My name is Rick . This is my first post. I have a94 fat boy with 30000 miles on it . I got it 2 years ago . I have a 70 tooth rear sprocket . 32 front sprocket . When I do 70 mph or more it's like sitting on a electric razor. At 60 it's pretty smooth . If I put a 65 tooth in back or a bigger one in front .that should fix it . Will I need a different belt ? Or does anyone have a better way to get 70 miles an hour smoother

 

Maybe this site can help.
https://www.rjc-choppers.nl/how-to-d...r-belt-lenght/
EVO 80" engines weren't the smoothest running. But that's the way they were designed. But be careful. Lowering the RPM's too much puts a strain on the engine and cuts your low end response.

 

remember this..... smaller sprocket on front will give you more power and less speed....larger will give you less power and more speed. Smaller sprocket on rear will give you less power and more speed, and larger rear sprocket will give you more power less speed. This is what we used on our dirt bikes.... we would change a front sprocket 1 tooth up or down to gain a bit more power depending on the course/track we were at.... I can't tell you how much or how little, but I know I usually carried a 1 tooth smaller front sprocket to gain a bit more power if I needed it. Changing rear sprocket was more work, so we could change front out and simply re-adjust chain.

 

I went up 2 teeth on my front pully. I did loose some low end grunt. I really could not tell a difference at 70. Would I do it again ? Nope.
Maybe you will have better luck.

 

A readily available smaller rear pulley was provided on the European models back in the '90s. I want to remember it is a 63 tooth. This took the vibration on my '91 Springer up about 5 mph or so, so 70 mph was a bit more comfortable. The cost to acceleration wasn't very noticeable, so I would do it again if I got another Evo softail. To answer one of your questions, this required a new belt.

 

I’m pretty sure the HDI rear pulley was 65 teeth. It was also used on ‘95-‘99 US Softails.

Funny, my ‘94 FLSTN was rock steady and smooth at 70 MPH. 85 on the other hand....

 

I left the sprockets/ pulleys stock on my 1995 Heritage Softail Classic. I changed the cam, had a little head work done, dynatek ignition module, screaming eagle air cleaner, rejetted the carburetor.

Not only does it have more power and is more fun to ride, it runs a lot smoother, even at elevated rpm on the interstate.

 

I’m pretty sure your ‘95 came with a 65 tooth rear pulley as opposed to the 70 tooth pulley on my (and the OP’s) ‘94.