Carburator sync/clean

Richard tea

Going to need the big guns for this one:p

Firstly this Is the tool I have for the job. It comes with two short brass tubes and two longer brass tubes.

After taking the advice from CJ on the general chat thread its become apparent that the longer tubes will not fit between the carbs and engine.

What I need to find out is can buying two more shorter brass tubes sort the problem or is there any other connections the brass tubes I have will fit in.

Or..........Must I use all four brass tubes at the same time ( most likely )
Any guides I have watched on youtube and so on, have the brass tubes coming off at an angle. Some guides show the brass tubes connected to the engine block and not the carbs.

Ill post some pics to give a better idea. Ill also post 2 pics from the Russian translated manuals. Maybe some can shed some light on the situation.

gctest50

STOP !

the photo "Shorter brass tube.jpg"

what it looks like you are thinking of doing is removing the idle air screws and trying to thread in the brass tubes

different threads - you will ruin your carbs

Richard tea

gctest50 wrote: »

STOP !

The one I circled in green.... Is this the vac connection?

gctest50

Richard tea wrote: »

The one I circled in green.... Is this the vac connection?

yip - the one circled in green is the vac connection

Richard tea

Ok after a frantic search I think I found the solutions here http://www.400greybike.com/forum/viewtopic.php?f=32&t=362:p

No bother as ill need this thread when I go to strip and clean and enter the funny world of float bowls and pilot jets:P

Thanks Gctest50

gctest50

those screws will probably be very tight - they're not actual "phillips" theyre jis or something - tiny tiny difference

you'll get caught out if you're just using some screwdriver you found in the shed somewhere

for some bizzare reason phillips were designed to slip

Richard tea

gctest50 wrote: »

those screws will probably be very tight - they're not actual "phillips" theyre jis or something - tiny tiny difference

you'll get caught out if you're just using some screwdriver you found in the shed somewhere

for some bizzare reason phillips were designed to slip

well spotted https://www.google.ie/search?q=jis+screws&tbm=isch&imgil=wOJ2k0PZP1TL_M%253A%253BE7AjWySgVv1DtM%253Bhttp%25253A%25252F%25252Fwww.pentaxforums.com%25252Fforums%25252F114-maintenance-repair-articles%25252F119344-cross-head-screws-caution.html&source=iu&pf=m&fir=wOJ2k0PZP1TL_M%253A%252CE7AjWySgVv1DtM%252C_&usg=__Ab9aWzQsgfqjqe1q_w89zV5XMwE%3D&biw=1680&bih=915&ved=0CCsQyjc&ei=VVOpVMzrL43W7QbH3oCYDg#facrc=_&imgdii=_&imgrc=wOJ2k0PZP1TL_M%253A%3BE7AjWySgVv1DtM%3Bhttp%253A%252F%252Fwww.pentaxforums.com%252Fforums%252Fattachments%252Fpentax-slr-lens-discussion%252F73294d1287169479-stuck-aperture-ring-50-1-7-jis-sd-jpg%3Bhttp%253A%252F%252Fwww.pentaxforums.com%252Fforums%252F114-maintenance-repair-articles%252F119344-cross-head-screws-caution.html%3B475%3B254

I think i have some

gctest50

you should be able to find new ones

kinda like


www.cmsnl.com/cbr400rg-nc23-japanese-domestic_model17062/screw-cross-5x10_93500050100a/

http://www.cmsnl.com

Richard tea

Ok I got it all set up fine. I wont attempt the job until I study up some more.

CJhaughey

I'd start by doing #1 and #2 Then #3 and #4
Then #1 and # 4.
You should blip it between adjustments as well.

gctest50

nudder thing .... if your carbs are hard to sort out - the little seals here n there might be gone off

the rubber in them was meant for petrol with no ethanol or other stuff in it

the ethanol "steals" something ( cant remember what tis ) from the rubber, then the little seals go hard, stop being rubbery and stop sealing

gctest50

this crew seem to has shares in Viton if you need seals

32 euro ish kinda thing for a kit


http://litetek.co/Carb_Kit_Honda_CB1_NC27.html

https://twitter.com/litetek_sales

maybe use an 02 debit card/paypal for stuff so far away if you do

.

