have a dead cylinder. can you help?

shark1979

shark1979

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i have just cleaned the carbs. installed a new fuel filter. getting ready for my local bike week coming up. so i went for a ride tonight. bike was running great. went about 20 miles. about a mile from my house turned a coner bike fell on its face. right cylinder was not firing. so i drove home really slow trying to keep bike running. pulled the plug. it looked good as far a rich or lean. had good spark when i put the plug on the block. it seems to have good compression. with the compression gauge i had 120psi after 2 or 3 kicks. is that good or bad? what could be making the cylinder not fire. i am thinking i am going to pull the carbs off tomorrow and check every thing? all ideas welcome.
 
120 isn't awsome but plenty good enough to run. Was the plug wet or dry? drain that float bowl into a container (hint cut up a quart oil can as a catch can) see what you see. Run some fuel out of the tank through that carb too.
 
i just checked the compression again after reading how to do it the right way. with the throttle wide open. 4 kicks i get around 150 on the right side.
 
That's a good number so if you have spark, carb is most likely. Just for grins do the compression test on the other side.
 
Just for grins. I checked the other side. Right around the same maybe a little lower. The left side plug looked a little white/ gray . I drained the bowls on both carbs. A couple black specks in both sides. Put it all back together and still on firing on the left side. So I guess my next step is to pull both carbs and clean the jets?
 
yeah maybe huff a little ether in the side see if she pops off that will pretty much answer it. Pulled apart a set of carbs that had recently been overhauled by the PO he had used automotive rubber fuel hose. There were chunks of that fuel hose blocking ports/jets in the carbs.
 
Your fuel filter may be done. I suggest putting a good quality inline fuel filter between the petcock and carbs and clean the carbs. Should do the trick. If the engine isn't firing it's one of three things: air, spark, or fuel.
 
Try a new plug on that side or switch plugs side to side. Just because it fires outside the cylinder doesn't always mean it will fire under load.
 
well here is a update, i cleaned carbs checked all jets, replaced my fuel filter, installed new plugs. still nothing. left side works great, right side nothing. plug is wet but nothing happing?
 
i just tried switching the plug wires on the plugs but not the coil still left side works but not right. every once in a while the right side will shoot a flame out of the exhaust. i am stumped i guess i will check the valves next?
 
I just switched the air screws from the left to the right and still nothing. Pull the plug it is a little wet and has plenty of spark. Still just shooting a flame once in a while?
 
shark1979 said:
I just switched the air screws from the left to the right and still nothing. Pull the plug it is a little wet and has plenty of spark. Still just shooting a flame once in a while?
Click to expand...

before i replaced the oring the plug was a little wet too it my not be oring but it does seem flooded to me
 
On BS38 carburetors, the mixture screw is a small brass fitting with slotted head,located
on the outward side of each carburetor, forward of the slide tower (see Appendix, item
9). Remove the screws and the springs below them and clean with solvent, and blow
out the seat areas. Carbs fitted to 1970-1975 (XS1-XS650B) require the 256 series
screw; it is shorter than others, and threaded all the way to the slot. The 584 series was
used on carbs fitted in 1976 and 1977 (XS650C and D); it is longer, with a relieved area
between the slot and the threads. The screw used in carbs fitted in 1978 and 1979 is
the longest. It is stepped, has a recessed area past the slot, and is sealed by an O-ring.
The screws cannnot be interchanged. Some fuel screws were fitted with plastic caps to
restrict range of adjustment. Remove the caps and discard them.
The fuel screw in the BS34 carburetor is recessed in a vertical tubular casting on the
carb body toward the center line of each carb, forward of the slide tower
 
i have the bs38. i will have to get 2 orings tomorrow. is there anything special about the orings, can i just go to a hydrolic shop and get the same size?
 

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