I found out that there's about six pages in one of the Easyrider Tech Tips regarding the Keihen butterfly carb. Can anyone tell me which of the tech tips books it is?

Dave Young

 

I don't have that issue handy, but the standard back in the day was to install the Andrews accel pump kit with the check ball (deleted in later Keihins), drill the low speed jet up one wire drill size (slip fit one bit, use next to drill, hold drill bit in vise-grip and spin jet between thumb and forefinger). remove the idle mixture adjusting screw plug (drill JUST through the plug then remove plug with a wood screw), and install an air cleaner that breathed decently. An Allen head float bowl screw kit is worth installing, since common screws are wretched by comparison. I did the above to several big twins and (Iron and Evo) Sportsters with good results. They start easier/run cooler/make more power. The other thing we did was to replace the Keihins with S&S carbs, often giving the Keihins to iron Sporty owners unfortunate enough to be afflicted with the Bendix. The Bendix would be stripped for parts or just thrown away. If I still had any Keihins or Bendixes, I'd sell 'em and grab an S&S shorty.

 

Thank you for the advice. I have already increased the size of the pilot jet, drilled out the plug above the a/f mixture screw and installed allen screws in the float bowl. I've also made an extended idle adjustment screw to make adjusting the idle easier, especially on the road.

I've been looking at the Andrews accelerator pump kit, but was concerned about flooding the carb (something I'd do trying to get the bike to start when before I rejetted and set the a/f mixture.). So that pump kit really is the way to go, huh?

Unfortunately a new carb isn't in the budget right now.

Dave

 

The pump kit really helps, and there is no flood risk. Observe the squirt volume before and after the mod. The check ball was deleted for emissions reasons only. Harley wisely kept their basic design and then strangled it for emissions compliance WITH EASILY REPLACEABLE PARTS that their clueful biker customers would alter or swap out. It was and is a boon to the aftermarket industry! The Keihin works just fine and is a reliable carb. If the Keihin were as large as an S&S I'd have left it in place. I don't bother with complex fuel management solutions because I prefer my bikes crude, simple, and easy to service in the field. If I wanted to go racing I'd buy a crotch rocket... Another mod is to observe the direction of the accelerator pump squirt (remove air cleaner, do this without the engine running) and then adjust the (remove the float bowl, squirter is a press fit, just turn it with a small ignition or adjustable wrench so you can observe the hole) accel pump squirter so it shoots dead center so as to serve both cylinders equally. I used K&N filters because it avoids hunting down replacement elements. Uni sock filters weren't durable (this may have changed over the years but I don't care to experiment since air filters are also flame arrestors during backfires!) so I didn't use them. Don't forget to ensure the float is adjusted correctly. If in any doubt about the needle seating I just pull the bowl, turn on the gas with the float held up, and lower the float until fuel flows. Usual fire precautions when playing around petrol apply, yadda yadda.

 

A guy from another forum sent me six pages that he had scanned from old Easyrider magazines (I thought it was from their Tech Tips book) earlier today. They echo exactly what you mention (setting the float bowl height, which I already did and aiming the flow from the accelerator pump which I'll do when the pump kit comes in). I ordered the Andrews accelerator pump kit from J&P this morning along with a better flowing air filter. The Easyrider article mentions using an the earlier model pump (pre-EPA, I guess mid-1970's?) pump housing and gave a part number (HD #27364-76 with costs $8.40 from Chicago HD ) which sounds to be the same as the Andrews pump kit (but I had already ordered one from J&P).

I'm getting more and more comfortable working on this carb. I came up with a flexible handled screwdriver to make adjusting the a/f mixture relatively easy, and the extended idle adjuster makes life much easier.




monckywrench, I want to thank you for taking the time to help me with this....

Dave

 

You are welcome. I like the adjusting screw! The HD part is obsolete, hence the Andrews folks taking over to supply it. Tech Tips are full of interesting biker history culled from Easyriders monthly tips, but do ask on this board when applying any but very obvious ones as they are also quite old. Last Keihin tip: If the fuel hose hardens on the plastic hose barb on the float bowl, gently cut it off with a sharp knife lest you bust off the hose barb by pulling on the hose.