Author Topic: Main jets... what do you use? (Read 5642 times)

Soos · « **on:** March 29, 2007, 12:40:39 AM »

What bike - make/year.
What filtration?
What engine mods(if any).
Stock exhaust?

You can vote 4 times for multiple bikes.

Soos · « **Reply #1 on:** March 29, 2007, 12:42:47 AM »

Last year ran stock airbox/stock filter.
'79 cb650
90 main jets

Trying pod filters this year, and hope I will have enough jets to dial them in well.

tmht · « **Reply #2 on:** March 29, 2007, 04:53:12 AM »

76 CB400F Stock airbox, 75 main jets (stock size)

Jonesy · « **Reply #3 on:** March 29, 2007, 05:45:20 AM »

I couldn't vote as there was no selection for 105...

1973 CB750K3
Stock airbox and filter
Dyna S igniton
Stock exhaust

736cc · « **Reply #4 on:** March 29, 2007, 06:22:33 AM »

120 mains oem

Superbiker_uk · « **Reply #5 on:** March 29, 2007, 12:45:12 PM »

'75 CB750
115, Pod filters (EMGO), Dunstall Power Street 4 into 2 headers, Dunstall Decibel Silencers, Stock Motor, Boyer Ignition
D8EA NGK plugs (runs better on these than with the DR8ESL)

hopterfixer · « **Reply #6 on:** March 29, 2007, 01:02:17 PM »

'74 750
110 Mains, 40 Pilots, Clip in middle slot.
Factory Airbox, Washable foam filter
Jardine 4 into 2 Mufflers (unmolested baffles) using stock headpipes
Stock Motor/Ignition w/NGK Iridium Plugs
815 feet elevation for miles in every direction

Spikeybike · « **Reply #7 on:** March 29, 2007, 05:32:15 PM »

75 cb550f 110 mains
pods
megacycle cam (mild)
Mac 4 into 1 exhaust
stock ignition/coils

as a side note i had bumped up my idle jets from 38 to 40, but it was way too rich so i switched um back

nteek754 · « **Reply #8 on:** March 29, 2007, 05:52:12 PM »

1973 750K 120 mains with a 1970 836 power plant, pod filters, kerker 4 into 1, NO baffle just cone piece and she runs great.

Pinhead · « **Reply #9 on:** March 29, 2007, 06:22:16 PM »

1979 CB650, open airbox (no filter cover), stock air filter, stock exhaust, stock ignition. 102.5 main's.

stueveone · « **Reply #10 on:** March 29, 2007, 10:10:13 PM »

130's

cb750 K4
K&N Pods
4 into 1 exhaust

. . . still tuning. . .

seaweb11 · « **Reply #11 on:** March 29, 2007, 10:33:50 PM »

Sea Level: I have my own beach

78K 750 stock engine
Pods
Dyna 2000 ignition
4-2 mac exhaust
138 mains
stock slow

mrbreeze · « **Reply #12 on:** March 29, 2007, 10:49:34 PM »

138.5 mains....stock 40 slows....clip at 2nd from top.....sea level (Modesto,Ca.).... Kerker 4 to 1 ...no baffle...cone piece....K&N pods....Dyna 2000 ignition....Accel coils & wires...........runs like a bat outa hell!!!!

kslrr · « **Reply #13 on:** March 29, 2007, 11:01:40 PM »

'72 CB350F
Pods at one time (working on fresh air intake system)
Hot street cam
Custom 4-1 pipes with minimal back pressure
75 main (stock)
35 idle (stock)
Needle clips at the bottom
Back in the '80's I was trying different combinations of larger main and idle jets but was always too rich. I did not know of plug chopping back then. When I finish the intake system, I will re-test over the entire rpm range.

moduleum · « **Reply #14 on:** June 19, 2007, 11:17:44 AM »

this thread is worthless w/o elevation. jet sizes are coupled with atmospheric pressure.

mlinder · « **Reply #15 on:** June 19, 2007, 11:32:58 AM »

Elevation : 50ft
69 cb750
HM341's
Pods
Dyna-S
Dyna 3ohm coils
mains : 110
Clip : Middle

