6th gear in mt Rev-Tech trans gets me 2500rpm @ 75mph. Wouldn't want to run it any lower than 2500 under load.

I am dropping the gear ratio by about 15% with the final drive chain conversion to make 6th more useable. A plus is better acceleration, because more is always better.

 

If you have a good running 5 speed, I would just deal with the higher revs.
An 88 will have a hard time pulling a 6th gear anyways.

If you blow it up, then it would be worth while to upgrade, but otherwise, just enjoy what you got.

Most mechanics say they have lots more problems with engines being lugged than with them running too high RPM>.

 

When I started riding, back in the 60s, the rule of thumb was that we could travel safely at around 3/4 peak rpms without harm. Repeatedly riding into that upper quarter was where the risk of harm lay! By contrast my late 70s BMW had a maximum sustained rpm the same as peak rpm - which translated to 124mph. It would certainly cruise at 115mph without stress.

Our current bikes are built to far higher standards today, so 3/4 of say 5,500rpm is just over 4,000rpm and any Harley will deal with that day in, day out.

 

Did I read this wrong "1998 Road King - 127" Ultima Engine" and you have a problem with acceleration? But then one can never have enough acceleration come to think of it

 

The bike is a strong 95" it pulls side by side with a 96" I live in southern Idaho with a lot of flat area what I am thinking is to be able to drop the RPM while running 80MPH to about 3000/3200 RPM

 

I've got a baker 6-speed gearset listed in the classified section right now, if that will work for you. It's new in the box for a very decent price. It's a DD6 setup for 700.00 les than the best internet price I've seen (in case you priced them).
I also have it listed on ebay for more.
Make me a offer if interested.

 

I was thinking I could gain maybe 3 miles a gallon by going with the six speed over drive..But after doing the numbers and seeing cost per mile between the two ($.01per mile for that 3 MPG average) It looks like I would have to ride some where around 100,000 mile before seeing any saving...I like my 5 speed

 

That's a shrewd observation! 5-speeds are just fine!

 

Been leaning toward going to the 6 speed sense Sept just had to put it in saving now if I could get 10 miles increase that may have been a different outcome. To get that it looks like the newer bike and I don't want to make that at this time anyway the Ultra is just about got everything on it that I want and don't want to start out again because of the new style frame knowing that most of the extras will not fit

 

Great