i did some searching, but didn't really get a clear answer on this:

I want some more torque out of my 80' i have andrews 27 cam, and it helped, but i want some more, without doing head work.... i got 14,000 miles on this rebuild... when i hit around 50k, i'm gonna drop in a 107 or 113 ultima....anyway, until then....

i want a little more low end, witout spending a lot of $$$...

can i change my gear ratio relitively inexpensive?? if so, what do i get?? and what are the pros and cons??

thanks guys!

 

What sort of dyno numbers do you have right now? And what other mods in addition to the EV27? Are you running straight pipes? Those are horsepower makers (if the rest of the setup is there), but they are torque killers. How much torque you are giving up, won't be known without a dyno comparison.

Head work will increase horsepower, but depending on the porting, may slightly decrease torque. It really depends on where you want to make the power.

A gearing change to a smaller drive pulley will give you more 'out of the hole' performance (and perhaps some 'roll-on' zip at certain speeds) , but will shift the speed/powerband into a different area that may not work well with your present setup. All dependent on how you ride the bike.

 

haven't dyno'ed the bike.... and used to run straight pipes... everyone said that was killing my torque, and they were right... i threw the baffles in, and wasn't happy with the sound, but the bike performed MUCH BETTER!!!

only performance mods are the pipes, hi-flow air filter, and the cam...

when the light turns green, i'm gone... i don't like to run over 70-80, and i only do that on the interstate.... i just like to cruise around 60, but i like to get to 60 ASAP... not a speed person, i just like acceleration.

thanks for the help!!

 

If i went this route, by changing the real pully... would i get more teeth or less for lower end??

according to my service manual, my bike has a 65 tooth rear pully.... i see 61's, (65's of course), and 70's....

which way would i go? and has anyone else done this?? do 4 or 5 teeth make that big of difference??

 

Yes, I've done this in the last few weeks to my 1990 FLHS. I bought the bike new and it is an International model, which came to the UK with a 61T rear pulley. I have just fitted a 70T, which brings it in line with the US spec of the time (with stock 32T gearbox pulley).

So to achieve your ambition you could fit a 70T rear pulley, but you will also need a new belt to get round the larger pulley. Going from 65T to 70T will give you an increase of rear wheel torque of 70/65 = almost 8%. It will also mean your gearing will give an 8% increase in engine speed, so if you normally cruise at say 3,000rpm, to travel at the same road speed your revs will increase to 3,230.

Going from 61T to 70T on my bike has given me more radical changes of approx 15%, which with my S&S 107 gives much sharper acceleration!

Hope that helps.

 

I would just change the drive sprocket on the trans to a smaller one.
http://www.andrewsproducts.com/motor...c.htm#beltNote

 

Changing from a 32T to 30T will give around 7% reduction, almost the same as a 70T rear.

 

If you have to pay to get any change done,changing either end will cost about the same the primary covers have to come off.

 

In theory if you have a choice it always better to go to a bigger pulley or sprocket rather than a smaller to get the desired results. This causes less strain wrapping the chain or belt around a larger radius.

 

My Indy did the sprocket in the tranny for $125. (23 tooth bought it used) major torque off the line, on the hiway the engine is turning some rpm's at 70 mph.