gctest50

carb diagram from there ( see attached )

gctest50

service manual for it from there maybe ?

http://litetek.co/docs/Manual_Service_Honda_CB_400F_CB1.pdf

gctest50

more seals closer to home


http://www.nrp-carbs.co.uk/

Richard tea

Thanks GC. I came across that crowd before alright. No harm in having new seals in just in case I suppose.

hrcbob

Doing carb sync is a god dam pain. MAKE SURE YOU FIGURE OUT WHICH ONE IS THE MASTER OR NON ADJUSTABLE CARB FIRST BEFORE ADJUSTING ANYTHING,.
If you dont do this you will spend all day chasing your tail. A good guide is to see where the throtle cable is located in the bank of carbs .if in the centre the master will be one of the two centre carbs, (you will need to look carefully to see which one is directly operated by the cable and which has the adjuster on it) If the cable goes on the end carb of the bank then the one closest to the cable is the master,

With the setup where the end carb is the master,(call it no.1 for this purpose) you must set no.2 first. then no.3 and finally no.4 as any adjustment on 2 will affect both 3 and 4 and will require you to adjust them again.

Best of luck

Richard tea

hrcbob wrote: »

Doing carb sync is a god dam pain. MAKE SURE YOU FIGURE OUT WHICH ONE IS THE MASTER OR NON ADJUSTABLE CARB FIRST BEFORE ADJUSTING ANYTHING,.
If you dont do this you will spend all day chasing your tail. A good guide is to see where the throtle cable is located in the bank of carbs .if in the centre the master will be one of the two centre carbs, (you will need to look carefully to see which one is directly operated by the cable and which has the adjuster on it) If the cable goes on the end carb of the bank then the one closest to the cable is the master,

With the setup where the end carb is the master,(call it no.1 for this purpose) you must set no.2 first. then no.3 and finally no.4 as any adjustment on 2 will affect both 3 and 4 and will require you to adjust them again.

Best of luck

I get ya. Just when I think I understand the workings I watch another video and Im back to square one. It will prob be march before I start to commute on the bike again so I have time (when I fu*k up ) not IF:rolleyes:

Richard tea

Anyone know if these remaining jets can be removed for cleaning? There are no screw heads to remove them and I dont want to twist or pull them in case I damage them.

My my new seals arrived today so I hope to put them back together over the weekend:)

Hotblack Desiato

Think the one at 7 o'clock is the needle valve seat. Leave it where it is unless it's blocked or worn out

The one at 2 o'clock seems to dip down into the fuel so I'm thinking it's an extra jet with a valve controlled by the choke cable, pull the cable, valve opens = more fuel.

No idea what the thing at 6 o'clock is. I'd leave both of these alone unless I was certain I knew what they were for and that there was a problem with them.

CJhaughey

Don't remove any of those pieces, If you can get them ultrasonically cleaned then it is well worth doing, ultrasonic cleaning removes stuff inside that you can never get clean even with carb cleaner spray and compressed air.
Also don't forget the Air screw at 12 O'clock, maybe record the turns in to seated and then record them so you can set them the same after cleaning.
I got a cheap ultrasonic cleaner from Aldi for 20 odd euro, it did a lot of work but eventually blew and I haven't got the receipt.
A good trick was to cut the top off a milk bottle and fill that with the cleaning solution and put the bottle into the little cleaner and top off with water.
this allows bigger parts to be cleaned in a small cleaner.
I may have a look at one of these ones next.

Richard tea

Thanks lads. I wont remove them. Like I mentioned before, the carbs worked fine before removal so im not removing parts that are not necessary. Im sure the US cleaner is best but the insides were very clean to start with. Just hope I can put it back together.

Hotblack Desiato

Check the float heights are correct before putting the float bowls back on, this should be the same across all the carbs to make them easier to balance, and any carb with the float height too low (= higher fuel level, you assemble the needle valves and floats with the carbs upside down and then check the height) will be more likely to flood

Don't overtighten any screws as carb bodies are usually made out of magnesium and very easy to strip threads. Brittle too, you can easily crack a carb body or float bowl by dropping it.

