My dad picked this bike up for me so I can do some riding when I go home on leave (I'm stationed overseas). Only 5000 original miles on the clock. He's told me that it doesn't like to idle steadily though. What can be done to fix that?
First of all check if tachometer reading is true. I've seen K3's (yours is a K4 by the way) that read 1700 rpm when in fact it was 1200 rpm. Everytime I tried to bring the idle down to 1100 rpm, the engine protested (ofcourse). Then by using a true external tachometer I found out the ND tachometer was wrong. That's one.
Check in the pitchdark if sparks jump over from the plugleads and -caps to the head. This is often overlooked (and people think the carbs are the problem), but sparkjumping occurs often. That's two. Checking the sparkplugs is not a bad thing either or replace them. They're cheap.
Step 3. Check for airleaks between carbs and engine. Spray brakecleaner or WD-40 and see if rpm changes. If so, you've found a leak. O-rings between head and inletmanifold are suspect, because of age.
Step 4. Bryan's method to adjust camchain tensioner is best. See FAQ. Do it and maybe do it again.
The type of carbs [PD] you have, are known to be sensitive to partially blocked idle jets. Elsewhere in this forum you can learn what to do with them.
The 4 venttubes that run from the carbs to somewhere in front of the rearwheel are known to give problems sometimes on he K3 (and I suppose K4 models as they're practical identical). In heavy rain they sometimes siphon water into the carbs. Don't ask me how they manage, but they do. Just cut one or two inches and check that the tubes vent freely.
Close the petcock and drain all 4 float chambers.
Add some stuff like Seafoam when you fill up your tank and take your bike for a ride and when I say ride, I mean ride. First 20 minutes you give the engine time to warm up nicely and then you give it the spurs.
If the bike did only 5000 miles I see no reason to suspect float levels. No need to sync the carbs either.
