popping sound

[garyrc]

it looks like number one in the picture

[garyrc]

also i drive about 25 miles on the highway eachway to work turning about 5 grand at 70 mph in 5th gear, 90 percent of my driving is on the highway. i have 4 into 1 kerker pipes yamaha shop that is way these pipes sound.?

[TopCatGr58]

After I put in my 117.5's, mine also still pop on Decel. I'm planning on replacing my exhaust gaskets, but if they keep popping, it won't bother me cause at least I KNOW I've done what I think is needed to keep it running at the right mixture range to protect my pistons, and I know my intakes aren't leaking either. Yes, some aftermarket pipes do pop as a normal way that they operate, was just trying to help ensure that you weren't going to burn things up internally. Enjoy, and ride on!!
T.C.

[garyrc]

thanks tc so if they look like i said they are ok? and if something was wrong at highway speeds it would surly show up right?

[garyrc]

also tc just a question as a precation i have been running in the last couple of tanks full can of seafoam. is that enough too much or should i try one more?

[TopCatGr58]

Hey Gary,

The Seafoam directions state just a few ounces per tank, so a full 16 ounce can is a bit much, but don't think you will be doing any damage to the engine, but not sure what affects it may have on the rubber parts in the carbs at that concentration!?

And, with that much in the gas, then you may not be able to depend on reading the plugs right now. You may want to get a spare set of plugs, and once you've run that tank out, use just a few ounces, and fill with gas, and then put the new plugs in, and then monitor their color! IF you do get some decent tan/gray color on the white insulator, then I would say that you've got it set okay. But again, the recommended test is the throttle chop, where you run it for a minute or so up a grade at modest load and rpm range, then KILL it, coast to the road edge and pull the plugs and look at them, that way you won't be getting any Pilot circuit contamination to the true condition/color!

I'm afraid and happy that I don't have any experience with running a machine too lean too far to burn holes in the pistons, so don't know what the symptoms would be, possibly pinging, not to mention overheating, sluggish response? Up there in Indiana, I would think the temps don't get quite as hot as in the south, but I think I remember temps still up in the 90's in the middle of summer, so that combined with the excessive heating affects of running too lean isn't a good combination.
T.C.

[garyrc]

thanks buddy you have been a great help

[garyrc]

one more question on about 2.9 gallons of gas i am getting 85 miles to a gallon does this sound right?

[fxrer]

Garyc,

I continue to believe that your problem is with the pilot jets. They control the fuel/air mixture from idle to mid range, when the main jet and main needle do the job. Since it sounds like your bike runs fine at all other throttle positions, the pilots are your problem.

After cleaning and sync, my carbs did the same thing you describe. Soft popping at idle, and on decel. My bike SG has stock pipes, so I was able to isolate the popping to the number 2 cyl. I kept turning the needle out until the popping subsided, then did the other carbs to match. The idle speed increased, so I lowered the idle rpms by the thumb screw. I continued to tweak each carb until it purred like a kitten. No more popping.

After it was purring I didn’t count the total turns (out from lightly seated) for each screw, but I’m guessing they were all more that the recommended 1-1/2 turns; maybe 2 ½-3 for each.

Other things to check: a leak on the intake side, like the manifold boots? You can try the spray test - squirt some WD40 or oil around the joints of each boot. If idle changes, you probably have a leak there.

And it’s possible your floats might be set too high (when measured upside down from gasket base), ie, low fuel level in the float bowl, which would cause it to be lean. But that’s a long shot since you would notice symptoms across all the throttle range.

As for mileage, I assume you mean 85 miles for 2.9 gallons? That’s 29.3 mpg which is a little low, but not terrible. Most members report mileage ranging from high 20’s up to 40 mpg, with the average seeming to be around 35 mpg.