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Cylinder 2 dead and carb 2 leaking

P

ProudGecko

Training Wheels
I've been doing the regular maintenance to get my bike ready for spring. I finished adjusting the valves and went to start the bike only to find that cylinder 2 was not firing. It's getting a good spark and appeared to be getting fuel because the plug was wet. I tried draining carb 2 to see if any gunk came out. I loosened the screw and nothing beyond a very slow drip came out of the hose i attached to the drain nipple. When I tightened the drain screw all of the sudden fuel started flowing out of the drain. Now it won't stop leaking, every time I turn the fuel on (I've got an auxillary tank hooked up) fuel immediately leaks out of the drain until the bowl is empty. Any thoughts? David S COG# 9062 1986 Kawasaki Concours 1973 Honda CB500
 
The symptoms you describe are very strange I have a feeling some PO may have cracked the carb bowl and fixed it with epoxy or metal-glue. As the drain screws are tapered they don't need much to tighten them. Could be it was over tightened in the past and it cracked. When you screwed it back in you dislodged the glue plug. Just a wild guess on my part. As for why the scoot would not start, make sure the coil wires are correct and you have the wires going to the correct cylinder etc. The initial problem is not necessarily the carb. I suggest you pull the carbs, buy a jet kit from Steve and a new set of float needles from Murph Take a look at the Fall 06 issue of the Concourier (I think that's the one) there is a writeup on how to clean and service the Carbs. That will put you right. CP
2606714340100596652OGFlOW_th.jpg
 
That glue plug idea could be right actually, there was a slight pop as I tightened the drain screw then it started leaking everywhere. What's the proper torque for the screws, I didn't see a value in the service manual? The bike does start by the way, it just won't fire on cylinder 2 (same cylinder with the leaky carb). I'll do some more investigation in the morning. David S COG# 9062 1986 Kawasaki Concours 1973 Honda CB500
 
Colin your diagnosis was correct, the drain plug stop had broken inside the float bowl. It doesn't look like there is any evidence of a previous, botched repair so I must have broken it when I tightened the screw. I didn't torque it much at although so it's possible it was already weak. I've noticed a lot of bolts on my bike that have been torqued way to much by the PO. Should I even attempt to repair the piece (JB Weld?) or should I just replace the bowl? David S COG# 9062 1986 Kawasaki Concours 1973 Honda CB500
 
You need to replace the bowl. At this point I don't know of any epoxy I would reliably trust in an ethanol environment. BTW, the tip if the drain screw is tapered, so it will drive into it's seat and crack the bowl rather easily if it's overtorqued. Steve
 
Those suckers do get pretty tight. if the screw itself sheared off then it snapped as you undid it. If the bowl is cracked you broke it as you tightened it up. If its just the screw snapped buy or make a new screw. If its the bowl thats fractured then as Steve suggests a new bowl is in order. You still have an existing issue that needs fixing, that was in evidence before the bowl screw was damaged. It may or may not be the carb. My suggestion still stands, pull them, odger new boots and needles and a jet kit and make the bike run better by the service and upgrade,
2606714340100596652OGFlOW_th.jpg
 
I finally found a carb bowl (actually a whole rack of carbs) and got my carbs back in the bike. I readjusted the valves the right way this time (first attempt I set all the valves way too loose) and synched the carbs. Everything seemed better, but I think cylinder 2 is still not firing. If I run the bike for a few seconds from stone cold, headers 1,3,4 feel warm but cylinder 2 is still cold. If I let the bike run for a couple of minutes header 2 warms up. I can't tell if it's getting warm because cylinder two is firing or if its heat from the adjacent cylinders. Other than the usual cold natured starting, the bike seems to run fine and has good power. I feel like it doesn't quite sound right but then again it's been over three months since i last heard it run. Anyone have any ideas/advice regarding the cold cylinder 2? Is it suppose to be like this? I doubt it. Thanks David S COG# 9062 CDA# 0316 1986 Kawasaki Concours 1973 Honda CB500
 
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