Chaharly Posted March 11, 2015 #1 Posted March 11, 2015 Well I got my girl running on all four yesterday, but It still has an intermitten misfire when not totally warmed up. I know they set the pilot screw really really lean from the factory, and I know mine have never been adjusted. What size drill bit do I use and exactly how can you tell when you've bottomed out into the pilot screw?
Venturous Randy Posted March 11, 2015 #2 Posted March 11, 2015 You need a small sheet metal screw and pick the drill bit in regard to that. When you drill thru the cap, DO NOT drill into the brass screw. Just be very careful when it breaks thru. There is plenty of room, just be careful and don't keep pushing. Randy
MiCarl Posted March 11, 2015 #3 Posted March 11, 2015 I like to use a sharp bit in a variable speed drill, at low speed (not much faster than you can turn a screwdriver by hand), just enough pressure so the bit is cutting continuous strips of material. As the bit punches through the back of the cap it grabs and the drill will stall. Then I back the drill out. Once the bit starts cutting you'll need very little pressure to cut like I described.
Chaharly Posted March 12, 2015 Author #4 Posted March 12, 2015 Ok that sounds simple enough. I thought the brass cap was right against the screw, but knowing that there is a gap between them totally takes my worry away. I drill for a living through light duty aluminum and the like so I'm fairly confident I wont mess it up too bad!!!
MiCarl Posted March 12, 2015 #5 Posted March 12, 2015 Ok that sounds simple enough. I thought the brass cap was right against the screw, but knowing that there is a gap between them totally takes my worry away. I drill for a living through light duty aluminum and the like so I'm fairly confident I wont mess it up too bad!!! If you can drill thin aluminum without slamming the chuck into the work this should be no problem for you.
Chaharly Posted March 12, 2015 Author #6 Posted March 12, 2015 If you can drill thin aluminum without slamming the chuck into the work this should be no problem for you. Of course I have been on disability for over a month so I could be a little rusty
Marcarl Posted March 12, 2015 #7 Posted March 12, 2015 Once you get the caps off you might find a screw or 2 to be 'frozen', so be careful in turning them. If you strip the head off of one, then the real fun begins,,,,,, don't ask me how I know, but it can be fixed.
Chaharly Posted March 12, 2015 Author #8 Posted March 12, 2015 Once you get the caps off you might find a screw or 2 to be 'frozen', so be careful in turning them. If you strip the head off of one, then the real fun begins,,,,,, don't ask me how I know, but it can be fixed. Would a shot of PB blaster hurt doo you think?
MiCarl Posted March 12, 2015 #9 Posted March 12, 2015 Penetrating oil will not hurt. Make sure your screwdriver is a very good fit! Every screwdriver I've seen with a blade the proper thickness is way too wide for the hole. I've got a couple that I've re-ground just for working on sticky pilot screws and jets.
Condor Posted March 13, 2015 #10 Posted March 13, 2015 One of our old time members Fred Vogt made a tool for adjusting the idle screws that was really neat. He took a flat 1/4"x 1 1/4"x 3/16"ID knurled washer/disc and tapped the hole to 1/4x20. Then took one of those no shoulder screw drivers with the shaft being close to the diameter of the idle screw opening, and cut the tip about 2" long and threaded that. Put them together with a little loc-tight, and it made a dandy idle screw adjustment tool. He even marked the face of the disc in order to keep track of the turns....
Prairiehammer Posted March 13, 2015 #11 Posted March 13, 2015 I made a pilot screw tool as well. Mine allows me to make pilot screw adjustments even when the fairing lowers are in place.
Chaharly Posted March 13, 2015 Author #12 Posted March 13, 2015 I made a pilot screw tool as well. Mine allows me to make pilot screw adjustments even when the fairing lowers are in place.[ATTACH=CONFIG]98056[/ATTACH] Too Cool! Thanks for the diagram I think I'm going to make those myself!!!!
MiCarl Posted March 13, 2015 #13 Posted March 13, 2015 The nice thing about that tool is so long as you don't turn it with a wrench you probably can't get enough torque to damage the screw. To avoid temptation you might grind the head round.
venturesome Posted March 13, 2015 #14 Posted March 13, 2015 I have a spare set of carbs that have pilot screws with damaged heads. Is there a good way to remove them without damaging the carb body?
MiCarl Posted March 13, 2015 #15 Posted March 13, 2015 I have a spare set of carbs that have pilot screws with damaged heads. Is there a good way to remove them without damaging the carb body? If they're not actually stuck and there is any of the slot left a proper fitting tool will probably get them. I have been known to use a Dremmel to cut a new slot, which is not fun. Another thing you can try is a very sharp left hand drill bit, at slow speed with lots of pressure so it cuts a big chip - you want it to grab rather than drill. DO NOT TRY TO BREAK IT LOOSE WITH A STANDARD BIT, IF YOU SPIN IT DOWN AND JAM THE NEEDLE YOU'RE DONE! A smaller pilot hole will help it grab. A good healthy soak of penetrating oil before you start won't hurt any either. I have not heard of anyone having success with screw extractors. Some heat can help stuck screws. You need to completely disassemble the carb to keep from damaging other parts. That includes removing the butterfly shaft and the seals on it, which are not meant to be disassembled. I have heated without pulling the butterfly shaft but you need to get a lot of heat on the screw hole fast, break it free, then quench the thing before the shaft seals melt.
Chaharly Posted March 14, 2015 Author #16 Posted March 14, 2015 Got it done guys! Really easy and the bike runs great! Got the back right one slightly stripped but that cylinder was running fine so I wont worry about it until later. Thanks for the great tips guys!!!
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