i cant seem to get my bike to idle at a low idle. it seems to rev at about 4000 so i adjust the carbs and the idle screw and when it does finally come down it comes down so fast it kills itself out right away. i cant seem to get it right. should i just keep playin with it or would there be sumthin else that i cant think of that would be making it do this. just wondering if anyones got any ideas
christack44
When you mention adjusting the carbs what are you actually doing?
Remove the plugs to get an idea of what the mixture is. If they are black and sooty you have a rich situation this will cause your problems....also if the idle at any rpms hunts...up and down the rpm range...this indicates a rich situation.
The pilot circuit controls the idle...as well as the idle screw. Screwing it in leans the mixture and out richens it.
Some are hidden under little caps that have to be removed you can do this by carefully drilling the cap ONLY and driving a small self tapping screw into it. Then you just pull the cap out of the recess using the screw.
Check the following also... throttle cable for smoothness, carb linkage for stiffness and choke cable/knob for full off position.
Good luck and let us know how you get on
Remove the plugs to get an idea of what the mixture is. If they are black and sooty you have a rich situation this will cause your problems....also if the idle at any rpms hunts...up and down the rpm range...this indicates a rich situation.
The pilot circuit controls the idle...as well as the idle screw. Screwing it in leans the mixture and out richens it.
Some are hidden under little caps that have to be removed you can do this by carefully drilling the cap ONLY and driving a small self tapping screw into it. Then you just pull the cap out of the recess using the screw.
Check the following also... throttle cable for smoothness, carb linkage for stiffness and choke cable/knob for full off position.
Good luck and let us know how you get on
Sounds like the throttle stop screws these control where the throttle position is held for idle.
This also sounds like a stuck throttle as it runs at 4000 then nothing. Try pulling the top off of the carbs and checking the throttle slides actually slide easily.
This also sounds like a stuck throttle as it runs at 4000 then nothing. Try pulling the top off of the carbs and checking the throttle slides actually slide easily.
from what i can tell everythiung seems to be moving good, i think it just might be running to rich or sumthin and its gettin burning up what it can then leans out so fast it dies. i got a picture here so i can u guys can kinda figure out what my jibberish means. Sorry its a bad pic %%%%ty camera.
The screws at the base of the carbs are pilot jets they control the mixture. In to lean... out to enrichen.
Standard setout is about two to three turns each. If you want to recalibrate all then turn them in so you feel a SLIGHT resistance. Turn out to factory specs...as stated above.
Do not over turn them in or you will end up either stripping the screw or the carb body thread. Also the tiny tips of the needles are very easily damaged.
The screws at the side/top are not throttle stop screws and control the carb sync.
If your motor hunts when hot it is too rich. If it wont take a blip of the throttle when cold it is too lean...general info only...more accurate tuning can be achieved once base settings are done.
Good luck.
Standard setout is about two to three turns each. If you want to recalibrate all then turn them in so you feel a SLIGHT resistance. Turn out to factory specs...as stated above.
Do not over turn them in or you will end up either stripping the screw or the carb body thread. Also the tiny tips of the needles are very easily damaged.
The screws at the side/top are not throttle stop screws and control the carb sync.
If your motor hunts when hot it is too rich. If it wont take a blip of the throttle when cold it is too lean...general info only...more accurate tuning can be achieved once base settings are done.
Good luck.
trying to remember back. when u move the throttle three of the idle screws will move and one should stay still. the stationary one is the idle the others are butterfly sync screws. Pm me if you want held setting the sync screws.
well i turned those screws in and leaned out the mix, it seemed to help quite a bit, or so i thougt. Everything ran smoothly, i slowly took down the choke and she kept comin down till the last little bit it seemed to stay at about 3 grand then came down a few short seconds latr and idled nicely at 1500. It idled there for about 5 min so i thought it was cured then i gave it a little throttle and revved it to about 4000 but when i let off it didnt. it took about 2 minutes to come back down and came back down to about 700 or so almost wanted to kill itslef out. So i played with the idle control and the mixture screws a bit more and same results. ive got it set at a ridable but not good setting right now. Im just wondering if the temprature outside would have a big thing to do with this being so tricky. Its about -10 C (20 F) here and i dont have my air filter in or the boots on the carbs to the airbox. Just wondering if that would have anythingto do with it. Gettin to much air or sumtin? Tho when i put my hand over a cou[ple carbs just lightly i can feel them sucking and it revvs higher. So i dunno, im stumped, might just have to wait for warmer weather? I checked my plugs and they all look to be a tan grey color w2hich is what they should be no? Weathers about all i can think of.
First things first.
Early Jap bikes did indeed have seperate idle screws for the carbs...yes four of them...a nightmare to sync.
Later ones went to a single which operated all.
The top screws shown in the pic are actually carb sync screws not idle stop screws...my bad
... which if are fiddled with without using a manometer will put all the carbs out of sync.
Right now for the bad news.
