Help tuning carb:Grampsize - Kawasaki Vulcan Forum : Vulcan Forums
 
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post #1 of 8 (permalink) Old 03-01-2018, 03:57 PM Thread Starter
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Help tuning carb:Grampsize

Grampsized per Wolf’s instructions. 170 main, 52 pilot, OEM needle, 1 1/2 turns out, K&N hi-flow. Cobra tapered exhaust w/welded in baffles.

Runs great until I cruise steady at say 55 mph, or 65 mph, then it starts stuttering. I pull choke out and it doesn’t sputter anymore indicating to me it needs more fuel. Lower speeds seem OK while accelerating. High speeds 80-90 mph, OK. Just that midrange speed while cruising steady. Tried blocking some of the air filter, no change. Even put in stock air filter, no change. Turned fuel mixture screw out in 1/2 turn increments and tested each. No change. Farther out, worse it gets.

Because it was mid-speeds acting up, I thought I’d shim the needle (stock) w/two brass #4 washers (very thin). No change in midrange speeds, but runs worse in the other speeds. However, I didn’t change the pilot jet to match raising of the needle, or should I have? Also, with the washers in, I screwed the fuel mixture screw all the way in while idling and bike never stuttered. So was thinking I should maybe change the pilot to next size smaller. I don’t know.

I put it back to square one now as if I just Grampsized. Ideas anyone? Not ready to give up. NOTE: Bike ran perfect before, I just wanted to try the Grampsize system. I did notice more power, and a cooler running bike (installed a temp gauge). Just that pesky stuttering/sputtering has me stumped Thanks for any help!

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post #2 of 8 (permalink) Old 03-01-2018, 05:08 PM
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Up the pilot jet T/G

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post #3 of 8 (permalink) Old 03-01-2018, 07:02 PM Thread Starter
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Thanks. I'll get one ordered and try that. T/G?

1996 Vulcan 800, Blue/Green
JUST SOLD: 2016 Indian Scout, Black
SOLD LAST YEAR: 2006 Triumph Rocket III, Black
SOLD LAST YEAR: 1967 Honda 305 Dream, Black

"Going up the country . . . "
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post #4 of 8 (permalink) Old 03-02-2018, 04:18 AM
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T/G=Texasgrape !LOL , It makes cense that the pilot jet is not big enough ! you pull the choke & the bike runs good , the bike runs good on the main jet with no choke !

Steve

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post #5 of 8 (permalink) Old 03-17-2018, 04:33 PM Thread Starter
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I upped the pilot jet to next size (55) it and wouldn't go over 50 mph--way rich. Can't get ole' gramps tuned, so I went back to stock air box and jetting. (I grampsized w/spare parts)

I'm afraid the only way to get it right is put it on a dyno, but that costs approx $350 here; I called two places--one in San Antonio and one in Austin. Ouch. Why grampsize? I like tinkering, plus the bike ran cooler and had a bit more zip. Oh well . . . guess I'll go ride Twisted Sisters next week, drink a beer or two in Bandera while pondering a name for her.

1996 Vulcan 800, Blue/Green
JUST SOLD: 2016 Indian Scout, Black
SOLD LAST YEAR: 2006 Triumph Rocket III, Black
SOLD LAST YEAR: 1967 Honda 305 Dream, Black

"Going up the country . . . "
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post #6 of 8 (permalink) Old 03-17-2018, 04:53 PM
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How F00000KIN Much !!!!! The last two Dyno's I used were £40 for 1 hour ! The last 1 we used for the whole afternoon & the guy still charged £40 ! be it he wanted to know HOW I had got 25bhp out of a 11bhp motor that we used for sand racing !

Steve

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post #7 of 8 (permalink) Old 03-18-2018, 03:43 AM
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Originally Posted by magicgrotto View Post
How F00000KIN Much !!!!! The last two Dyno's I used were £40 for 1 hour ! The last 1 we used for the whole afternoon & the guy still charged £40 ! be it he wanted to know HOW I had got 25bhp out of a 11bhp motor that we used for sand racing !

Steve
For me to get a custom tune on my VRSCR, its going to cost me £240.
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post #8 of 8 (permalink) Old 03-18-2018, 07:34 AM Thread Starter
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I think if you only get a diagnosis on a Dyno, it's pretty cheap. But then add tuning onto that when they start pulling the carb off a few times and installing jets, etc., the labor costs get you.

1996 Vulcan 800, Blue/Green
JUST SOLD: 2016 Indian Scout, Black
SOLD LAST YEAR: 2006 Triumph Rocket III, Black
SOLD LAST YEAR: 1967 Honda 305 Dream, Black

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