REPRINT FROM OLD HTT: 65 TO 70 TOOTH REAR PULLEY

[ClassicRider2002]

DISCLAIMER: THIS IS A REPRINT TOPIC FROM "OLD" HTT

I have saved many great topical discussions as "links" over the years and would hate to see these lost, so I am reprinting this TOPIC here, which may "perhaps" help some.

TOPIC:  65 TO 70 TOOTH REAR PULLEY  01-29-06

     
From: Fatboy997  (Original Message) Sent: 1/29/2005 4:54 AM   Message 1 of 17 in Discussion
I'm changing from a 65 to 70 tooth rear pulley on my 97 Fatboy. Will the belt be long enough or will I have to get a new one?

[ClassicRider2002]

From: scooterbanes Sent: 1/29/2005 7:17 AM   Message 2 of 17 in Discussion
Your Fat Boy uses a 130 tooth belt with a 65 tooth pulley.  In order to keep the axle in the center of the adjustment slot, you will need to go to a 135 tooth belt.  Gates company sells a belt this length and can be purchased for $167 through Dennis Kirk...J&P Cycles may handle them also and would probably be cheaper. Part number for DK is H02-009 and their phone number is 800-328 9280.


From: scooterbanes Sent: 1/29/2005 7:38 AM   Message 3 of 17 in Discussion
Just looked up J&P...Phone # 800-397-4844
     Gates 135 tooth Belt#  600-628
     Price is $153.99 or $138.59 w/gold membership
 

From: studs331 Sent: 1/29/2005 9:43 AM   Message 4 of 17 in Discussion
Why would you want a 70 tooth pulley?  At 70 mph your engine will be turning higher.  I have a 65 and I was wondering about changing to a 61 tooth to save the engine at highway speeds.  Oh, I got it, you want to ride two up.


From: JohnS_Rosamond_CA Sent: 1/29/2005 1:37 PM   Message 5 of 17 in Discussion
As mentioned above, you'll have to get a new (slightly longer) belt in order to make the 70 tooth belt work.  Previous to 1993 Harley had received complaints that the Softail vibrated too much at road speed due to overall gearing.  In 1993 Harley used a very tall (61 tooth pulley), then people complained that this was too "tall" - so they went back to what they were running previously.  In 1995 Harley came out with the 65 tooth pulley and made changes to the prinary gearing also.  I have rideen all three and my opinion is that the 1995 and later gear ratios are the best overall, even for riding two up.  However, if you tow a trailer, or you have an engine that is completely stock, then changing the gear ratio will give you a little more low end grunt and the bike will respond a little faster on the highway.   John S,  
   

From: HellsGateMC1 Sent: 1/29/2005 6:40 PM   Message 6 of 17 in Discussion
If you put a 30 tooth transmision pully on and keep your 65 rear pully the acceleration will be better, plus the bike will not vibrate as bad as having a 70 tooth rear pulley. You can use your stock belt by doing it this way. Your stock system has a 2.92 overall gear ratio, if you added a 70 tooth rear pulley it will have a 3.15 overall gear ratio, if you added a 30 tooth transmission pulley overall gear ratio is 3.12. I would never put a 61 tooth rear pulley on.
   

From: Meg Sent: 1/29/2005 7:22 PM   Message 7 of 17 in Discussion
Why do you want to do that? Makes no sense to me, it will only increase your engine revs and vibrations.


From: Meg Sent: 1/29/2005 7:27 PM   Message 8 of 17 in Discussion
You can always just keep your fatboy in 4'th gear and achieve about the same thing as changing over to a 70 tooth pulley.
Anyway, good luck.


From: spotddawg Sent: 1/30/2005 11:34 AM   Message 9 of 17 in Discussion
Studs
If you go 61t, you will have to get a shorter belt so plan ahead.
Good Luck
   

From: tlboilermaker Sent: 1/31/2005 1:29 PM   Message 10 of 17 in Discussion
Does any one have an idea as to how this combination is going to perform? I already have this equipment but have'nt installed it yet. 61 tooth rear sprocket w/32 tooth trans. sprocket ( supposedly produces 2.94 ratio). Had engine work done w/ 10:1 SE pistons, installed Andrews EV46 cam, stock heads( valves&springs). Am doing frame up build & wondering if I should make any changes before I finish assembling this bike. Any thoughts on this? Thanx. TL
     

From: Redrocket_ Sent: 1/31/2005 2:13 PM   Message 11 of 17 in Discussion
FXR used a 70t The FXRP used a 65. The 70 will make the bike feel lighter, but with no rubber mounting like the FXR it could be buzzy. Dont forget you can re-gear the primary to get more pep down low...


