jetting question

lotus168 · March 14th, 2011, 12:56 AM

currently i'm using leovince full system, with standard needle mj 100(keihin) pj 40(keihin) with knn replacement air filter, air snorkle remove.

my question is, would it be ok if i shim my needle with 1 washer without changing the air mixture and syncing the carb again? cause the middle rev kinda lean, and is the current setup too lean or to rich?

i just up mj 1 step to 100 from stock(98), cause above 8rpm is too lean...

any help with insight would be appreciated

thank you very much

henry

kkim · March 14th, 2011, 01:02 AM

try shimming the needles using 2 or 3 washers each and remove the snorkel. I think you'll like the results.

if the bikes idles with a rhythmic pulse, you most likely means you need to resync it.

when you had the carbs apart to work on them, did you also remove the plugs that cover the mixture screws?

lotus168 · March 14th, 2011, 01:15 AM

thanks kkim for answering, i've been setting the carb at the dealer, i wanna try doing it myself, i'm still looking for all the tools i need first.

i don't know the answer to your question, since i haven't got my hand dirty yet.
if i shim it with 2 washer each and stay with the same mj and pj, would it be to rich? or do i have to bring down mj pj 1 step? thanks

kkim · March 14th, 2011, 01:23 AM

Henry,

just know that jetting will take a lot of trial and error to get perfect. All I can do is lead you to what has worked for most people and you'll need to fine tune from there. Learning to do your own work will be the most economical way to achieve the correct jetting as most do not get it spot on the first time around.

I highly suggest you get a set of JIS screwdrivers to work on the carbs.

for your setup, I'd recommend you shim the needles with 3 washers each. I had a similar setup before and this worked very well with the stock pilot and main jets.

have you taken a look at our jetting database here? perhaps some others have a similar setup to yours and you can get some ideas from them, too.

http://www.ninjette.org/forums/showthread.php?t=10208

almost40 · March 14th, 2011, 12:20 PM

Quote:

Originally Posted by kkim

Henry,

I highly suggest you get a set of JIS screwdrivers to work on the carbs.

have you taken a look at our jetting database here? perhaps some others have a similar setup to yours and you can get some ideas from them, too.

http://www.ninjette.org/forums/showthread.php?t=10208

+1 on the screwdrivers

lotus168 · March 27th, 2011, 08:53 PM

another question, the idle mixture screw, is it normal the number different turn is more than 1?

left is 2.5 turn out, right is 3.75 turn out roughly, needle using sportisi needle 3rd clip, pj 38(stock), mj 98(sportisi).

the 1+ different happen during syncing the idle mixture screw(i keep note on the number of turn )

plis help, thank you

hen ry

kkim · March 27th, 2011, 10:48 PM

usually when changing to aftermarket needles, which should be identical as opposed to the stock needles which are different left and right, the idle mixture screw turns should be approximately the same. something doesn't sound right.

btw, syncing is not done using the idle mixture screws.

regardless... how does the bike run?

lotus168 · March 28th, 2011, 04:58 AM

Quote:

Originally Posted by kkim

usually when changing to aftermarket needles, which should be identical as opposed to the stock needles which are different left and right, the idle mixture screw turns should be approximately the same. something doesn't sound right.

btw, syncing is not done using the idle mixture screws.

regardless... how does the bike run?

the bike runs great,

this is what i do,

during syncing, i turn up the idle using the button that can be reach at the left side fairing to about 3000 rpm, then i started playing with the idle mixture screw, thats number turn above make the movement from 1 bottle to the other stop.. i guess it sync....

any insight? thanks

henry

lotus168 · March 29th, 2011, 02:25 AM

i resync the carb, thanks to kkim pointer...
i nailed it, 2.5 turn out and 3 turn out, it sync at idle and 3k rpm...
thanks kkim

kkim · March 29th, 2011, 02:44 AM

Henry,

have you tried syncing at 1500 rpm instead? When I was playing with syncing, I noticed that the vacuum draw would change as the rpms rose. I tried syncing at 3k and again at 1500rpm and still again about 2000-2500 rpm to split the difference. I found they all made a slight difference on how the engine responded from idle to greater than 3k.

I ended up liking how the engine responded when synced at 1500 rpm, so that's what I use. Try it at different rpms and see what you like best.

to ease checking the carbs when syncing, I extended some tubes out to the side of the bike to under the side cover to make accessing the vacuum ports easier.

here you can see the 2 vacuum lines that I ran out to the side of the bike with the blue caps on them. Once the side cover is on, you can't see them.

lotus168 · March 29th, 2011, 07:34 PM

kelly, i see on your bike pic u use fuel filter, how is the maintenance on the fuel filter? does it need cleaning? i'm thinking of using it, but i'm afraid if it got clogged there will be no fuel going into the carb, i guess i have to push the bike at that point....

kkim · March 29th, 2011, 07:41 PM

well, the reason I did that was to get rid of the stock filter which is at the end of the fuel line just as it enters the carbs. If you think the filter I added will get clogged, you should see the size of the stock filter.

The main reason I added an inline filter, though, was so that I could visually see when crap started to build up in my fuel system, but to date I have not seen anything in the filter. I have not done anything to it since 2008 and it has remained trouble free.

