A Mikuni HSR for my Harley? which one?

afterburn 549 · 02:47 AM

Ok up and running pretty good here.....
But
It is now dwn to perhaps-
FDR, and a better carb ,
To outline not brag-
The stats are -
A 1994 Evo FLHR 5speed
Stock stroke.
Axtel 85 inch 10.5 CR forged pistons ,cast iron cyl (less less movement )
Head cut to fit pistons
.030 squish band,
Dual plugs run by Daytona twin tech.
Dave Mackie 530 cam and springs
slight port polish
.060 over Manly valves.
Thunder headers.
Now my Question - Which Carb? HSR 42, to 45?
Or a Flat sided one?
I have done all the tricks to the CV but it lacks.
BUT-
There are so many choices .....
I do use this as a cruiser too.
I get the pitch that the HSR42 (more velocity )is better, to the 45 bigger,Bigger is better theory .
Confused in a mid life crises here ! LOL
At 500 bucks a whack mistakes are hard tolerate .
Thanx.

asphaltgambler · 06-04-2015, 07:25 AM

ONLY set-up to run: Zippers Performance - modified S&S Super "E" with Thunderjet (3rd - high speed fuel circuit) installed with adjustable air bleed for mid range. Go to their web site or call to get quote for your combination. Absolutely no other carb can compare except for closed loop fuel injection.

PM me if you have any other questions

afterburn 549 · 06-04-2015, 08:24 AM

I am glad you saw this .
Your answer surprises me. But does not shock me.
I know you know your stuff.
So thats the all around best set up? not just a TT (tavern to tavern )
I will putt putt over to their sight and look in the window......

afterburn 549 · 06-04-2015, 08:43 AM

this one?
S&S
I see they have a "G" also

Chocaholic · 06-04-2015, 10:40 AM

I have the factory Mikuni on my 06 88" and it's been flawless. Just a data point.

Can spend a lot of money to end up with a slightly less slow-poke Harley, so I didn't go down that road. SE pipes and jetted for better music.

Ride safe.

asphaltgambler · 06-04-2015, 10:48 AM

Hi - yes that is the one. Their "E" carb is well suited well to your combination. The "G" carb is for larger 100"+ engines. S&S (like Holley) makes great carbs, but only as a starting / foundation point.

Harley engines are 'under-squared' design which means the stroke is larger than bore. When you modify them even just a bit, the air flow requirements @6000 RPM's are huge. Very different animal then say sport bike inline-4 engines; which are 'over-square'. Those engine air flow needs per-cylinder is waaay less even @10,000 RPM's.

All motorcycle carbs have just 2 fuel circuits: low speed and high speed. Modified Harleys need so much air above 4500 that it is impossible to properly jet for mid-range and then WOT. By adding a 3rd fuel circuit (Thunderjet) you then tune the existing main jet as a mid range circuit and the T-jet is set for 4500 RPM and above. BTW, the T-jet draws fuel and then is partially atomized prior to entering the carb throat. So the tune is very precise.

By adding an adjustable air bleed for the main jet (now mid range) you control when that comes in. When set-up and jetted correctly you cannot believe how much difference it makes

afterburn 549 · 06-04-2015, 11:10 AM

Good to know !
You have guess for jets with my stats?
thanx!
( i will get the E with the thunder jet)

asphaltgambler · 06-04-2015, 12:04 PM

I have an idea, but you should call Zippers. They will either ask then or may email / supply a data sheet form where you fill in the blanks with your combination along with average altitude where you are.

They are extremely knowledgeable, well versed in what make a street or race Harley run 'in-da-front'

I have done countless conversions on street Harley's in the past years from someone else's 'trick' carb to this or "G" similarly prepared - with nothing but smiles on the faces of my customers afterward. Tuning a long stroke air cooled engine is an art - and they have it!

afterburn 549 · 06-04-2015, 04:11 PM

Thanx
I will do just that !

KevinTodd · 06-05-2015, 03:42 AM

Agree on the Super "E". I've been running this set-up on my highly modified 1340 for years and it works like a champ.

asphaltgambler · 06-05-2015, 06:53 AM

Also the air cleaner / filter setup is crucial. Best to go with the S&S 'tear-drop' with the taller K&N filter. Looks very old skool but it has a h3ll of lot-O-science / air flow technology behind it. Always makes me laugh when I see those ridiculous butter-fly air cleaners or forward facing funnel scoops on Harley's.....................

afterburn 549 · 09:29 AM

Quote:

Originally Posted by asphaltgambler

Also the air cleaner / filter setup is crucial. Best to go with the S&S 'tear-drop' with the taller K&N filter. Looks very old skool but it has a h3ll of lot-O-science / air flow technology behind it. Always makes me laugh when I see those ridiculous butter-fly air cleaners or forward facing funnel scoops on Harley's.....................

