NoOne65 Posted March 29, 2016 Share Posted March 29, 2016 I need some ideas please. I think I have been at it too long so was hoping for something fresh I might not have thought of. I am having some issues with my 97 carbed blackbird. Its running like its missing...no power at any speed...number 3 cylinder is not as hot as the other 3. I have had the carbs off and apart 3 times. I have never had issues removing, cleaning, and tuning carbs. I swapped coils. decrease fuel/air mixture way lower than normal (1.5 turns). I did notice debris in the float bowls so installed additional fuel filter on each line. Spark plug is black as if its too rich...correct me if I am wrong a rich cylinder will be cooler than the normal ones right? Anyway any ideas? Quote Link to comment Share on other sites More sharing options...
Peepa Posted March 29, 2016 Share Posted March 29, 2016 Have you tried new plugs? If the plug is black it should be getting enough fuel but lacking enough spark. When you swapped coils was it still #3 that was the problem? And have you pulled the wire to check the spark? Quote Link to comment Share on other sites More sharing options...
John01XX Posted March 29, 2016 Share Posted March 29, 2016 If you have the plugs out, check compression in each cylinder Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 29, 2016 Share Posted March 29, 2016 (edited) "Running like it's missing"-misfiring at idle and under power? "no power at any speed"- like a 50cc moped could outrun you, or just not achieving XX power? Carbs appart 3 times trying to cure this, or in the past? Yes, a rich mix can cause a cold burn, I assume by temperature you mean that exhaust pipe is colder? Are there any vacuum hoses on #3 that aren't on the others? I'm thinking maybe the fuel valve and maybe it's leaking, or maybe a canister purge hose, or something else-I don't recall the vacuum hose set-up. If not a hose issue-compression check, replace or at least swap the plugs around, test plug wires with an ohm meter. Edited March 29, 2016 by superhawk996 Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted March 29, 2016 Author Share Posted March 29, 2016 18 hours ago, polysyllabicgibbs said: Have you tried new plugs? If the plug is black it should be getting enough fuel but lacking enough spark. When you swapped coils was it still #3 that was the problem? And have you pulled the wire to check the spark? Plugs are new. I did check the spark at the coil and yes problem was still number 3 after the swap 17 hours ago, John01XX said: If you have the plugs out, check compression in each cylinder I have a friend coming Friday with a tester so going to check that 14 hours ago, superhawk996 said: "Running like it's missing"-misfiring at idle and under power? "no power at any speed"- like a 50cc moped could outrun you, or just not achieving XX power? Carbs appart 3 times trying to cure this, or in the past? Yes, a rich mix can cause a cold burn, I assume by temperature you mean that exhaust pipe is colder? Are there any vacuum hoses on #3 that aren't on the others? I'm thinking maybe the fuel valve and maybe it's leaking, or maybe a canister purge hose, or something else-I don't recall the vacuum hose set-up. If not a hose issue-compression check, replace or at least swap the plugs around, test plug wires with an ohm meter. misfiring at idle and under acceleration...sounds like my friends SV650 no power as in crack the throttle and just kinda bogs down in any gear or any speed and since i am so use to the power yea like a 50cc moped to me! lol Carbs apart 3 times to solve this issue but not the first time I have had them apart. I hit every hole with carb cleaner... If I spray water on 1,2,4 it evaporates quite fast but on number 3 just kinda sizzles and evaporates no hoses on number 3...fuel valve is on number 2...not sure what a canister purge hose is. I will check the wires friday when I do compression test Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted March 29, 2016 Share Posted March 29, 2016 Is the float level in the carbs OK? No small drips of fuel under the bike? Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted March 30, 2016 Author Share Posted March 30, 2016 5 hours ago, blackhawkxx said: Is the float level in the carbs OK? No small drips of fuel under the bike? Yes the level is good, valves are good and no fuel leakage. I did notice something about the diaphrams sliders. Two of them have small holes and the other have two holes. dunno if that has anything to do with my issues but could it be a contributing factor? I referenced some old carbs I have and the center 2 have the larger hole and the outer the smaller Quote Link to comment Share on other sites More sharing options...
JB4XX Posted March 30, 2016 Share Posted March 30, 2016 Plug wires... Sell it! Buy my concours! 1 Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted March 30, 2016 Share Posted March 30, 2016 1 hour ago, JB4XX said: Plug wires... Sell it! Buy my concours! Agreed! I miss my carby. I'll buy yours at full scrap value. 1 Quote Link to comment Share on other sites More sharing options...
