Author Topic: Successful carb settings redeux  (Read 32782 times)

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Ice

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on: March 19, 2013, 05:45:34 am
 We used to have a thread "successful carb settings" that was lost during the jump to the new forum format.

 It contained tons of useful information posted by our forum members.

Lets REbuild it by posting our carb type, jetting and settings, altitude intake engine and exhaust mods and other pertinent information here.

Mods, delete this thread if it's inappropriate or turns out to be a flop.
« Last Edit: March 19, 2013, 06:47:35 am by Ice »
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DanB

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Reply #1 on: March 20, 2013, 05:41:36 pm
Updated 4 June 2013

Bike: AVL, 500 Electra.
Carb: BS-29 (CV carb by Ucal, Mikuni design & jets).
Filter: K&N DU-0100, in stock electra airbox, box drilled, and internal walls removed per this thread: http://www.enfieldmotorcycles.com/forum/index.php/topic,117.0.html.
Exhaust:  Unrestricted short bottle; No cat. in pipe; No baffle
PAV: Removed and plugged at head.
Altitude: sea level, plus a couple hundred feet.

Pilot jet: 17.5 (Stock is 15) - VM22/210 (from Jets R US)
Main Jet: 117.5 115 (Stock is 110) - N102.221 (small - understand you can also use N100.604)
Needle Jet: 4DHL38.  Plastic washer, 2.45 mm thick, 8.2 mm OD, tight fit but moves, middle clip setting. 
Piston Valve (CV slide): Bored out the 2x vacuum openings by +1/16 inch.  Crisper response... doesn't appear to affect fuel/air ratios.  Does affect fuel consumption.

Performance notes: The carb pulls very nicely throughout the power band. Have to say, I'm impressed with its 'zippy ness'.  Have a bit of hesitation between 1/8 and 1/4 throttle.  Going to shim needle richer.  If that doesnt work, will remove .7 to .8 mm of slide piston (making it richer).

Update:  After plug checks, moved to a richer main jet.  I have both a 117.5 and a 120.  Using the 117.5 now as its warmer (60's to 70's);  Will use the 120 in the fall.  Starting:  Both hot and cold were difficult to kick start.  Learned to grab about 1/8 throttle on kicking, and now i get 1 kick starts.  I thinking the AVL likes more air at start or it could be a result of the enlarged holes in the piston, i dunno.  Generally, one is instructed not to touch the throttle on a CV carb; not true for my bike.  Also, the 17.5 pilot is almost too rich.  The mixture control screw is very sensitive and is currently working best between 1/2 and 1/4 turn out.  The bike didn't like 15 pilot; even at 6 turns out(!) it was starved & lean when rolling onto the throttle
« Last Edit: June 04, 2013, 05:35:54 pm by DanB »
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2006 AVL Electra


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Reply #2 on: March 24, 2013, 07:58:50 pm
This can be very helpful! I think every one of us should post our Carb Jetting specs here :)

-Sanket


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Reply #3 on: April 02, 2013, 09:12:58 am
Here's my carb settings

Carb Name - Mikuni VM34
Carb type - Round Slide

Jets used -

30 size pilot jet (vm22/210)
220 size main jet (4/042)
6DH4 NEEDLE - Stock needle, that comes with the carb
159 N-8 - Needle Jet

Alterations & Minor mods - Free flow megaphone, Uni Airfilter (not oiled), PAV Removed, Cat-Con removed.

Altitude - 3000 FT

After this upgrade things changed! and the bike now offers better crispness throughout the rev range. Also, till now I have noticed no flat spots either. Mains running slightly rich, compared to pilot and needle (Needle on 4th slot, going to switch it back to 2nd).

Mileage - 25kmpl~28kmpl in city, 30kmpl~35kmpl in the highways.


