Triumphrat

adamoverdrive

I know this is probably the most frequently asked question in this section of the forum, but I don't feel like sifting through all the posts. Yes.... JETTING!!!

I have the 790cc bonnie with British Customs Predator pipes, stock needles, AI removal, and airbox elimination kit using the K&N filters. I'm going to have it Dynoed, but I want to get it as close as possible so I don't have to spend as much $$$. So what should I be using? I'm also in Pennsylvania at about an average elevation of 500ft above sea level.

What size main jet?
What size pilot jet?
How many shims on the needle?
How many turns on the mix screw?

Thanks in advance!!!

[ This message was edited by: adamoverdrive on 2007-03-11 15:45 ]

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whoa

I asked a similar question to my specifics. It looks like a best tire or best oil question.

I was referred to Pats Jetting Calculator. Based on what others are saying, I think it is indicating too high. I'm going with the suggestion from my mechanic, but he hasn't done one with my config yet.

jetting calculator

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05 Thruxton

sweatmachine

adam, I had the same setup but on an 865 motor.

I was running
42 pilots
1 shim on Thruxton needles
155 mains
1 turn out on idle mixture

I think I could have even used 160 mains and had a better mix.

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Macgruber!


Click for a picture of my slightly modified Bonnie

Loxpump

I used Jenks bolts info my starting gauge and I'm pretty close to it now. 140 mains, 42 pilots, thruxton needles no shims. about 3 turns out. I have a 790, no air box with K&N pods , AI removed, Emgo Short Reverse cones. It runs good, seat of pants only, even has that wonderful decel popping! I wouldn't know what to change without a dyno test.

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SCCTrim

Taking the bike to Martin Eurosports? If so let them handle it, they installed my 904 kit and the dyno operator up there is awesome at tuning. I think his name is Mark...( it's been a while )

I believe my bike ended up with
152.5 mains
45 pilot's
3 shims on stock needles
3 turns out on left bank
2.75 turns on right bank

( it's been a while since stock carbs as well )

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LitzerSki

Of course it'll indicate too rich...it's designed to be most accurate for BA's & SM's. And even then, you gotta realize that all bikes are different and even though your's may be set up perfect with 135's & 42's, the next guy with an identical setup will be better off with 130's & 45's.

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Mark

Apparantly I'm allergic to leather because every time I wake up with my boots still on, my head kinda hurts.

WS

I have similar set-up, but have Thruxton needles, no shims, 45 pilots, 150 mains, B.C. sprints mufflers with no baffles. 62 h.p. at the rear wheel. air/fuel ratio just about perfect.

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"Simplicity is more"

Marde

I've git the set-up you reference on my '06 Black.
BC included jets with their shipment. They were:

Mains @ 145
Pilots @ 42
1 shim under each needle
Running with three turns out.

These mods were done late last year and because of the season, I haven't been able to ride as much as I would like, (but then isn't that always the case?). There is some popping on decel, and cold starting is different in that if I pull the choke out all the way, the bike won't start. Half way out works best. Hope this helps.

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Mo, Larry- The Triumph!

RedBird

What size main jets? 155 (ballpark) I run 158's.
What size pilot jets? 40 or 42--either will work equally well.
40 (2 turns out on adjustment screw)
42 (1 turn out on adjustment screw)
How many shims on the needles? 0
How many turns on the airmix screws? See above.

Take 4 each 0.5mm shims with you to the dyno shop--be sure to get a dyno run with EGA. Also, take a pair of Thrux needles and a pair of TBS needles--you will want to try them all to see which gives the best midrange. Remember, you do MOST of your riding on the needles. The pilot screws should be adjusted for proper mix using the EGA. I also recommend taking the following main jets with you: 150, 152, 155, 158, 160 (in pairs).

'03 T-100, NARK, NH Togas...158 mains, 42 pilots, stock needles, 0 shims, 17 tooth counter sprocket, modified igniter with 8100 rpm rev limit, 50+ mpg average over the last 12000 miles. My needles are a little rich (12 A/F ratio); however, many have said their carbs are too lean with the stock needles--the EGA should tell you which is better.

Larry

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Larry
2003 T-100 (790cc), NARK, NH Togas, 8100 rpm rev limiter, 158 main jets, 42 pilot jets (less than 1 turn out on pilot screws), stock needles--no shims. 13 A/F ratio from 1100 rpm to 4000 rpm; 12 A/F ratio from 4000 rpm to 6000 rpm; 13 A/F from 6000 rpm to 8100 rpm.:D
2007 Tiger 1050--White:D--SW-Motech crashbars, Skidmarx rear hugger/chain guard, Calsci +7 windscreen.

Jimbonnie

What Redbird said! That's how to do it correctly.