Lugging a twin cam engine

[PoorUB]

Low cylinder pressure + high flywheel inertia permits smooth running at much lower RPM.

"the V8 doesn't have two rods with oddly-timed pressure pulses banging on the same crankpin"?
They all do - every "V" engine does.

My ex-work toy idled at 200, power between 1,100 and 1,250.

Leroi H-2000 V8.

It is silly to compare a modern V8 to a Twin Cam. First off the V8 is a pressure lubed, plain bearing engine. The bearings are flat and smooth and ride on a film of oil, no oil pressure and the bearings die. The Twin Cam has pressure lube, but roller bearings for crank and rod bearings. The bearings could care less if there is any oil pressure, as long as there is oil present, they are happy. Plus a roller bearing has extremely small contact areas compared to the modern V8 engine.

I own a 1936 John Deere. The engine is pressure lube, plain bearing, and redline is 975 RPM. It will idle so slow you can almost count the revolutions of the flywheel. You can make out the words cast into the flywheel when it idles. I wonder at what RPM is considered lugging?

[N-gin]

Well I don't think it's a good comparison between vehical engine and a v-twin. For the simple fact a v 8 has 4 power strokes per revolution. So obviously it will runn smoother at lower rpm.
As for the 4 cylinders I don't see any puttin around on the highway under 2500 I know mine is happy at 2800 at 60. The Geo has a three cylinder and like 3100 on the highway.

As far as our bike go, I know for a fact that when I was tunning it. It would surge and buck at 2000 rpm with a bad tune. Now that it tuned properly I can go to 1500 at cruise and be ok. I just can't twist on the throttle fast.

A good rule of thumb is if I can hear my comp. it's time to drop it a gear.

[1FSTRK]

Here are the quotes as to not muddy the waters, these came from Wolf.

"S&S Cycle, Inc. Luggin your motor does more damage than you think. Riding below 2,800rpm is lugging, in any gear at anytime. Just because you have a 6th gear, does not mean you need to use it. Be a wise rider, shift when you need to, don't be lazy."

In response to what would be to0 high of an RPM:

"S&S Cycle, Inc. too high? that would depend on your motor design over all.I'd like to see 6250 once in a while, but i don't stay there. Constant, ride all day at 2,800/3,500 long live the motor. you could ride at 4,000 i guess but that might shake things apart on your bike, but not hurt the motor, as much as lugging it would."

"S&S Cycle, Inc. I don't believe it does say this in manuals, hence why I feel it is important to share this with American V-Twin Owners. Your motor loves the 3,000 rpm range, anything below you start to enter the unbalanced lugging area. depending on stroke, pistons, compression. But any and all V-Twins I have ridden or operated have always loved the 3,000 range. It's something I have always felt and I have seen testing to prove it."

And:

"S&S Cycle, Inc. in town driving is not the same as Highway driving, (which is where the most damage can be done). the occasionally town ridding, i can see and would accept the 2,000/2,500 rpm. It's the highway pulling the big gears, lugging that is so damaging. the amount of time spent at this RPM while lugging the motor is the smoking gun, so to speak."

Are these quotes from S&S printed materials that they send with ever motor or from a person at S&S expressing his personal opinion?

[Jaycee1964]

Here are the quotes as to not muddy the waters, these came from Wolf.

"S&S Cycle, Inc. Luggin your motor does more damage than you think. Riding below 2,800rpm is lugging, in any gear at anytime. Just because you have a 6th gear, does not mean you need to use it. Be a wise rider, shift when you need to, don't be lazy."

In response to what would be to0 high of an RPM:

"S&S Cycle, Inc. too high? that would depend on your motor design over all.I'd like to see 6250 once in a while, but i don't stay there. Constant, ride all day at 2,800/3,500 long live the motor. you could ride at 4,000 i guess but that might shake things apart on your bike, but not hurt the motor, as much as lugging it would."

"S&S Cycle, Inc. I don't believe it does say this in manuals, hence why I feel it is important to share this with American V-Twin Owners. Your motor loves the 3,000 rpm range, anything below you start to enter the unbalanced lugging area. depending on stroke, pistons, compression. But any and all V-Twins I have ridden or operated have always loved the 3,000 range. It's something I have always felt and I have seen testing to prove it."

And:

"S&S Cycle, Inc. in town driving is not the same as Highway driving, (which is where the most damage can be done). the occasionally town ridding, i can see and would accept the 2,000/2,500 rpm. It's the highway pulling the big gears, lugging that is so damaging. the amount of time spent at this RPM while lugging the motor is the smoking gun, so to speak."

Are these quotes from S&S printed materials that they send with ever motor or from a person at S&S expressing his personal opinion?

2,800 in any gear?  Damn,  I don't think my town cops would like me much or my wallet from the tickets i'll get.  3,000 at highway cruise in 6th is a nice spot but not going going in excess of 4K well damn, those 640's in their 124" crate are just waking up at that RPM!

