Topic: Jetting spreadsheet project

[DavePhipps]

I've had an idea floating around my head for a while.
We have specs for the stock airbox, motor, and exhaust. What we don't have is consolidated information about jetting that works with alternatives. More specifically setting that work well, no hesitation, surging or bogging.
I would like people to post their specs so I can put them in a spreadsheet.
I will need to know Bike, cam, ignition, ported head, exhaust, filter, main jet, slow jet, air screw, needle, and location so altitude can be added in.

Thanks
Dave

[wrenchmuch]

It might give a good place to start but what about the effects of porting ? It would be hard to quantify that .

750 K1 advancer ,Dyna s and dyna 3 ohm coils,D8EA's,Wiseco 836 ,Kibblewhite intake and exhaust valves (smooth transition into combustion chamber),Kibblewhite guides , and springs ,mild porting ,webcam #41 ,Mac 4-1 megga , stock carbs , #125 main , #35 pilot , needle clip in the middle , solid air screw (no holes in screw ) 1 turn out , K&N filter in stock air box , Toronto , Ontario , Canada .
Mike

[Cuts Crooked]

78 750K - Emgo Pods - 120 mains - everything else is factory stock settings/parts/exhaust... except for a "parts unknown" ignition system replacing the points &  condensors.


Almost fergot: Central Iowa

[DavePhipps]

It might give a good place to start but what about the effects of porting ? It would be hard to quantify that .

OK, I edited to add porting.

[cobra2411]

76 750F

Uni pods, stock F 4-1 exhaust, and stock non-pumper carbs. I had the stock points but now I have a Hondaman ignition.

I've got stock #40 slow jets and 112.5 mains; needles in the stock position (3rd clip). I had 107.5 with the same combo and it was lean and popping. I want to try some 110's because the 112's look just a touch rich.

[wookie]

If enough CR guys chime in maybe a second spreadsheet would help others behind us.

K3, Wiseco 836,Stock head with DP295 cam and kw springs, dyna ignition w/ 3 ohm coils and ngk DR8ES-L, CR 29 carbs 125 mains 240 air, air screw @7/8 turn out, YY9 Needles (one leaner) on fourth clip, pod filters, 4 into 1 exhaust (yamiya)

This bike makes a solid 72 ponies at the rear wheel.   I just rolled 1000 miles and spent the better part of the summer trying to set the carbs right.  As it stands right now it pulls hard thru the throttle range with just a mild hesitation @3/4 to wot.  Tried 122's but it felt lean. Can't tell if it's a lean or rich or flow problem.  Plugs are a nice choc/tan.  
and i'm at sea-level

[DavePhipps]

Cmon guys. I know there's more people than this that own bikes here.
Give to the cause.

[flybox1]

givin' it. 
'73 350F
stock ign/airbox/motor/needle.
jardine 4 into 2
D8EA's, floats@24mm, jets - #35/#78
AF screws 1 turn out.
Sea-level to 1000'
seattle

[jessezm]

'77 CB400F
--Webcam Grind #2, stock valvetrain components, no porting
--Stock headers
--MAC muffler with Kerker 2" competition baffle installed
--466cc big bore (ebay kit from Taiwan)
--Dyna-S ignition
--Dyna 5 ohm coils
--K&N Pods
--90 mains
--38 pilots
--1.25 turns on airscrew
--Needle one position lean from center (second from top, or 4th from bottom)
--Location:  Macon, GA!!!

Still making fine adjustments, but this is rocking so far.  some gurgling and popping on closed throttle deceleration.  But great throttle response, and clean plugs

[DavePhipps]

Keep em coming guys.
I've seen jetting questions on the main page in the last couple days.
If we get a wide enough sample this will ROCK!!

[brandEn]

This is a great idea and I would love to see the results. I will be having to tinker with the jetting on my 78 CB750 F3 here in the future once my build is done so I am sure any info you gather could be invaluable.

