QuestionI rebuilt a Honda SL 350 K1 including the carbs. It runs good under throttle but won't idle. The fuel petcock is new, I checked the valve clearance and timing. When I try to adjust the carbs the idle adjust screw on the right carb does nothing no matter which way or how far you turn it. (This is with the bike running on just the right cylinder) I have taken the carb off twice and soaked it and blown compressed air through it with no improvement. A local bike mechanic suggested "drilling a hole" somewhere in the carb but I have no idea where to drill as this is beyond my expertise. He said if drilling does not work I may need to replace the carb. Any suggestions? Also, IF I do have to replace the entire carb any idea where to find one? No luck on ebay, just rebuild kits which I already have done. Thanks.
AnswerBill, if you have these carbs:
http://www.cmsnl.com/honda-sl350-motosport-350-k1-us_model733/partslist/E++18.ht...
They are pretty straightforward to repair and tune.
Recheck your basics first.... you mentioned doing the valves... what is the compression readings for the cylinders? Should be close to 175psi on both sides.
If compression is good, check your ignition timing carefully and make sure that you don't have the points closed down below .014" on each side. If you have the points too far closed, they will both be closed momentarily at the same time and draw down the voltage for the other coil, causing a misfire. Make sure that the spark advancer is not hanging up during advance/retard phases.
Carb settings are: 25mm float level, #40 idle jet and #120 main jet. Needle clip goes on #4 notch from the top and the idle mixture screw gets 1 turn out. Check your floats to see if they are starting to sink (pinholes make them less able to float normally).
Be sure that the cross drilled holes in the idle jet and main jet holders are all clear and clean.
The main jet and idle jet air passageways in the carb throats need to be clear, as well.
Spray some WD40 or carb cleaner around the intake manifold on the affected side. The carb insulator spigot mounts can split open at the base of the metal and rubber connection.
I tend to shy away from many of the KEYSTER carb products as they are often not made to OEM calibration specs.
As it only affects one side, I guess you didn't reverse the carb slides which often happens.
The K1-K2 carbs look the same, but have different calibrations, so make sure your carbs match any replacements if you find some.
I have a ton of PDF files for 350s available on CD, if you need them.
Final word: DO NOT DRILL HOLES in your carbs.
Bill Silver
www.vintagehonda.com
