Hello CBRForum members- I just joined today after lurking the site while I was repairing my bike. I have a few questions about my bike and I'm sure you have experienced some of the symptoms as well. Thanks in advance for any help you guys offer, it's much appreciated. So, I bought a bike.....

Background:
Bought this from a neighbor after noticing it sit in his garage for a year. Casually struck up conversation, in which the P.O. stated it hadn't been ridden for three years and has been sitting for a while. Before sitting, the bike ran but struggled a bit at low rpm. The PO also mentioned that the bike had also sat for a while prior to him getting it, since both he and his friend were in the national guard. The bike has 2,500 miles (actual miles), had been dropped several times on both sides, and has some replacement cosmetic parts (but nothing mechanical from what I can see). So I bought the bike in hopes of fixing it and having a sweet cheap bike (I have fixed up several bikes prior to this, have a basic working knowledge). The bike did not run when I bought it

What I have done so far (and the result):
*Carb cleaning- lots of green crap in carbs 1 and 2 (lean of the bike on the kickstand?) as well as enamel. Jet's all cleaned- all crap gone from the carbs- bike started running!!
*New Fuel Filter
*Checked that the fuel pump works (it does)
*New spark plugs (old ones were pretty bad)
*Carbs synched- idles much better and more power on the low end
*New Battery

Issues:
Here is where I need some help. I just got done riding for 20 miles, the bike runs decent, but still has some issues.

Issue #1) While idling- the bike keeps backfiring through the exhaust. If I increase the idle over 2000 rpm or so, the backfire goes away. Stock exhaust

Issue #2) Cylinder 1 and 3's exhaust pipe are not nearly as hot as 2 and 4- they are all working, but a quite noticeable temperature difference.

Issue #3) The exhaust pipe on cylinder #1 seems to be leaking- haven't investigated too much yet

Issue #4) Power, great over 4-5000 rpm, still a little sluggish below that number. I would say the bike is running at 85-90% like it should.

Like I said, the bike is getting close, but just not quite right. Thanks again for your help!

 

Attached is a pic of the exhaust from cylinder #1- not sure if this helps or not

 

Hello,
So I took off my exhaust today to do some more investigating (wet exhaust on cylinder #1) and I found that the pipes 1 and 3 are quite wet, 2 and 4 are quite dry. Is there some sort of relationship between cylinders 1 and 3, like both run off the same coil pack, or is this something completely coincidental? I'm guessing the moisture is gas? If so, I can see how this would cause the backfire, now the question is why are those exhaust pipes wet. Thanks again for any help!

 

Another thought, when I cleaned my carbs, I did not have the d-shaped pilot jet tool to remove the pilot jets. There was quite a bit of crud in the carbs and the jets were pretty plugged up. If I didn't clean the pilot jets, would this cause the symptoms listed above? Thanks

 

Runs good over 5000. Manual says 1 & 4 and 2 & 3 are paired on the coils. Could be too much fuel at low revs. Chk pilot screws on all carbs, should be pretty close to the same for each setting. Example, #1 2 1/8 turns, the rest should be within 1/8 of a turn. Manual says stock setting is 1 1/2 turns out, 1 7/8 out for Calif models.

 

Just a quick update, I bought a d-hex driver from mac tools that will hopefully be here next week- I did actually clean the low speed pilot jet, however, I never took the adjustment screw out and cleaned that way, or even checked to see how they compare to one another. My hope is that a quick adjustment of the pilot screw on cylinders 1 and 3 will cure the issue, if not, off with the carbs for another cleaning. I found the procedure for adjustment via the F3 manual, seems straight-forward using cylinder 3 first and then repeating the tuning procedure from there.
Hopefully this works and I don't burn my hands too bad in the procedure. Update to follow

 

Update again (maybe final update)- I'm smacking myself for being so unobservant. The previous owner incorrectly setup the spark plug wires. They are even numbered!!! After changing them to go 1-2-3-4 and not 3-1-2-4, the bike sounds like a mean running machine again. I'm about to take it for a spin, very excited that I've finally found out what the heck was wrong with it. Do you think that there will be any damage caused by the bike being setup like this for a while? Anyways, thanks again to everyone on this site- very very helpful. I'm sure that there will be more in the future.

 

Fouled plugs and carbon build up in the cylinders. It'll burn off with use.