Pulley Change(s)
Thread Starter
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Intermediate
Joined: Dec 2019
Posts: 32
Likes: 6
From: Okemos, Michigan
Pulley Change(s)
Has anyone ever swapped pulleys on their M8 street glide or other touring bike? I'm doing a 124ci big bore kit right now on my 2018 SGS and was wondering what the benefits would be? do people change the transmission pulleys or the pulley on the back tire? I'm just starting to look into this and haven't found to much information. Thanks in advance.
Thread Starter
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Intermediate
Joined: Dec 2019
Posts: 32
Likes: 6
From: Okemos, Michigan
looking for additional torque, i'm fine with loosing a little mpg, I don't ride on the highway often. I more so ride on back roads. But if someone has information on what would be changed and pros/cons of changing it?
Stellar HDF Member
Joined: Nov 2005
Posts: 3,183
Likes: 836
From: KMHT KFMY
are you looking for more oooomph on the bottom end or dropping the RPM's on the high end?
On my rice bikes dropping a tooth in the front made the front wheel come up, going up one tooth dropped the RPM's at 75 MPH down about 600RPMS which was just below where the bike had a buzz.... one tooth in the front was equal to 3 in the back, some guys worked both to get the effective gear ratio they were looking for.
Some of what you are asking is limited by the amount of adjustment in the belt.... it isn't like you can add or subtract links to get the belt short enough to be able to adjust it
You may get some guidance here: https://www.hdforums.com/forum/softa...p-to-13-a.html
On my rice bikes dropping a tooth in the front made the front wheel come up, going up one tooth dropped the RPM's at 75 MPH down about 600RPMS which was just below where the bike had a buzz.... one tooth in the front was equal to 3 in the back, some guys worked both to get the effective gear ratio they were looking for.
Some of what you are asking is limited by the amount of adjustment in the belt.... it isn't like you can add or subtract links to get the belt short enough to be able to adjust it
You may get some guidance here: https://www.hdforums.com/forum/softa...p-to-13-a.html
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Road Warrior
Joined: Jun 2008
Posts: 1,344
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From: Watertown, CT
10' RK , changed the front pulley from a 32 t to a 30 t . Lots more low end torque. It's great for the hills of New England but I'm vacationing in Fl. now and I would never have changed it if I lived here. At fifty mph I can shift into 6th.gear and still have usable passing torque.
Advanced
Joined: Dec 2012
Posts: 54
Likes: 9
From: Michigan
I changed my 09 FLHTCU front pulley from 32T to 30T. The 30T pulley is from a TriGlide although aftermarket people also make a smaller pulley. I also changed the drive belt from 140T to 139T to accommodate the smaller front pulley to keep the rear wheel in the correct position. I used a Gates Polychain belt. Always use a Gates Polychain belt, there is poor field experience/short belt life with non-Gates belts.
The change made a nice improvement in launch and 6th gear can now be held easier. The change is almost 7% (30/32), 7% more torque at the rear wheel and 7% speedometer error. The speedometer reads about 54 when the bike is actually moving at 50 MPH.
Half the bike needs to be disassembled to make this change and a special socket wrench is needed for the pulley fastener. Inner and outer primaries (including compensator, clutch basket, primary chain) along with rear wheel, much of the exhaust, and the rear swing arm/rear fork must be removed to change the front pulley and drive belt. I did the change as part of the job replacing a noisy inner primary bearing race (more unique tools required) and upgrading to the SE compensator {new alternator rotor required ) to eliminate clunking, banging, noise, and chunking associated with the original undersized compensator. Harley didn't get the compensator right until around 2014.
Bike runs great now. Launches smooth, inner primary bearing growl gone, compensator chucking during starting gone too. Only had 35k on the bike at the time the inner primary bearing started to growl. I replaced the auto primary chain tensioner, too, as there are some opinions that the auto adjuster can keep the primary chain too tight and overload the inner primary bearing, I used a Hayden spring loaded primary chain tensioner. 3000 miles since all this work and still loving it.
The change made a nice improvement in launch and 6th gear can now be held easier. The change is almost 7% (30/32), 7% more torque at the rear wheel and 7% speedometer error. The speedometer reads about 54 when the bike is actually moving at 50 MPH.
Half the bike needs to be disassembled to make this change and a special socket wrench is needed for the pulley fastener. Inner and outer primaries (including compensator, clutch basket, primary chain) along with rear wheel, much of the exhaust, and the rear swing arm/rear fork must be removed to change the front pulley and drive belt. I did the change as part of the job replacing a noisy inner primary bearing race (more unique tools required) and upgrading to the SE compensator {new alternator rotor required ) to eliminate clunking, banging, noise, and chunking associated with the original undersized compensator. Harley didn't get the compensator right until around 2014.
Bike runs great now. Launches smooth, inner primary bearing growl gone, compensator chucking during starting gone too. Only had 35k on the bike at the time the inner primary bearing started to growl. I replaced the auto primary chain tensioner, too, as there are some opinions that the auto adjuster can keep the primary chain too tight and overload the inner primary bearing, I used a Hayden spring loaded primary chain tensioner. 3000 miles since all this work and still loving it.