LARGER CARB?!
- kdxmaniac
- Supporting Member
- Posts: 595
- Joined: 09:01 pm May 24 2010
- Country:
a video of the bike running would be good!
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
- David_L6
- Gold Member
- Posts: 235
- Joined: 01:07 am Jun 04 2010
- Country:
- Location: Northwest Louisiana
That doesn't surprise me. Weaker signal....moto_psycho wrote:Definitely needs a larger pilot jet, will get a few on order 2moro
I have fooled with carbs a LOT on boat motors. Not so much on motorcycles, but theory is the same.
From experience - 44 cubic inch 4 cylinder outboard with 2 carbs:
Motors come with two 1" carbs. Mercury made several other sizes of carb for different motors - 1 1/16", 1 1/8", 1 3/16", 1 1/14".... The motors were designed to turn ~ 5500 RPMs stock. We turn them ~ 8500 RPMs on our hydros. We can't do ANYTHING to increase compression ratio. We can port them all we want to (in fact, we can remove all the metal we want to - just can't add any). The 1 1/4" carbs are way too big for anything. The 1 3/16" carbs are way too big for racing. The 1 1/8" carbs run good down the straights on a 1 mile course, but they give up too much coming out of the turns and they are too big for 3/4 mile. The 1 1/16" carbs worked out to be the best 1 mile courses. The stock 1" carbs are tough to beat or courses shorter than 1 mile. I run 1 1/16" carbs everywhere. Some of my competitors switch between 1" and 1 1/16" carbs depending on the course. The smaller carbs work better on the shorter courses. Why? The motors spend more time accelerating on the shorter courses. Even though I can run a Holley 4 barrel, it wouldn't do me any good. The motor can only use so much carb.
2000 KDX200 / 2002 CR250 / 2003 CR250 / 2008 TT-R230 / 2011 Brute Force 750 / 2012 Brute Force 750 EPS
It is definitely a jetting issue at the moment though, it doesn't feel like too much carb atall (I've over carbed before!) this is literally a case off to small an idle jet, the bike is hunting at idle and I have a smaller jet installed than recommended for the carb.
But as you say, weaker signal, but with the carb being so much closer to the action I definitely believe it is made up for, as the second the needle comes into play (just over 1/4 throttle) the bike takes off like... a powerboat
But as you say, weaker signal, but with the carb being so much closer to the action I definitely believe it is made up for, as the second the needle comes into play (just over 1/4 throttle) the bike takes off like... a powerboat
Interesting, when I snapped the throttle shut the needle got jammed in the main jet had to make a shim up for it.
Also, fitted 50 pilot jet, has cleaned up the bottom end, but I really think I need to get a leaner slide so I have more adjustment on the needle. Then from that I need to get a needle that is slightly richer at 1/4 throttle.
The bike feels nigh on perfect atm, but there is always more to be had
Also, fitted 50 pilot jet, has cleaned up the bottom end, but I really think I need to get a leaner slide so I have more adjustment on the needle. Then from that I need to get a needle that is slightly richer at 1/4 throttle.
The bike feels nigh on perfect atm, but there is always more to be had
- SS109
- KDXRider.net
- Posts: 5770
- Joined: 05:11 am Aug 23 2009
- Country: USA
- Location: Tucson, AZ, USA
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Not worth my time.
Last edited by SS109 on 02:17 pm May 21 2011, edited 1 time in total.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
- Tedh98
- Supporting Member II
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- SS109
- KDXRider.net
- Posts: 5770
- Joined: 05:11 am Aug 23 2009
- Country: USA
- Location: Tucson, AZ, USA
- Contact:
Not worth my time.
Last edited by SS109 on 02:17 pm May 21 2011, edited 1 time in total.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
Do me a favour and get me a schematic of the valve that shuts off the idle jet at anything over 1/4 throttle then please mate...
And no, my idle is perfect, if you really want I could use a timing light to find exactly how many hundred rev's it is idling at. Air screw is 1.5 turns out which is directly in the middle of the adjustment range, it is perfect.
Also, the idle circuit on this carb bypasses the slide completely, at idle the slide is 100% shut.
Pilot jet 45
Needle CEL top clip
Main jet 190
best setting so far :D, gonna try 200 main 2moro, though I doubt it will improve, but I'll never find out if I don't try!
Quote from a well known jetting guide;
"It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving."
Source - http://users.conwaycorp.net/virtus/page ... etting.htm
And no, my idle is perfect, if you really want I could use a timing light to find exactly how many hundred rev's it is idling at. Air screw is 1.5 turns out which is directly in the middle of the adjustment range, it is perfect.
Also, the idle circuit on this carb bypasses the slide completely, at idle the slide is 100% shut.
Pilot jet 45
Needle CEL top clip
Main jet 190
best setting so far :D, gonna try 200 main 2moro, though I doubt it will improve, but I'll never find out if I don't try!
Quote from a well known jetting guide;
"It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving."
Source - http://users.conwaycorp.net/virtus/page ... etting.htm
- SS109
- KDXRider.net
- Posts: 5770
- Joined: 05:11 am Aug 23 2009
- Country: USA
- Location: Tucson, AZ, USA
- Contact:
Not worth my time. Good luck to you and good bye.
Youtube Channel: WildAzzRacing
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
AZ State Parks & Trails OHV Ambassador - Trail Riders of Southern AZ
Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
Hah! How am I not worth your time? You've learned something quite important about jetting from me, what have I learned from you?
I find it quite funny, before I fitted the carb half of the forum was swarming on this thread, itching to read of my absolute failure, now it works far better than expected, everyone buggers off.
I find it quite funny, before I fitted the carb half of the forum was swarming on this thread, itching to read of my absolute failure, now it works far better than expected, everyone buggers off.
- kdxmaniac
- Supporting Member
- Posts: 595
- Joined: 09:01 pm May 24 2010
- Country:
moto_psycho wrote:Hah! How am I not worth your time? You've learned something quite important about jetting from me, what have I learned from you?
I find it quite funny, before I fitted the carb half of the forum was swarming on this thread, itching to read of my absolute failure, now it works far better than expected, everyone buggers off.
i havent learned anything from you.....you put a carb on your bike and made it run{somewhat}......but, did you not take a carb off your bike that was running?
i just dont see why you want to go thru the trouble to install that carb, when you could have jetted the stock carb.
but, i guess if your THAT bored, go for it.
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
- Julien D
- KDXRider.net
- Posts: 5858
- Joined: 07:53 pm Nov 07 2008
- Country: USA
- Contact:
As far as I can see, it's working about as I expected.moto_psycho wrote:Hah! How am I not worth your time? You've learned something quite important about jetting from me, what have I learned from you?
I find it quite funny, before I fitted the carb half of the forum was swarming on this thread, itching to read of my absolute failure, now it works far better than expected, everyone buggers off.