out with the L5 , in with the C grind

[76shuvlinoff]

I ran a B in my 93 for a while, I was not all that impressed. To me it was not much different than the L3S. I felt the L3S was a step up from it but maybe I am too dense to pick up on the nuances. In between the B and the L3S I ran an S&S 560 with an E carb and a Thunderheader, with those the 93 kicked ass up top but that's not where I ride any more.

  I really want to get the bike out with the 7 and new carb but I've been a bit under the weather, the stars are not co-operating for me to take a test run but I'll get there.

Mark

[monty101]

To get this down to the basics:

If you keep the same ramp slope and you increase the lift dramatically .485 to .525 your lobe ramp has to start sooner on the cam shaft circumfence to get the higher lift.  By starting the opening cycle sooner you  will have the valve opening starting sooner and
closing later. This is called duration.  If the lift is higher you will get more fuel and more "Bang" and power but the trade off is the
valve opening sooner and closing later could mean valve opening overlaps the closing valve  and you will loose compression and power at the lower RPM.

Once the RPMs get higher the loss becomes not a problem.  I suspect it is due to a combination of factors . One: is because they open and close too fast for the compression to escape and two: the bigger bang at the higher rpm offsets the loss.  Scooters with C cams are easier to kick through than a B cam because of the overlap issue .  A L3s has a lot of compression and that makes it harder to kick over . It has  240 duration and very little if any overlap. That is why it pulls so hard at the lower rpms but has no top end because the lift is only .480.

The L51 gets around this loss of power at the lower rpms by having fast cam ramps and also higher than stock lift. The cam still have a high lift and can still open more than a  stock cam  and may actually stay open longer because of the steeper ramp. This also means you get a bigger bang.

The loud bark of the L51 proves it gets plenty of fuel. Its a lot louder than a B cam. It pulls a 6 speed in overdrive .85-1 real well at
60 and it has the same duration as the b cam but lots higher lift and the fast ramps. i guess those factors allow it to overcome the overlap
that the b cam has. A b cam won't pull a 6 speed without lugging down in 6th. You need to be running 95 or more to use it.  You can
shift into 6th at 60 with a L51.

I ran a c cam in a stock 74 once. I pulled a b cam to test it. It did not pull as hard and I could not get the 74 up in the rpm range to
get any benefit from the higher lift. That cam is setting around in my shop now. i stuck the b cam back in. I suspect if I had been running higher compression it would have had a lot more power and that power might have offset the overlap problem at the lower rpms. I never ran it again so I don't know....

I have found cams can only be evaluated if you run two in the same scooter. I actually figured my 96 incher would need a 240 duration cam like a woods cam to solve its power problem at lower rpms in 6th. I was wrong even though the duration of the l51 is the same as the duration for a b cam the higher lift and fast ramps overcome the overlap problem.

As far as I am concerned if you want to keep stock gears and run a 6 speed 96 inch torquemonster it is about as good as you can get if you main concern is freeway riding.  You don't loose the lower end power and you get a big increase in power at the top end too. Just need ear plugs because it will bark at you.  With it you don't loose the low end torque or the topend power.

[79FLH]

  Thank you all for the input !!   I should have mentioned that I am still running a 4 speed tranny..  I made the decision a few years ago to rebuild the 4 speed, because I didn't have the cash to upgrade to a 5 speed..
   & I'm runnin solid lifters, So, that V-Thunder 4020 likes Hydraulic lifters I think....  & I'd like a little more lift....  But ,Thanks anyways Billbuilds !!
     I really like everything I'm seeing about the Andrews #7,  I'll wait to see what 76 has to say about it after he gets to put a few miles on his...   
     Till then,  I'm watching it snow right now, & the roads are covered with salt, So it'll be at least a couple of weeks till I get out...   I have to try the C grind, It's in & clearances are all good. 
     

[76shuvlinoff]

I'll wait to see what 76 has to say about it after he gets to put a few miles on his...   

That might be awhile, coming off a bout of pneumonia has me dragging tail. Temps this week are going back to winter with possible snow. The wife and doc have me on a short leash. Hell I haven't had a shot or even a beer in over two weeks. I was tempted to get her out today but elected to sit tight and do a PowerPoint for work. Probably the right choice, by the time I got her off the lift and out of the barn I'd be too whipped to hang on.   

monte, that's a real good explanation, thanks.

