2 dead cylinders?

[M_Hills]

The Back Story:Hey guys, my name is Marcus and I am totally new here. I am super pumped because I just got my first motorcycle!!! I have been watching CB650's on craigslist for about 6 months. I wanted one bad!! Then the other day I walked into a friend/neighbors garage to help him with something, and there it was... a 1981 CB650. My heart skipped a little when I saw it covered in about an inch of dust!!! I asked him a little about it but didn't want to put him on the spot or anything. I then went home and decided to leave it alone as to not put any weird strain on a relationship with a neighbor that I am just getting to know. I prayed about it and purposed not to say anything to my neighbor. I figured if that was the bike that God had for me He could bring it to pass without my help (and I sure hoped that He would). Long story short, my neighbor came up to me about a week later and said that God had laid it on his heat to give me the bike a couple of months before that!!!! I had never said a word to him about it!!!! CRAZY!! (I am not trying to bore you guys with a story like this, but I feel that it deserves to be told. God is good!!! )

The Question: Here is my question.... I got the bike started and the left two cylinders (as I am sitting on the bike) are not firing. I can actually take the plug wires off and the bike runs no different. They both have good spark. (Trust me, I felt it good! ) I have not checked the compression yet. I will do that as soon as I get a tester for it. I am wondering if there is any way to check and see if my carb is getting gas to the cylinder? I do know that there is gas in my float bowls, but beyond that I have no idea if the carb it doing what it is supposed to be doing. If there is a way to test my carb, I don't know what it is. Any tips?

I appreciate any help I can get here. I am super excited and want to get riding!!!!
Thanks

[Volker_P]

Welcome here, Marcus!

Great back story! Hope we can bring it to a happy ending.

First thing to check out for you is if your plug wires from the left coil go to 1+4 while the plug wires from right coil go to 2+3. Easily mixed up.

Then a look into the tank is always worth it. Dirt in there will soon cause carb trouble (or already has). A fine enough inline filter may help to avoid that.

[M_Hills]

I am so pumped with this forum!!! I have been learning a lot just browsing other threads on here!!!! I think that everybody knows more than I do about motorcycles

I raced home after work last night and checked the wiring of my bike and sure enough, I had something screwed up!!! Now my 1,2,&4 cylinders are firing and my #3 is not.... When I had it wired previously, 1&2, were not firing and 3&4 were firing.... I guess that this tells me that they can all fire I just have to figure out how to get them all firing at the same time.... Is there a good picture/diagram that shows the order to wire my plugs? I know that this is very elementary stuff, but I am a newb, what can I say?

I really appreciate this forum as a resource, and hope to be able to add value as I grow in my knowledge here!!!

I am sure that I will have more ?'s soon

BTW, I was wondering why there is no fuel filter on this bike. I will add one tonight, I think.

[Folsoml]

First thing to check out for you is if your plug wires from the left coil go to 1+4 while the plug wires from right coil go to 2+3. Easily mixed up.

Take a look at this free on-line manual:

http://cosky0.tripod.com/

It has everything you need--including a section on electrics with diagrams of your ignition system.

[unleashed]

Its good to see another newbie here as I am also & recently bought my 1st CB650, an 81' & am like you reading other threads & learning as I go. You know they say "Its better to learn from anothers mistake then from your own" & its so true.
As to a fuel filter, no, there is a course screen above the fuel petcock(fuel on-off-reserve lever) but its not good for catching fine rust or debri. Go to you auto parts store & buy a clear plastic inline fuel filter. Mine had 5/16" fuel line so check yours before you buy & see what size filter you need & buy a few fuel line hose clamps & at least 1' of new fuel line (should be 5/16") & use it.

[cgswss10]

Lets go back to real basics here. to run we need spark, compression, and fuel. You indicate you have spark and by switching around wires it would appear that you have compression. So before we spend a lot of time tearing stuff apart we can find out a few things with some simple tests. Go to the auto parts store and get a can of started fluid (in a spray can). Take off the right side side cover and take out the 3 bolts that hold the filter cap in place.

