Lets talk jetting

[zore]

I'm basically looking to share some things I've found and made a few confirmations.  First, I want to confirm that the 82 carb had a 122.5 for the front and 127.5 for the rear.  That said, here is what I experienced.  I had those jets in the bike.  I did the usual yics fix, carb sync and adjustment but the bike still didn't feel very strong.  I thought maybe it's running a bit lean, so i put a 127.5 in the front and a 133 in the rear.  This caused the usual bog on opening the throttle to become really bad.  I then put in a 130 in the rear and this seemed to clear it up.  The bike however still didn't feel like i would expect it too.

Off to deals gap.  I take the bike off the trailer and ride off about 40 miles.  The bog is back and just as bad as before.  My plan was to bring my 122.5 with me but I forgot it.  I made it to Wheelers the next day and picked up a 120 and a 125.  This certainly corrected the problem at most of the elevations except 5000+ feet where the bog returned to some extent.  But, that said, the bike was certainly ridable.

Here is where things get interesting.  I get home to NJ where the elevation is almost sea level.  My usual transportation (triumph sprint st) is at the dealer ship getting a heated grip warrentied so I'm riding the vision 130 miles a day.  To my amazement, with the new jetting, it felt like a completely different bike.  The bike now climbs to the indicated 85mph with ease.  Fuel mileage is almost 50mpg now and there are no stumbles at any rpm range.  I can wack the throttle wide open at any speed and it doesn't even wince.  I'm going to check the plugs this weekend to see how they look, but I think I have found my fix.

Anyone else play with jetting?  I'd like to see what you found.

[Night Vision]

we did some jetting on cherrybomb and here's what we ended up with.

bike came with (air pilot) 130's front and back. Tried 135's and it ran like crap. Went back to the 130's, nickle tricked the flapper, set air screws at three turns out........

runs like a possessed hoover  ;D ;D ;D
pulls very linear throughout all rpm ranges, no flat spots anywhere. 

oh yeah... at about 350' above msl

main jets are stock 122.5 front 127.5 rear

[Night Vision]

to the contrary.. there's smokebomb...

came with the stock jets, vaccum flapper and AN 82 FILTER!!  >:( >:(

I put in a Uni filter (83 style), 135's and have the same mixture settings (three out)

I have an intermittent stumble around 4250 rpm, I tried 1/4, 1/2 out (didn't help, went back to three)

smokebomb seems to have more umph though ;D ;D ;D seems to come on quicker and stronger so I can live with a stumble now and then. I will try to tune it out as soon as I shake her down some more.

again, around 350' amsl

[Superfly]

On my blue bike w/ 82 carbs, I ran 122.5,127.5, and 135's for the air jets, with mac pipes the bike pulled very hard, and I was pleased.  I got a little over 50mpg with that setup.

[h2olawyer]

I run the same jetting as Superfly.  Dealer in Steamboat Springs installed the larger air jets when he did the 82 airbox & carb upgrade.  But, I still have the stock exhaust system.  I live at 5,000 ft. & all my riding is from there to over 12,000 ft.  Distinct loss of power above 10,000 ft. but after finally getting the carbs clean, adjusted & synched, I only have the rarest stumble when the bike is hot.  My mileage is closer to the 43 ~ 45 MPG range.  I tried the jets on either side of the stock sizes & got more stumble either way I went.

H₂O

[ps2/bikevision]

im waiting for the day that i tear the carbs out of mine because the guy that had mine first knew what he was doing with the carbs. i dont have the updated air box and no yics. and it runs like a dream. though i do now have a little popping when i let off the throttle but i think its my exhaust. still have all the power i had.

as a side note i switched to full synthtic oil this year and OH MY GOD  it made a word of difference when i crack open the throttle it feels like the front tire is going to come up. my front end is a little soft but im used to it and i like it this way. if it was a little stiffer id put money on it i could bring the tire off the ground. you can feel the front end lift and youd better be hanging on. i let a buddy take it down the road and when he came back he asked "how much" as if id sell my baby. what a fool.

[corwin]

My Vision runs on 130 and 135 jets, because thats how i got it. Moves like animal and the top speed is still 178+ km/h (111,25 m/h), just keep the carbs and air filter clean ;). There are some problems too, apparently related with air-filter element, which is homemade and become too thick, but i am going to replace it soon.

I wonder, how it would go with original jet set although i doubt it comes out any better.

the average fuel consumption for last 2000 miles remain still good - 48mpg, perhaps 50/50 city/highways and often heavily loaded.. but I checked my fuel-diary and it seems i´ve once got 60mpg on a 365 miles trip constantly cruising at 60 to 65 mph  :o

[Night Vision]

My Vision runs on 130 and 135 jets, because thats how i got it.

the average fuel consumption for last 2000 miles remain still good - 48mpg, perhaps 50/50 city/highways and often heavily loaded.. but I checked my fuel-diary and it seems i´ve once got 60mpg on a 365 miles trip constantly cruising at 60 to 65 mph  :o

my vision runs on 130 / 135 pilot air jets because that's how it likes it  ;D
your mileage is very similar, with 55mpg being my best so far

[corwin]

my vision runs on 130 / 135 pilot air jets because that's how it likes it  Grin
your mileage is very similar, with 55mpg being my best so far

I understand You completely  :)

The difference might become for that i have Euro model and didn´t it have lower RPMs than US model. I am doing 90 km/h (or 55mph) at 4300 RPM or so--
actually, i am not quite sure, because her original speedometer doesn´t work properly and i use digital...

[Night Vision]

yes, the Euro gears may help in gas milage. I'm doing around 5,000rpm at 55 mph.

my 55 mpg was not constant highway miles. mostly hilly, twisty rural backroads. not much stop and go. in the city, I may get around 40-45mpg

I'm hoping one of my next projects will be Euro gears.