JB4XX Posted March 30, 2016 Share Posted March 30, 2016 Want to try a different coil and wires? 1 Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted March 30, 2016 Author Share Posted March 30, 2016 (edited) 3 minutes ago, JB4XX said: Want to try a different coil and wires? I appreciate the offer! I did switch the coils and the problem didnt move to another cyclinder...I have a friend gonna help me check compression and leakdown friday Edited March 30, 2016 by NoOne65 Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted April 5, 2016 Share Posted April 5, 2016 Did you guys do the tests? 1 Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted April 5, 2016 Author Share Posted April 5, 2016 1 hour ago, superhawk996 said: Did you guys do the tests? yes I did and all 4 are within %10 percent of each other...I am at a total loss Quote Link to comment Share on other sites More sharing options...
CBR-RR-XX-CESS Posted April 5, 2016 Share Posted April 5, 2016 Just a shot in the dark but once had a carbed GPZ that had a pinched fuel tank vent tube with similar results as yours. Quote Link to comment Share on other sites More sharing options...
JB4XX Posted April 5, 2016 Share Posted April 5, 2016 I had one start missing, run on 2 or 3 cylinders, then run fine. ... Turned out the plug wires had made contact with radiator fan, spark was occasionally jumping to the radiator. Tested it by wrapping them up, started and idled fine...changed out plug wires...no problems! Quote Link to comment Share on other sites More sharing options...
jon haney Posted April 5, 2016 Share Posted April 5, 2016 Good idea, Josh. Also, you mentioned you had another set of carbs. Have tried switching out the slide (with diaphragm) to see if maybe that's the problem? Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted April 5, 2016 Author Share Posted April 5, 2016 28 minutes ago, JB4XX said: I had one start missing, run on 2 or 3 cylinders, then run fine. ... Turned out the plug wires had made contact with radiator fan, spark was occasionally jumping to the radiator. Tested it by wrapping them up, started and idled fine...changed out plug wires...no problems! You mentioned earlier you had a set of wires and coil? 11 minutes ago, jon haney said: Good idea, Josh. Also, you mentioned you had another set of carbs. Have tried switching out the slide (with diaphragm) to see if maybe that's the problem? The other set of carbs isnt complete but the 3rd carb was good and I swapped it out and no change...so #3 compression is good,carb is good and coil swap most likely means they are good that leaves plug wires (Plugs are actually new)...could any other carb cause this issue? I only assume its number 3 cylinder issue because of the temperature difference between 1,2,4 and 3...I am considering swapping out 1 and 2 also...number 4 spare I had to drill out pilot screw and now it has brass stuck in the threads...I need to find a tap that fits it to make it useable Quote Link to comment Share on other sites More sharing options...
HANKSXXX Posted April 5, 2016 Share Posted April 5, 2016 Have you checked carb sync? Only reason I ask is I you said you changed the #3 carb for another one. Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted April 5, 2016 Author Share Posted April 5, 2016 2 minutes ago, HANKSXXX said: Have you checked carb sync? Only reason I ask is I you said you changed the #3 carb for another one. Yes carb sync was checked and done if needed after each removal and remount Quote Link to comment Share on other sites More sharing options...
jon haney Posted April 5, 2016 Share Posted April 5, 2016 There could still be something wrong in the carb, but I dismissed that, seeing as how you had them apart 3 times and still have the issue. Only thing left is the plug wires. Hope you figure it out. 1 Quote Link to comment Share on other sites More sharing options...
JB4XX Posted April 5, 2016 Share Posted April 5, 2016 I have a coil and two plug wires that are good, send me address and it will go out tomorrow Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted April 5, 2016 Share Posted April 5, 2016 So if you have the spark plug in the cap grounded to the outside of the motor, does the plug fire when cranked? 1 Quote Link to comment Share on other sites More sharing options...
NoOne65 Posted April 6, 2016 Author Share Posted April 6, 2016 So I went ahead and swapped out the other 2 carbs and short test run it has mid and hi range power back...now I just have to futz with the idle...After throttle is applied it kinda hangs and then slowly decreases to idle...too lean? Quote Link to comment Share on other sites More sharing options...
HANKSXXX Posted April 6, 2016 Share Posted April 6, 2016 Check for vacuum leaks Quote Link to comment Share on other sites More sharing options...
superhawk996 Posted April 6, 2016 Share Posted April 6, 2016 (edited) 7 hours ago, NoOne65 said: So I went ahead and swapped out the other 2 carbs and short test run it has mid and hi range power back...now I just have to futz with the idle...After throttle is applied it kinda hangs and then slowly decreases to idle...too lean? Likely lean, maybe sync issue. And possible leak as Hank said. Edited April 6, 2016 by superhawk996 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.