March 16th, 2015, 02:51 PM | #1 |
ninjette.org member
Name: Russ
Location: California
Join Date: Mar 2015 Motorcycle(s): '12 EX250JC Posts: 25
|
Full service manual says to turnout one carb pilot more than the other....why?
And for good reason. Were at 9,000 mi and doing all maintenance items on the list, incl carb cleaning and valve checks. ALL is good.
For curiosity we welded up a "tuning purposes only" exhaust system that isolated the cylinders and housed O2 sensors. After syncing within 1 mm Hg one side had to be enrichened drastically to make the O2 sensors match, as the full service maual says "Pilot Screw Setting: #L: 2 1/2 #R: 1 3/4" (pg 3-16). Plugs look great now. But the question still burns, Why'd the engineers at Kawi do this, and why do the O2 sensors concur? Note: the factory setup and tune (sync and pilot turns) makes one cylinder work substantially harder than the other. Last futzed with by RcTechnologies; March 16th, 2015 at 03:00 PM. Reason: attaching photos-cant nevermind |
|
March 16th, 2015, 03:29 PM | #2 | ||
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
|
Did you bench sync, or running on the bike sync?
Here's my personal write-up on synchronization, once you understand what you've done, the answer will be clear. Quote:
Also here is my write-up on pilot screws tuning, Quote:
__________________________________________________
violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
||
|
March 16th, 2015, 03:53 PM | #3 |
RIP Alex
Name: Cuong
Location: Houston, TX
Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot.
Blog Entries: 2
|
Welcome Russ!
So you're saying the factory pilot adjustments make the bike run more efficient? Wen I was tuning te bike, I found out that the pilot needles are not at equal heights if you set it at 2.5 turns out. Adjusting it to factoring settings equated it equal heights. My thought was the flow of fuel from one end to the other carb probably had to be compensated.
__________________________________________________
HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days |
|
March 16th, 2015, 04:03 PM | #4 |
ninjette.org member
Name: Russ
Location: California
Join Date: Mar 2015 Motorcycle(s): '12 EX250JC Posts: 25
|
Both actually. It was my idea to bench sync with wire feelers, and my coworker insisted on a manometer (multiple rpm test points). The question is why have one cylinder work so much harder than the other at low load conditions? Does it have something to do with two cylinders firing immediately after each other?
Update. Finished lab setup and put the leovince back on. Sounds audiophilicly eargasmic! You can hear an incredibly consistent "buda-buda-buda-buda". throttle response beautiful with a .30 second hang at 3000 rpm when you snap it closed (to reduce engine braking effects). Must ask oneself "did I just set myself up for a blown piston/thrown rod later on?" Is there a reason the factory and manual have one carb richer than the other, resulting in crazy EGT differences between cylinders (at idle/low load)? |
|
March 16th, 2015, 04:14 PM | #5 |
ninjette.org member
Name: Russ
Location: California
Join Date: Mar 2015 Motorcycle(s): '12 EX250JC Posts: 25
|
thanks nutz. funny thing was, the rich side was the carb closest to the fuel inlet hose (from tank)
|
|
March 16th, 2015, 04:32 PM | #6 |
RIP Alex
Name: Cuong
Location: Houston, TX
Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot.
Blog Entries: 2
|
Do you still have the stock needles? IIRC, the needles are slightly different from left and right due to having different part numbers but do not know physically if there is a difference.
__________________________________________________
HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days |
|
March 16th, 2015, 10:07 PM | #7 |
wat
Name: wat
Location: tustin/long beach
Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much.
Blog Entries: 5
MOTM - Oct '12, Feb '14
|
perhaps it is an unintentional defect from manufacturing processes, and the adjustment is simply to account for the known defect
__________________________________________________
|
|
March 16th, 2015, 10:17 PM | #8 |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
|
I know from personal experience from doing the idle mixture screws modifications, removing the anti-tamper caps, I've never found both of them the same, not even close.
Some of the worst ones are at least a full turn difference, or not more in extreme cases. As I stated earlier in my quickly pilot screws tuning, you adjust each one separately for best performance. For the most part they are pretty close to each other, but never exact In the end.
__________________________________________________
violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
|
March 16th, 2015, 10:59 PM | #9 |
Freedom for Germany
Location: This World
Join Date: May 2011 Motorcycle(s): Ninja 250R-FI Posts: A lot.
|
When one wants to do this right, it needs in each pipe of the header a hole (which can be closed with a screw) from where the co measurement is done separate for every single cylinder.
|
|
March 17th, 2015, 09:40 AM | #10 |
ninjette.org certified postwhore
Name: Spooph
Location: Golden, CO
Join Date: Jul 2010 Motorcycle(s): '08 Ninja 250R Posts: A lot.
MOTM - Oct '15
|
The reason each cylinder is different is because Kawi designed cylinder 1 to be the "torque" side, and cylinder 2 to be the "power" cylinder.
The 250 is down on power, we all know this. To keep things cheap it was easier to split the power load between the two cylinders to make a more rideable bike, providing more power down low compared to the pre-gen 250's. I'm sure you noticed the headers are different lengths between the two cylinders. When adding on an aftermarket header, which has equal length headers it's best to replace the needle and idle mixture screw on cylinder 1 with a set/part number intended for cylinder 2. Example: So, cylinder 1 is the torque cylinder, with a longer header tuned for more torque. Cylinder 2 is the power cylinder, with a shorter header tuned for more top-end power. If top end power is what you're after, with an aftermarket exhaust system with equal length headers, you should match the internals of cylinder 1's carb with those of cylinder 2. IF you're tuning for torque down low to make get the bike more pickup below 4K RPM's, you'll have to weld up your own header, equalizing pressure and tuning for more torque and match the internal of cylinder 1's carb. Now this is all applying to the inifinite degree. What most people do with aftermarket headers is to go to the dynojet needles and to not worry about the idle mixture screw in cylinder 1's carb and fudge it close enough, however, you seem to be going to the infinite degree, so I would recommend to also match the idle mixture screws to those found in Cylinder 2's carb. I hope all of that makes sense.
