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Gear drive - size of oversize gear?

Started by -deuced-, September 29, 2021, 04:58:00 PM

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-deuced-

September 29, 2021, 04:58:00 PM Last Edit: September 29, 2021, 05:22:06 PM by -deuced-
I'm installing gear drives in '01 softail. Crankshaft runout was measured at pinion without camplate installed, it was approximately 0.00175". It's definitely less than 0.002". Installed cams into camplate. Installed camplate into engine. Installed outer gear on rear cam. Cams spin freely. Bit tricky, need about seven pairs of hands, but measured inner gears backlash at between 0.0005" and 0.001". Sweet. Installed outer gear on crank. Play is immediately noticeable between outer gears, you can see it and hear it. Thought I might need a ruler but measured outer gears backlash at 0.002". Measured at different locations and used different dial indicators and got 0.002" every time. Instructions say no more than 0.002", so within spec but play is so obvious I'm sure it's going to rattle. All measurements were taken with gear teeth clean and dry.
How much will backlash reduce with an oversize pinion gear? If it's more than 0.002" then it won't fit. If it's between 0.001" and 0.0015" then it could be perfect. I reckon most would just run it as is but I would appreciate if someone could tell me how big an oversize gear is.

Hossamania


I would think the gears grow a bit once they are warm?
Mine was the opposite of yours, a little tight, had to go undersized on the pinion gear.
If the government gives you everything you want,
it can take away everything you have.

-deuced-

Do your remember the difference in backlash between standard and undersize?

Hossamania

I don't. It was 16 or 17 years ago. S&S should be able to help you out. I can't even remember where I ordered it, either from my indie, or possibly Dennis Kirk or Drag.
If the government gives you everything you want,
it can take away everything you have.

Ohio HD

Quote from: -deuced- on September 29, 2021, 04:58:00 PM
I'm installing gear drives in '01 softail. Crankshaft runout was measured at pinion without camplate installed, it was approximately 0.00175". It's definitely less than 0.002". Installed cams into camplate. Installed camplate into engine. Installed outer gear on rear cam. Cams spin freely. Bit tricky, need about seven pairs of hands, but measured inner gears backlash at between 0.0005" and 0.001". Sweet. Installed outer gear on crank. Play is immediately noticeable between outer gears, you can see it and hear it. Thought I might need a ruler but measured outer gears backlash at 0.002". Measured at different locations and used different dial indicators and got 0.002" every time. Instructions say no more than 0.002", so within spec but play is so obvious I'm sure it's going to rattle. All measurements were taken with gear teeth clean and dry.
How much will backlash reduce with an oversize pinion gear? If it's more than 0.002" then it won't fit. If it's between 0.001" and 0.0015" then it could be perfect. I reckon most would just run it as is but I would appreciate if someone could tell me how big an oversize gear is.

Did you take measurements at four places, 0°, 90°, 180° and 270°? S&S suggests taking all four values. If you have lower values at 90° intervals, you might over tighten the gears going oversize.

Hossamania

September 29, 2021, 07:09:28 PM #5 Last Edit: September 29, 2021, 07:29:03 PM by Hossamania
Quote from: Hossamania on September 29, 2021, 06:54:52 PM
I don't. It was 16 or 17 years ago. S&S should be able to help you out. I can't even remember where I ordered it, either from my indie, or possibly Dennis Kirk or Drag.

A quick follow up, in all that time and 100,000 plus miles, I have not thought about the cam chest once as far as maintenance goes. Cams and lifters are probably getting a little worn by now, but it still runs great.  Definitely one of the best mods I did.
If the government gives you everything you want,
it can take away everything you have.

-deuced-

I took measurements at more than four places. 0.002" at every location. Happy with the consistency just a little disappointed in the number.
Alternative gears are not cheap and I'm wondering if price might partly reflect on their accuracy. As you guys know, single and double oversize and undersize gears are available. I doubt they're like 0.01" difference because if you needed to overcome that much clearance then problem is probably elsewhere. I'm certain I've seen something before about the actual sizing but I can't find anything.
I emailed S&S before my first post here, haven't heard back yet but it's only been a minute, lol.
Only 25,000 since the last time I was in there and nothing wrong with it. Didn't really want to open it up because it was running so good. But. In lockdown, bit bored, started tinkering with the bike. I might relocate my coil. Next thing I know bike is in pieces, had those gear drive cams sitting on the shelf for ages. And of course as soon as the bike is in pieces, get called back to work. Now I'm time poor. Lookout, I'm hijacking my own thread, lol. Might post about the other mods in another thread but back to this one.
I seem to remember something about alternative gears being single 0.0015" and double 0.003".

Ohio HD

I can tell you that the drive gears in my 124" are right at 0.0014" ~ 0.0016" backlash. They don't make any noise at all. Crank is tight, pinion shaft runout was 0.0006" on the Darkhorse crank. 

PoorUB

Funny how 15 years ago your question would have been answered in minutes. Everyone was putting in gear drives to get rid of the crappy tensioners. I remember tons of posts on gear drive back in the early 2000's. Now the tensioners are pretty decent, gear dives are not as popular as they once were.
I am an adult?? When did that happen, and how do I make it stop?!

OldBogie

My 2000 FLSTC engine got early Andrews/S&S kitted. Probably should have gotten .001 over as the set up was consistently loose but not more than .002. When the 20W50 gets over 200 degrees which is city stop and go or long desert mountain grades they rattle a bit. They've got around 80 kilo miles on them; was in there a few years ago to just look around having forgotten my father's warning of "if it ain't broke, don't fix it", anyway I looked but didn't fix as everything was fine.

Love 'em haven't had to clean out orange plastic chips ever since putting them in.

Bogie

-deuced-

 :up:  S&S replied to my email
Size of oversize gear is approximately 0.002"   :chop:

Ohio HD


FSG

I remember running strips of newspaper (local rag) through the gears when I installed them 

booker49

put in andrews g26 gear drive cams in my 2000 road king at 46,000 miles now ihave 135,000 miles and no problems. i didn't like those orange pieces on chain tentioners either.