main jet ques?

[Rick Romero]

my 78 750 has the vm26`s, the main jet are 100`s, it always ran lean, revs better with some choke, whats the next size up to try? & anyone have some jets lying around? really cant afford to buy new jets, im a broke azz student

 

[tkent02]

Get the jets from Z1, $2 ea. Try a set of 102.5.

 

[niclpnut]

What set up you running. Pods, pipe?

 

[tkent02]

Is it lean at wide open throttle or just all the time a little lean?

 

[Rick Romero]

i think its lean thoughout the rev range, idles great but really give it gas it tends to bog down... im running pods & stock 4n1 pipe w/baffle in.

 

[tkent02]

In that case go way bigger, maybe 120 or so.

It will take a bit of trial and error to get it right.

 

[Toasty]

Shim the needles while you're at it.

 

[TeamDar]

Shim the needles while you're at it.

Just raise them a notch are two. These are vm26 carbs with adjustable needles.

 

[allojohn]

Shim the needles while you're at it.

Yep, position four on the e-clip.

 

[Rick Romero]

i have already tried the 4th notch on the needles, result was died at a light & would not run, plugs were black black black

 

[allojohn]

i have already tried the 4th notch on the needles, result was died at a light & would not run, plugs were black black black

Dying at a light had nothing to do with how the e-clip is set - wrong circuit.

 

[Rick Romero]

your right! after some riding w/the clip 4th notch, it fouled the plugs, when i stopped at a light it died cause of that, installed new plugs & returned the clip back to the middle notch, never ran that rich again....but i do have a bog when reving it, its on the lean side

Messing w/the needles wont cure this prob.

 

[allojohn]

your right! after some riding w/the clip 4th notch, it fouled the plugs, when i stopped at a light it died cause of that, installed new plugs & returned the clip back to the middle notch, never ran that rich again....but i do have a bog when reving it, its on the lean side

Messing w/the needles wont cure this prob.

Have you cleaned these carbs? Properly?

 

[Rick Romero]

actually have this problem for years now but the bike is very rideable. crabs are clean, i think these bike ran lean from the factory and i am running pods, cant go back to the air box due to my aftermarket valve.

float height is 1 inch, piolet is #15, main is #100
i might try 1/2 turn out on the fuel screw & readjust idle air screws.
i will post a before and after video.

 

[allojohn]

actually have this problem for years now but the bike is very rideable. crabs are clean, i think these bike ran lean from the factory and i am running pods, cant go back to the air box due to my aftermarket valve.

float height is 1 inch, piolet is #15, main is #100
i might try 1/2 turn out on the fuel screw & readjust idle air screws.
i will post a before and after video.

There are a few guys on here with 78 750's running K&N pods and V&H 4-1. The consensus is float height 24mm, #15 pilot, main 117.5/120, e-clip position 4. Then fiddle with fine tune from there. A Colortune can really help - never had much luck with plug chops.

 

[TeamDar]

Make sure that they are indeed 100 mains. A Lot of people drill out the jets instead of buying new ones.

 

[allojohn]

Make sure that they are indeed 100 mains. A Lot of people drill out the jets instead of buying new ones.

Ugh, good point.

 

[Rick Romero]

update...replaced the pilot jets with a set i drilled out slighty larger, rev much better