[bigbearkiller]

I don't have a tach on my 95" five speed but I can say I rarely get to fifth until 55 mph.A warm engine benefits from slightly higher rpm's.I test rode a new 96"/6 speed and didn't feel comfort at 75 mph in 6th...in truth a six speed transmission is sort of useless to me...imho.

[NHBagger]

What is the definition of" lugging the engine"
What damage does it cause in a twin cam and why/how?

1FSTRK, thanks for posting this!  i kinda took it on the chin in another thread about being able to run at lower RPMs.

[1FSTRK]

It seems that many consider any rpm under what there bike runs at lugging. You have to wonder if they have ever ridden a bike that has a great torque curve that starts at 1800-2000 rpm. I guess I can understand the point of view if they are riding a open pipe bike with a tq dip that makes less than stock at 2500 rpm. 

[Hillside Motorcycle]

Would lugging be considered 2500 rpm's in 1st or 2nd gear?

[guydoc77]

Would lugging be considered 2500 rpm's in 1st or 2nd gear?

Exactly!
The original question was answered be Ron in post #3, page 1.

[NHBagger]

It seems that many consider any rpm under what there bike runs at lugging. You have to wonder if they have ever ridden a bike that has a great torque curve that starts at 1800-2000 rpm. I guess I can understand the point of view if they are riding a open pipe bike with a tq dip that makes less than stock at 2500 rpm.

My setup at that time made almost 100 ft-lbs of tq at 2000 rpms.  With 3.36 gears, you could esily cruise a flat backroad at 1800 with prudent throttle usage.

[panic]

It is silly

Did you mean "I disagree", or were you just being rude?

[Jaycee1964]

All I am\was saying is that why use a 4th, 5th, 6th gear in a situation that warrants a lower gear?  I have a 124" that will pull thru anything but it doesn't mean I do.  At 2K in 5th gear it is about as responsive as my wife is after 25 years of marrige........... 

[wavlovr1]

My 95 motor makes power between 4000 and 7000 rpm. jb

Wow,
Your 95" Twin Cam pulls to 7 Grand? What cam and set up is in that?
Did you post it in the Dyno Section?

As far as lugging, just listen to your motor and it will tell you what is a happy rpm-Simple as that. No tach needed for me-just a shift light, which is a whole other conversation...
Been riding a Screamin' Eagle VRod while we are working on the G2 126" (which was all done at 6,400-6,600) and man, the VRod doesn't even wake up till 5k and the sweet spot seems to be 5-8,000-and thats not even hammering it...

2002 softail Deuce w/95 inch;
Keith-Black dome pistons, 11:1 compression.
HQ 0033 gear drive cams, springs, lifters, pushrods, HQ ported/polished heads.
SE Intake, V&H Propipe.
SE clutch with Aim VPC.
Newer more narrow drive belt and pulleys to get a 200 tire in rear.
Twinscan with Wego IID and SERT for tuning.
I don't collect dyno sheets but last dyno pull was 114-116, cant remember which was which.
It sees 7000 rpm several times every time I ride it. Been turning it up like that for ten years now.
The only breakage I have had was cam chains took out cam and oil pump once (thus the gear drives)
and sheared off the rear drive pulley bolts.
18 inch wire spoke rim snapped off 6 or 7 spokes (so replaced with alloy wheels).
Still runs, still fun. If 7000 ever kills it I will let everyone know. 

[pwmorris]

My 95 motor makes power between 4000 and 7000 rpm. jb

Wow,
Your 95" Twin Cam pulls to 7 Grand? What cam and set up is in that?
Did you post it in the Dyno Section?

2002 softail Deuce w/95 inch;
Keith-Black dome pistons, 11:1 compression.
HQ 0033 gear drive cams, springs, lifters, pushrods, HQ ported/polished heads.
SE Intake, V&H Propipe.
SE clutch with Aim VPC.
Newer more narrow drive belt and pulleys to get a 200 tire in rear.
Twinscan with Wego IID and SERT for tuning.
I don't collect dyno sheets but last dyno pull was 114-116, cant remember which was which.
It sees 7000 rpm several times every time I ride it. Been turning it up like that for ten years now.
The only breakage I have had was cam chains took out cam and oil pump once (thus the gear drives)
and sheared off the rear drive pulley bolts.
18 inch wire spoke rim snapped off 6 or 7 spokes (so replaced with alloy wheels).
Still runs, still fun. If 7000 ever kills it I will let everyone know. 

Man, thats amazing-
Was checking out the specs of that cam and I have never seen 7 Grand power pulled from anything close to those specs in a street comp twin cam (went to the HQ site as well and their stuff is done by 6-6,500)-Went thru about 5 pages of dyno posted sheets as well to try and find something comparable but came up empty

http://www.harleytechtalk.com/htt/index.php/topic,49947.msg524367.html#msg524367

That must be one hell of a combo!


