#4 cylinder exhaust cold please help!

Hey be gentle its my first post. I got a free 81 550 maxim! Previous two owners had difficulty with the bike. I rode it 6 blocks and left me stranded and had to push it home. Anyways sat for six months and when me and my buddy tore into it it had no spark. Did some research and found it was a safty switch. So we pulled the rely to eliminate all of them. Got spark on all 4 and hit it with starting fluid to get it to fire with fresh gas just to clarify it ran, and it did. So figured a good carb cleaning oil change and breaks and it would be ready to start the cafe work. Well went back to his place and did the above and installed the mac 4 to 1 oil. New batt. Velocity stacks fired up and noticed only 1 2 and 3 cylinders manifold got hot #4 stayed at ambient temp of 56°f got late so the next day there was oil and gas on the ground i pulled the oil cap and it reaked of gas. Most likely due to 4th cylinder we thought. checked coils and both tested fine carbs were cleaned thoroughly. We tried #4 air fuel mixture and couldnt get the temp to raise help me please. I dont want the i told u so from previous owner lol see him on a weekly basis thanks in advance

 

Spark on all four, but one cylinder won't fire.

You did not do a good carb cleaning.

The Church of Clean

Further required reading here:

The Information Overload Hour

Welcome aboard

Yoiu have a bunch of work to do before you start on any modifications. Make it run sweet in stock configuration, tend to the safety items (those brake lines are over 30 years old).
Also, fair warning, say no to pod filters. Stock airbox: keep it, use it, love it.

 

+1 on the above suggested reading

sounds like your needle valve(s) are not seating allowing fuel to pour into the carb(s) and crankcase.
you should also be doing a wet fuel level check on the carbs before you install them setting the fuel height in the bowls this could be the problem as well.
when you fill the carbs for the first time you may have to tap on the bowls with a screwdriver handle to make sure the floats rise freely and seal the needle valves.
when you install them on the bike leave the v stacks off if your carbs are still flooding out you will see it before you start the bike. you can start the bike without them.

mac 4 to 1 did you figure out where the l bracket goes? mounts on the left side in the exhaust mounting hole on the foot peg bracket it holds your center stand down far enough to clear the chain and keep it from bouncing off of the muffler.
I will post a photo of my carb holder set up in the morning.
do you still have the air box?
what did you have for an exhaust system before the mac?

 

I had rusted out stock exhaust and love 4 to 1 look. And it mounted on the clutch side of the bike. Unfortunately i jumped the gun removing stock airbox and cracked it "brittle plastic..." im going to call sportwheels and see what the charge for a airbox. Massive motorcycle junkyard. May be a stupid question but my bike has a 155 main air jet and read the 81s are supposed to have a 165 main air jet.? Another problem? Anotger question how do u adjust tge floats with the bowls on the carbs "wet" havent had a chance to read the full carb cleaning guide listed above.

 

Don't worry about that--- actually, let him say that.... As often as he wants, but each time just say, "that's ok, we're taking care of it's gonna be something awesome when we're done....".

Leave it at that.

You're gonna find that, in the end, your "problems" are really pretty simple and you can correct them. Too many people don't understand these bike and give them up quickly because "the stupid thing doesn't run right and it will cost too much $/time/frustration to fix. It's junk and you can have it if you want...." And don't take the time to learn what the simple fix actually was. That's ok, cuz that's how I get a lot of my bikes.

That said, leave you comment at " we'll fix it"..... There will be the day that you blow his doors off, and YOU get to say " I told YOU so".

You're HERE...... And with our help, you'll get it done.

 

Thank you everyone for the replies. Ive never done any 4 bank carbs befor this, everything seemed really clean going in. But i will use the church of clean method. Should i change out the main air jet from the 155 is has now to what i think is stock 165? The bike is at my friends house where we are working on it and i hope to get back to it this Monday to drain and replace the gas filled oil and filter. Bull the bank of and tear it completely apart following the guide Get new plugs and check the gaps and hunt down a stock air box. Anything else that i should do? Anybody have a link to the bikes wiring diagram? Thanks again everyone thought id be alone in this mess and almost gave up

 

Main Jet #112.5 Air Jet, Main #70
Needle Jet O-8
Pilot jet #35 Air Jet, Pilot #165
Starter jet #35 Throttle Valve #130
Jet Needle 4GN

 

Found a stock airbox on ebay clean no cracks or leaks with 4 boots to the carbs for 91 bucks jumped on it cause through larsons cycle its 80 bucks for one boot alone. Also got a guage for checking valve clearance. Still trying to track down the YICS tool for carb synchronization and gonna adjust cam chain tension. Will post feed back after i complete "church of clean" thanks again much appreciated

 

Don't bother. It's not necessary. Carb synch can be done without blocking the YICS ports.
If you really want one Chacal sells them, and there is a diagram around here somewhere so you can make one (or you can just use Marvel ystery Oil soaked rags).

