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Carburetor and plug advice needed for BB upgrade

863 views 8 replies 5 participants last post by  ViennaHog 
#1 ·
Hello,
thanks for all the advice I got on this list in my quest of upgrading my engine.

At this moment all parts for the 95" with flat tops and the SE-204's are ordered (including the Cometic 0.30)
I will use the stock head to start with.

My question: what is the starting point for my carburetor after installing the BB?
At this moment it has the 45 and 195 jets (stock) installed and the plugs look black on the outer ring, point and isolator look good .

Should I change to different jets immediatly (and to what size) or can I start
running with the present set-up and work from there.

Is the 'Nightrider' solution OK ? (Sportser needle with 165 main jet) ?

And do I need different plugs ? Hotter or colder ?

Many questions again, I know.

Best regards ... Jef
 
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#3 ·
I ran the Sporty needle and a 46 slow (try CustomChrome, DragSpecialties etc.), and the stock main with BB95, 203s, a/c and a free flowing exhaust. Main 165 (Nightrider is somewhat outdated) is too small.

As to where to start with the slow:
If you need more than 3 turns out to get idle and low range right, go one size up on the slow jet, like wise if you start with a 48 and you need only 0.5.-1. turns, go one size smaller. It's not rocket science, takes some patience.

The CV 40 is good for least 90 HP, you are still a few ponies away from the number with your build. I would put the money for the carb toward a DTT or Crane ignition and have it dyno-tuned by an expert. What exhaust are you running?
 
#6 · (Edited)
Remember, It's hard for someone to recommend jetting unless they have the same or very similiar build (displacement, carb, exhaust, cam) and live in the same conditions (temp, altitude, etc.) You can try their advice to get you started, but just make sure you get it dyno-tuned as soon as possible (AFTER it's broken in). It's the ONLY way to get the mixture correct. Some shops will do a part-power tune up with an AFR meter to get your jetting close in the meantime.

Plugs? Stock plugs are fine for just about any performance engine. "Hotter" or "colder" plugs do not create a hotter or colder spark! They just dissipate heat from the heads more quickly or more slowly. Also, don't get ripped off with something like the splitfires.. they are just snake oil. :)
 
#8 ·
Thanks for all the responses.
As I have the Sportser needle and a 48 jet on the shelves and reading the different replies I understand that basically I can find a working point with the a combination untill I have the bike dynoed.

Some answers to specific questions from some of you:
bigoscycles: I would like to start with the stock CV as it appears to sufficient and I travel up to 9000 feet sometimes.

ViennaHog: I'm running SEII's, pretty happy with them so far. I have Cycle Shacks, Khrome Werks and a SE 2-1 tuneable on the shelves. So plenty of optimization options :)

murphdog : I'm pretty close at sealevel (100ft) but do travel into the mountains (see above).

ToddM : :))) yes I know hotter and colder does not chance the temp of the spark. But you can alter that black outer ring to a nice tanned color with a plug of the correct temp value. I do understand this will not be the first and most point to look into. Will use the stock ines to start.

Thanks ... Jef
 
#9 ·
Jef said:
Thanks for all the responses.
.............ToddM : :))) yes I know hotter and colder does not chance the temp of the spark. But you can alter that black outer ring to a nice tanned color with a plug of the correct temp value. I do understand this will not be the first and most point to look into. Will use the stock ines to start.

Thanks ... Jef

I wouldn't mess with changing heat range of the plugs unless all other tuning options to get the mixture and the power right are exhausted (no pun intended). With a different heat range you throw another variable in an equation that's already a little complicated.
 
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