Richard tea

Im just about ready to refit the carbs, maybe tue or wed. Im just wondering what to expect when I connect up the fuel again. How long should it take for fuel to work through the carbs again? I can imagine it will take a fair few attempts to start the engine?

Whats the crack with valve shims clearance? I have read that when carbs are removed and cleaned you should check the valve shims clearance. I have a feeler gauge for this job but it seems complicated. Should I bother or just refit the carbs with fingers crossed? Dont forget the engine ran mostly fine before carb removal so my thinking is the shims should be ok

Whilst im at it. I have found a K&N air filter that fits my bike. Its €50 though:eek:. Are they worth it?

Kevin McCloud

Richard tea wrote: »

I have read that when carbs are removed and cleaned you should check the valve shims clearance.

I would not believe everything you read off the internet.

Hotblack Desiato

Valve clearances change due to wear - nothing to do with the carbs.

The K&N is worth it if the cost of the disposable filters you'll use over the length of time you expect to keep the bike is dearer - don't forget the K&N still needs to be cleaned and re-oiled at intervals and you need to factor in the cost of filter cleaner and filter oil

If the K&N flows more air than the standard filter, your mixture will now be too weak and you'll need to re-jet the carbs. I really wouldn't bother. My bike came with a K&N from the previous owner, but it's fuel injected.

Richard tea

Christ almighty. Hardest part is refitting the carbs. So hard to get the carbs into the rubber boots. When you wedge one side the other miss aligns. So after a pint of blood spilt from cuts on my hands I finally got the fitted.

Im not sure if I connected the throttle cables up right. The throttle return is not flicking back into place without physical help. Or I damaged the cable with a kink. Not too fussed about that one for now though as the main thing was to fire up the bike.

After 5 attempts she started up. The Rev's slowly increased but it was very sluggish. Prehaps the system is just filling back up and the extra cold nights didnt help. Time was not on my side so I have to pack it in for the day. The main thing is she started. I can get to adjustments another day. I set the air screw mixture ( 4 of them ) to 2 3/8 turns out from seated. This type of info & spec is hard to track down. I didnt adjust the idle screw at all so I shouldn't need to go near this.

Richard tea

Took ill last week so did SFA:o I rigged up the fueling system today and connected up the carb sync tool. I have the Idle screw nearly adjusted. On the carb sync tool all 4 gauges were just about the same. I think cylinder 3 was slightly off. Then the bike started to die. Im hoping its cause the battery has been sitting out in the cold for the last few nights and not been used. Ive stuck it on the trickle charger for now.

Going to have to spend the evening doing more research as its trickier than I thought.

Richard tea

Its amazing what you can do with bungie cords and a coal sack

Richard tea

Think Im a little confused from reading conflicting suggestions on another site.

I plan to tune the carbs in this order 1. adjust idle screw 2. adjust 4 air mix screws 3. Balance carbs. Is this the correct sequence?

Should be finished with the frosty/ice nights by the end of the month. I really want to have the bike back up and running by then:eek:

Hotblack Desiato

Balancing is the last thing you do because it's the only step where the settings of each carb affect the other. Ideally there will only be slight variation in throttle position to adjust out, if you've done everything else right up to that point.

The other settings, idle screws etc. are from a fixed reference point and don't have an effect on each other in the way throttle position does.

Richard tea

Decided to remove carbs again as they didnt seem airtight around the rubbers. Also reseated the mixture screws and gave them 2 rotations instead of the 2 3/8 I initially done as this seemed off. I got it all back together and was delighted at how snug it fitted. I wanted to give the idle mixture screw a few turns just to have it idling ok. The poxy thing came off in my hand:mad: I have had enough for today. I just home I can refit the screw by feel or ill have to remove the carbs again:( Im also waiting on a 90 degree screwdriver to be delivered.

Richard tea

Any reason why the bike will die after a few mins of having the carb sync tool connected up? it seems to be the breather/vac pipe that goes to the fuel tank that causes the problem.