« Last Edit: April 03, 2013, 05:57:38 am by dampking »


Arizoni

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Reply #4 on: April 03, 2013, 12:30:38 am
Hopefully those numbers are Km/Ltr?
If they are they would be equal to around 65 miles/US gal city and 75 miles/US gal highway. :)

Jim
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Reply #5 on: April 03, 2013, 05:58:01 am
Sorry for that! I fixed it :)


mattsz

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Reply #6 on: April 03, 2013, 03:17:33 pm
Sorry for that! I fixed it :)

I was gonna say... this is a thread for successful carb settings!   ;D ;D ;D


DanB

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Reply #7 on: May 10, 2013, 03:12:00 am
I copied this from bedlam and his Mikuni tm32 off the uk forum. An excellent read, photos and dyno graph. Hope you dont mind bedlam.

Link: http://tinytim.forumcircle.com/viewtopic.php?t=2631

"MAIN JET 4/042-Size 200 Note: VM jets are NOT the same as TM jets, and the sizes are calculated differently.
PILOT JET VM22/210-Size 30
NEEDLE JET 785-24001-Size (389) Q-2 (as supplied)
JET NEEDLE 5FP17 Clip groove #3 (as supplied)
STARTER JET VM17/1002-Size 60 (as supplied)

These are the settings I'm using at the moment. A minor improvement might be gained from raising the float height slightly from the stock position, but I haven't bothered. The slide is the one supplied with the carb. This particular main jet hasn't been checked on the dyno but it's almost certainly correct - maybe even one too rich. A 185 was too lean. It's very sensitive to pilot screw settings and is happier with the pilot set a bit rich because there's no accelerator pump. "
Suppose I were an idiot, and suppose I were a member of Congress; but I repeat myself. ... Mark Twain
2006 AVL Electra


D the D

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Reply #8 on: June 03, 2013, 01:49:32 am
Settings I arrived at with help from Ace and everyone.
Bike: 2007 Iron Barrel 500 ES Military.
Carb: Mikuni VM28-418 (TM28 Flatslide)

Filter: K&N RU-2450 in stock airbox.
Exhaust: Baffled India short bottle (baffle in bottle like stock muffler, not added reducer type in pipe), India head pipe, no Cat, no PAV.
Altitude: ~280ft.

Pilot jet: 25 VM22/210
Main Jet: 180 VM4/042/180 (large hex)
Needle Jet: P-0
Needle: 2nd slot from bottom (richer side of middle)
Slide 2.5

Results: Good idle, good torque, crisp response and smooth through all ranges, great drivability, one kick starts in warm weather.  Vast improvement over Mikarb.  The smaller 28mm Flatslide seems to like one or two jets smaller than TM32 people are commonly using.  May restrict top end, but I don't know to what extent as I haven't exceeded 65mph via GPS reading (Speedometer reads ~5mph high at 60) and I generally don't exceed 55.  She'll cruise at 65 without effort, just don't want to punish the stock bottom end.
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH


ace.cafe

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Reply #9 on: June 03, 2013, 11:49:14 am
Settings I arrived at with help from Ace and everyone.
Bike: 2007 Iron Barrel 500 ES Military.
Carb: Mikuni VM28-418 (TM28 Flatslide)

Filter: K&N RU-2450 in stock airbox.
Exhaust: Baffled India short bottle (baffle in bottle like stock muffler, not added reducer type in pipe), India head pipe, no Cat, no PAV.
Altitude: ~280ft.

Pilot jet: 25 VM22/210
Main Jet: 180 VM4/042/180 (large hex)
Needle Jet: P-0
Needle: 2nd slot from bottom (richer side of middle)
Slide 2.5

Results: Good idle, good torque, crisp response and smooth through all ranges, great drivability, one kick starts in warm weather.  Vast improvement over Mikarb.  The smaller 28mm Flatslide seems to like one or two jets smaller than TM32 people are commonly using.  May restrict top end, but I don't know to what extent as I haven't exceeded 65mph via GPS reading (Speedometer reads ~5mph high at 60) and I generally don't exceed 55.  She'll cruise at 65 without effort, just don't want to punish the stock bottom end.

