number two no run

[tadtl1]

Hi All,

Ive searched all over the site, got a lot of good ideas but need some help. Ive got an 80 midnight, 11,, last fall so it was put away pronto, it ran good when I got it in October. I know you guys will get me looking for the right things to do. Ive taken compression, its good all the way across.

I put seafoam into the tank in december and ran it for a bit, but cylinders one and two wouldnt run as per the cold pipes. Ive taken the octy off today. Its been started up every couple weeks since December and numbers one and two, pipes warm up extremely late and never do get as hot as the other two in five mins of running. Ive got the tank off, and a special built tuning tank is on to feed gas while I tune. Ive had the plugs out today, they are quite a dark gray where they should be tannish . But about the only thing Ive been doing is running it with at least partial choke.

All four wires spark the plugs very nicely when they are grounded and the starter spins. The air cleaners are all off, the box is removed and I plan to put individual cleaners on from georgefix. I am wondering if having the air box off, could be althering airflow enough to allow the carbs to blow back a little bit when its cold. I havent had the carbs off at all yet. Also, the vaccuum advance is unhooked, and plugged although I do feel a bit of vaccuum even when the hose is off at the end of the vaccuum, hose,,, how is that possible? It doesnt seem to matter whether the vaccuum advance is off or on, I put it on the manifold, and it changes nothing while rough idling. Is the manifold at the carb base, where that is supposed to be?? Ive heard something about another port on the carb for some reason. Also, it appears that I have 81 carbs, since there are four gold carb tops on the bike. If you z can help get this thing idling on all four, it sure would be appreciated.

[psycoreefer]

My advise, put the airbox and vacuum hose back on, put new plugs in and go for a short ride, go to the gas station and fill up with fresh gas. You've probably fouled the plugs by running with the choke on all the time. When I start mine I need full choke for less then a minute and half choke for maybe 2 minutes if its really cold.

The vacuum hose should be hooked to the port on the #2 carb body, not the one on the boot between the carbs and the motor.

The vacuum advance will not do anything until higher RPM's. It is supposed to advance the ignition when your cruising on the freeway for better economy.

[fredintoon]

Hi All, - - - All four wires spark the plugs very nicely when they are grounded and the starter spins. - - - the vaccuum advance is unhooked, and plugged although I do feel a bit of vaccuum even when the hose is off at the end of the vaccuum, hose,,, how is that possible? It doesnt seem to matter whether the vaccuum advance is off or on, I put it on the manifold, and it changes nothing while rough idling. Is the manifold at the carb base, where that is supposed to be?? Ive heard something about another port on the carb for some reason. Also, it appears that I have 81 carbs, since there are four gold carb tops on the bike. If you z can help get this thing idling on all four, it sure would be appreciated.

Hi Tad,
if 1 & 4 or 2 & 3 don't run, most likely it's ignition.
If 1 & 2 or 3 & 4 don't run, most likely it's fuel supply.
If only one don't run, most likely it's a dirty carb.
The vacuum advance is tapped off a connector on the #2 carb body.
The vacuum taps on the four carb manifolds are for balancing the carbs.
Any one or two of those taps can be used to operate an octopus or vacuum gas taps if the bike still has them.
Taps not used for vacuum gas taps should be capped off except when connected to a manometer for balancing.

[cywelchjr]

+1 on the 1, 2 and 3, 4 thing. Also if the temps were different between 1 & 4 and 2 & 3 on an 80 it could be just the jetting as the stock jetting is a little richer on the center 2 to make them run a little cooler, don't know if that works or not, but it's the way they did them.

As for the gold tops, being a midnight that is how they would be, not sure if all 4 would normally be like that, but the outside 2 would for sure, and someone may have changed the inner 2 to match.

I agree with the new plugs, fresh gas and would add some fresh seafoam as well, and go for a ride, you may well find things to be different when you get done. Then again you may not.

Can't say much for the carb cleaning, as I have never done anything to mine other than adjust them, but then other than balancing/syncing I haven't had any trouble with them either. The riding ALL year round probably helps with that. If I had to park it all winter I might have an issue, but when I parked my 400 (uses the same carbs) in the past I drained the tank and the carbs and didn't have to clean them when I put it back on the road, but then after it sat for 13 years I had to completely rebuild them before they worked right.

Hey, just noticed, only 40 to go to guruhood.

[tadtl1]

Update on mns

Hi, I think that I read somewhere that the eightys only have the outside gold caps on the carbs, the eighty ones have all four gold caps, I believe it was Fred that wrote that.

Fresh Gas, in there, and since my tuneing tank is small, I tossed an ounce or two of B12 with toluene in there, but can and will get some seafoam next.

It now has the new plugs in and doesnt run different at all, it actually may be worse but I did run it for ten minutes or so standing, and it seemed to demand more choke the as it got hotter.

Number two is dead as hay, the rest of the pipes get hot to touch but after ten mins, number two can be held by hand but its warm.

I havnt put the air box back on yet, is it imperitive and Id like to ask, how so if I could.

Vaccuum advance line is now hooked up, to the number two carb, on the carb body. That didnt seem to make any difference.

