carb needles?

[yampug]

Honestly, if you can afford the easy solution, it's the best by no small margin.  Just buy whatever Randy tells you to buy, and you'll be golden.  Probably 40 pilots, 122.5ish mains, and a set of known needles.

see how i get on with what i've got then i may enquire with randy what he'd recommend.(or i might have got it sussed and know what jet to ask for by then   )

Otherwise, be cautious and do a number of plug chops from various rpm/throttle positions to ensure you've got things set dead on.  That sort of tuning is time consuming, but actually sort of fun, unless the cops see you winding fourth gear out to check your plugs...

this is what i'm aiming to do but didn't want to start until i understood what it was i was aiming for, last couple of evening i've been reading how mikuni carbs work trying to understand what each jet does and when it comes into play. interesting reading now i've just got to spend the time setting it up.

initially i went for the easy route buy a kit and bung the bits in didn't really have a clue what it did but it looked shiny.

one other question for you lot does it make a difference that i live in the uk with what jets i'd fit? i notice earlier 3000feet mentioned i assume that means 3000 feet above sea level in relation to atmospheric pressure?

[FJ_Hooligan]

Hopefully you're reading the carb info in the FILES section.  Lots of good FJ specific carb info.

You seem to be wrapped up in main jet selection.  If you read the carb files, you'll find that idle circuit jetting and the needle position are far more important to a majority of riding conditions.

[yampug]

Hopefully you're reading the carb info in the FILES section.  Lots of good FJ specific carb info.

You seem to be wrapped up in main jet selection.  If you read the carb files, you'll find that idle circuit jetting and the needle position are far more important to a majority of riding conditions.

yep been reading a lot of good stuff from there.

made a quick sketch while i was reading stuff using bits i'd found on various pages to help me understand which bit did what.



what i found strange is different people were using different names the same bits just to confuse me even more.

[yampug]

any one on here ever change the main air jet when doing work on their carbs? part of the ledar air corrector jet kit was a replacement jet for this which i fitted you had to drill out the old jet cut a new thread then screw the new jet in.

does the main air jet only get used at full throttle same as main fuel jet?

not the one with the arrow the other one -


picture of my carb with jet fitted

[racerrad8]

That is the fixed #30 "starter jet" for the "choke" circuit according to the GYSM. It does nothing when the choke is not in use.

I have always been baffled by the carb kit sellers that have you change that jet.

What size jet did you install?

Randy - RPM

[yampug]

That is the fixed #30 "starter jet" for the "choke" circuit according to the GYSM. It does nothing when the choke is not in use.

I have always been baffled by the carb kit sellers that have you change that jet.

What size jet did you install?

Randy - RPM

i'm not sure what size the jet it was as it didn't say in the instructions, is there a way to measure jet sizes?

what amused me about the kit when i was fitting it was that i asked on the uk fj owners forum if others had fitted this jet and how they'd gone about it. the response i got was that they'd fitted it infront of the original pilot air jet? i asked what would be the point of placing a larger jet infront of a smaller jet but no one seemed to know. i drilled my old jet out and fitted this new one instead.

something tells me this ledar air corrector jet kit wasn't worth the money. http://www.fjcatalogue.com/catalog/item/7214426/7422355.htm

unfortunately i hadn't heard of rpm at that time. 

[andyb]

what i found strange is different people were using different names the same bits just to confuse me even more.

Like the people who call hoses 'pipes', or those who call gasoline 'petrol'?!?!?!?!

[FJmonkey]

Like the people who call hoses 'pipes', or those who call gasoline 'petrol'?!?!?!?!

Petrol pipes and gas hoses... Or gas pipes and petrol hoses.... I am willing to bet they also drive on drive on the wrong side of the road... Maybe Klavdy will chime in because he discovered they also wear ass-less chaps... Or are a part of some secrete Power Ranger society...

[yampug]

amazing how much hassle our little tiny island can cause the rest of the world. 

some more-

trunk/boot
bonnet/hood
trainers/sneakers
belly pan/ think i heard some one call it a chin spoiler on here?

[yampug]

been checking/adjusting shims today only two were out one inlet and one exhaust. shims ordered, new plugs to go in then carb balance.

plus an oil/filter change.

roll on the summer

[FJmonkey]

been checking/adjusting shims today only two were out one inlet and one exhaust. shims ordered, new plugs to go in then carb balance.

plus an oil/filter change.

roll on the summer

You have the spirit of it..

Sleeping police man = speed bump
ToLet = To Rent
Tube = Subway

[FJ_Hooligan]

That is the fixed #30 "starter jet" for the "choke" circuit according to the GYSM. It does nothing when the choke is not in use.

Randy,
I don't think that's the correct description.  That orifice leads directly into the needle jet.  I've seen it called a main air bleed by Kevin Cameron.  He said it is important when at WOT.  It bleeds air into the main circuit to keep that circuit from swamping the intake with too much fuel (hopefully I described that right, can't find my copy of the book).

Wouldn't the starter jet be in the float bowl since that's where the choke draws its fuel from?

[racerrad8]

Randy,
I don't think that's the correct description.  That orifice leads directly into the needle jet.  I've seen it called a main air bleed by Kevin Cameron.  He said it is important when at WOT.  It bleeds air into the main circuit to keep that circuit from swamping the intake with too much fuel (hopefully I described that right, can't find my copy of the book).

You are correct, I got myself crossed up when I was typing...the air bleed for the choke circuit is the four small hoses not that jet.

That jet is what I have been explained to be more of a vent. What it does is allows the fuel level around the emulsion tube to fill higher level than the float bowl level to allow complete distribution of fuel to the holes in the side of the emulsion tube. I am not sure how changing that jet size will affect the circuit as I have never done that.

Randy - RPM

[yampug]

stuck waiting now till my two new shims turn up.

any one ever tried down sizing a shim on a diamond stone before?

[FJmonkey]

stuck waiting now till my two new shims turn up.

any one ever tried down sizing a shim on a diamond stone before?

If they are case hardened then you will be in for a rude surprise. If case hardened, only the surface will be  hard, and the center soft, and you will have shims that hollow out quickly. If they are hard all the way through (100%) then you can grind and polish them till they are too thin to use... If you grind them down. let us know how they work...