Bonneville America Forums Forums Technical Forums The Vault Intake / Carbs

The snorkle is under the seat.

Pat's Triumph Site (Dinqua)

Triumphants web page

Keihin CVK40 Courtesy of Ron LaMantia. Discusses "The Care & Feeding Of Your Vulcan Carb" Albeit we have two CVK36 carbs.

Carb Tuning
(The way the idle circuit is explained is correct if the air mixture screws are on the air filter side which ours ARE NOT. On ours, turning the pilots in leans the mixture, turning them out richens)

Thanks Pete! : PDF Tuning Manual

Web-based version of Dinqua's jetting calculator for you Mac, Windows Vista and Windows 7 users.

TBS needles are N3RF and the Thruxton needles are NBZT
(TBS needles, Triumph part #T12410240)

Link from Grump: K&N filter cleaning

Advice from Pat: I soak mine in hot water with Dawn dish soap, rinse with hot water and spray new oil on them,. Air filter oil from any auto store.

Pod filter part numbers: LEFT side RC-2890 and Right Side RC-2900
The standard replacement filter is TB8002

From Greybeard:
Start on one side and adjust the mixture for fastest idle. You may have to slow the idle down a bit as you do this because if it gets over maybe 1200 the rest of the carb circuits start to activate. For summer riding, you will want to set the mixture about 1/8 turn richer (screw out) than that spot for cooler running.
Reset the idle speed to normal, then repeat on the other side.
It is a good idea to go back and forth, tuning for best idle speed 2 or 3 times to get the mixture balanced. If you have the equipment, it would be a good idea to rebalance the carbs when you are done, then go back and readjust the mixture for best idle once more to fine tune the carbs.

You can get an approximation of balancing the carbs without a vacuum gauge or balancing rig by first setting the mixture, then set the balancing screw so that the engine idles at the same speed with either sparkplug disconnected. This is not terribly accurate, but better than nothing.
If you have the Calif emissions system, you will have to disconnect the hoses to the fittings on the carbs near the manifolds and block the fittings. These feed fuel vapors to the engine from the collection canisters and have a side effect of acting like putting a balancing hose between the manifold fittings when the AI is removed.

From Pete:
honda part # 16075-KG8-901 is a honda mixture screw o-ring.
it is like $2 and change for 1 and can be ordered as 1 or more.

From Phil:
Spring goes on first, then washer, then O-ring.
Or, O-ring is closest to tip

Here's a link to a photograph of the secret fuel filter aka the "t" filter located where the fuel line meets the carbs.


Edit: Here's a new suggestion from Reid.
]http://store.knfilters.com/search/product.aspx?Prod=81-0241
This K&N Fuel filter is perfect and allows you to get rid of the "hidden filter".
It's 5/16" barbs and easily fits between the petcock and top of carbs.
It's clear and you can easily see if you got into some junk fuel.
And only $6.38 direct from K&N.

Remove seat.
Remove snorkle and Air filter.
Remove any more snorkles from inside airbox towards carbs (not in Speedmasters).
Notice the bottom of the airbox has small dimples that hold the air filter in place. DO NOT DRILL THESE OUT, stay inside them as you do the mods.
Stuff some clean rags into the airbox so that plastic particles stay out of the carbs.
Place a piece of wood, we use 3/4" plywood, under the airbox on top of the swingarm as not to chip the swingarm podercoat when you drill through the bottom of the airbox.
Use a hole saw,(smaller than the distance between the oval dimples) or make several smaller holes and then dremel them into a larger hole on the bottom of the airbox, staying inside of the little protrusions that hold the air filter in place. (They are in an oval shape).
Then vacuum all the little pieces of plastic from the inside of the airbox and remove the rags. be sure you get ALL the little pieces. Plastic in the carbs is not a good thing and can easily gum up.
Then as an added precaution, we cut a piece of light guage stainless steel screen door material (or you can even use the plastic stuff too) into a slightly larger oval than the protrusions.
For added safety, and to prevent water entering the bottom of the airbox (which can happen but is extremely rare and only if you ride several miles on water logged roads), you can cut two equal sized pieces of screen material and place a thin piece of foam, like the uni filter foam stuff, between the two layers of screen material. You can also add some of the filter oil to this new bottom filter as well. Then bend the edges of the screen material over so it secures the layers of screen and foam.
Then take the screen piece, be it one or two layers, place it into the bottom of the airbox completely covering the oval dimples.
Cut the bottom out of your air filter but be sure to just cut the inner part out of the bottom, leaving the outer thick edges for grip in the bottom of the airbox.
Firmly press the air filter in place on top of the screen you inserted, it should "POP" a bit as the screen deforms and seats itself between the filter and the airbox.
Be sure the air filter is down far enough to reinstall the top holding plate for the air filter. If not, press it down harder, or use a less rigid stainless screen for the bottom filter assembly.
Replace the top part that holds the air filter in place.
Put the seat back on and ride away.
You will most likely have to rejet after this mod as it allows about 50% more air into your carbs and you will need to balance the gas to match.
This modification is easily reversable by simply replacing the air filter with a new one. The uncut bottom of the filter should plug the hole completely, if not, just cut a small piece of plastic/rubber the same size as the holes and place that under the new air filter, or glue it in for a better seal.

Thanks Pete!

PDF Tuning Manual

4 mm stainless steel washers from Ace or wherever. They are .50mm thick (.020 inches).

Various historical credits, but member Popcorn spelled it out recently.

These are the rubbers on the front of the Carburetors that attach to the intake manifolds. There is a particular orientation when installing the OEM ones part number T1240092. Last time I bought the OEM ones they cost under ten bucks each.

Thanks to member Pete (snekeptp) who posted on Wed Jun 27 2007 04:26 PM

Quote:

---

the divider between the clamps is wider on top
narrow on bottom.
now for the front to back ( engine to carb )
there is a small raised tab on the top of the boot
this is the front ( engine ) side of the boot.
see arrow in photo

---

The raised tab Pete speaks of is tiny. One has to look at the mold seam closely to discern it.

In the bold boxes.

Member Gregger sent me this link to TriumphTwinPower.com which shows how to adjust the throttle position sensor.

Throttle Position Sensor Adjustment

Grits and hog jaws

Referenced Thread

Parts used by Bonnevilleamerica.com member Brett's (08America)


Brett's (08America) motorsickle


Brett's (08America) motorsickle


Bonnevilleamerica.com member Damien's (damien) motorsickle


Bonnevilleamerica.com member Ken's (B02S4 ) motorsickle


Bonnevilleamerica.com member Geoff's (05tba) motorsickle


Bonnevilleamerica.com member chris' (oldgimmer) motorsickle


Other thread(s)...
Bonnevilleamerica.com member Dave's (roadworthy) motorsickle


Home Made Carb Braces for FREAK


Store bought

Bentzoni Stainless Steel Carburetor Support Brace

BCE-048 Carburetor Support Brace