I cant really take it on the road as it isnt registered yet, and am very sure it doesnt have power to pull at all anyway as its every bit a sputtering and dies without the choke . I will let the new gas and b12 set in the carbs overnight and then try tomorrow and run it in the gears on the center stand to see if there is enuff pull to even roll the rear wheel. Thanks guys, I should also say, that I do have cracked carb boots, but when spraying wd on em, it doesnt make any difference at all. It looks like PO put something on the carb boots, its kind of yellowish looking plastic looking stuff.

[thewiz]

sounds like a fuel issue ..

and very possibly the fuel line feeding the 1 and 2 carbs could be pinched but still allowing a trickle of gas to get into those two carbs. Would be worth a good look before pulling the bank of carbs though, right mate? .

[tadtl1]

crankcase vented to atmosphere

When I pulled the air box off,, I vented the crankcase directly to the atmosphere. Does that have any bearing on how it runs. I can see maybe where that might make it run proportionally leaner.

I will put the airbox back on tomorrow too and rehook the vent pipe back to it if it doesnt come up and run right to begin with.

Near where the crank vent entered the airbox, there is a second entry point thats open, but I dont recall anything such as a hose being on that when I took it apart. Its slightly smaller than the crank vent hose opening.

[foreda]

Dead Cylinder

Have you put a set of carb tune guages on it and tried to sync. It can only be one of 3 things, air. fuel or ignition source.

[tadtl1]

gotta find em

Hi,
I have a set of Honda four gauges but have to find them in the barn full of STUFF. I never figured to need to use them again, so theyve been sitting for twenty years. I know the vaccuum lines on them have to be replaced since they are hard.

I have a couple of regular automotive vacuum gauges at hand here, I think its possible to do this with just two gauges isn't it.

Ive been looking for a master idle screw, but havnt found one yet. Is it visible from the top, or the bottom?? Also, there only appear to be three ways to adjust the carbs with screws, not the four or five including the master screw, that I was expecting. Is there a master carb that isnt adjusted , but just has the other three adjusted to it? If this were the case, there would have to have a master idle screw wouldnt there?? Since I couldnt find a master idle setting screw, I tried to adjust the cable at the bar, with the little barrel. It seemed to run rougher the more that I shortened the available cable casing, such as to tighten it up.

[tadtl1]

master idle found

I found the master idle screw spoken of in the previous post, its on the bottom where its hard to see.

[XSBell]

There are only three screws for syncing the carbs. I think you sync 1/2 then 3/4 then the pairs to each other. CV carbs have a tough time running smooth without air box, they need some vacuume to function.

[Yard Dogg]

Yup, vacuum to function. New vacuum hoses, fresh gas, sync the carbs. But I think the real problem your having more than anything is dirty pilot jet ports. I have the exact same bike as you. I have cleaned my carbs like mad and am still having trouble with the pilot jets because they are probably still plugged. Here's a picture schematic that will help you when you decide to clean your carbs. There are little ports inside that will plug and leave you guessing so here you can see what needs to be cleaned. Like a dude told me today, you have to clean an opening, plug it, fill it with cleaner, plug the next opening, then clean and plug until all port holes are clean. I didn't do that, depended on the carb dip I bought do do it's job.

http://www.xs11.com/forum/images/tip...bs_cutaway.gif

If it's just idling and the pipes are not heating, this tells me it's getting no fuel at idle. I'll bet if you took it for a ride and kept it above 2500 rpms killed it and touched the pipes real quick, they will be just as hot as the rest.

Motorcycle carbs are pretty much the same. The air fuel mixture screw adjusts the air fuel from idle to 25% throttle, the slider needle adjusts the air fuel mixture from 1/4 throttle to 3/4, the main jet determines the air fuel ratio from mid 3/4 to full throttle. The floats adjust the amount of fuel in all rpm ranges. Forgive me, I'm drinking. Others will clean up my post for me, no worries.

[Yard Dogg]

I just noticed that in your post you mentioned you thought you had '81 carbs because all 4 carb covers were gold. Mine also has all 4 gold, well did until I painted them. I think your still at factory for the carbs. If not, then I don't think there would be a whole lot of difference except for the jet sizes. I know between 79 and 80 there were a few different jet sizes to be aware of. I guess that would tell the tale. If you need to know the factory jet sizes, post or send me a personal message, I have a Clymers manual that will tell you what you need to know. I don't have an image scanner, but there are places on this site to download the whole service manual for your bike.

I really think you should look into getting a manual for your bike. There is a lot to know about these bikes that is specific to the bike. These bikes were tuned pretty scientifically for some reason or another.

[tadtl1]

manual

Hi,

I wouldnt have anything out of warranty without a manual for it. I have both the Yamaha manual and the Clymer manual for the bike, but the clymer manual is for 79 so the carbs wont really be part of that one or at least thats what I think.

If you have a manual for up to an 81, and can scan carb pages,,, that would be wonderful. I did get the images of the carb that was posted last night, thank you.

Ive got to get vacuum lines today, find the honda four gauges for synch, and in the meantime will check with my two auto vacuum gauges to see if number two is way off the mark.

The fuel lines do have fuel in them and arent kinked at all.

tad

[psycoreefer]

you really should update your profile with your location, maybe there is another member near you that could swing by and take a look at your bike to help you figure it out. Also along the same lines you should put your year and model in your signature so that in future posts everyone knows what bike you have.