with the intended stock heat range plugs. You may have to put more miles on the motor to get a proper plug reading. Other than that, if there's a good dyno/tuner in your area, with a dyno that can accomodate the long wheelbase, it would be wise to let him tune the bike. He also may be able to install an adjustable - tunable ignition. It's ALL about icing on the cake. I find some "G" carb owners, have trouble getting a PERFECT tune. The dyno doesn't lie. . Also, I would add some back pressure to your pipes, before tuning.
John

 

[john sachs]

A bolt and nut about an inch, and a half in from the bottom rear of the pipe/pipes usually will create enough back pressure to stop the decel popping. Be sure the pipes are perfectly sealed in the port with NO exhaust leaks, and good gaskets. Another way to add some back pressure, is this. That will never hurt power, and possibly pick up some torque. Pics = 2004.

 

[QMChief]

A bolt and nut about an inch, and a half in from the bottom rear of the pipe/pipes usually will create enough back pressure to stop the decel popping. Be sure the pipes are perfectly sealed in the port with NO exhaust leaks, and good gaskets. Another way to add some back pressure, is this. That will never hurt power, and possibly pick up some torque. Pics = 2004.

I have new gaskets, a slide hammer, and Vance & Hines quiet baffles on the way! Something tells me I'm going to be bitchin' like a mf taking the old baffles out but hopefully the slide hammer ($29.99 at Harbor Freight) will be the ticket! And that should be my ticket to quietdown the decel pop problem but the folks at V&H said these pipes like to pop!

 

[Jersey Big Mike]

I have new gaskets, a slide hammer, and Vance & Hines quiet baffles on the way! Something tells me I'm going to be bitchin' like a mf taking the old baffles out but hopefully the slide hammer ($29.99 at Harbor Freight) will be the ticket! And that should be my ticket to quietdown the decel pop problem but the folks at V&H said these pipes like to pop!

I ran these in my V&H till one left one day https://bigcitythunder.com/collecti...fles/products/2-1-8-qq-thunder-monster-baffle
Will be putting them in my Blue K-9 shortly.
Got another set of quiet baffles years ago that were really short -- no decel pop in the efi bike with them in. Trying to find the brand I used. Will update if I find it.

 

[Sven]

No leaks. Dialed in the S&S tuning, took her for a ride. Need opinions on plug color (both are the same color). If this is on the lean side, should I go 1 up on the intermediate and dial it down with the tuning? Better to run rich than lean correct?
View attachment 125797

1. Looks like a 'lean is mean' plug. You have to ass yourself, ass? Do I still feel the sputter at the first post of 'runs like raped ass monkey,' but when walks it sputters, etc. So are we cleared of all driveability problems as stated in post 1?

2. You need a plug reader that can read all the way down to the porcelain end, not the nose. So the shot is moot.

3. Is the engine putting out too much heat with all the test rides? No. Then it's not that lean to cook the engine hotter.