Triumphrat

Jhtjon · 10-31-2007

I had my local tech install a shim under the needle, and change the mixture screws from 2.25 (Stock) to 2.75 per the Jenks manual, in preperation for a high flow air filter and removing the snorkel. Well When I took the bike for a test ride with the snorkel out and stock airfilter, the bike nearly stalled about half way through the RMP range. checking the plugs confirmed an over lean condition. Re-Installed the snorkel and the bike feels great. And is right about where it should be A/F wise.

Now I am concerned about installing my UNI, much less removing the snorkel.

I am not going to be getting pipes any time soon. Right now I am working on just the intake.

Should I go to 42 pilots and 112 mains? Should I add another shim? Where do I go from here.

ohiorider · 10-31-2007

What was your tech's advice?

Bob

Wombat · 10-31-2007

Standard jetting is for the standard setup
If you remove the snorkel, you are allowing more air into the system, so you will need to increase your jet size to suit.

Jhtjon · 10-31-2007

My tech wants to go to a 42 pilot and he thinks that the mains are OK. Or get a Dynojet kit for it and start at the leanest settings and go from there

Geoff · 10-31-2007

This is on a 865 bonny? you dont need 42 pilots. just go another 1/4 turn out on the adjustment screws, or more if needed. You can go to 3.5 if you have to
G

ToeCutter66 · 11-01-2007

I have a 07, w/tors only. I have 2 shims and 3 turns out on the screws. It runs good with the snorkle, and like crap without it.

amanger · 11-01-2007

Quote:

Originally Posted by Jhtjon

I had my local tech install a shim under the needle, and change the mixture screws from 2.25 (Stock) to 2.75 per the Jenks manual, in preperation for a high flow air filter and removing the snorkel. Well When I took the bike for a test ride with the snorkel out and stock airfilter, the bike nearly stalled about half way through the RMP range. checking the plugs confirmed an over lean condition. Re-Installed the snorkel and the bike feels great. And is right about where it should be A/F wise.

Now I am concerned about installing my UNI, much less removing the snorkel.

I am not going to be getting pipes any time soon. Right now I am working on just the intake.

Should I go to 42 pilots and 112 mains? Should I add another shim? Where do I go from here.

Checking the plugs is only going to give you a reading of the revs at which the bike was last running at.So if the bike was idling before you pulled the plugs that is the reading you ll get.If you want a reading where the bike is stalling you will have to get the engine running at that speed then immediatly stop the bike with the kill switch then take the plugs out there on the roadside and read them.
I think your running way too rich for the standard filter.Just fit the high flow and pull the snorkel,but you really have to do something about getting all that extra gas out too,like a less restrictive exhuast.

BillT100 · 11-01-2007

You can actually go all the way out to 4.5 turns on the pilot screws but around 3 turns with the stock #40 pilot jets should be good, you don't need to go to 42s. Also I would go to 112 mains without the snorkel. My experience is that you will lose low speed and off idle throttle response without the snorkel regardless of the jetting.

The snorkel is apparently increasing air velocity at low speed and small throttle openings and providing a more "crisp" throttle response by causing the slides to lift a little quicker. WOT is where the improvement becomes noticeable without the snorkel. For me the trade off wasn't worth it because I don't ride around on the street redlining the bike very often so I stuck the snorkel back in for the better low speed throttle response. Others may have had a different experience.

If you keep the snorkel on and just put in the UNI or K&N filter you can probably get but by just going out to about 3 turns on the pilot screws without going up on the main jets.
Personally I like paper filters because they trap more dirt. I've got a feeling you may not like the way the bike runs after changing the filter, pulling the snorkel and changing the jetting. The snorkel is a restriction but it does improve low speed throttle response IMO. On the other hand, you could always put the bike back where you started if you don't like the changes.

Personally I would leave it alone and just ride it since you say it runs great as it is now and it doesn't sound like you're trying to extract every last fraction of HP anyway.

SpeedyPete · 11-03-2007

Spend a little time bonding with the Jenks tuning notes, it makes you think a bit and in the end it gave me the right solution for my set-up. Here's a hint: try the thrux needles instead of the shims.

BTW, you might want to think about doing some of these adjustments yourself. None of this is rocket science and you may find you like turning a few wrenches. I did.

P

ggRAT · 11-03-2007

Take a look at this.

Go to Pat's Triumph Site ... http://www.dinqua.com/index.html
Download the "Jetting Calculator"
(It's a very small executable.)

Most of the information on his site is based upon 790cc engines with twin
Keihin CVK36 carburetors, albeit on a Speedmaster. Still it translates very
well to our Bonnevilles and Thruxtons.