Read My Plugs

[DirtyErnie]

New season, new jets, here we go!

Last week, about 40°F, fired up the bike in the driveway and she wasn't happy. Lean racing, difficult to control with the enrichers. First gear couldn't pull it back up the shallow angle of the driveway into the garage. #40 Pilots are definitely lean.

This morning:
Dropped in a set of #45 pilots, set screws to 2 turns. 35°F, started on the second kick, idled well, still a little lean-race on the enrichers, but controlling it was easy by sliding them back about half shut. Smelled a bit gassy, but ran well and easily pulled itself back into the garage. Considering a ride to work in the AM. This is at the cold end of my range, I'm expecting things to be way too rich once normal weather gets here.

Oddly, the BS34s we're around a #45 pilot, too. Wondering if I should up the mains to the same #145 from the 140 that's in there.

 

[TwoManyXS1Bs]

...Last week, about 40°F...

Justa thought.

Your last posts were in the August summertime.
Summer blend fuels have a lower reid vapor pressure, reduces excess fuel evaporation.
Winter blend fuels have a higher reid vapor pressure, helps fuel vaporization in the cold.

If you have Summer blend fuel in your tank, and it's cold out, expect difficult starts, lean running.

Opposite with Winter blend fuel in the Summer, expect rich running.

Do you have last year's Summer blend fuel in your tank?

 

[DirtyErnie]

Stabilzed non-oxygenated 91. Lost about an inch over the winter. Honestly, I don't remember if it was gas station gas from last summer or from my gas can before that.
35° isn't that cold around here I'd worry about it at -35°, and I'm not that worried. It'll burn.

Plus, this will definitely help me find the rich limit and time down from there.

 

[TwoManyXS1Bs]

...35° isn't that cold around here ...

Haha, youze guys are eskimos.

Down here, below 60° is serious "stay inside" weather...

 

[DirtyErnie]

Haha, youze guys are eskimos.

Down here, below 60° is serious "stay inside" weather...

Yeah, I did a week just south of Austin in Buda, TX last summer. You can keep that 110°F stuff to yourselves. hehehe
3 quarts of water before lunch without going to the bathroom is pretty nuts. I'm quite happy putting more clothes and burning something.
Great BBQ down there, though.

 

[gggGary]

Cold is;
20 minutes of dressing to spend 10 minutes outside.
It's spring in Wisconsin; the night snow melts by 2PM

 

[DirtyErnie]

OK! Test ride at 50°F:
Pilot: 45
Main: 140
Needles: JJK

TWO sizes up on pilots, one step fatter on the needles, 2nd lowest/leanest notch.
Starting to see what the hype is all about with this swap. Finally got almost enough fuel right off the throttle, and it's real clean. Fatter needles leaned out the stupid-rich mid-range. Need more main jet, though. WoT Hill climb above 4k, there was a noticible increase in pull by backing off the throttle a bit, so I'd better get more going there. Wasn't shooting ducks, though.

Getting Closer!

 

[xjwmx]

Plugs look ok. Definitely has a chance at winning international speed championship of world's slowest motorcycle.

 

[DirtyErnie]

Plugs look ok. Definitely has a chance at winning international speed championship of world's slowest motorcycle.

No new plug pictures since last August. Might grab some in the near future.

 

[DirtyErnie]

Pix. Much healthier color on the nose. Still too much timing, going to have to crawl for pickup relocation threads. Definitely lean on the top end. Might raise the needles and find their breaking point. I have a set with the same width and a leaner taper on hand.

 

[TwoManyXS1Bs]

I have this 3-tier approach to plugs and tuning.

Coarse
Use the plugs as a rough guide for diagnosing rich/lean.

Medium
Tweak the carbs/timing for best seat-of-the-pants power, response.

Fine
After response and power is solved, adjust plug heat range...

 

[DirtyErnie]

looking at this:
http://www.jetsrus.com/carburetor/carb_keihin_PWK28_carb_exploded_view_parts.html

do the EX500 carbs use the same needle jet, #34

Has this been answered over at the big EX500 conversion thread?

 

[DirtyErnie]

Think I got enough pilot now. #48. Gotta play with the screws and see where they're happy. How many turns out it's the "sweet spot" on these CVKs?

 

[DirtyErnie]

Got some garage time today. There was a free weed-eater that wouldn't run and had inaccessible carb screws. I have a hacksaw, screws are accessible, slotted, and tuned. Free weed eater works. But back to the show:
Took a few tuning rides:
Pilot jets back to #45.
HKK needles on #4 slot, might need to be dropped one.
Still #145 mains.
Slotted the top screw on the ignition pickup and moved it as ''late" as I could, still runs nice. Think it's almost time for a fresh set of plugs to set timing, and then we'll drop the NGK iridiums back in and just ride the damned thing.

 

[5twins]

I think those plugs look very rich, too rich really, with the 48 pilots, unless all that black is from choke starting.

 

[DirtyErnie]

I think those plugs look very rich, too rich really, with the 48 pilots, unless all that black is from choke starting.

No, that was after a ride around the neighborhood. Dropped pilots back to #45 and the ride cleaned up a lot. First start the bike was idling at about 3,000rpm from how far I had to open the idle speed screw to get the #48s to run. Cruises at 60 with maybe 1/8-1/4 throttle. Real nice running.
I'll get more pictures in a bit.

 

[5twins]

Choke starting blackens the plugs up almost immediately and it takes a good ride, maybe 5 to 10 miles at cruising speeds, to burn them clean again.

 

[DirtyErnie]

The check rides were longer than that, with a few good WOT uphills to boot.
Final setting:
Pilot: 45
Main: 145
Needle: HKK 3

I just lowered the needle to the 3rd notch, and will get the idle mix screws sorted out eventually. It runs, I'm happy.

Moving the timing pickup looks like a good thing, the heat Mark on the strap is where it should be now. Can also see that the swirl I ground into the port job is doing things, too.

 

[gggGary]

Is that both plugs? second shot what are the whitish blob type marks on the black base?

 

[DirtyErnie]

Both plugs, yeah. I think the blobs are a trick of the flash and some edges in the carbon chunks.