MORE jetting problems
11-07-2007 | 01:34 AM
#1
Thread Starter
Senior Member
Superstock
Joined: Mar 2007
Posts: 268
From: San Diego
MORE jetting problems
So I thought my final setup was good. That wasn't the case.
Setup again:
Dynojet kit
ART high mounts
k&n filter
no emissions, no pair
sea level
Settings were:
#48 pilots, 185F 188R, needles on 5th clip, 2.5 turns out.
Alright, with these settings the bike was jerking and hesitating at freeway speeds with a good 1/3-1/2 on the throttle in the midrange.
I raised the needles one more clip and the bike was okay at the low & great at midrange, but lagged alot on top end due to richness.
I bought a 190 main and i'm running 185r 190f. Now, the bike doesn't jerk as bad as it did, but it's still jerking at the midrange. I don't want to raise the needles, as that will make it run TOO rich. Would changing to a 188f, 190r help alleviate the problem? Or would I have to run something like 188f, 192r, or 190f, 195r?
I've torn into the carbs at least nine times, and i've had to remove my fairings and bleed the radiator almost as many.
This is getting very annoying
Setup again:
Dynojet kit
ART high mounts
k&n filter
no emissions, no pair
sea level
Settings were:
#48 pilots, 185F 188R, needles on 5th clip, 2.5 turns out.
Alright, with these settings the bike was jerking and hesitating at freeway speeds with a good 1/3-1/2 on the throttle in the midrange.
I raised the needles one more clip and the bike was okay at the low & great at midrange, but lagged alot on top end due to richness.
I bought a 190 main and i'm running 185r 190f. Now, the bike doesn't jerk as bad as it did, but it's still jerking at the midrange. I don't want to raise the needles, as that will make it run TOO rich. Would changing to a 188f, 190r help alleviate the problem? Or would I have to run something like 188f, 192r, or 190f, 195r?
I've torn into the carbs at least nine times, and i've had to remove my fairings and bleed the radiator almost as many.
This is getting very annoying
Last edited by Anto; 11-07-2007 at 01:59 PM.
11-07-2007 | 01:46 AM
#2
Senior Member
MotoGP
Joined: Aug 2007
Posts: 2,547
From: Way Out West
Anto;
I notice a couple of things. You're supposed to run the richer jet in the rear carb and per what you've written you're doing it backwards.
Also, are you sure about the #188 jet? The Dynojet kit comes with 170-175-180-185-190-195 but not a 188.
I notice a couple of things. You're supposed to run the richer jet in the rear carb and per what you've written you're doing it backwards.
Also, are you sure about the #188 jet? The Dynojet kit comes with 170-175-180-185-190-195 but not a 188.
11-07-2007 | 10:26 AM
#6
Senior Member
SuperBike
Joined: Jul 2004
Posts: 1,015
From Factory Pro Site for adjusting CV Carbs. And yes the bigger jet goes in the rear cylinders carb.
4. Idle and low rpm cruise
Fuel Screw setting (AKA mixture screws)
There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -
Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)
Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.
Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.
NOTE: A rich problem gets worse as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.
NOTE: A lean problem gets better as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!
4. Idle and low rpm cruise
Fuel Screw setting (AKA mixture screws)
There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -
Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)
Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.
Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.
NOTE: A rich problem gets worse as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.
NOTE: A lean problem gets better as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!
Last edited by Thumper; 11-07-2007 at 10:28 AM.
11-07-2007 | 10:40 AM
#8
Senior Member
SuperBike
Joined: Jul 2004
Posts: 1,015
Factory Pro Jet kit site. You cannot copy the sub page link, but go to www.factorypro.com
Click on Product support at the top and then in the main frame window click on CV Carb Tuning near the top left of the large frame then on the next page click on the High RPM Engine link on the right side.
Print it and safe it. This used to come in every FP jet kit and i have used this procedure successfully many times on my carbed bikes and others.
Simple and breaks it down to what you should tune first and the refine the other areas.
Good Luck....
Click on Product support at the top and then in the main frame window click on CV Carb Tuning near the top left of the large frame then on the next page click on the High RPM Engine link on the right side.
Print it and safe it. This used to come in every FP jet kit and i have used this procedure successfully many times on my carbed bikes and others.
Simple and breaks it down to what you should tune first and the refine the other areas.
Good Luck....
11-07-2007 | 02:01 PM
#9
Thread Starter
Senior Member
Superstock
Joined: Mar 2007
Posts: 268
From: San Diego
MY MISTAKE
185 F 188 R.
I'll go for a sync.
No $ for a dyno, i'm a broke college kid.
I bought the 188 main at Fun Bike Center, it's not from the kit.
I'll try the screws again.
ughhj
185 F 188 R.
I'll go for a sync.
No $ for a dyno, i'm a broke college kid.
I bought the 188 main at Fun Bike Center, it's not from the kit.
I'll try the screws again.
ughhj
Last edited by Anto; 11-07-2007 at 02:03 PM.
