High RPM Bogging / Sputtering (With Pods)

[lunchbox3651]

Hi, I've been browsing this site for help ever since I bought a junker 1988 454 LTD for $150. Its mufflers had already been drilled out by the previous owners, but that is the extent of their modification. I cleaned and rebuilt both carburetors, the fuel petcock, the gas tank, and the drum brakes. I have also replaced the air box with pods, changed main jets to 135's, and done a valve adjustment.

My problem:

• While in neutral, the bike idles perfectly. When I twist the throttle, the bike will rev smoothly up to 8K, and then cut out.
• While riding on the road, the bike will smoothly accelerate up to 4K - 4.5K and then start spitting, sputtering, and surging like crazy.

I have restricted the pods with the tops of cans to limit some air. I have also played around with the air mixture screws but it seems to run best at 2 1/2 turns on both (This did not effect the sputtering).

I'm leaning towards increasing the size of the jets again, but I would like other opinions before I do too much.

Thanks in advance.

Here are some pictures:

imgur.com/a/vfxgqou

[knoizy]

No experience with pods myself but seen plenty of them on here and FB and it seems most folk have a lot of trial and error to get them anywhere near stock airbox performance. At 4k upwards the carbs should be on the main jets so mixture screws no longer in the equation. Perhaps you'll have to buy a selection of main jets and keep adjusting the airflow to compensate, I imagine that's a complete PITA if the bogging only shows under load. Did you ever have this bike running smoothly on stock jets and airbox?

[lunchbox3651]

I had the stock airbox installed for a very short time. It seemed to run well, but I was dead set on switching to pods for easy access to the engine area. 

[Blaine]

May 26, 2019 8:59:03 GMT -6 lunchbox3651 said:

I had the stock airbox installed for a very short time. It seemed to run well, but I was dead set on switching to pods for easy access to the engine area. 

Ok ...You will need to change your main Jet.....I also clipped 3 turns of the Diaphram spring So the slide can lift with less vacuum... It also gives faster throttle response. .