- Mark

[HotRodShovel]

Monty, thanks for the explanation. That pretty much seals an L51 in my motor. 
Good info, thanks. 
Mark, don't F with pneumonia.  I had it twice.  The Doc told me you only get it 3x in your life because After the 3 rd it will kill you.  Go easy, rest.  The bike ain't getting sick and its no good to you if you can't ride it.  Heal brother.... Heal.
Hopefully next week I start the rebuild. 

[76shuvlinoff]

Well damn Rudy, this is #2 for me too. 

I'll be waiting to hear how the L51 works out for you. I need something to do next winter. 

[billbuilds]

    Mark, I had acute bronchitis in early January that kicked my ass like nothing I've ever had before. Have you given up the smokes too?  I tried inhaling after two weeks w/o and it was a bad idea. Maybe loosing them for good would be a positive outcome for having been so ill.
     79, It's my understanding that there are cams that are ground such-as to require solid lifters but that it's ok to run solids on cams that are designed for hydraulics. I was running the 4020 with VelvaTouch's. Don't see where they prefer hydraulics though. The motor I had it in is a stock stroke 88" big bore. Pistons are 8.5:1. Not sure what actual compression is. I was thinking of buying Mark's L3S to put in it but funds are kinda tight and I've had a brand new Andrews 2 grind since last fall that I should really try first. Too cold to work in the garage and that motor is in the basement so I'll probably yank the 4020 out of there today or tomorrow. John, not sure what compression you're at in your 98"er but if you want to try this 4020 (got the L77-84 gear) you are welcome to.  Bill     

   

[shovelbill]

I'll wait to see what 76 has to say about it after he gets to put a few miles on his...   

That might be awhile, coming off a bout of pneumonia has me dragging tail. Temps this week are going back to winter with possible snow. The wife and doc have me on a short leash. Hell I haven't had a shot or even a beer in over two weeks. I was tempted to get her out today but elected to sit tight and do a PowerPoint for work. Probably the right choice, by the time I got her off the lift and out of the barn I'd be too whipped to hang on.   

monte, that's a real good explanation, thanks.

- Mark

feel better Mark.....and take good care with yourself

........i had me another bout with pneumonia (3rd since '86)before Thanksgiving........older we get the harder to shake it.

[76shuvlinoff]

Damn! I hijacked a cam thread with snot in my lungs. Sorry.

Today Doc says I'm nearly out of the hole, still weak but lungs are clear and X-ray only shows slight scarring from a bout I had in 94, that one hospitalized me but there are no new issues now.

Bill, I never smoked cigs but I grew up in a house where the old man had better than a 2 pack/day habit, had bronchitis almost every year back then.  I did get all wrapped up in cigars 6-7 years ago but got over it pretty fast. I still take one if offered but they usually just go out while I chew on em.

shovelbill, thanks, I hope you're all mended. I know I don't bounce off this crap like I used to.

Back to cams guys!

[easyricer]

"Back to talking cams" .... I'm still tickled pink over the Crane 288 2B that Bill sent me to try out. Between the .060 over slugs with a hefty bump in compression, the cam and now the dual plugs all firing. I feel like I could pull an old Lincoln around behind me. The temps outside are just a little on the cool side for a t-shirt but I toughed it out and blasted down 7 mile hill, and then back up again. 70-75 MPH back and fourth and she never gave me any fits. With the oil cooler turned on she never made it over 150 degrees while pushing the fairing through the wind. I can't be much happier.
Mark, get out when you can and get some bugs in your teeth!
EASY

[HotRodShovel]

Bill very generous of you on that 4020. I'll do some comparison on the specs and let you know.
General note: quit smoking and put the $$ into your bikes. 20 years clean. Cigarettes that is.

[76shuvlinoff]

Easy,
I have always ran an oil cooler and since I installed the 93"er in 04 I have never seen oil tank temps over 185. Just for giggles before last season I turned the crash bar into my oil cooler. The highest I saw was 170-175 but last year kinda sucked and I really didn't get SQUAT for miles....and this is Michigan. If you are seeing those oil temps in Texas you are doing really well.

