Carb issues

[PKarl]

Ok so been haveing this problem for a year and nothing has worked. So far changed spark plugs .wires.adjusted pilot jets 2 turns out run several canns of seafoam thouugh re synced carbs all are perfect i have a miss like its running on 3 cylinders heres what i find. While running from the right side of the bike sitting on it. Cylinder 1 and 2 on left. exhasut pipe temp is around 250 260. Right side 2 cylinders 3 is about 160 175. 4 is usually about 110. I have spark at all cylinders. Turning pilot jet on cylinder number 4 does nothing pulling plug wire off number 4 while running changes nothing Do i have bad diaphragm in the carb There is gas in bowel if i open carb drain

[triton28]

Several things come to mind:
1) exhaust pipe temperature should initially be taken at idle RPM only, around 800-1000RPM. If temperatures at idle only RPM are similar to each other then the idle circuits are OK. If temperatures vary a lot then either the float levels are mismatched or an idle circuit/s is partially blocked, not enough to not function but enough to cause a lean mixture in one or more cylinders.
2) If 1) above checks out as OK then allow the engine/pipes to cool. Restart the engine and then at a steady 2-4000 RPM and, once the pipes have had enough time to heat up, take the temperature again and see if the temperature difference changes. This RPM range is, approximately, the diaphragm influenced range. If temperatures at idle and now at 2-4000 RPM are similar to each other then the diaphragms are probably OK. If not then possibly you have a slight tear/rip in a diaphragm or possibly a partially blocked main jet which would cause a lean condition and higher temperature. Above this RPM range one is utilizing the main jet as the diaphragms, if working, have raised the jet needles to their fully raised position.
3) The last resort; if the above DON"T check out as OK then I would do a compression check on all the cylinders. This one I hate to mention but it is a possibility for the initial symptom you raised in your post. I hope I am wrong with this suggestion but it is a basic diagnostic step.
4) DO NOT allow the engine to overheat.
Others may have a more succinct way to diagnose your problem and hopefully will chime in with their suggestions.
Dave

[cushman eagle]

If the cooling fan is working as it should,it should kick on before the engine would overheat
In stop and go traffic,in hot weather,my fan will kick on when the gauge goes up 2 lines drop down 1 line,and continue that cycle until I am back up to speed.
When stopped it is cooling as a stationary water cooled engine except the fan is cycling instead of running full time.

[triton28]

While I agree with your opening statement cushman eagle, some bikes have suffered neglect/end of service life issues by POs and don't have a functioning fan switch/assembly. Others having a working fan switch/assembly may have partially blocked radiator cores or buildup of crud in the coolant interior passage walls in which case the OEM fan assembly may not be able to keep up with the demands imposed upon it, so I mentioned 4) as a cautionary item for those situations.
Personally I utilize a supplementary fan when running an engine at normal operating temperature for testing purposes just to be sure there are no overheating issues. This may be overkill but it is just how I have always done it. Probably a throwback to my air cooled engine days.
Regards,
Dave

[cushman eagle]

While I agree with your opening statement cushman eagle, some bikes have suffered neglect/end of service life issues by POs and don't have a functioning fan switch/assembly. Others having a working fan switch/assembly may have partially blocked radiator cores or buildup of crud in the coolant interior passage walls in which case the OEM fan assembly may not be able to keep up with the demands imposed upon it, so I mentioned 4) as a cautionary item for those situations.
Personally I utilize a supplementary fan when running an engine at normal operating temperature for testing purposes just to be sure there are no overheating issues. This may be overkill but it is just how I have always done it. Probably a throwback to my air cooled engine days.
Regards,
Dave

Yes,triton,I fully agree on an air cooled bike except my Cushman [It has fins on the flywheel like a lawnmower engine to blow air past the cooling fins]

[PKarl]

Well i dont have a cooling issue and the problem is less above 2500 rpm ..all plugs are firing i have good compression the plugs are white like its lean..now have regular ngk plugs in it for shits n giggles i changed out number 4 plug with a iridium plug i had and now it is now brown why i dont know the other thing i noticed while bike wasnt running with ignition on the white wire going to the 10 block connector was hot, i took connector apart and found the white with black stripe wire was burned at the connector the white wire looks ok so now im getting another fuse box off ebay and 4 ne to get w iridium plugs..the other thing i did was take the pilot screw out and put carb cleaner up in the hole and tried to get air up through to blow it out i run it with the screw out and theres vaccum there so its not plugged

[ekap1200]

Well i dont have a cooling issue and the problem is less above 2500 rpm ..all plugs are firing i have good compression the plugs are white like its lean..now have regular ngk plugs in it for shits n giggles i changed out number 4 plug with a iridium plug i had and now it is now brown why i dont know the other thing i noticed while bike wasnt running with ignition on the white wire going to the 10 block connector was hot, i took connector apart and found the white with black stripe wire was burned at the connector the white wire looks ok so now im getting another fuse box off ebay and 4 ne to get w iridium plugs..the other thing i did was take the pilot screw out and put carb cleaner up in the hole and tried to get air up through to blow it out i run it with the screw out and theres vaccum there so its not plugged

[/quote ]
Question, did you notice the o-rings and backup washer on the pilot screws. How is the clean air sys ? all the boots look good all the way around and had been that way before you bought it. Well with all four plugs white , she aint running rich. Any pictures , we like pics.

[PKarl]

The backup washer was on the screws but no oring hard to tell if its up inside the carb

[PKarl]

I will check boots like said been fighting this issue for awhile so i had the air filter box out last year pretty sure got all boots on right its the stock air filter not kn

[PKarl]

Ok so update time. Put new plugs in checked sync again its still perfect rode today about 60 miles above 2250 rpm its smooth as can be. Below that its kinda jerky. While riding id come to stop had to turn idle down 3 separate times. Ordered new carb kits going to try put new pilot screws in with o rings see if that does anything. Any other suggestions ? Its about to get sold if can’t figure this out. Now i have oil leak at water pump to