I own a 2010 Ultra Classic. I'm wanting to reduce my rpm by a few hundred while cruising. I mostly ride long distance at around 80-85 mph in the western U.S. and my 124 motor runs smoothest in the 2800-3000 rpm range and I get some vibration over 3000 rpm. Currently I'd need to run in excess of 3000 rpm to maintain my desired speed. As a result, I'm looking at options to get my rpm a bit lower at the speed I desire. Evolution Industries makes a 33T and 34T transmission sprocket. OEM is 32T. Is changing the transmission sprocket the easiest and best way to get me there? Will the stock belt fit a 34T sprocket? I'm open to other suggestions as well. Thanks.
I did my 2002 lowered the rpm's around 500. I kept my stock belt with no issues. oh I went with the 34 tooth.
Quote from: Tarkus60 on June 17, 2020, 05:09:14 AM
I did my 2002 lowered the rpm's around 500. I kept my stock belt with no issues. oh I went with the 34 tooth.
The 02 is a different swingarm from 09 - up.
I believe the "easiest" way is to replace the comp with a solid sprocket, nothing more than opening up the primary cover. Unless you have a chain conversion, then you could just add a smaller rear sprocket.
Also, changing the comp gearing won't affect the speedometer. At least not on my '01.
But it will effect the cruise and sixth gear light, unless the tuner is used to adjust it. But then he can adjust the speedometer with the tuner too.
Primary gear ratio changes could involve chain also.
I am not concerned about affecting the cruise control (including green light 6th gear) or the speedometer. I use a Mastertune and have worked with Steve Cole when he custom modified my calibration specifically when I had a Grudgebox and he got that all squared away and working great, then I adjusted my speedometer setting myself. I would think Steve could do the same with different sprockets.
I guess I should modify my initial comment and say I'm not looking for the "easiest" way to do it but rather the most reliable and bulletproof way, sticking to stock as much as possible. It isn't for lack of skills to tear into the primary and the transmission, but I like easy and cost effective availability of parts and you can't beat Harley for that.
Surprisingly even though Evolution Industries sells a 33T and 34T transmission sprocket they don't know if the OEM belt will work. He suspected it would with the 33T sprocket but kind of doubted it would with the 34T, and he did not know how much either sprocket would affect my RPMs. It would be nice to know those answers. He thought possibly Harley Davidson sold an international model that might have different size belts but that was speculation. So I turned to HTT to see if any members have gone through this. I do not want to convert to chain drive. I know most members go the other way...they are looking to increase acceleration and performance off the line but I'm looking for the lower rpm at higher speeds.
Put all your numbers in the Bigboyz calculator. It'll give you rpm etc. and the results are known to be dependable.
http://www.bigboyzheadporting.com/Gearratio.htm
Quote from: kd on June 17, 2020, 09:36:58 AM
Put all your numbers in the Bigboyz calculator. It'll give you rpm etc. and the results are known to be dependable.
http://www.bigboyzheadporting.com/Gearratio.htm
That is a nice tool, thanks.
... :gob:...both my evos have 34 t trans sprokets... :chop:
I went the other way on my '08 and on my '15.
One of the reasons is I did not like the tall 1st gear and resultant need to ride the clutch.
I went with a 30 tooth pulley on both and have not looked back. The '08 has 107000 miles on it now and the belt and pulley are fine. Doing the pulley change seems pretty fool proof to me. I know there are other ways to skin the cat though.
You will need to drop the swing arm to change the belt.
I had to go to a one tooth shorter belt on both bikes with the 30 tooth pulley. I was also told I could maybe get by with the stock belt if I had gone to 31 tooth. I have no doubt that you will need to change belt size with the 34 tooth pulley. So be sure what exactly you want to accomplish as far as final gearing. Also, being able to use the stock belt with a 33 tooth pulley is not a sure thing.
Quote from: guydoc77 on June 17, 2020, 10:39:58 PM
I had to go to a one tooth shorter belt on both bikes with the 30 tooth pulley. I was also told I could maybe get by with the stock belt if I had gone to 31 tooth. I have no doubt that you will need to change belt size with the 34 tooth pulley. So be sure what exactly you want to accomplish as far as final gearing. Also, being able to use the stock belt with a 33 tooth pulley is not a sure thing.
Guydoc, on your 15, did you use a 1 tooth shorter OEM belt or aftermarket?
Aftermarket. HD apparently doesn't sell them anymore.
Quote from: guydoc77 on June 18, 2020, 08:01:06 AM
Aftermarket. HD apparently doesn't sell them anymore.
Thanks! :up: There is another thread on here regarding changing the front pulley that had me look for a OEM.
I couldn't come across one.