HQ0033-
Intake     19/47     246   .600" lift
Exhaust  52/24     256   .530" lift

Are you watching a tach when you spin it up to 7G's? What is you rev limiter set to-7,200, 7,500?

[Jaycee1964]

That's crazy.  When I had my 98" with 211's at 11:1 I pushed 6500 a couple times.  There aren't many street cams out there that are not tailing off by 6200 max.

[Breeze]

Everything I've seen/read on the HQ0033 shows it is  after 6,000.  But I've not seen that combination.

[rbabos]

I'm thinking piston speed at 7k will be more threatening then lugging would.
Ron

[1FSTRK]

He never claimed it made power at 7K he just said he ran it up there. Remember this is a lugging thread and he stated that he uses the shifter to keep the rpms up where he likes them.

[pwmorris]

He never claimed it made power at 7K he just said he ran it up there. Remember this is a lugging thread and he stated that he uses the shifter to keep the rpms up where he likes them.

Actually he did-

My 95 motor makes power between 4000 and 7000 rpm.
jb

But you are right, this is a thread about lugging, and I don't want to hijack it.

[jam65]

I don't want to jack the thread either but Paul, your "in box" is full.

[Homeward Bound]

I would have defined "lugging" more by the load the engine is being subjected to rather than simple rpm, e.g. an engine in a stationary motorcycle at a healthy tickover is not lugging at all, whereas whacking open the throttle in a high gear at low speed is. Ditto, cruising down a hill is not, whereas pulling up one at the same rpm might be, especially if then going to overtake.

Where I live 2500 rpm in high gear is 6 mph over the speed limit on the state highways.

Yes, this is a problem and the theory is it's all to do with H-D struggling to pass to EPA noise testing rather than developing a motorcycle that works as it should. In short, the chosen gear ratios are all wrong for real world riding with an impossible designed top speed of around 140 mph for a bagger or cruiser. H-Ds are massively overgeared, a situation which is even worse in markets like Europe and Japan where noise regulations are even more strict.

This has led to folks developing the habit of lugging their engines in a far too high gear rather than spinning it, and thinking it's fun/normal/healthy rather than stressing their engines.

The reason is the EPA 50-foot test standard (Link to 40CFR205) which is conducted along a limited length test track, the distance from the acceleration point to the end point possibly be as little as 32.8 ft, during which a big-twin has probably just manage a breathy 'dok-dok-dok'.

Hence folks sticking on 70T pulleys or 21/24T compensator sprockets in an attempt to make the bike what it should be, e.g. with a reachable designed top speed of, say, 120 ... but then running into problems with too low first gears.

I'd love to know how the engineers would have designed it had they not have had to squeeze it through the needle of the EPA's eye. I'd guess higher first gear, lower top gear ... 4 gears with an over-drive.

Or may be they really do need lower first gears for all the 200lb riders plus passengers?

I had my 124 out today...and yesterday. I can roll it down to 1800 rpm's in any gear ...

Yah, it's a different game if you have all that power but, honest question, what sort of oil pump have you in there?

It's slightly off topic but related ... lower rpm, less oil circulating.

[bigfoot5x]

Wow! Sure is a lot of input on this thread. Not much said about elevation or terrain that you are riding in. My bikes will pull comfortably in high gear at 2000 rpm or just over, but I live in Texas near Houston where it is flat. I travel a lot and have noticed often times that in hilly terrain or mountains, the engine will not pull so well and I use a lower gear. To me it is all about listening to or feeling how the engine is responding. The owners manual does state that 6th gear can be used for speeds above 55 mph. Works great around here but not in New Mexico. I have a friend that insists 6th gear should not be used at less than 70 mph. He likes to just roll on the throttle to accelerate. Personally I'd rather be in 6th and downshift to pass. Who's bike will last the longest? Don't know.

[1FSTRK]

I had my 124 out today...and yesterday. I can roll it down to 1800 rpm's in any gear ...

Yah, it's a different game if you have all that power but, honest question, what sort of oil pump have you in there?

It's slightly off topic but related ... lower rpm, less oil circulating.

We touched on the oil supply earlier in the thread. Do you have any actual info on the affects of running these motors on the amount of oil supplied by the stock pump at say 2000 rpm?

[FXDBI]

The load on the engine is greater than the power being produced by the engine at the time of acceleration to increase speed of travel. That would be my definition of lugging a twin cam or any engine for that matter.  Every engine has its "Power Band" that's  where some like to ride some like to float . Its yours ride it like you want          Bob

[MaxxV4]

 "The load on the engine is greater than the power being produced by the engine at the time of acceleration to increase speed of travel."
                       
Great and simple description. If my motor is idling, is it then lugging? No because there is no load on the motor at idle just like there is little to no load on a motor while cruising down a hill of even flat ground without a headwind. The taller the gear, the more critical that becomes. So, as long as you are in tune with your ride, you know when you should downshift and that will be before you feel your comp sprocket talking to you.
JMHO
Mike