11-07-2007 | 02:38 PM
#10
Senior Member
MotoGP
Joined: Aug 2007
Posts: 2,547
From: Way Out West
Anto;
You don't say who manufactured the #188 jet, and I don't know if it is the source of your problem, but the Dynojet numbering system doesn't match up with the # system for other jet makers.
For example; A #180 Keihin and a #180 Dynojet are not the same size.
If the needles are Dynojet I'd only use Dynojet mains at least to rule out that as a source of the problem.
You don't say who manufactured the #188 jet, and I don't know if it is the source of your problem, but the Dynojet numbering system doesn't match up with the # system for other jet makers.
For example; A #180 Keihin and a #180 Dynojet are not the same size.
If the needles are Dynojet I'd only use Dynojet mains at least to rule out that as a source of the problem.
11-07-2007 | 07:47 PM
#12
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
As bling said why?!... Why does jetting problems cause you to bleed the rads?
Removing the fairing... ok fair enough, access migth be better to some parts... but definetly not neccesary...
Removing the fairing... ok fair enough, access migth be better to some parts... but definetly not neccesary...
11-07-2007 | 08:18 PM
#13
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World Champion
Joined: Dec 2004
Posts: 105,287
From: Fulton, MO
I think he's bleeding the rad because of the carb heating lines. Hint: Use some hemostats or other clamping device to clamp the lines shut before unhooking them. You lose very little coolant that way.
11-07-2007 | 08:27 PM
#14
Senior Member
SuperBike
Joined: Jul 2004
Posts: 1,015
+1 I use pointed Needle nose Vise Grips with several layers of duct tape on the jaws to protect the hoses.
11-07-2007 | 10:09 PM
#15
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MotoGP
Joined: Aug 2007
Posts: 2,547
From: Way Out West
He probably followed the service manual. One of the dumber instructions in the service manual is to drain the coolant before removing the carbs. I don't even plug or clamp 'em.
They just dribble a little and quit.
They just dribble a little and quit.
11-07-2007 | 10:16 PM
#16
Banned
MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
I've never plugged them either and have never lost more than a oz of fluid and normally it about half of that or less. Once in a great while the line will still have some pressure on it but that rarely happens and after 10 yrs and going through two different jet kits to get how I wan't it, I've had those carbs off more times than I can remember. 
11-08-2007 | 01:21 AM
#18
Thread Starter
Senior Member
Superstock
Joined: Mar 2007
Posts: 268
From: San Diego
Oh come on guys, I'm not THAT stupid to drain the rad every time I pull the carbs.
I don't lose much coolant at all to begin with, the main problem is that my TEMP gauge fluctuates because the air in the lines. It shoots from 0 to 1/4, then 1/4 to 1/2 in slow traffic.
RK, i'll try to get a hold of the dynojet jets to install. Thanks for that tip.
I'll report back.
I don't lose much coolant at all to begin with, the main problem is that my TEMP gauge fluctuates because the air in the lines. It shoots from 0 to 1/4, then 1/4 to 1/2 in slow traffic.
RK, i'll try to get a hold of the dynojet jets to install. Thanks for that tip.
I'll report back.
11-14-2007 | 05:10 AM
#20
Member
Squid
Joined: Oct 2007
Posts: 45
From: Newcastle, Australia
Anto.
Carb sync will not help.
People have so much trouble jetting engines and usually the problem is right bang samck in their face. It is not guess work. Look at the tell tale signs. Go for a ride and hold the throttle at steady revs then kill the engine. Check your plug colour. It will be white. I guarantee.
The motor is lean.
Most people here have been through this but I know for a fact it is your idle mixture. Mains will have minor effect on your low end mixture. Dont go richer than clip 5. As you said it will die in the ***.
I am actually running the same jetting as yourself but I am running 3.25 turns out on the screws. 2.5 is not enough with 48s. Also note if you are getting lean surge at 4000rpm cruise it is a good indication that you will achieve good economy if you wind out your mixture screws until the lean spot goes away. Once you achieve this focus on getting the sync right.
I have ran upto 52 pilots. The motor ran very smooth but used an extra 2 litres per 100kms. So I went back to 48 pilots and went one richer to clip 5 on the needle.
My wide band will be turning up shortly so hopefully I will post a log up here.
Regards
Joel
Carb sync will not help.
People have so much trouble jetting engines and usually the problem is right bang samck in their face. It is not guess work. Look at the tell tale signs. Go for a ride and hold the throttle at steady revs then kill the engine. Check your plug colour. It will be white. I guarantee.
The motor is lean.
Most people here have been through this but I know for a fact it is your idle mixture. Mains will have minor effect on your low end mixture. Dont go richer than clip 5. As you said it will die in the ***.
I am actually running the same jetting as yourself but I am running 3.25 turns out on the screws. 2.5 is not enough with 48s. Also note if you are getting lean surge at 4000rpm cruise it is a good indication that you will achieve good economy if you wind out your mixture screws until the lean spot goes away. Once you achieve this focus on getting the sync right.
I have ran upto 52 pilots. The motor ran very smooth but used an extra 2 litres per 100kms. So I went back to 48 pilots and went one richer to clip 5 on the needle.
My wide band will be turning up shortly so hopefully I will post a log up here.
Regards
Joel
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