any room at the inn?

[Devon Jarvis]

I changed the spark plug cap yesterday with a known good one. No change. Here's the annoying "thing"- the bike starts perfectly well with choke, rain or dry. It idles fine, runs very strong in the midrange and top end. In every way it's excellent, except: On the overrun, once the revs fall to what sounds like 2500 or so I get persistent, flatulent popping out of the exhaust. If a full-on backfire sounds like a shotgun blast, this is more like a loud fart. At or about 1/8 throttle, if I open it slowly from low revs, there is a spot where the bike stops accelerating for a moment. This is NOT affected by the pilot mixture screw, and the bike seems to run a bit hot at low speeds. I don't have a temp gauge presently but the fan runs in slow-moving traffic at maybe 75% of the time. There are a few ports under the butterfly valve, meant to transition from the idle circuit to the main circuit. It almost seems like these are clogged, but I can't imagine blowing them out any more thoroughly. I removed the jets and emulsion tube and soaked them separately. I hosed off the carb with water, then blew it out with 100psi compressed air. I held the emulsion tube up to the light, all the holes were clear. If I swap carbs with Tumu, in the process I'm going to poke 40 or 50lb test monofilament fishing line through all the ports and see what I come up with. Devon A15

> > Last time I did carby work I gummed the works with a temporary > diagraphm repair using RTV. Hey guess what, that didn't work. When > I was cleaning the carb I pulled the main jet and the atomizer stem > that sat behind it. With the jet clean I noticed the small outlet > holes on the atomizer residually plugged. This after plenty of > spraying with carb cleaner. Was impressed by how much came out. > Have to assume yours would have cleaned with the soaking, and > wouldn't think such a blockage would lead to backfiring, but I'll > throw it into the mix. Also had poor starting on mine and had it > improve when I trimmed half an inch off the spark plug wire and > reinserted it into the cap. Much better spark afterward. > Good luck, > Todd

-- "It's a troublesome world, all the people who are in it, are troubled with troubles almost every minute" Dr. Seuss

[planetequipment]

--- In DSN_klr650@yahoogroups.com, Devon Jarvis wrote:

> I changed the spark plug cap yesterday with a known good > one. No change.

snip/snip

> At or about 1/8 throttle, if I open it slowly from low revs, > there is a spot where the bike stops accelerating for a > moment. This is NOT affected by the pilot mixture screw, and > the bike seems to run a bit hot at low speeds. I don't have > a temp gauge presently but the fan runs in slow-moving > traffic at maybe 75% of the time.

snip/snip Devon: If you have exhausted all other possibilities, you might consider looking for things like worn throttle shaft bushings, intake boot leaks, and leaks at the flange where it attaches to the head. Those kinds of an air leaks can give you a lean condition at minimum throttle openings/low rpms where vacuum is high. It would be hard to notice at higher rpms. Ron

[Murray Dochstader]

Looking to Share Accommodations In preparation for my trip to the CMC, I called Canyonlands Campground to see if they had any cabins available. While they had tent sites left, the cabins were all booked. Has anyone booked a cabin that has a spare bed, and would they be willing to share it with a fellow KLR'er? If you do , please contact me off-list. dochstader@... Thanks, Murray Dochstader B.C. Canada. [Non-text portions of this message have been removed]

[Ted Palmer]

Devon Jarvis wrote: [...]

> I removed the jets and emulsion tube and soaked them > separately. I hosed off the carb with water, then blew it > out with 100psi compressed air. I held the emulsion tube up > to the light, all the holes were clear.

[...] How is the slow air jet? Mister_T Melbourne Australia

[Devon Jarvis]

> How is the slow air jet? > > Mister_T > Melbourne Australia

I blew out both air jets, and the tiny little pressed-in jet at the bottom of the main jet "tower" that feeds the starting enrichener system. They looked OK, but they're pretty damn small and that's a good place to look. On a lighter note, I turned out the idle mix screw to 2 1/4 turns, and the bike ran fine all the way to work. No unusual heating up in traffic, no hesitation, and only the absolutely slightest popping on the overrun, which only I can hear since I'm hyper-sensitive to it by now. The really odd thing, is I had the carb set to 2 1/2 turns last week when I was diagnosing this and it totally didn't help. On Friday night, with 2 gallons in the tank, I dumped 1/2 a bottle of Techron into the tank (triple strength) and then drove around for 15 minutes. Then I parked the bike for two days. Sunday night I drove it a few miles to fill up, no improvement. Monday and Tuesday I drive to work, no significant improvement. Today I turn out the pilot mix screw to a setting LEANER than I tried last week, and everything's fine. WTF? Devon A15 -- "It's a troublesome world, all the people who are in it, are troubled with troubles almost every minute" Dr. Seuss