'81 XJ 650 only running on 2 cyl.

Hi everyone.
I just bought my frist bike, been a car guy for a long time and though this would be a fun project.

I purchaced the bike about two weeks ago and it ran great. I have receipts from last year that all the carbs were rebuilt and tuned. I have a new battery and plugs.

So now comes the problems, after a 40 mile or so ride this weekend i parked the bike in the garage and put it up on the stand so that i could change the oil. I drained the oil and pulled the filter i then noticed the oil cooler on the bike is most likely an aftermarket unit. Replaced the filter and tighten the drin pulg, then oil started to leak around the oil cooler adaptor. so i pulled it off cleaned it and replaced. I filled her back up with 10w 40 and fired her up. it stumbled a bit but then the idle smoothed out. I shut it down and checked the oil level, topped it off. then i fired it up again and it only runs on cyclinders 1 and 3. I could tell this by the pipes on 2 and 4 were ice cold and 1 and 3 were warm. I pulled the plugs and all looked good except for cyl. #3 pulg which was gunked up all black. I cleaned it off and tried again but still on;y runs on 1 and 3. If i give it any throttle at all it will bog down and stall. also it is still slowly dripping oil around the top edge of the oil cooler adaptor.

Any ideas of what to look for or replace. also where can i get a good repair manual for this bike. I have seen the Haynes but they are notibly bad for cars. thanks in advance.

 

First off what kind of bike do you have? ( edit: dah! seen it now in the post title) Second welcome to the xj site. Hopefully someone that has more knowhow in this matter will chime in soon. For a service manual you basically have 3 choices as far as I know. Factory,Haynes or Clymers. I have the first 2 and they are fine by me for what I have done so far. Good luck!

 

If it ran fine for 40 miles it has to be something you knocked loose, pulled off, leaned against.
As for the oil cooler it should just be an O ring to seal it, try a new one.

 

Before you take the carbs off the bike, check the float level.
Bike on centerstand, run, then stop.
attach a clear hose about 6 inches long to the drain nub on the float bowl, and loosen the drain screw.
Hold the hose next to a bowl mount screw, tell us how far up the fuel comes in the tube- - do all 4.

Next test: while the engine is idling on 2, spray just a whiff of starter fluid into the airbox, if the other 2 fire up for a second, then back to 2, then it's absolutely, definitely a bit of crud lodged somewhere in the Pilot circuits of #2 and 4.

 

Great! I will give the take a look at the carbs when i get home from work.

As for an o-ring on the oil adaptor i didn't see one, i thought this was odd when i was puting it back together, but there must be one i will give it a look.

Thanks guys i will reportback with my findings


The Hound: FZ is the man!

 

so i did the test on the carbs and the fuel rose to about 1mm under the top of the float case on all the carbs. This is where it should be right?
The carbs are super clean. as i said before freshly rebuilt.

I don't seem to be getting a spark on cyl 2 and 4 could this be the coil?
if so where can i get a replacement, or would it be okay to get a universal kit from dennis kirk?
I really want a new one no junk yard or parts bike parts for me when it comes to electronics. that is if this seems like a resonable solution.

 

As TheHound stated I would look around the bike to make sure nothing got knocked loose. The Number 1,4 cylinders are run off 1 coil and 2,3 another. So it doen't make sence that it would be that. I could be wrong(has been known to happen). New coils can still be bought through Yamaha but they are 100-120 each. Aftermarket coils can also be used but finding the ones that fit your bike is another story altogether. I however would look into other possibilities. I have nothing to suggest looking at though. I am sure someone will chime in.

 

Okay then i think it maybe the plugs themselfs i'm going to pick up a new set tomorrow and hopefuly that should do it.

 

Could two of the plug wires be mixed up?

 

There numbered, so i have them in the right spots and i didn't remove them before it started to run badly.

 

I hope that it's that simple, new plugs are cheap, maybe you fouled two of them.

 

So i changed to new plugs today and i got spark on all cyl. but now it won't even start with out starter fluid.

So i pulled the carbs again and pulled the bowls... wow was i ever wrong about the cleaness of the carbs . number 4 carb was so cloged with this yellow colored gel and number 2 the main jet was clogged right up and varnished over. I have the jets and bowls soaking in some carb cleaner. also number 4 float jets piston spring was not popping back it was just stuck down. so i have that soaking this should allow the float to work a little better.

All i can think is that the long ride loosened some of that gunk up and it clogged things up. I should have them back on tommorow and i will report back. Fingers crossed.

 

Bottlecape, be sure to run some Seafoam or Berrymann's Chemtool through the tank, it'll clean up the smaller details nicely.
1/4 can of either to a full tank of premium should do the trick. Then just take a very long ride to get it worked through the system.

 

Robert this is just what i did. 1/4 bottle seafoam in the tank and then topped it off.

I got her started today running strong on all 4 cyl. Yeah!
I was nearing giving up ready to put the for sale sign on it, then tried it again and sprayed a ton of starter fluid in the air box and she came to life. Took it for a nice 5 mile ride and it is running better then ever. I'm so happy.

Thanks for all your help guys.

 

Excellent, now get those carbs synced and colortuned!