I've had my 73 FLH for about four weeks now. I have been fixing something about every week, but I'm having a little fun doing it. The bike runs pretty well around town. Out on the highway, it seems to want to top out at about 65 to 70 and seems to sputter a bit at that point. Any ideas on what to look at first? It has an S&S carb (I don't know the difference between an E and a G carb). I haven't messed with that at all yet as I don't know anything about carbs. Thanks.

 

My first guess would be running out of gas, either the jetting is too lean or the float in the carb needs adjusted to keep the bowl fuller.

 

I had a similar issue with a CV... the float was set wrong and would die at that speed... actually while coasting I would release the clutch in gear and the bike would run again, after some more gas filled the bowl.
Unless you have a big inch motor, it would be a super E, not a super G.
If you have a stock 74", a super G would be overkilling

 

Thanks for the replies. I think that it is an e carb also. I will reset everything on the carb and start from there. I didn't see anything on checking or adjusting the float. Any help on that would be appreciated. Also, the PO gave me a bottle full of intermediate and main jets. What is a good place to start for those jets. The motor appears to be completely stock. Exhaust is a little on the loud side, but certainly not straight pipes. It has mufflers on it. That is about all of the info I have on it. Thanks.

 

Check the timing advance unit behind the points plate , if there's any sign of rust or the weights rubbing replace it that's the most common failure item when they start falling off and running rough. Next is get a can of brake clean and at an idle give it a couple short squirts aimed at the intake clamps, idle freaks out you have intake leaks.

 

Too much fuel will make it fall on it's face, I'd start with 28 and 66 on the jetting. Creep up from there until it doesn't run any better then go back one.

 

I took the carb apart and the intermediate was a 265 and the main was a 70. The float needed adjusted a bit. I get no different throttle response when I adjust the accelerator pump screw. I put a 295 intermediate in and that made it worse and it was blowing some black smoke when I gave it gas. Went back to the 265. It seems to run pretty good with that up through 3rd gear and the lower part of 4th. I dropped the main down to a 68. It ran better at higher speeds, but not much. Wouldn't pull up a hill on the highway, but picked up when I got back on level road. My speedo said that I was going a little over 70 at that point. My neighbor was riding his bike behind me and he said that I was going 80, so I guess my speedo is off. I want to try a 66 main, but I didn't have one. I ordered it and I'll try it next weekend. Thanks for the help and suggestions.

 

I'm still working on this, but I haven't gotten to the point of frustration yet. It still goes flat under load in fourth gear out on the highway. Could a bad accelerator pump cause this?

 

Just a thought. Have you pullled the fuel filter and made sure it is clean?

 

Yes, last weekend. There was a little crud in it. I cleaned it off. I also eliminated the in-line fuel filter just in case that was it. Still does it.