whats the best jetting for ............?

sinister_customs

hello i am wondering if anyone can help me out here, i have a 1980 xs650special 2. I am running the BS34 carbs, stock airbox and MAC 2 into 2 Pipes, whats is the best start for jetting, i have the carbs soaking in the cleaning tank at my work and tomorow will be rebuilding them so i was hoping maybe i could luck out and make it a one shot deal, just build them and run em! any hints? Looking for any and all specs
Float Height?(I hear 27mm is too high)
ain Jet?
Pilot Jet?
Fuel Mix Screw?
and needle position
thanks!
Jon

xsjohn

Jon.....That just happens to be my area of expertise.....would have you covered there with one of my kits.....can't be done right with the stock parts......pm me if you are interested....sure could save you years of hassle ...xsjohn

royfisk

save yourself the hassle and get the kit, those carburetors are a real pain to dial in, and the hours you will spend trying could be put to good use elsewhere. John has done all the work and has what it takes right out of the box.

sinister_customs

how much?

xsjohn

see
650rider.com/index.php...pic&t=2291

Instead of ordering noisy rain soaked pods....I noticed no one even bothered to see the above post or comment on it.......and your own dreamed up elements over the existing wires cost nothing.......

I like the 1" ID extra inlet........sings ......

xsjohn

royfisk

John did you open your inlets on your bike? Did you ever finish 38mm kits? If so what kind of results did you get with it? Havent forgotten your damper rods, doing forks this weekend so will have you covered shortly.

xsjohn

Added one extra per side with 1"ID black tubing from lowes....and took all the baffels out of just the cover.........cool......Have 38 needles ....all we have come up with so far is licking the right cylinder but that's a lot right there.........xsjohn

cfinn1

Definately go with Johns kit. I spent countless hours trying to deal with the issues just to get close to what John has available to us (his kit wasn't available at the time I was doing the work). I must admit I learned alot in the process but if you want to skip all the hastle and get it right the 1st time John's kit is the way to go. Even after I did all of the tweaking I still ended up ordering the kit.

ukie.eagle

I went with John's kit for my 1980 & am liking what it's done..
I still think I need to tweak it a bit, though...
I've got his needles/shims, 47.5 Pilot Jets & 135 Main Jets [with my K&N big pods & MAC 2-into-2 pipes]..
Could the 47.5 Pilots be too much?..My combined City/Highway MPG is less than 40...
I know I'm so close that I can taste it!

Thanks,
Andy

xsjohn

ukie......My custom 46 pilots are less than one turn out......you probably have them too far out...will kill gas mileage.....I get about 50...turn one in till it starts to act up so you know where the limit is....then shut it down and count the turns......then turn it out just a bit from acting up and set the other one the same ane try it.....adjust out from there if needed.....the mix screws are the hardest part for me too.....your pilots are awful big and was not something I recommended ........bet you will end up at a turn or so....

xsjohn

nj1639

'83 sk with stock carbs, stock air boxes, 2 into 1 exhaust and Johns' kit. So far it runs perfect. Now I've got a full tank of high test and trip meter set on 0. Just waiting for some time to ride and see what the mileage is.

xsjohn

Remember we are on the pilots most of the time till we hit the throttle and the pilot feeds continuously through the entire throttle range.....it they are set too rich there will be no gas mileage.....I set mine kinda toward the lean side because there is not much load on the engine at cruise where we want the mileage.....and the bigger pilot gives good decel even set that way.......xsjohn

ukie.eagle

xsjohn:

Sorry, but now I'm confused, so be patient: so am I better off going back to my stock Pilot Jets?...
And, when you say: 'My custom 46 pilots are less than one turn out', are you talking about the air-fuel screws?...or are you talking about the Pilot Jets themselves?...I thought that [like the Main Jets] Pilot Jets should be screwed in all the way until they're snug... Confused

Andy

xsjohn

I made my own 46 pilot jets........exact .018 thousands......45's should be plenty and can be set too rich easily ....darkening the plugs thinking that other jetting is wrong.......and yes the pilot jets should be tight.....sorry sometimes I say pilots when I am really talking about mixture screws.....just smack me when I coin words and confuse people......xsjohn

If the mix screws are set too rich it just crouds the main needle when it starts to come on the begining of the slope as you roll the throttle on and goofs up cruise and gas mileage...........and plugs....and brain...crank them in till you start noticing problems instead of cranking them out till you find problems.....that's how I get 50 mpg from these kits and it still runs like a bat out of hell when I twist it.....and smooth at cruise too......xsjohn

blahcap.....here isan 80 carb describing how to set them on the bike after determining the compressed spring measurement......I show 22mm for the 80 compressed.....I actually use 23 now...........that makes my 135 MJ look like a 134 because the fuel level is slightly lower.........and lowes allens in the foat bowl for easy access on the bike.....10 minute float or jet change......81-84 carb floats and the 38's will be different measurements but the same theory persists....

xsjohn

blahcap

ok go to lowes/homedepo get m5-.80 X 16 and #10 lock washers got it Smile

8 of them?

xsjohn

Yup....will save you hours later for sure.........xsjohn.....

read this post over especially the 1" extra air inlet on the air box and removing the baffels on the cover........for when you use the 135MJ.....breathes like a dragon now...and quiet too....screw pods....xsjohn

650rider.com/index.php...pic&t=2291

xsjohn

With bigger pilot jets it is easy to set them too rich...turn them in until problems not out until problems....the bigger pilot I have found will give great deceleration even when set leaner than you might think..maybe because of the increased suction at that moment from deceleration in relation to cruise with the throttle opened slightly ...lowering the vacuum pressure...... if you set them too far out it will hose cruise and mileage and plugs....and cause you to fart with main jets and needle position in vain....good way to tell is if it's to rich with larger pilots is if starts after a few hours without the ole need some choke thing....and the heavy report from the mufflers when taking off......and pilots feed through the entire throttle region.....causing all sorts of problems if set too rich........xsjohn

ukie.eagle

OK: I took out the 47.5 Pilots Jets & put the 45s back in [thank goodness I took xsjohns advice for putting in those allen bolts!]...
I left the 135 Main Jets in, though...
This weekend I hope to get the idle mixture screws right [now that I've gone to the smaller Pilots] & see if I can get better milage...

xsjohn

Got some 134 Main Jets in the works.......already runing them in mine......like a little airplane on the express and every where else for that matter.......So I'm running the 46 pilots at 1 turn and the 134MJ..... wow.......xsjohn

JUST FILED UP
52.69 PER GALLON
134MJ with the thin shim.....Right and Left Needles
Stock air box with 1"ID extra inlet on each side and stock mufflers
geared 18/29 with 140 sized rear tire......80SG
I used just 3 of mikes stiffer clutch springs....
along with the three originals...now I
can run the V1R racing oil 20/50 which I always thought
made the engine run slicker..........without clutch slippage....
still easy pull too....

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