 

Sounds good if i can find the diagram id more than likely make it but if i cant find it and its not necessary i wont bother.

 

you have to remove the carbs remove the bowls..
tip the carbs upside down and measure the float height to give you a referance point
then you reach in with tiny needle nose and tweek it a little
remeasure float height to confirm change
or take a wood dowel place it on the pin hplding in the float and gently tap the pin out adjust tang and reinsert float
if fuel level is high you bend tang towards needle valve
if too low bend away from needle valve
this is my set up for doing carbs off of the bike


I have a mac 4 to 1 nice set up but wait untill you have to change the oil filter the housing will not come out between the pipes but you can turn it for access to the filter.

 

What size is that pvc? I did have a little chance to read some of that church of clean

 

i think it is 1 inch I will check in am I cut slots in the elbows with my table saw it holds carbs tight
I did not glue the back tees to the outside elbows so I can tilt them if needed.
just use a level on the carbs and shim to level as needed
I plan on putting screw feet on it to make leveling easier than wood shims .
gas tank 5$ at the local repair shop it is a lawn mower tank I use a petcock from hard ware store and a filter

when you are set to test you test level with the tube on both sides of the carbs

you want the base to be big enough to fit a catch basin in it under the carbs for gas leaks
if your floats are off it will overflow the carbs in the holes in the airbox side that are at 9;00 and 3;00

 

Do u know how i order from xj4ever? I want the carb rebuild deluxe kit

 

1. See the banner/engine pic at the very top right corner of every screen? Click on it.

Or

2. Start a conversation with listmember " Chacal ". That is Len Chacal, owner of xj4ever. That's who you'd be ordering from anyway-----

 

Also thanks for this reply super helpful. Still scared to break up the carbs from each other especially since i dont have the service manual

 

check your inbox about the manual

 

L

 

Check manifold boots for air leaks my #3 was cold found out manifold boot was cracked bad and was sucking air changedmanifold boot bike runs on all four. Start bike spray some carb cleaner at boots if change in idle you have a leak

 

I will chech that out thank you

 

Ok after i got some free time i pulled the engine out to throw the air box i got back in. Checked my valve shims and as follows
intake: cyl #1. (.07) #2 (.12) #3 (.14) #4 (.05)
exhaust: cyl #1 (.14) #2 (.16) #3 (.18) #4 (.14)
Intake Cyl #1 and #2 had a 260 shim
Exhaust cyl #1 had (280) and cyl #4 (270) shims
So i ordered a 255 for cyl #1 intake and 250 for #4 intake
And for exhaust 275 for for cyl #1 and 265 for cyl #4.
Now that thats out of the way.
I ordered new carb to engine boots, my shims come in tomorrow so ill be installing them then doing a compression test, carb cleaning will be done this coming sunday. Ill be posting my compression numbers wet and dry tomorrow thanks for the help everyone

 

Installed shims and performed a compression test. The guy helping me had a compression tester and red way hight 165 170 on 1,3,4, 2 was 150ish range and my tester read 65 across 1,3,4 and 50 is on number 2. His compression tster had the rubber nipple u hold in the plug hole with a metal shaft to the guage and mine was a screw in with a rubber hose. Idk what to go off off
P.s. carbs were still at my house being rebuilt so the were off the bike during the test but exhaust was in place

 

Nobody?

 

i need some help can u read my last post in this thread?

 

The numbers from your friend's gauge sounds closer to being correct. The numbers from your (screw in type) seem too low... though the readings across your four cylinders are consistent with #4 being lower than the rest. I don't have the numbers for your engine (I have a xj700), but I'm sure someone here will chime in soon. Hopefully the difference between the high and low pressures is in ok range. For my bike, the manual states that the difference should be no more than 14 psi.

 

I once had a CB750 that has a cold cylinder , turns out after replacing plug, coil pack to no avail ...was the plug cap was corroded threaded off and trimmed end of the plug wire , fixed problem. your post about cold cylinder just some random thought you might have a similar problem.

 

Thank you