__________________________________________________
My therapist has 2 wheels and a seat. If you are ever in doubt to my tone, please refer to my avatar. |
2 out of 2 members found this post helpful. |
March 17th, 2015, 09:58 AM | #11 | |
wat
Name: wat
Location: tustin/long beach
Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much.
Blog Entries: 5
MOTM - Oct '12, Feb '14
|
Quote:
__________________________________________________
|
|
|
March 19th, 2015, 08:32 AM | #12 |
ninjette.org member
Name: max
Location: bali
Join Date: Nov 2012 Motorcycle(s): ninja 250 Posts: 60
|
Hi,
today i am trying to sync my carb using bench sync. I am using a couple wire steel do this and gues what? my stock ninja with stock mixture screw diffrent left and right, now my 7dle very smooth, needles tach not bouncimg....very amazing guys. Before I go to dealer to sync my carb but idle not smooth as now. |
|
March 19th, 2015, 08:40 AM | #13 | |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
|
Quote:
__________________________________________________
violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
|
|
March 19th, 2015, 06:16 PM | #14 |
ninjette.org member
Name: max
Location: bali
Join Date: Nov 2012 Motorcycle(s): ninja 250 Posts: 60
|
Float height was stock and idle mix stock. Honestly My bike newer idle better with stock, even sync on dealer. So...I trust hand sync then manometer or bottle sync haha. Very happy.
|
1 out of 1 members found this post helpful. |
March 20th, 2015, 01:35 PM | #15 |
ninjette.org member
Name: Rolf
Location: Sweden
Join Date: Jul 2014 Motorcycle(s): Ninja 300 Posts: 70
|
Aren't the cylinders also inherently unbalanced by the ignition sequence? Unlike most three- or four-cylinder engines, the sequence is uneven for a two-cylinder (not all but most commonly). I guess this has most effect on the exhaust side, so with lucky timing the gasses from cylinder 1 has just blown by when cylinder 2 valves open, helping to evacuate gasses from cylinder 2? At high revs?
Not that I can make any sense of this myself. Cylinder 2 is right? So would need more fuel? Or could have a slightly longer intake and still make same power at high revs. Of course the opposite is also possible that at some point the gasses from cylinder 1 are just bouncing back from the exhaust when cylinder 2 valves open. At medium high revs possibly. Or on the intake that when cylinder 2 wants to take air the airbox has just been emptied by cylinder 1. |
|
March 24th, 2015, 08:43 PM | #16 |
ninjette.org member
Name: Russ
Location: California
Join Date: Mar 2015 Motorcycle(s): '12 EX250JC Posts: 25
|
Well done everyone.
After EXTENSIVE analysis, a number of things have become evident and a little lab work was required to prove them as well. Ghost, thanks for pointing out the specifics of syc, not very many know that, and neglect other factors that influence vaccum.
Spooph, from what we can tell you are most likely correct. The design of the header does in fact maximize use of exhaust pulse from the cyl #1 to generate low end torque in cyl #2. (firing 1-2-1-2). Manufacturing defects not withstanding, header design will have a profound effect on the amount of A/F charge at low rpms, especially with 13.25" (ver?) header length. And, of course, our mains kick in past certain throttle positions, rpms etc... Finally , we filled the header with mineral spirits and did volume measurements. Just from the math, it is the case that to make useable power below 4K rpm and beyond 2nd gear, extensive low end tuning had to be performed on a motor that is realistically only effective at high rpms (due to its displacement). Well done to all of you! |
|
March 24th, 2015, 09:12 PM | #17 | |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
|
Quote:
Well thx u for understanding my carburetor synchronization write-up. I have also done some research and have found that the NewGen uses two different main jet needles, one for the left, and one for the right,. Would you happen to have the measurement/micrometer data on the differential of the two? Also the NewGen uses a different style main jet holder with what seems to be less emulation holes? What you happen to have any data on this as well? I'm curious if one could use them in a PreGen carburetor, and if it would be a better design, than the multiple emulation holes? Less chances to clog? Etc....
__________________________________________________
violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
|
|
March 25th, 2015, 09:45 AM | #18 | |
ninjette.org certified postwhore
Name: Spooph
Location: Golden, CO
Join Date: Jul 2010 Motorcycle(s): '08 Ninja 250R Posts: A lot.
MOTM - Oct '15
|
Quote:
Regardless, keep up the good work, very interesting stuff this...
__________________________________________________
My therapist has 2 wheels and a seat. If you are ever in doubt to my tone, please refer to my avatar. |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Newgen Service manual, owners manual & tool kit | Hero Danny | Motorcycle-related | 0 | September 20th, 2014 07:29 PM |
Service Manual... | mar3s24 | General Motorcycling Discussion | 3 | June 8th, 2012 01:03 PM |
The right service manual? | Coyote175 | 2008 - 2012 Ninja 250R Tech Talk | 5 | March 27th, 2011 08:46 PM |
Owner's Manual / Service Manual | indr | 2008 - 2012 Ninja 250R Tech Talk | 3 | December 29th, 2010 01:09 AM |
service manual | ivanro_jo | General Motorcycling Discussion | 15 | June 12th, 2009 02:58 PM |
|
|