The plug wires are simple. Left side goes to cylinders 1 and 4. It doesn't matter which of the two wires go to 1 (or 4) right side coil goes to 3 and 2. again of the pair doesn't matter which is 2 and which is 3.

turn the bike on and get ready to spray the starter fluid in the side cover where you just removed the air filter cover. Hit the starter and give it a short spray of starter fluid. keep it running with shot sprays of started fluid.

How check to see if all 4 are running. The starter fluid bypasses carb. problems If one of the cylinders is still not running try switching wires on that coil- if 1 is not running switch wires with 4, same goes for 2 & 3. If the same cylinder is not running, switch plugs on the same coil

If you find everything is running on starter fluid, then you have a carb problem and we can walk you thru the most fun part of getting a '81 650 running

[M_Hills]

Thanks guys!!! I will get on it tonight and get back to you with my results

[M_Hills]

All right.... now this thing won't even run on its own. I can get it started and keep it running with starter fluid but then, it pukes if i stop feeding it. With the starter fluid it was only running on three cylinders though. At first 1,3,&4.... then I switched the wires on 2&3 and 2 started firing and three stopped. I have a feeling that I have compound problems here.

[Volker_P]

So it seems you now have a fuel issue, too.
Did you clean out the tank?
Another option might be the vacuum shutoff. If present, try to bypass it.

Looks like you also have a plug cap or cable problem.

[M_Hills]

I have seen mention of cleaning out tanks quite a few time on the forum!!! I gather that a dirty tank causing problems is a common factor around here?

When you say "cable problem" are you speaking to the throttle/choke cables?

Thanks so much for all of your help on this

[Volker_P]

No, I talk about the cables from the right coil to the spark plugs at cylinders 2+3 which obviously do different things. Swapping them should make no difference.

[cgswss10]

After doing the test you have done so far, we have a pretty good Idea that one of your spark plug wires or the cap is bad on your right hand coil. The plug wire pushes on to a little spike inside the coil and then is held in place by a rubber washer when you screw the cap back on. The plug cap just pushes on as well. I'd be thinking of getting a new set of wires and caps, but for now you can just pull the wire, cut off about 1/2 inch, and plug them back in. That may help your spark problem

I was very pleased with these

http://www.ebay.com/itm/Honda-CB650-Spark-Plug-Wires-Cables-SOHC-CB-650-/390445827765?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item5ae86286b5#ht_4647wt_1308

you can put a piece of tubing on the drain of one of the carbs. If you have the bike on the side stand use #1 (left) Now with the gas turned OFF at the tank, use a screw driver to open the drain on that carb. It should stop draining in a short while. Now open the petcock on the gas tank and see if you get a strong full flow(out the drain tube). If you don't, turn the tank to reserve and see if that changes anything. We are guessing that something is keeping the carbs from getting gas as it is unlikely that all 4 carbs would go "bad" at once.

[cgswss10]

By the way- I hope you got the tool kit as well, you are going to need a specil 18mm plug wrench to pull the plugs on those inside two cylinders. For the next run test, I'd like to switch the #2 and #3 plugs so we can see if the problem is the plug.

[M_Hills]

HA!!! I figured that out the hard way already ...... I have to pick up a thin walled socket don't I?!!!

[cgswss10]

You can get the orginal honda wrench for like $17-25. Or there are a number that you can get that are real spark plug wrenches that you can get off e-bay or from amazon

http://www.amazon.com/Motion-Pro-Spark-Plug-Wrench/dp/B001DDABGG/ref=sr_1_1?ie=UTF8&qid=1343422695&sr=8-1&keywords=18mm+spark+plug+wrench

http://www.ebay.com/itm/HONDA-CB550-CB550SC-CB650-CB650SC-SPARK-PLUG-WRENCH-/120946535437?pt=Motorcycles_Parts_Accessories&hash=item1c28f9ac0d&vxp=mtr#ht_545wt_1074