98 INDY 500 BOGS ON TOP END

[JERSEYJOE]

NEED HELP WITH A 98 INDY 500. LOW MILES, GOOD COMPRESSION, CARBS CLEANED. STARTS FIRST PULL, IDLES PERFECTLY AT AROUND 1000, LOW END IS FINE. AT ABOUT 5500 IT STARTS TO BOG. FUEL IS FRESH AND CLEAN FILTER, PLUGS NEW, THINKING IT COULD BE A BAD CDI UNIT ALTHOUGH MOST DEFECT CDI UNITS RESULT IN A NO START CONDITION. COULD IT BE A TIMING ISSUE AT HIGH REM? TRYING TO HELP OUT A BUDDY

 

[MrSled]

NEED HELP WITH A 98 INDY 500. LOW MILES, GOOD COMPRESSION, CARBS CLEANED. STARTS FIRST PULL, IDLES PERFECTLY AT AROUND 1000, LOW END IS FINE. AT ABOUT 5500 IT STARTS TO BOG. FUEL IS FRESH AND CLEAN FILTER, PLUGS NEW, THINKING IT COULD BE A BAD CDI UNIT ALTHOUGH MOST DEFECT CDI UNITS RESULT IN A NO START CONDITION. COULD IT BE A TIMING ISSUE AT HIGH REM? TRYING TO HELP OUT A BUDDY

Have you check the clutching for warn parts?

 

[JERSEYJOE]

Clutch is perfect. More descriptive would be to say it's cutting out that's why I think it can be the CDI box mis firing at high rpm, or is it a case where it either works or does not run?

 

[nosnow]

Have you check the clutching for warn parts?

I had same problem with my 96 XLT Sp last year it bogged down at about half throttle. Put in a new fuel pump and it snapped right out of it.

 

[vetygud]

I had the same problem a couple of years back on my 99 Indy 500 and replaced crank seals on both ends. Runs strong like a new sled.