On a side note, the carb mixture screw tool I ordered is no use. Its too small:mad: €24 down the drain

Roadcraft

Richard tea wrote: »

Any reason why the bike will die after a few mins of having the carb sync tool connected up? it seems to be the breather/vac pipe that goes to the fuel tank that causes the problem.

On a side note, the carb mixture screw tool I ordered is no use. Its too small:mad: €24 down the drain

You will have to blank off or plug the vacuum pipe so there is no suction on it.

Richard tea

Roadcraft wrote: »

You will have to blank off or plug the vacuum pipe so there is no suction on it.

Ill close off the valve going to that gauge and see if it makes a difference.

Roadcraft

Richard tea wrote: »

Ill close off the valve going to that gauge and see if it makes a difference.

If it is coming from one of the carbs to your gauges you would have to leave it open, if it is from the fuel tap you would have to plug it.

Richard tea

Roadcraft wrote: »

If it is coming from one of the carbs to your gauges you would have to leave it open, if it is from the fuel tap you would have to plug it.

Each of the 4 gauges connects to a slot on the engine block. This one in particular connects to the vac pipe on the left side of the engine close to where the fuel tap is. Im nearly sure its a vac pipe anyway.

2 pipes coming from tank. 1 is fuel and the other is the vac? Correct?

Roadcraft

Richard tea wrote: »

Each of the 4 gauges connects to a slot on the engine block. This one in particular connects to the vac pipe on the left side of the engine close to where the fuel tap is. Im nearly sure its a vac pipe anyway.

2 pipes coming from tank. 1 is fuel and the other is the vac? Correct?

If you are using your fuel tank to run the bike to balance the carbs & it has a vacuum feed to the tap & you have not got the vacuum pipe connected to the tap it will not run right & run out of fuel. Plug the vacuum hose & put the tap in the prime position so that it does not need the vacuum to make the fuel flow.

Richard tea

Roadcraft wrote: »

If you are using your fuel tank to run the bike to balance the carbs & it has a vacuum feed to the tap & you have not got the vacuum pipe connected to the tap it will not run right & run out of fuel. Plug the vacuum hose & put the tap in the reserve position so that it does not need the vacuum to make the fuel flow.

Ahhh good stuff. That makes sense.

On a side note. Has anyone ever heard of colourtune. This thing looks the biz for fine tuning. http://www.carbtune.com/colortune.html

Hotblack Desiato

It's for seeing if you are running rich or lean, but you can do that for free with a plug chop. No use unless you are changing jets/needles, the mixture (above idle) is fixed by the needle/jet combination. A lot of bikes have plug caps that cover the entire spark plug hole, so you couldn't see this thing anyway.

CJhaughey

Hotblack Desiato wrote: »

It's for seeing if you are running rich or lean, but you can do that for free with a plug chop.

I can't make out anything with plug chops these days, they all look the same.
This new petrol is funny stuff, must be the ethanol.

Richard tea

CJhaughey wrote: »

I can't make out anything with plug chops these days, they all look the same.
This new petrol is funny stuff, must be the ethanol.

Seems like alot of effort but I guess its a sure way of fault finding

CJhaughey

Richard tea wrote: »

Seems like alot of effort but I guess its a sure way of fault finding

I used to do it with 2 strokes back a few years, but these days the plugs don't show much difference.
They all seem to be a light tan, running lean all the time is what they look like to me.

Richard tea

Ok I have her running well ( I think ):P

I took the bike for a quick blast but 5 mins into the ride the bike died. Turns out I left the fuel in the off position. I found it hard to restart the bike so I ( for the first time ever ) jump started the bike. The battery was dying very fast so I really needed to get the bike going quick or it would have been a 30 minute push home.

When it idles at say 1200 rpm, now and again it will jump a little to 1300 rpm. Just for a second and pop back to 1200. Is this normal? I cant remember what it was like before I cleaned the carbs.

Wossack

yea they can hop and vary, and the bikes tach isnt great at reading at the smaller end of its scale (think they recommend idle adjustment with a dedicated tachometer for that reason)

Richard tea

All is not well. Started it up today and it sounded like it wanted to die with the choke on. If I tried to open the throttle it would die. Im guessing its too rich or too lean. Im sure the culprit is the air/fuel mix screw under each carb. There are 4 of them.

