Thanks for post feature available again: viewtopic.php?f=7&t=17581

S&S Carb on BIG Flathead

All flathead topics
Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

S&S Carb on BIG Flathead

#1

Post by Blind Melon » Sun May 01, 2016 2:52 pm

Hello All,

I just joined this forum in search of anyone who might share any experience/s using
an S&S E carb on a big twin flathead.. I've been running a 101" VL for about 20 years.
Huge stroke (5 1/4") with a Keihin carb off a 1978 Shovelhead... The carb works great
but I want a bit more top end..I have the S&S and it looks like it will fit up about the
same...Does anyone have experience on using this or close to this setup? Just wondering
what I might expect...Oh, the Keihin works best with original jets..



58flh
Posts: 3340
Joined: Sat Jun 26, 2010 1:54 pm
Bikes: 1958flh 1969sporty,had a knuckle but sold back to original owner
Location: NEW JERSEY
Has thanked: 195 times
Been thanked: 259 times

Re: S&S Carb on BIG Flathead

#2

Post by 58flh » Sun May 01, 2016 4:32 pm

Blindmelon----Sounds like a nice machine you have!--Unfortunately going with the S&S-E wont help you there,/Even if you run with stock jetting!.Its just to much fuel for the motor??/I question this as /you did not mention on using aftermarket cam/Bigger valves???.This all comes into play.Your better off being Under-carburated a little then going over bourd.You did say that your looking for more TOP-END!//If your chasing the clock with 1/4-mile runs/Then you want that fuel!!!--The Kehien is more then capable of handling this task.It has the stock jetting in it//so you can bring your reamers or other jets that will come in .002 increments/& work the Hi-speed from there.I prefer opening jets myself as you can get the in-between sizes that are not made/as far as I am aware of/I can be wrong.But if your really into beating that clock/.001 can mean more speed!(be it ever so slight!/better times are GOOD when Clock-running.)/But if she is a street runner,There are other ways to get that Top-End X-tra that you want!/& alot cheaper then a $500,S&S-E/that you (no-doubt)/will be adj. for weeks to come before you find what your looking for!.---Just some thoughts from a former Clock-Chaser/---Respectfully----Richie

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#3

Post by Blind Melon » Sun May 01, 2016 6:08 pm

Richie,

Thanks for the reply. Have you run the E on a stroker? That's what I'm hoping
to find. Someone who has run an E on a big inch flathead.

To answer your questions.... I do have welded up cams... Increased the lift from 0.385"
to 0.485 with very little change in duration. Stock valves, polished but they are in
UL type cylinders (20 year old FHP, from Sweden)..

I attempted to improve the jetting on the Keihin a number of times (long ago)... The
best overall performance was the original Harley settings.. The carburetor came off
a 1978 Low Rider, 74 cu in.. So, I am guessing the engine breaths about the same as
a Shovelhead, at least up to 3,500 RPM.. After that it is pretty flat..It will outrun any
stock Harley (Knuck, Pan, Shovel) up to 80 mph, from a standing start.. I have a self
imposed RPM limit of 4,200 RPM (105 mph) because the piston speed gets a little
scary and the mechanical drag above this is huge.

So, I know my quest is a little out there. But, I also know lots of folks experiment,
all the time... Just looking for others experience, if they care to share.

kitabel
Posts: 853
Joined: Tue Aug 03, 2010 7:10 pm
Bikes: 2008 96" Fat Boy TC
Location: Lynbrook, New York
Been thanked: 84 times
Contact:

Re: S&S Carb on BIG Flathead

#4

Post by kitabel » Sun May 01, 2016 7:08 pm

What does your intake tract look like? Manifold? Nipples?

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#5

Post by Blind Melon » Sun May 01, 2016 7:45 pm

Kitabel,

The intake is pretty much stock UL.. I did smooth out the ports the intake manifold
is a stock UL except the port ends were shortened so the manifold would fit..The UL
ports are lower when UL cylinders are on VL cases...I made an aluminum adapter
that is 2" long between the carb and the manifold.. It's tapered from 1 1/2" diameter
on the carb end to 1 3/8" on the manifold end... It keeps the carb from touching
the cylinder fins and gives a bit of "ram effect"...

I plan on opening up the adapter a bit on the carb end.. I really just want to know
if anyone has run an S&S E carb on a big twin flathead. And preferably a stroked
88" or bigger engine..

I really am not looking for a "how to" on this subject... I am looking for a " I did this
on my flathead stroker and here's how it turned out"...

rigidpanman
Posts: 123
Joined: Fri Jul 01, 2005 2:44 pm
Bikes: 49 fl,71 honda 750 sohc k1,98 cbr600f3,2)gl1100 goldwings
Location: hopewell va
Contact:

Re: S&S Carb on BIG Flathead

#6

Post by rigidpanman » Mon May 02, 2016 4:32 pm

interesting bike

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#7

Post by Blind Melon » Sat May 07, 2016 11:23 pm

S&S 002.JPG
S&S 002.JPG (214.69 KiB) Viewed 2707 times
S&S 001.JPG
S&S 001.JPG (193.86 KiB) Viewed 2707 times
Here's the S&s with 7" air cleaner to disguise the carb.. I just added the stand alone
enrichener and heli coiled the air cleaner adapter plate.. On the 1st test, the engine
was bit too lean in the mid range... So, I remove the carb and went from a .295 to a
.310.... I'll be testing again on Monday.. The experiment is to determine if the S&S
carb will help the top end performance.. The intake tract and air cleaner are NOT
optimum.. I'm just looking to see if the bigger carb will make a difference.. The
engine is huge and just might appreciate a carb with a larger venturi (Keihin 38 vs.
S&S 50 mm carbs).

