Compensator Sprockets - Harley Forum

tstevens06 · #1 05-25-2009, 11:35 PM

I'm kind of a technical guy I think. So I have been trying to understand the whole compensator sprocket thing. What is it compensating? It seems to be pretty important and has a lot of work put into it but it is not used on some chain primary bikes and as far as I can tell it is not used at all on belt drives. I think it has something to do with excess torque not damaging the primary chain but it only works in one direction. Does anybody know what gives? Does it need to be replaced at any interval or is it good for the life of the old scoot?
If that thing is warn out I will likely go to a belt drive since the cost of a new one is most of the belt system cost.
I have about 30,000 miles on my 79 FLH-80 classic. If I can wrap my head around this issue it may change my course with the whole primary thing. Thanks for any help you can give.

1haugster1340 · #2 05-26-2009, 09:49 PM

Someone please correct me if I am wrong on this.... I think the compensating sprocket is designed for your safety in mind. If the motor would lock up as you are cruising down the highway, the momentum of the bike would keep the chain turning via the rear wheel. The compensating sprocket would keep turning even though the output shaft on the motor would be stopped. This would keep your rear wheel from locking up and causing your bike to skid.

tommyglide · #3 05-27-2009, 12:10 AM

I'm probably wrong but is it not a bit of a shock apsorbtion within the primary? I don't think the sportsters have a cs. Now the smart folk can correct me.

frisco-rigid · #4 05-27-2009, 05:07 AM

Whoa Nelly,, this topic got me up outa bed..

Ok, I have 2 CS units, an older style and a newer style, on the bench and one in the 127" sickle.. I didn't check that one but I was gonna if I couldn'ta measured the others sufficiently..
This is what I came up with.. From the back of the Slide Cam to the Hard inside surface of the spring unit is approx. .600"..
The travel needed for the Slide Cam and the Sprocket cams to slide over and past each other is .700",,,,, and thats Before the spring is screwed in even closer------ which means the motor sprocket would get locked up 350 gazillionths of a second After a motor seize..

Your guess 1Haugh was a good one but, if I measured correct, the CS unit is prob only for shock absorbance..

TsT---
I've seen them worn but never seen one destroyed.. The cams thickness on the newer style unit I have is .312", the cams on the older one is .155" and it still looks good enough to run..
Actually,, those Cams will slide/run in both directions..
If you get a wild hair,,,, you can easily find a Motor Sprocket by itself,, no CS at all.. Just be sure to space correct and you'll be good..

I've never seen a CS unit with a belt drive but I've only run 3 diff makes..

45Duece · #5 05-27-2009, 08:56 AM

Newbie here. Left a forum that went from free to $60/yr. Tommyglide is right about it being a shock absorber. The Evo has a higher running comp. than the shovel and the uneven firing order causes the bike to jerk when coasting or slowing down to stop. Drag race types put a solid sprocket on because it's stronger. Belt drives use a dry clutch which is noisy and wear out quicker from being exposed to dirt. They are wider which will affect where your peg will be. And chew on your pants leg. Your stock clutch is far from being worn out. A fresh set of friction plates and maybe a primary chain would fix it. My bike has 63,000 mi and a 90 hp motor with the original chain and clutch and they are in great shape. Don't do dragrace starts much either.

frisco-rigid · #6 05-27-2009, 06:53 PM

I'm gonna have to vigorously dis-agree with 45..
Some of your statements are stated as definitive fact and are just plain wrong..
45 have you run a belt drive that chewed on your pants legs,, or have you ever worn out a set of clutches in a belt-drive because of dirt exposure OR are you just repeating somebody else's hear-say.?

First of all Evo's have nothing to do with this thread and Shovels can easily run the same comp as an Evo and the firing order is exactly the same for Evo's and shovels, soo, what were you trying to say.?
But yes I think it is correct that the CS is for shock absorbancy..

I've been running belt-drives with old 4-spd trannys exclusively on every sickle I've built since 1978 with Open primarys exposed to all the dirt the air has to offer..
I use old-style stock OEM drive plates and fibers disc's and have literally Never worn out a set..
In fact the clutches in my 93" shovel were old & used when I installed them back in the early 80's and run perfect today with literally hundreds upon hundreds of Hole-shots..

They DO NOT stick out any farther than the stock position Unless a guy gets one of those silly 3" Open systems..

I also currently run a 1978 4-spd behind my 120" EVO with an old used set of OEM stock clutches ( I used to get alota stuff at swap-meets) with a few hole-shots a week with absolutely NO probs..
BTW-- these sickles get run almost everyday even in the Phoenix Valley 116* days..

45--- statements made as Difinitive fact are likely to get challeged by others that know better sooo,, I suggest you stick to what you have as Hands-On First-Hand experience..

tstevens06 · #7 05-27-2009, 08:03 PM

Thanks for all the advise. Ill keep running the comp and chain until I have the cash and knowledge to change it out myself. Probably this next winter. I never do hole shots since my bike has about 50 remaining horses.

45Duece · #8 05-28-2009, 10:02 AM

Sorry if I offended your shovelness. I was at the 105th last year and open primary bikes were rare. Guys around here with 96's or bigger are running Barnett's or Baker setups because the stock basket would crack. Don't know any running 4spd either. A couple have done 5 to 6 or 6 to 7tc swaps geared for 1:1 top gear 3.5:1 final for drag race fun. Have a friend with a 79 with a 5spd though.

frisco-rigid · #9 05-28-2009, 02:55 PM

Ha,, your shovelness,,, that's cute..
Another comic..

Sooo, you were at a function, great..
And guys that are around where you hang run a certain product,, big deal..
In-other-words you yourself have ZERO experience with what you were talking and it's all based on what others are Running and Saying and alota 2nd hand BS..

Maybe those fellas with over 96" simply have a difficult time setting up their stuff if they're busting OEM baskets..
My old stock '86 OEM 5-spd handles the 127" I installed with no prob..

Now,, 45,,,I'm not trying to bust your chops or make you feel un-welcome but Hands-On First-Hand experience is all that get's respect & credibility on this forum..
Maybe it was Ok and acceptable to lay down 3rd person 2nd hand hear-say on the other forum you came from but it don't cut the mustard here..