99 Interstate is running very lean.

[BigMac (SoCal)]

Since I've had my 99 Interstate I always have had a vibration when passing or decelerating at high speed. ( 85 mph plus)
I know it's not in the drive line so I pretty sure it's in the fuel delivery. With a 136,000 miles I've never had the carbs out of the bike. I took a plug reading when I got back from a ride to Death Valley and they are all dry and insulator is white. That been said it looks to be a lean running condition. What would be the best route to take in solving this problem. I've bought the 38 and 105 jets to install or would just turning out the pilot screws out take care of the problem. The bike as been desmoged and other wise runs good.

Thanks,
Dave 

[da prez]

  Go back to basics. Check the vacuum lines , intake runners and air cleaner (first).If you service the carbs and did not diagnose the problem , then you get frustrated and miss riding time.
  Most will dis-agree with this method. With engine running , a light spray of starting fluid at base of intake runners and then the vacuum lines and all the fittings in the intake system . Light ,pinpoint spray only. If engine RPM increase , there is a vacuum leak. The fuel petcock should be checked for the vacuum diaphram and the filter screen should be checked. If all this is O-K , then look at the carbs.

                             da prez

[Louis Durocher]

Agree but be very carefulle with starter fluid.Highly explosive

[BigMac (SoCal)]

Little more information,
Bike has K&N filter with pre filter, pingle pet rooster non Vac, DanMarc shut off valve and completely desmoged. Intake orings were replace but it has been some time. 3/2/08 56000 miles.

[pocobubba]

Seems I recall a lean problem occurs when using the pre filter with the K&N .These Valks are touchy when it comes to any modification to the air box and filter . Check the archives for more info.

[Ricky-D]

I think you should look again regarding your interpretation reading the spark plugs.

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

http://www.dragstuff.com/techarticles/how-to-read-plugs.html

Your engine in not a normally lean running engine.

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