jetting

[TheCafeKid]

Did you raise compression to drop jet size?

I was just about to ask...

[67fire]

10.45:1 Is that what you need to know?

Eric

[chef1366]

10:25-1???

[Spyderman]

ok here we go
i just finished tuning my new set of 29MM smoothies and i have the following settings
pilots #25
pilot air screws set to highest RPM
throttle valve cutaway 2.0
jet needle on P3
needle jet O-6
main jet #115
float height 24MM

i also have a 78 GS100 with a ported head cams that are degreed
29MM smoothies hindle 4 into 1 race pipe
so your close to me in set up (not as radical)
only difference is your at 585ft ASL and I'm at 3500 ft ASL
more info would be good
like
pilot jet size
throttle valve cutaway 1.5. 2.0 ????
position of the clip on your jet needle
(farthest from the point of the needle is P1 closest to the point is P5)
needle jet
main jet size
float height



here's what i suggest you start with
#115 main jets
#20 pilot jets
needle on P3
adjust the air screws for highest RPM
set the float height at 24MM

some basics on tuning
remember that each circuit corresponds to a throttle opening (not RPM)
idle to 1/4 pilot
1/4 to 3/4 jet needle
3/4 to WOT main jet
don't forget that each circuit overlaps the previous one
and float height affects all circuits
if your mains are too rich then your jet needle will also be too rich as the fuel is coming in though the main jet and is then metered by the needle to be correct

start with the main jet and work down to the pilot
this will be a trial and error effort you need to start with what i outlined first
start with the main jet
then the needle clip position (if you change the clip position then you have to re sync your carbs)
then the pilot circuit

you have to ride it and see what it does and do a plug chop
then come home make a change and ride it see what difference that made and do a plug chop see what the plugs tell you
then go home make another change and ride it again do this till you get it right
here is a plug chart to help you in reading your plugs
http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html
you can print this and have a hard copy to use when checking your plugs

i hope i have shed some light on this for you and helped you out a bit or at least put you on the right track to getting your bike running correctly

[67fire]

My head was milled a little (forgot the exact amount as it was over 15 years ago ) the intake and exhaust valves are 2mm larger, I ported the head a little,
the valve reliefs were cut .020 deeper and wider. I am at 4,500-8,700 feet. I have not touched any other parts, yet. Getting closer. (wink)

Eric

[Spyderman]

My head was milled a little (forgot the exact amount as it was over 15 years ago ) the intake and exhaust valves are 2mm larger, I ported the head a little,
the valve reliefs were cut .020 deeper and wider. I am at 4,500-8,700 feet. I have not touched any other parts, yet. Getting closer. (wink)

Eric

my head has not been milled and I'm not sure if the valves are larger i think they are they looked larger than the other 1000 head i have here at home but i didn't measure them when i had the head off 2 weeks ago i just had my head redone new valve stem seals cleaned and all the necessarily helicoils put in it's like new when they checked the valves and guides the specs were as new according to the Suzuki Manuel same for the cam journals
my head is fully ported and polished
he's in Chicago and is at a way lower elevation than we are if we were at his elevation then we would be jetting a lot richer than we are right now i know this for sure

[67fire]

When I was at closer to Sea level in Fairfax County,Va., all of it was the same except for the head work and valve relief work also
the header went into a regular center pipe and slip-on muffler.. It had 34CV carbs and ran the best with 112.5 jets. If that helps.
Not quite apples to apples.

Eric

[BassCliff]

Hi,

These very thorough articles may help. Thanks to Mr. Matchless for hanging onto them.

http://www.mediafire.com/?2udlmulmomw

http://www.mediafire.com/?7malviyy2z3
http://www.mediafire.com/?1tfmvxwtomi
http://www.mediafire.com/?5vjhwddomyc

Just about all you ever wanted to know about carb theory and jetting.


Thank you for your indulgence,

BassCliff

[Spyderman]

When I was at closer to Sea level in Fairfax County,Va., all of it was the same except for the head work and valve relief work also
the header went into a regular center pipe and slip-on muffler.. It had 34CV carbs and ran the best with 112.5 jets. If that helps.
Not quite apples to apples.

Eric

CV"S and smoothies are two completely different animals all together
i know that i ran 120's for mains at sea level and I'm down 2 sizes here
however i had just gotten the bike and was not really familiar with it yet
now though that is a totally different story 17 years later
i only have 4 things left to do
1 finish the paint (halfway through primer grey ATM)
2 add an oil cooler
3 add a oil pressure gauge
4 put a wisco 1085 kit in
just put the Dyna S on today man what treat couldn't believe it took it all apart installed the Dyna S put the pick up plate on and thought this might be a PITA to get to run as i had no idea where the timing was
fully prepared to spend some time getting it running i thought well here we go turned the key hit the starter and away she went i was stunned hooked up the timing light and was only 5 degrees out on both 1-4 and 2-3 made a small adjustment and i was done sometimes it's good to be that lucky

[67fire]

Be careful!
From about 6,000 up, my bike is feakin' scary!!! The front wheel... will come up at will!!! (lean forward!) In every gear!
And, the engine is mounted 1 inch further forward.

Eric

[bigbabee]

thanks for the info. I think I will start with the 120 main jets