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| < Engine Clinic - Mini Off Road Buggy ~ Carb - Change 'pilot' jet? |
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I've been reading a LOT of threads here on BN for the last couple weeks. I've noticed that most of you guys replace your Main jet in your carb after modding the intake, filter and exhaust. What about your pilot jet? Are none of you having idle problems, hesitation just off idle, or cold natured, hard to start problems?
And what about needle positions?
We usually have to change the pilots and adjust the needle position in our bike carbs when we start opening up airways and getting more gas/air through the engine. I personally cannot stand, nor will I put up with an engine that will not idle, bogs, or hesitates off idle.
Anyone?
_________________
Tomberlin Crossfire 150R
Bikes ... 
On your mark, get ready, let the Modifications begin!
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| garider wrote: |
I've been reading a LOT of threads here on BN for the last couple weeks. I've noticed that most of you guys replace your Main jet in your carb after modding the intake, filter and exhaust. What about your pilot jet? Are none of you having idle problems, hesitation just off idle, or cold natured, hard to start problems?
And what about needle positions?
We usually have to change the pilots and adjust the needle position in our bike carbs when we start opening up airways and getting more gas/air through the engine. I personally cannot stand, nor will I put up with an engine that will not idle, bogs, or hesitates off idle.
Anyone? |
i think most of the everybody gets by with the pilot jet that comes in there 150 carb. every now and then i will read somebody has to change to bigger pilot jet .i think all you will have to do is richen it up a little with the air fuel screw.for example i had to bump up from 1 3/4 turns out to 2 1/4 that might be a little rich for some just setting around idling but when i climb down on the gas she takes it and goes,pretty fast.i have my choke converted to manual never need it until cold weather gets here hit the switch and it starts.
for me i just left the needle position the way it came but i have heard some say its a good mod and other say no.my carb does well the way it is setup.
pud
_________________
2006 sunl 150b
Dr. pulley 10 gram sliders, 1500 torque spring,39 tooth sprocket,2000lb winch, red neck uni filter, 125 main jet at 1,450 elevation, drilled out exhaust,ngk iridium plug,performance intake
trying a set of 10gram rollers now
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yes, garider I understand what u r saying,I'm working on my pilot jet,round slideand jet needle to dial it in perfectly, but not everybody runs mikunis.
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most of the time you can run the stock pilot jet, if there is a stumble you can chage to a #40 or 42 pilot jet. I stock the 40 and 42 jets. they are the most common for the pilot.
Funnyman, how close is the carb now?
_________________
Blade buggies,Carter buggy's, ams (manco) , joyner, parts for almost anything
MRP dealer
Tucker Rocky Dealer
Vega Helmet dealer
I.T.P. tire and wheel dealer
www.mcdonoughpowersports.com
Eric Jackson
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I haven't even looked that close yet, but is the fuel screw plugged?
_________________
Tomberlin Crossfire 150R
Bikes ...
On your mark, get ready, let the Modifications begin!
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on some the air fuel screw does have a plug over it
_________________
Blade buggies,Carter buggy's, ams (manco) , joyner, parts for almost anything
MRP dealer
Tucker Rocky Dealer
Vega Helmet dealer
I.T.P. tire and wheel dealer
www.mcdonoughpowersports.com
Eric Jackson
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You described my issues to a tee, garider... but I'm still in the process of trying to dial in my carb properly. I recently did the air/exhaust/jetting mods, and also changed to a 42 pilot jet, but it's still idling like crap, hard to start, studders on take-off, and just doesn't sound very good at all up to about 1/4 throttle. I still need to check compression and adjust my valves, so I'm hoping that will solve some of the issues. If not, I may have to experiment with a couple other pilot jets to see if that helps. So I'm not convinced that the pilot jet alone is my problem.
_________________
05' Carter Talon GSX 150 2R
39t rear sprocket
9.5g sliders
NGK Iridium Plug
H.O. Bando Coil
Dr.P Hit clutch (backup)
1500# torque spring (soon...very soon)
125 main jet
42 pilot jet
MRP Air Filter (rednecked)
Drilled out stock exhaust
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| MikeK wrote: |
| You described my issues to a tee, garider... but I'm still in the process of trying to dial in my carb properly. I recently did the air/exhaust/jetting mods, and also changed to a 42 pilot jet, but it's still idling like crap, hard to start, studders on take-off, and just doesn't sound very good at all up to about 1/4 throttle. I still need to check compression and adjust my valves, so I'm hoping that will solve some of the issues. If not, I may have to experiment with a couple other pilot jets to see if that helps. So I'm not convinced that the pilot jet alone is my problem. |
mikek after you do your compression test and adjust valves.
i think you will find out it is easier to dial in one jet at a time.if it was me i would put the stock pilot jet back in ,get the main jet dialed in so you will know were you are at there.then if you can't get the stock pilot jet dialed in with the air fuel screw then try the bigger pilot jet.doing both jets at once its hard to tell which one is wright and which one is wrong
did you completely gut your muffler with nothing left inside.
just my thoughts
pud
_________________
2006 sunl 150b
Dr. pulley 10 gram sliders, 1500 torque spring,39 tooth sprocket,2000lb winch, red neck uni filter, 125 main jet at 1,450 elevation, drilled out exhaust,ngk iridium plug,performance intake
trying a set of 10gram rollers now
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Well, no.. that could be part of my problem too. I didn't completely gut the exhaust, basically just drilled a few 1/4" holes through using a really long bit. I ride around town and to work quite often (at 6am) so I need to maintain a little noise dampening. That said... maybe a slightly smaller jet would be better? I got a 125 in right now and it seems to run pretty nice, although a little too rich still. But I assumed adjusting the air/fuel mix might help that. I put the stock pilot jet back in and it helped with idle and low throttle, but it seems to be getting worse which is why I'm guessing the valves are out of adjustment. So before I tinker anymore with jetting, I'm gonna adjust the valves and do a compression test to make sure the engine is running smoothe first.
_________________
05' Carter Talon GSX 150 2R
39t rear sprocket
9.5g sliders
NGK Iridium Plug
H.O. Bando Coil
Dr.P Hit clutch (backup)
1500# torque spring (soon...very soon)
125 main jet
42 pilot jet
MRP Air Filter (rednecked)
Drilled out stock exhaust
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If I remember right from another post you are about 4500' in elevation. You will be running a jet that is two or three sizes smaller than someone at sea level. Your tuning should be somewhere between 120-125 on your main jet with the stock pilot jet.
_________________
08 Joyner SandViper 250
07 Joyner SandSpider 650
06 Tank Urban Touring 150SE
04 Yerf-Dog Spiderbox 4209 GX150 (SOLD)
04 Yerf-Dog Spiderbox 3206 GX150
81 Honda Passport C70B
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