Sounds good!
The reason for the smaller main jet on the 28 is that it is a smaller carb than the 32, so at full throttle it is not passing as much air as the 32.
The 28 does have enough flow capacity to flow as much as the typical stock Bullet head, but barely.
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D the D

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Reply #10 on: June 04, 2013, 07:50:21 pm
The TM-28 is good for my putting around the area.  If I do anything more for better breathing/performance, I'll get a TM-32 and Ace Air Canister.
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH


jedaks

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Reply #11 on: June 09, 2013, 12:43:33 am
Instead of always reading I'll contribute too.

Bike: 2004 Kick only 535
Carb: Factory Mikcarb VM28
Filter:  Ace Canister
Exhaust: "Goldstar" style
PAV: Removed and plugged at head.
Altitude: sea level

Pilot jet: 27.5, air screw 3 turns out from bottom.
Main Jet: 127.5
Needle Jet: Stock, clip on bottom (richest) setting
Piston: Accralite 535 (8.5:1) 150psi


Performance notes: It took a while to dial everything in, due to living in the middle of nowhere and having heaps of information to digest. However once I got everything to co-operate the bike pulls like a team of mules with no ping at any throttle opening and a steady reliable idle. Engine starts on 1st or 2nd kick. I'm probably running a little bit rich, but this combination of jets gives the best power, performance and fuel economy. (24 kilometers per litre) I also always use premium fuel 98 octane (93 in US me thinks).


D the D

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Reply #12 on: August 30, 2013, 02:52:56 am
Bike: 07 Iron Barrel
Carb: Mikuni TM32
Filter: Ace Canister
Exhaust: Indian Headpipe and Indian Short Bottle
PAV: Gone
Altitude: ~ 180 ft according to FAA

Pilot Jet: 30 1.5 turns on the Pilot Screw (+ or - 1/8 turn)
Main Jet: 190
Needle Valve: P-4
Needle: 5FP17 (Stock Needle) Clip in the middle
Throttle Valve: 4.0 (Stock Throttle Valve)

Easy kick starts.  Don't need Choke when it's in the 80's F.  Could probably drop the needle a notch, but would probably have to raise it back when the weather cools.  I run out of motor's ability to breath before the carb can restrict it now, but WOT doesn't bog from being too big either.  Don't need as much throttle to maintain the same speeds as the TM28 or VM28 did.
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH


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Reply #13 on: October 31, 2013, 07:07:04 am
Bike: 2008 AVL 500, BW piston mod to bump compression, Mildly ported Head (smooth'd down the steps on short radius)
Carb: Mikuni TM34
Air Filter: K&N R-1100, No PAV etc
Exhaust: Short bottle with straight thru Removable Baffle, Original Header pipe with Hot tube removed
Altitude: 2950 ft~3000 ft
Temperatures: 24-33 Deg C around the year

Pilot Jet: 25,  2 turns out (+/- 1/4 turn)
Main Jet: 210
Needle Jet: 389-Q2 (Stock)
Needle: 6DP17 (in lowest position)
Throttle Valve: 4.0 (stock)

Easy starts in the morning, Needs choke on cold mornings but not during the day. Accelerates pretty strong all the way to 135 Kmph ( Radon Digital meter readout). Can potter around at 40Kmph in top gear and pulls away cleanly with light throttle.

The plug pic attached. Checked after 400 kms of installing the carb with the new needle.


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Reply #14 on: April 26, 2016, 06:48:22 pm
Bike:2008 AVL Classic Bullet 500
Carb: BS-29
Air Filter: Stock paper in tool box
Pav removed and plugged
Catch cup removed, with added beather tube and duck bill
Exhaust : Stock header with removed hot pipe, long India after market muffler exhaust ( glass pack)
Main Jet: 115
Pilot Jet: 17.5
Needle : Stock setting
Air/Mix screw approx. 2.5 turns counter clock wise ( out)

Starts well, engine more crisp, can lift the front end a few inches during acceleration in first gear.  An occasional pop during hard deceleration.
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