You need the filter and the boots attached as to do it without will give false readings
If you have fiddled with the sync screws you will almost have certainly upset the carb syncronisation. This will have the effect of making the engine run terrible.
The first job is to sync the carbs to each other so they are working in unison. The rpms need to be at about 1500. for this so the motor in its current set up should keep running long enough for this to be achieved.
The carb to the LH is a fixed one and is the base setting for all the others.
The second from the LH is the sync screw for setting 3 to 4 carb. The far RH one is for setting 1 to 2 carb.
The middle screw is for setting bank 1 and 2 carbs to bank 3 and 4 carbs.
You will need to find the vacuum port of all carbs...usually towards the side and facing up. They should have a little rubber cap over them. Prise this off and attach the manometer to the vacuum port.
Warm the engine and check what the vacuum is at #4. Screw the appropriate screw in or out to achieve the same at #3
Check the vacuum at #1 and again using the appropriate screw set #2 to the same.
Whatever 1 and 2 are pulling needs to be the same as 3 and 4. If it isn't then use the center screw to make it so.
To do all of the above is quiet involved and requires the removal of the fuel tank, use of an auxillery tank and, in some cases a fan to keep your motor from overheating. You will also need a manometer or a set of carb sticks.
If you are not too familiar with this, I had to do mine three times before I got it right but then I was using a single vacuum gauge with a fancy switching device, you should take it in to get them done.
To adjust the mixture the bottom screws are used. If you didn't fiddle too much with the sync screws you should be OK to get it to run at idle by turning these in or out to set your mixture.
These screws are not used to set idle other than to smooth it and provide sufficient mix at low throttle openings.
Now for the good news......... sorry none today!
Good luck
Early Jap bikes did indeed have seperate idle screws for the carbs...yes four of them...a nightmare to sync.
Later ones went to a single which operated all.
The top screws shown in the pic are actually carb sync screws not idle stop screws...my bad
... which if are fiddled with without using a manometer will put all the carbs out of sync.Right now for the bad news.
You need the filter and the boots attached as to do it without will give false readings
If you have fiddled with the sync screws you will almost have certainly upset the carb syncronisation. This will have the effect of making the engine run terrible.
The first job is to sync the carbs to each other so they are working in unison. The rpms need to be at about 1500. for this so the motor in its current set up should keep running long enough for this to be achieved.
The carb to the LH is a fixed one and is the base setting for all the others.
The second from the LH is the sync screw for setting 3 to 4 carb. The far RH one is for setting 1 to 2 carb.
The middle screw is for setting bank 1 and 2 carbs to bank 3 and 4 carbs.
You will need to find the vacuum port of all carbs...usually towards the side and facing up. They should have a little rubber cap over them. Prise this off and attach the manometer to the vacuum port.
Warm the engine and check what the vacuum is at #4. Screw the appropriate screw in or out to achieve the same at #3
Check the vacuum at #1 and again using the appropriate screw set #2 to the same.
Whatever 1 and 2 are pulling needs to be the same as 3 and 4. If it isn't then use the center screw to make it so.
To do all of the above is quiet involved and requires the removal of the fuel tank, use of an auxillery tank and, in some cases a fan to keep your motor from overheating. You will also need a manometer or a set of carb sticks.
If you are not too familiar with this, I had to do mine three times before I got it right but then I was using a single vacuum gauge with a fancy switching device, you should take it in to get them done.
To adjust the mixture the bottom screws are used. If you didn't fiddle too much with the sync screws you should be OK to get it to run at idle by turning these in or out to set your mixture.
These screws are not used to set idle other than to smooth it and provide sufficient mix at low throttle openings.
Now for the good news......... sorry none today!
Good luck
I still have the set of four Honda vacum gauges from when I used to do the Kawka 400 long time ago. However setting the sync of the butterflys with feeler gauges is usually considered best but requires the caqrbs being removed
Falcon
Yes I was going to do a similar thing to mine until I got hold of a good vacuum gauge and a set of four little valves used to control an air pump for an aquarium.
I simply piped up the gauge to the four way switching valve then piped that to my four carbs. Presto! I could switch between carbs and adjusted them perfectly.
While doing this I notice in the carb throats a small groove machined into the surface. Removed the carbs could be synced using that. Just adjust the butterflys till they all lined up with it.
Anyway Chris if you take the bike in to get them done at least they should fine.
Failing that remove them and use the butterfly adjustment system mentioned either by Falcon or me.
Good luck.
Yes I was going to do a similar thing to mine until I got hold of a good vacuum gauge and a set of four little valves used to control an air pump for an aquarium.
I simply piped up the gauge to the four way switching valve then piped that to my four carbs. Presto! I could switch between carbs and adjusted them perfectly.
While doing this I notice in the carb throats a small groove machined into the surface. Removed the carbs could be synced using that. Just adjust the butterflys till they all lined up with it.
Anyway Chris if you take the bike in to get them done at least they should fine.
Failing that remove them and use the butterfly adjustment system mentioned either by Falcon or me.
Good luck.
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