I went with 2 turns out from seated and she started and I adjusted the idle screw until it ran well enough ( or so I thought).

The procedure for these screws is as follows

1. manufacturers recommedned ( 2 or 2 3/8 out from lightly seated )

2. adjust screw by 1/4 out or until engine starts to die.

3. put screw back to original position and turn 1/4 in until engine starts to die.

4. At this point you should be able to find a happy medium where the engine runs smooth.

My question is, with my carbs there are 4 screws to adjust. Do I follow the above procedure for each screw/carb

According to the Russian translated manual I have im nearly sure I should start from 2 3/8 turns out from seated but many forums posters state they start from 2 turns out?

Im also aware that this must be done with a fully warmed up engine.

The carbs are balanced as I confirmed with the carb sync tool.

Hotblack Desiato

You can do that on a single carb engine (adjust one way until too rich, other way until too lean, then find a sweet spot in between) but you can't on a multiple carb engine, so you'll have to set all the screws to the same position. If you can get confirmation of what the correct number of turns out is, that should work well (assuming engine/carbs are stock parts not modified)

This only affects the idle circuit anyway

You can't balance the carbs properly unless all other settings are right, you need to get the bike idling ok and then re-balance it.

Is the choke cable correctly adjusted, is the choke linkage moving properly when the cable is pulled, are the little plungers (or whatever) on each carb moving when the choke linkage moves? Were all of these parts reassembled correctly?

Richard tea

Hotblack Desiato wrote: »

You can do that on a single carb engine (adjust one way until too rich, other way until too lean, then find a sweet spot in between) but you can't on a multiple carb engine, so you'll have to set all the screws to the same position. If you can get confirmation of what the correct number of turns out is, that should work well (assuming engine/carbs are stock parts not modified)

This only affects the idle circuit anyway

You can't balance the carbs properly unless all other settings are right, you need to get the bike idling ok and then re-balance it.

Is the choke cable correctly adjusted, is the choke linkage moving properly when the cable is pulled, are the little plungers (or whatever) on each carb moving when the choke linkage moves? Were all of these parts reassembled correctly?

My way of looking at it was this. Before I removed the carbs they were fine afaik. I removed the jets and cleaned them and cleaned the carbs. I did not disassemble the carbs at all, only removed them cleaned and fitted new seals. So I shouldnt have to adjust any screws except for the 4 air/fuel mix screws. Curiosity got the better of me and I removed them to clean them but didnt take propper note of the position they were at. They are Keihin carbs but for the love of me I cannot find any decent guides on the settings for it.

Regarding the choke and throttle cables... I will have to replace them as they have a slight kink in them. The choke linkage moves fine.

Richard tea

So after spending €55 on 2 special screw drivers ( one broke & the other was no use due to its size ) I managed to reach all the air/fuel mix screws and adjust.

I knew the bike was running 75% ok but when I hit 6000 or 7000 rpm the bike would just hit a flat spot- if thats the right term. This flat spot might last for 3 to 7 seconds then sort itself.

So I turned each of the mixture screws out another 1/4 this morning and tested the bike. She pulled like a train:) ( stop laughing at me cb:P ) 3rd gear and full throttle was unreal, I dont think it ever had such poke. Anyway I went up through all the gears and the bike had no trouble getting above the 7000 rpm range.

Im going to stick a fresh filter and fresh oil in the week and shake off the cobwebs. Dont think jack frost will be back again any time soon.

Thanks all who helped out with info

Richard tea

Back to square one:(

I have removed the carbs again and will strip them tomorrow and recheck float heights and so on. Im going to order new rubber carb boots also as the ones I have now are not great.

Cpuld someone take a look at the 2 pictures and tell me what they are. One of the pics is a hole in the side of the engine between the fins. It could be just for fitting crash bungs but I just want to make sure its not for something else.

The other pic is a tube that comes from the top of the engine to the airbox. The tube that was connected was split.... What is this tube for and how could a split tube affect performance???

blade1

Pic 1 if I am looking at it correctly is a breather hose.
Pic 2 is a weep hole.
Fix pic 1 and pic 2 should be like that.