From: JohnS_Rosamond_CA Sent: 1/31/2005 5:52 PM  Message 12 of 17 in Discussion 
tlboilermaker,  Personally I do not like the 61 and 32 tooth pulley combo.  The gears are way too tall.  When you hit the throttle, it takes the bike a while to "spin up" and start to feel like your moving faster.  On the highway, when you want to pass, you'll have to gear down.  Not because your engine is weak, but it just wont gain rpm very fast.  That's a pretty poor description, but like I said, I personally don't like it.   John S,  

[ClassicRider2002]

From: tlboilermaker Sent: 2/1/2005 11:19 AM   Message 13 of 17 in Discussion
John S., I already have the pulley & the belt. I could probably replace the rear pulley, fairly inexpensively, but the belts cost quite a bit. Do you or any one out there know exactly which pulley combinations would use the 128 tooth belt? I see that the '94 International Softails used a 128t w/a 65t rear pulley. What tranny pulley did they use? These pulley combinations, you guys are talking about, are they w/ chain primary drives or belt primaries. I guess I'll have to go out and count the teeth on my primary pulleys to see what my overall drive ratio would be. Whats the signifigance between the secondary ratio & the overall ratio? Might just use what I have till I wear out this belt. Unless I don't like the ride. Thanx for your input. TL


From: HellsGateMC1 Sent: 2/1/2005 2:03 PM   Message 14 of 17 in Discussion
These are chain primary drives. Depending on what year your bike is the 85-93 has a primary ratio of 1.54 (24 tooth compensating sprocket & 37 tooth clutch hub sprocket). The 94 & up has a primary ratio of 1.44 (25 tooth compensating sprocket & 36 tooth clutch hub sprocket), this is a taller gearing than the 85-93 bikes. I would recomend the 29 tooth transmision pulley with the 61 tooth rear sprocket ( uses the 128 tooth belt) if your primary ratio is 1.44. This set up will give you a 3.02 overall gear ratio. Use the 30 tooth transmission pulley if your primary ratio is 1.54, this will give you an overall ratio of 3.13. All of my customers like the 3.12 to 3.13 overall gear ratios. This will give you a smooth ride and still have the gearing to accelerate quickly.
   

From: tlboilermaker Sent: 2/2/2005 1:43 PM   Message 15 of 17 in Discussion
Thanx, H.G.  I'll go count them. TL


From: studs331 Sent: 2/2/2005 4:56 PM Message 16 of 17 in Discussion 
tlboilermaker,
My 97 FLSTC has a stock final drive of 2.92 so your in the ball park.  For a chart of gear ratios see pg. 539 of the 2005 JPCYCLES catolog or find it in last years book.


From: Trickynick471 Sent: 2/6/2005 8:38 AM   Message 17 of 17 in Discussion
I have a 1998 softail springer which came with a 65 on the rear. I changed it to a 70 a couple years ago and everything workes perfectly. No new belt was required. All I did was change the sprocket. The bike always had some vibration as the engine is rigid mounted and it still has some vibration but I can't tell its any worse. I ride a lot in the mountains and wanted to gear down a little for riding double on the mountain roads. I am satisfied with the gear change and wouldn't go back to the 65 tooth.

[ClassicRider2002]

Anything added beyond this point is new information.

Regards,

"Classic"

[ClassicRider2002]

Below you will find a "excel" spread sheet gearing calculations program that you can either choose to simply open and use or down load to your computer for use anytime.  This is an excellent program that will help you figure out how the gearing you decide upon will ultimately affect your engine's RPM's.

I have been asked in the past how accurate is this excel program:

I have found the calculations to be SPOT on.....but let's face it.....at best our individual "tacs" are always prone to error...where as this spread sheet is a math formula not prone to error really.  But to answer the question I have found the attached "excel" spread sheet to be spot on.

LOL, I really used this spread sheet when I was changing the primary gearing in my 2002 RKC and was doing some "cross checking"......have you ever really attempted to R&D this stuff? 

What I mean is going down a highway while trying to read one of those mini tacs that we put on our RK's and then compare it to mph and keep from KILLING YOURSELF lol lol lol.....I have....lol testing my bike in every gear within every 250 range of RPM's it took hours and I almost ran out of gas, (done on a quiet country road) my eyes were bugging out....LOL trying to remember a couple of different RPM levels and stopping and transfering memory to paper....oh and let's not forget that I lost one piece of paper to a gust of wind...and  had to start over after I was nearly finished the first time.....LOL....but you had to know this right? LOL? you did right?

So to answer your question I did do a "real" road test to determine the accuracy and like I said I found it spot on....but as I also said for emphasis sake tacs are prone to be off by as much as 150 rpms which wouldn't be uncommon at all......

I would also personally suggest reading this particular "THREAD" which does a pretty good job of talking about gearing....this particular "THREAD" will talk about the gearing for a 1993 FXLR, but regardless it is working with an EVO engine and within this generation of bike so this thread will help to formulate some input for all bikes.....so here it is, simply click over the TOPIC below:

CLICK HERE:    LET'S TALK ABOUT FXR GEARING

Regards,

"Classic"

[NOTE: Please remember that putting your curser next to the paper clip icon just below will allow you to either simply open the excel spread sheet gearing chart or you can also simply choose to save it to your computer.]

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