BTW, this is the secondary filter as there is a filter in the fuel petcock.

lotus168 · April 10th, 2011, 02:26 AM

yes u r right kkim, the number of turn have to be the same and try to sync it, it sync at idle about 1400 rpm and sync at 3500 rpm...
the number of turn for my carbs is at 2 something... roughly 2 1/4, coz i start at 2 1/2 is too rich....

i haven't test it for a run, hopefully it gets better.... thanks for your help

henry

March 14th, 2011, 12:56 AM	#1
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	jetting question currently i'm using leovince full system, with standard needle mj 100(keihin) pj 40(keihin) with knn replacement air filter, air snorkle remove. my question is, would it be ok if i shim my needle with 1 washer without changing the air mixture and syncing the carb again? cause the middle rev kinda lean, and is the current setup too lean or to rich? i just up mj 1 step to 100 from stock(98), cause above 8rpm is too lean... any help with insight would be appreciated thank you very much henry

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March 14th, 2011, 01:02 AM	#2
kkim Join Date: Nov 2008 Posts: Too much.	try shimming the needles using 2 or 3 washers each and remove the snorkel. I think you'll like the results. if the bikes idles with a rhythmic pulse, you most likely means you need to resync it. when you had the carbs apart to work on them, did you also remove the plugs that cover the mixture screws?

March 14th, 2011, 01:15 AM	#3
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	thanks kkim for answering, i've been setting the carb at the dealer, i wanna try doing it myself, i'm still looking for all the tools i need first. i don't know the answer to your question, since i haven't got my hand dirty yet. if i shim it with 2 washer each and stay with the same mj and pj, would it be to rich? or do i have to bring down mj pj 1 step? thanks

March 14th, 2011, 01:23 AM	#4
kkim Join Date: Nov 2008 Posts: Too much.	Henry, just know that jetting will take a lot of trial and error to get perfect. All I can do is lead you to what has worked for most people and you'll need to fine tune from there. Learning to do your own work will be the most economical way to achieve the correct jetting as most do not get it spot on the first time around. I highly suggest you get a set of JIS screwdrivers to work on the carbs. for your setup, I'd recommend you shim the needles with 3 washers each. I had a similar setup before and this worked very well with the stock pilot and main jets. have you taken a look at our jetting database here? perhaps some others have a similar setup to yours and you can get some ideas from them, too. http://www.ninjette.org/forums/showthread.php?t=10208

March 27th, 2011, 08:53 PM	#6
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	another question, the idle mixture screw, is it normal the number different turn is more than 1? left is 2.5 turn out, right is 3.75 turn out roughly, needle using sportisi needle 3rd clip, pj 38(stock), mj 98(sportisi). the 1+ different happen during syncing the idle mixture screw(i keep note on the number of turn ) plis help, thank you hen ry

March 27th, 2011, 10:48 PM	#7
kkim Join Date: Nov 2008 Posts: Too much.	usually when changing to aftermarket needles, which should be identical as opposed to the stock needles which are different left and right, the idle mixture screw turns should be approximately the same. something doesn't sound right. btw, syncing is not done using the idle mixture screws. regardless... how does the bike run?

March 29th, 2011, 02:25 AM	#9
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	i resync the carb, thanks to kkim pointer... i nailed it, 2.5 turn out and 3 turn out, it sync at idle and 3k rpm... thanks kkim

March 29th, 2011, 02:44 AM	#10
kkim Join Date: Nov 2008 Posts: Too much.	Henry, have you tried syncing at 1500 rpm instead? When I was playing with syncing, I noticed that the vacuum draw would change as the rpms rose. I tried syncing at 3k and again at 1500rpm and still again about 2000-2500 rpm to split the difference. I found they all made a slight difference on how the engine responded from idle to greater than 3k. I ended up liking how the engine responded when synced at 1500 rpm, so that's what I use. Try it at different rpms and see what you like best. to ease checking the carbs when syncing, I extended some tubes out to the side of the bike to under the side cover to make accessing the vacuum ports easier. here you can see the 2 vacuum lines that I ran out to the side of the bike with the blue caps on them. Once the side cover is on, you can't see them.

March 29th, 2011, 07:34 PM	#11
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	kelly, i see on your bike pic u use fuel filter, how is the maintenance on the fuel filter? does it need cleaning? i'm thinking of using it, but i'm afraid if it got clogged there will be no fuel going into the carb, i guess i have to push the bike at that point....

March 29th, 2011, 07:41 PM	#12
kkim Join Date: Nov 2008 Posts: Too much.	well, the reason I did that was to get rid of the stock filter which is at the end of the fuel line just as it enters the carbs. If you think the filter I added will get clogged, you should see the size of the stock filter. The main reason I added an inline filter, though, was so that I could visually see when crap started to build up in my fuel system, but to date I have not seen anything in the filter. I have not done anything to it since 2008 and it has remained trouble free. BTW, this is the secondary filter as there is a filter in the fuel petcock.

April 10th, 2011, 02:26 AM	#13
lotus168 ninjette.org member Name: henry Location: jakarta Join Date: Mar 2011 Motorcycle(s): ninja 250r Posts: 13	yes u r right kkim, the number of turn have to be the same and try to sync it, it sync at idle about 1400 rpm and sync at 3500 rpm... the number of turn for my carbs is at 2 something... roughly 2 1/4, coz i start at 2 1/2 is too rich.... i haven't test it for a run, hopefully it gets better.... thanks for your help henry