[dave500]

cb500,ist oversize bore with xl125 pistons,4 into 1 with automotive straight through resonator,boyer ignition,stock cam/ports,foam filter in stock air box,100 main jet,44 pilot jet,needle raised one slot.,the 44 pilot is a new addition today! it was a 40,and had a little flat area just of idle.cured that,id like a 42 to try.its always been an easy starter even if not started for a month(raining here non stop latley) and the choke can be turned off straight away,although a little soggy till warm,im yet to see it cold with the 44 slow jet.these are the type one carby.the 100 and 40 were the stock jets in this model.UPDATE,having another fiddle,now im using the 40 slow jet again and replaced the jet screw with a 1.2 hole to a solid type,and now use 104 main jet,much more mid range pick up,im keen to try a 38 slow next,ive been doing one change at a time off course and doing a good half hour ride to guage the changes.

[scottly]

Keep em coming guys.
I've seen jetting questions on the main page in the last couple days.
If we get a wide enough sample this will ROCK!!

Just a suggestion: when stating what jets were finally used, also state the stock jets and needle settings in parentheses, for example, main jet 115 (110).

[DavePhipps]

Don't worry. When I compile this there will be basline listed for each model.
I'll be repairing my other laptop this week so I can get on this. I on a tablet that I only use for email, and websurfing.

[Tintop]

Great project, and will definitely contribute once my final jetting is sorted.  When listing needle position, it would be helpful to also know what needle & jet are being used, eg K / F.

There is a second project that would also be very helpful, the needle profiles. 

[blackhog02]

Great Ideal - Here are my setups for my non stock bikes.

1977 CB 550K - uni air filters, 4 into 2 cross over drag pipes, main 115, needle moved from 2nd to 3rd  rest stock.
1978 CB 750K - cheap pods, 4 into 2 with long turn outs, main 125,  rest stock.

Location Charleston, SC  about 18ft above sea level.

[dave500]

im still sorting mine,ive been riding it for three years and only have just decided to get a little more out of it now run 38(40) slow/104(100) main/solid air screw(had the dilled type),needle one step rich(was in the centre),it starts easy still with the leaner slow jet,im going to go up in the main jet to a drill#58 or 42 thou=1.066mm over the weekend.

[kslrr]

'81 CB650C with '79 engine:
Stock 4-4 pipes
Emgo Pod filters
Idle jets 47
Main jets 110
Throttle Valve (slide) 56B
Jet Needle 35B
Idle screw 1 turn

Bike still takes awhile to warm up, but pulls strong once it is.

[odiewan]

73 CB750 K with:
- Carpy 4 into 1 exhaust
- Pods
- Dyna coils
- Dyna magnetic induction pointless ignition
- Stock 40 idle jets
- 130 Mains
- Stock spark plugs.
It starts with out the choke which would imply to me that the idles are a bit big.
When the bike is cold and I go from 3/4 throttle to WOT, it falls off a bit.
Once it's nice and warm, it runs quite nice all the way up to WOT.
It has a slight stumble right off of idle. I wonder if that is because of the pods.
At some point soon, I am going to dyno the bike to get a base line, so that will go a long way to determining if the jetting is right.

[singedebile]

spark plugs maybe as well?

[Spanner 1]

1970 K1 750....
Stock airbox/filter
120 Mains ( 120 is stock )
40 Slow    ( 40 )
HM 341 pipes, last 2 baffle chambers drilled-out  ( HM 300 ), has exhaust tips installed
D8 plugs
Stock ignition
'Mildly' cold-blooded
About 500 - 1,000 ft elevation

Pulls hard to redline each gear........... No complaints  

[dave500]

i use the denso X22ES-U,which is the ngk D7EA equivelent,i think the bosch equivelent XR4CS run a little colder,ngk or denso are both good,who likes champion?

[faux fiddy]

Genius idea bouncing around in there.
This may make some wonderful shortcuts for modding.

[flybox1]

Keep em coming guys.
I've seen jetting questions on the main page in the last couple days.
If we get a wide enough sample this will ROCK!!

This has the potential to be a huge resource for mods, or for de-mod'ing a bike if thats your flavor.
post 'em if ya got 'em!

[jacquesleclochard]

Bump. I know I'll add mine when I finish up.