Triumphrat

bendavanza · 07-06-2007

Hello
I read the Jenks Carb tuning pdf, and I want to confirm some things with US real world knowledge. I'm in Dallas, TX, by the way, which is only about 500ft above sea level.
I have predators, K&N pods w/ bc's ark to install, AI is already removed, and standard carbs for an 01 (790) Bonnie. I ordered thruxton needles. The carbs were jetted for the D&D pipes previously and I do not know what's in there, but I have 42 pilots and 140 and 142.5 mains handy.

Jenks says for std needles
140 [145] mains
42 pilot jet
1-2 shims
2.5mm hole (no drilling of slide)

Jenks says for Thruxton needles (on 790 bonnie)
130 [135] main
40 pilot
1 shim
3 mm hole

I don't think I want to drill the slides, but my local dealer suggested the 140 main jets, and the 42 pilots, and I read about the thruxton needles having better midrange performance, so I ordered a pair. He rides a later model 865 Thuxton, though.
Hopefully I will be getting rid of the gnarly airbox this weekend.
I'd like to get this thing as close to right as I can the first time, as I'm kind of overloaded with bike projects and although I do like to tinker, this is supposed to be my gas up and go bike.
Any suggestions? I do not have shims handy though there may be some in the carbs already. The Jenks guide is an interesting reference, but could the thruxton needle make that big of a main jet difference (10 needle points?).
Oh, I got one of those procom units on ebay and I will probably plug that in once I get the jetting correct. The bike has 20k miles so it should be fully broken in and ready to take a few more RPM's.
Thanks in advance,
Ben

[ This message was edited by: bendavanza on 2007-07-06 10:27 ]

SHRuuM · 07-06-2007

I live just a couple hundred miles south of you, at sea level on the lovely banks of the San Bernard river and this is the set up I've got on my Thrux. 140 mains, 42 pilot and 2.5 turns out on the idle. Shims I left stock. When you pull the AI of don't forget to pull the tank and get rid of the airpump, hoses leading to the carbs and plug the carbs where the airpump led to. I got the rubber plugs from the auto store for a hot 20cents........by far the cheapest mod you'll ever do. She runs like a bat outa hell with no stuttering or back firing.
Enjoy the bike and welcome to the club. Maybe before summers out we can get a bunch of us Texas boys to show up some where central[like Canyon Lake or such] and go for a showboating putt!

bendavanza · 07-06-2007

shruum-
But your Thruxton has an extra 74 cc's, I wonder how that would effect me. AI was gone before I got the bike, fortunately.
I am interested in a ride/meet somewhere, Sweat was talking about some kind of get together just south of Austin in the Hill country. What say you, Sweat?
-Ben

unitedrocker · 07-06-2007

If using Predators, 140's should be pretty good. (some like 145's) I've been messing with pilots quite a bit. (40 42 45) I'm back to 40's with one shim on the needle and she runs pretty clean. Plugs look right on. I'm at sea level, and playing with an '05 Thrux, box cut up, K&N's and Predators. (AI torn out as well as the "heaters".)

I'll also throw in that the drilling the slides is a joke... super easy. You are drilling through 1/8th inch of aluminum if that. I believe I used a 7/64th just under 3mm.

Drilling Slides

[ This message was edited by: unitedrocker on 2007-07-06 11:16 ]

sweatmachine · 07-06-2007

Quote:

On 2007-07-06 10:52, bendavanza wrote:
I am interested in a ride/meet somewhere, Sweat was talking about some kind of get together just south of Austin in the Hill country. What say you, Sweat?
-Ben

I say I wish it would quit FUC%ING raining!

bendavanza · 07-06-2007

No ****e sweat! This rain is out of control....
You know the 19th is national ride to work day. I will ride come hell or high water, which the water is already high. Rain riding does suck, but it is fun once you're totally soaked and don't care any more.
Maybe I should do a pontoon mod to my bike, and use a big sand tire on the back, I could float to work...
-Ben

SHRuuM · 07-06-2007

Dudes its the 24th straight day of rain here in southern Texas and
I'm darn sick of it!!! Are we going to try and meet up[at least a week after that parked low moves on] and go for putt? Its one thing to be called a SHRuuM its another to turn into one.....

bendavanza · 07-06-2007

Shruum
You have a benelli 250? I have a MW riverside, a 350 benelli sold through monkey wards, It's a 67 but the bike had no changes for years, they were titled as the year sold. I've been doing a bunch of go fast on it, it's been fun to mess with. here are some pictures:
My MW Riverside 350 overhaul
some of the pics are broken
I'd like to see what your Benelli looks like. I just got a high compression piston for mine, put on a huge amal carb, a 12v solid state alt/ignition, and I have a NOS fork for it.
cheers
-Ben

SHRuuM · 07-06-2007

The Bennelli is my late dad's Isle of Mann TT racer that I'm restoring. V-twin 3 in front 3 in back, 6 speed Amal carbs with a float bowl under the seat for anti-foaming of the gas at high speeds. Parts pretty much have to fabbed up and its at my bud's Lonnie's shop, in a thousand pieces sitting proudly next to a '54 Arial Four Square that still cranks on TWO kicks. Hope to have her up and running by the end of the year....IF IT WILL STOP RAINING!!! hahahahaa dang it

bendavanza · 07-08-2007

OK
I got the airbox out, Predators on, 142.5 main, 42 pilot, 2.5 turns out.
GPS read 104mph (woo hoo!) on the way home, and here is my spark plug.
BTW, I need to do more research on the accuracy of a GPS but at ~96mph it looked right on to the speedo on the bike. I read somewhere that the speedo's get more accurate as they are broken in? 20k miles on this bike.
There was a little rough spot, hesitation in the midrange, but then pulled really hard.
I have thruxton needles I have yet to put in. This would make a big change in the jetting, I may have to go with 135's as suggested by Jenk's Bolts guide.
At WFO I feel a small pulse... Could be my slippery clutch though. I know I was hard on it last night, it lets go about 6k when I'm straight into it, That's the next project.
Any suggestions for needles or flat spot? 01 bonnie stock needle.
-Ben