/edit:

Also, the voting system is screwed up.
If you run 120's, do you vote for 110-120, or 120-130?

tmht · « **Reply #16 on:** June 19, 2007, 11:56:46 AM »

Elevation: -6 ft (No, I'm not kidding)
Bike: 76 400F
Intake: Stock
Exhaust: Kerker header, home-made can
Main: 75
Slow: 38
Needle: Middle

luvhonda750 · « **Reply #17 on:** June 19, 2007, 02:04:15 PM »

1977 CB750K7

Main jets 115
which is stock and the size that was in the keyster rebuild kit, I'm running the needles 3 notches down from the top, Portland is near sea level, but my house is on top of a 200 foot bluff. Stock air box

jdpas29 · « **Reply #18 on:** June 19, 2007, 06:14:14 PM »

110 mains, stock airbox.

tried pods... almost choked myself out in frustration.

pddpimp · « **Reply #19 on:** June 19, 2007, 08:48:46 PM »

1977 CB750K engine, stock
Pod filters
Dyna w\stock coils
4-1 stock F head pipe, Supertrapp muffler
3 turns out on idle mixture
bottom clip on stock needles
130 mains (running a little lean on highway, 4000-4500 rpm, with wind)
875ft elevation

ic455 · « **Reply #20 on:** June 19, 2007, 10:03:30 PM »

750 K6
stock airbox
Mac 4-1
stock ignition/coils
clip in middle groove
115 mains

Soos · « **Reply #21 on:** June 20, 2007, 02:30:33 AM »

Quote from: Soos on March 29, 2007, 12:42:47 AM

Last year ran stock airbox/stock filter.
'79 cb650
90 main jets

Trying pod filters this year, and hope I will have enough jets to dial them in well.

Having tried pods for a few months..... I don't think I like them overall.
Nice on most days/foot postions.
On headwind days it seem like ran lean, sideways strong wind, negligible effect, tailwinds, no noticible effect...
FEET UP ON THE CRASHBARS at 85mph(ooh, Thats 65 there occifer.

) KILLED engine performance.
I cound top out at 70 or so.
With feet on footpegs, I would pull a ton on the way to work a few times a week.

Seems that when i cruise with my feet up on the crachbars...... it does something to the outside 2 carbs.
Completely looses power.
Lean?/rich?simply cannot get enough air? due to turbulent air stream with legs and size 13 steel toes in the way.

And YES, this is of enough importance to me to switch back..

Going back to stockairbox..
And the fun begins...again.

l8r

kuyarico · « **Reply #22 on:** June 20, 2007, 06:10:31 AM »

Did you try oiling your pods? It helped me significantly. Although I'm still working out some issues.

Altitude: 849 ft (Cleveland, OH)
Running 130 mains
Pods
Dyna S + Dyna 3 ohm coils
middle clip position
.04 gap on the plugs
1.5 turns on the airscrews
2 in competition baffle in the Kerker can

Soos · « **Reply #23 on:** June 20, 2007, 01:04:16 PM »

Yeah, I did. I even splurged on the K&N brand oil, and cleaner.
Oh, with pods I ran 107.5's, dyna 3.0 ohm coils, stock everything else, slightly advanced timing.
5000ft elevation.

l8r

.RJ · « **Reply #24 on:** June 25, 2008, 07:38:49 AM »

Quote from: seaweb11 on March 29, 2007, 10:33:50 PM

78K 750 stock engine
Pods
Dyna 2000 ignition
4-2 mac exhaust
138 mains

Another data point here:

74 Stock 750 engine
Uni pod filters
Kerker 4-1
Dyna S ignition/3 ohm coils

135 mains
40 pilots
Air screws 1-1/4 turns out
Needle lowered 1 clip (leaner)

It runs great, real crisp, good throttle response, but the plugs are looking a little lean - I think i am going to go to 138's and maybe raise the needle back up to the stock (middle) position.

News:

Poll

What size mains do you use, and what air filter type is on your bike?

Author Topic: Main jets... what do you use? (Read 5642 times)

tmht

Superbiker_uk

tmht

luvhonda750