[shovelbill]

"Back to talking cams" .... I'm still tickled pink over the Crane 288 2B that Bill sent me to try out. Between the .060 over slugs with a hefty bump in compression, the cam and now the dual plugs all firing. I feel like I could pull an old Lincoln around behind me. The temps outside are just a little on the cool side for a t-shirt but I toughed it out and blasted down 7 mile hill, and then back up again. 70-75 MPH back and fourth and she never gave me any fits. With the oil cooler turned on she never made it over 150 degrees while pushing the fairing through the wind. I can't be much happier.
Mark, get out when you can and get some bugs in your teeth!
EASY

if my oil temp only got up to 150* i'd be concerned........i'd loose the cooler for starters.

[easyricer]

Yeah Bill I would be concerned if the temp stayed like that but this is Texas and we don't get a bunch of 55 degree evenings. This time next month, I'll be reminiscing about these temps. If I can keep this old gal cooled down to under 200 during the 100+ degree days and 90+ degree nights, I'm as happy as can be. Before the rebuild, there was no chance the motor would stay below 200 with the windshield or fairing on. It always overheated before I got 20 miles out of it.
EASY

[shovelbill]

i tried to add to my post but it didn't take..........

i would guess you didn't ride her far enough to get up to full operating temperature......my memory isn't very good, but i seem to remember that cam having something like 10* more duration on the exhaust side.....most folks say that cam helps to run some cooler.

i'm glad you're happy......enjoy!

[HotRodShovel]

Hey Bill, reading  VThunder's specs on the 4020 and they say it needs hydros.  I'm running solids. I think you said you had Velva Touch.. I'm not sure how it would mate with solid lifters.  Any ideas?

[shovelbill]

Hey Bill, reading  VThunder's specs on the 4020 and they say it needs hydros.  I'm running solids. I think you said you had Velva Touch.. I'm not sure how it would mate with solid lifters.  Any ideas?

i know you're not talking to me John, but

just don't run a solid cam with hydros........plenty of people run hydro cams with solids............ can run any solid cam with Velvas  . Dave's running a "blem" special right now too.

[billbuilds]

     John, It's my uderstanding that it's ok to run hydro cams with solids but not ok to run solid cams with hydros. As shovelbill says, it's ok to run solid cams with VelvaTouch lifters. Bill

[HotRodShovel]

Bill & Bill. Thanks. How does this 4020 compare in lift and duration to the L51 ?

[billbuilds]

4020     .485 lift
                    17/45 intake - 242 duration @ .053
                    45/17 exhaust            "
                      .103 lift @ TDC

L51       .508 lift
                    40/65 intake - 256 duration @ .053 - .218 lift @TDC
                    74/30 exhaust - 255 duration @ .053 - .146 lift @ TDC
                     

[HotRodShovel]

Thank you Bill....appreciate the time and effort...I'll get back to ya re PM...

[Hillside Motorcycle]

You can run those Vern Ott lifters on any cam.
"Let 'er rip, 'tater chip."
Scott

[shovelbill]

You can run those Vern Ott lifters on any cam.
"Let 'er rip, 'tater chip."
Scott

speaking of Vern........

[HotRodShovel]

Scott, got plain old solids....seem to work for me...thanks much.

Bill  (anyone)...question about cam specs.  I get duration and lift. What I don't get are the values for the intake and exhaust such as 17/45 intake & 45/17 exhaust on the 4920 as compared to 40/65 intake & 74/30 exhaust on the L51

Also looking at L31 which has a 480 lift 244 duration at .053 and intake 44/69 & exhaust 77/36

I don't think Ill ever decipher these cam specs.Confuses the hell out of me.  If anyone can explain...I'm all ears.

Consider the factors: 98" 6 speed. Not so much concerned about drag and speeding in the streets, a red light every two blocks takes all the fun out of that. but my zone is highway. I want enough throttle to pass cages and have plenty of throttle in 5 & 6 gear and pull my 120lb wife along.

All comments appreciated.....

[76shuvlinoff]

That's pretty much the same thing I'm looking for out of my 93 John. You are going to love your new 98.

I gotta get out with this Andrews #7 one of these days. Got a ton of stuff to do Saturday and out of town Sunday, (looks like snow Sunday anyhow) but I will be rolling up my tarps "winter" walls on my work area this weekend and at least get a path cleared toward the barn door.