LOL when i see those things i know I am looking at "wantabee no nothing novice" (the butterfly things).If only they had a clue.Right ?
plus are they not like 700 bucks!-?
But at least i know not have to wast my time talking "shop" with them.
Changing air in the tires I am sure is a challenge
Next
Ok i talked to Pete at zippers.
700 .00 bucks and I can have a thunder jet super E...
I am going to add my potato chips up here..........
He said it is the carb for a gear head, and a Mukuini for a just bolt on better performace

asphaltgambler · 06-05-2015, 10:32 AM

............Pete would be right. Most any carb out there will work OK, but their "E" is the *****. I've even modded a few stock CV carbs for the Thunderjet conversion for bone stock set-ups where the jetting was changed, T-jet and proper air cleaner added - made a huge difference!

afterburn 549 · 06-05-2015, 11:33 AM

Pete was vacillating between the E and the G carb
Being i do not have a race bike, just want a good all around performer the smaller E will do better, with more velocity ...............?
i guess thats a question..
You all ready said use the E.

asphaltgambler · 06-05-2015, 12:03 PM

Their "E" is perfect and more than enough airflow for your application. It really is the best all around street performance carb for smaller displacement engines such as yours. I have seen the "G" carb work well on one 96" motor but it had a lot of camshaft, really good aftermarket heads and 11.3+ mechanical compression. It really was a high effort small displacement (these days) 'street-able' engine.

afterburn 549 · 06-05-2015, 12:44 PM

Ok
Great !
The people on this board are geniuses ! Thanx so much for the advice and help ( as usual )

asphaltgambler · 06-05-2015, 01:06 PM

.....me...................a genius? Ha!! I do have a lot of experience with performance Harley's tho.............I have tried some of the not-so-good-as promised parts and failed too. I've definitely spent tons on $$ experimenting.

afterburn 549 · 06-05-2015, 01:29 PM

Tis funny-
On a harley forum all it ever is, is the same old crap .
No new thoughts.
Mostly Twin cam stuff.
So again Asphaltgambler -thanx for the help.
On this board there is a LOT of different talent for most anything a guy needs.
I even asked for help with a articular pick up at someone else house to be shipped the other day.(west coast and I am on the East )
(a helicopter rotor head)
Someone on here volunteered to do it for me.
It did not work out,(because the seller is a butt) but there are a great bunch of people here.
Thanx again

asphaltgambler · 06-05-2015, 01:44 PM

Agreed! ......................................best forum car content or otherwise on da planet! I cannot tell you how much others here have helped me directly or indirectly - possible some pitied me and did anyway. VERY diverse group and like a dive bar where you might meet an attorney or a lady of the night always interesting !!

Jeff Higgins · 06:38 PM

Great thread, and pretty timely for me.

As some of you know, I've been playing with my '76 Sportster (bought as second owner in 1980). I've been completely through it, and pretty much used the "best of everything".

It's still stock displacement, but features S&S rods/wheels, Wiseco 10:1 pistons, Andrews R5 cams, Jim's "big axle" lifters, chrome moly pushrods, heads by Dan Baisely (roller rocker tips, minor cleanup around the guides), Kibblewhite valves, springs, and retainers, and... a first gen S&S Super E that's been on it for 20 years. It's currently jetted 26/170.

It seems I have two choices - screaming top end from 4,000 to 7,000 rpm with a burbling, flat bottom end below that when I run it on 1 3/4" x 40" straight cut drag pipes; or stump pulling torque down low, but an inability to even rev above 5,500 rpm when running it on staggered dual mufflers of some indeterminate brand.

I have a set of Cycle Shack slip-ons coming as we speak. The plan is to cut the drag pipes to serve as the head pipes. These have a great reputation for providing both the high-end power I enjoy with the straight drags, and the low-end the mufflers provide. Thoughts on this?

And, in the end, carb jetting - specifically, the Thunderjet. Would there be any advantage to running one on my (smallish) displacement Ironhead?