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#8

Post by Blind Melon » Sat May 07, 2016 11:29 pm

One last thing... I was told long ago that you can't stroke a VL engine out to 101 cu. in.
I've been told that an S&S "E" carb won't work on a big inch VL...

I now know that big inch Harley BT Flathead work, stay together and put out decent power.
(18 years experience)... I now see to find out if this setup will work with an S&S "E" carb.. On
the street, in traffic, on the freeway...

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#9

Post by Blind Melon » Sun May 08, 2016 7:31 pm

OK, I couldn't wait. I just got back from a short test..And, I still had a stumble going
into mid range.. Just like S&S says, I adjusted the idle, the mixture screw and cut
the accelerator pump travel to zero...Wallahh, the stumble is gone! And it seems
I now have more mid range and top end..I'll continue to test tomorrow.

So, YES! An S&S "E" will work just fine on a big inch flathead..

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#10

Post by Blind Melon » Sun May 08, 2016 8:17 pm

VL and S&S 004.JPG
VL and S&S 004.JPG (181.14 KiB) Viewed 2679 times
VL and S&S 001.JPG
VL and S&S 001.JPG (171.26 KiB) Viewed 2679 times

Bigincher
Posts: 2830
Joined: Tue Dec 18, 2007 2:10 pm
Bikes: 1941/59 EL
1952 FL
1977 FLH
1994 Fatboy
Has thanked: 21 times
Been thanked: 100 times

Re: S&S Carb on BIG Flathead

#11

Post by Bigincher » Sun May 08, 2016 8:25 pm

Looks great, Melon.
I have to ask: do you attribute your success to eliminating the accelerator pump function?
I know it's a common mistake that many make, setting the a/p to come on too soon or too much, causing stumble. Will your further tuning be to play with a/p, bringing it into play?
Been following your thread, but unable to comment as I have no experience with a stroked big bore flatty!
(But I am running the Super-E on my stroked shovelhead.)

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#12

Post by Blind Melon » Sun May 08, 2016 8:37 pm

Hello,

Yes, I turned off the a/p to test...And that cleaned up a stumble going into mid range.
And yes, I will continue to test and adjust for a few hours more, next week... I am
surprised that with a total running time of about 25 minutes, this thing really works.
Hell, my intake adapter is a restriction, and my intake manifold is pretty much stock
and yet going from a Keihin 38 mm carb to the S&S makes more power...

The engine was an experiment from 18 years ago that worked...Ever heard of anyone
stroking the living crap out of a VL? Well, I have heard of BIG UL's running @ Bonneville
but not a VL... I never have much money or time but, sometimes I get lucky..

Thanks for your interest. My last Shovelhead (sold 17 years ago) had 4 5/8 wheels in
it and ran like a raped ape... My current highway bike is a V-Rod with floor boards..
This VL (actually a VD) is my play bike...It keeps me thinking and out of the bar..

58flh
Posts: 3340
Joined: Sat Jun 26, 2010 1:54 pm
Bikes: 1958flh 1969sporty,had a knuckle but sold back to original owner
Location: NEW JERSEY
Has thanked: 195 times
Been thanked: 259 times

Re: S&S Carb on BIG Flathead

#13

Post by 58flh » Sat May 14, 2016 11:40 am

Melon----Great news on the vl!///I have a ??---Are you using a Foam/oil type air filter?//or a Paper-pleated one?//Reason I ask is I had Way better times with a Paper-pleated type.It was a K&N round type that would fit your round arrester perfectly.This was on a stroked Shortster/Yrs. ago using a S&S-B carb.I loved that dam B carb.!--It was put on a few different mills /(& set-up for them ofcourse)--I found that that drilling the airbleed & screwing in a 120 mainjet made the B act as if it had a Accel-Pump!//You could snap the wick open fast & it instantly would respond/As per stock airbleed ,the throttle needs to be rolled open to wide open.---Best of luck with that VL--Very nice machine you have!----Respectfully----Richie

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#14

Post by Blind Melon » Sat May 21, 2016 1:59 pm

58flh,

Yep, I am using a K&N filter element in the air cleaner can. I've also had great luck using an S&S "B"
carb..They seem to make a bit more power on a shovel or pan than the shorty carb.. But with this
flathead, the overall length of the intake tract is a consideration..Mostly for style and riding comfort.
I've had this monster on the road now for 18 years.. I ride it on lots of AMCA national and chapter
rides.. I really need the left leg clearance, so I went with the shorty ..This carburetor change is
the biggest departure from using original Harley parts...With the exception of the S&S 5 1/4" flywheels.

Blind Melon
Posts: 38
Joined: Sat Apr 30, 2016 11:32 pm
Bikes: 1935 Harley VD
Location: So Cal

Re: S&S Carb on BIG Flathead

#15

Post by Blind Melon » Mon Jul 16, 2018 4:00 am

OK, after screwing around the the S&S E carburetor, I switched back to the Kiehn... I also switched to S&S aluminum heads and a
set of American Cycle Fab custom cams... These are brand new.. A combination of a new gears from a shop in Orange County, new
shafts from a local machine shop and new lobes by Paul P. @ ACB back East... The new cams are .485" lift and about 290* @ .010 lift.
Starts and idles very well... And the 101" stroker VL now makes significant power above 3,000 rpm.... It always pulled great at low rpm
but it's even stronger now... And with much more "SNAP" above 2,000 rpm (55 mph with current gearing). The new heads were much
easier to cut for valve clearance than the iron heads..........[media]Image[/media]

Post Reply

Return to “Flathead and Servicar”