need longer legs - Harley Forum

Reverend Outlaw · #1 07-07-2009, 01:43 AM

hey all I'm new to this site and don't know what I'm doing so I'll just put it out there. I have an 02 heritage twin can 88 with a 95 ci upgrade with Andrews gear drive and Andrews cams 510 lift. The bike is awesome, once broke in it really gets with it, but the engine seems to be running at pretty high rpm's at cruising speeds. Does anyone know the best trans sprocket to rear wheel sprocket ratio for such an application? I could do the old hit and miss method but with the rear spkt costing $300.00 ea and the tranny spkt costing $115.00 ea it's a little spendy. any help on this would be appreciated. PS right now I'm at 70 teeth on the rear and 32 teeth at the tranny.

frisco-rigid · #2 07-07-2009, 03:43 AM

Hi Rev

I guess it depends on what is "cruising speed" to You..

I bet your 02 has a 25 T motor sprocket & a 36 T Clutch Shell sprocket which gives a 1.44 primary drive ratio..
Your 32 T trans. pulley & 70 T wheel pulley gives 2.1875 rear drive ratio for an over-all final drive of 3.15.. (1.44 x 2.1875 = 3.15)
That is quite high..
At 67 mph you're prob only doing about 2800 Rpm,,, heck daddio, that's barely above Lugging Rpm's for these motors..
At 91 mph you are prob about 3800 Rpm's..

No offense meant and hopefully none taken on your part----- perhaps your admitted in-experience & Un-familiarity with the machine is giving you the perception that your Rpm's are high when In Fact they are quite low..

Hypothetical example-----

Let's just say there is enough belt adjustment available and you installed a 34 T trans. pulley giving you a rear drive ratio of 2.0588..
If there's Not enough belt adjustment available you'd have to get a new belt too..

Your final drive would then be 2.96 and your Rpm's would be 2600 at 66 mph, certainly in the lugging range for Rpm's..
All that work and exspense for a measley 200 rpm's..
Sooo, for you motors sake you should Drop down a gear and lose all the benefits of the Change or speed up to increase Rpm's,, will you be able to speed up whenever you wish to keep from Lugging.?

Have a ball

Reverend Outlaw · #3 07-07-2009, 04:04 AM

when i said i didn't know what i was doin i meant posting on this site, i've been riding since 1967, every thing from honda 50 till now my third harley. this is my first twin cam and i have had it a while. the only thing strange to me is the sound of that new gear drive. kinda like the timing gears on that old 66 chevelle i had back in 1973, ya know what i mean? The bike is like it still needs anouther gear and i am hoping i can get a little help with a 29t tranny pully, you think not-- mayby the best thing i can do is put a tach on it and see what is for sure?

Fattdog · #4 07-07-2009, 01:29 PM

Quote:

Originally Posted by Reverend Outlaw

w The bike is like it still needs anouther gear and i am hoping i can get a little help with a 29t tranny pully

You need a bigger tranny pulley for more top end...not a smaller one or, a smaller wheel pulley

old no. seven · #5 07-09-2009, 03:20 PM

Are you hearing more engine noise from the engine since the gear drive? That's the primary reason why HD was told by the EPA to ditch the stock gear drive plan and they had to go to chain drive for the cams. I 've the 95" kit with the S/E 203 cams and my engine sounds real busy at freeway speeds.

whiskey · #6 07-09-2009, 10:16 PM

I have an 03 Heritage, virtually the same. Had the 95" kit, SE gear cams, etc... Really noticed the noise after the gear drive was put in. I love it, just uses a little more gas at high speeds.

Reverend Outlaw · #7 07-09-2009, 10:31 PM

Yeah I realllly notice the noise, I like the piece of mind that comes with it though knowing those chains and tensioners are gone. The noise is really accentuated by the windshield, I took mine off just for giggles right after the upgrade, you'd be surprized how much quieter it is. I've really thought about what frisco rigid had to say about cost per rpm so i'm gonna just ride it for a while and see what shakes.

street bob · #8 07-11-2009, 02:45 AM

Welcome to the site Rev..........

Digger · #9 07-26-2009, 05:42 PM

I have the same set up as you. I was wondering what your fuel mileage and engine temps are?

Reverend Outlaw · #10 07-27-2009, 09:04 AM

I'm getting 35 mpg I don't know what engine temp is running at for sure but it doesn't seem excessive. I am running red line synthetic , it tends to run cooler and quieter