Kiss my Keyster (carb kit needles)

[Hotshoe]

They look a touch lean to me as well. Are you doing throttle chop readings, or just a generic reading?

What I usually do for a street bike is sort of a combination Davo - on cleaned plugs, I do about a 30 min ride moving through the entire RPM range then make a full power run through the gears and letting it rev up before shutting off and coasting home.
Do you think the chop technique gives a better overall reading or is it more for a top end snap-shot?

I read plugs a little different Steve;
- the circular base of the threaded body shows low speed (<1/4 throttle)
- the ground arm (strap) and electrode tip show top end (>3/4 throttle)
- the electrode insulator shows overall burn in the combustion chamber
Not saying that's necessarily correct, it's just the way I've always done it.

Anyone out there have a pair of 145 main jets they'd like to sell?

Thanks, Chuck

[davomoto]

It's basicall whatever throttle opening you hold for 15-20 seconds, pull in the clutch, and kill the engine. It can be done at idle, 1/4, 1/2, 3/4 and wfo.

Davo

[e3steve]

I read plugs a little different Steve;
- the circular base of the threaded body shows low speed (<1/4 throttle)
- the ground arm (strap) and electrode tip show top end (>3/4 throttle)
- the electrode insulator shows overall burn in the combustion chamber
Not saying that's necessarily correct, it's just the way I've always done it.......

Chuck, that's an interesting method of 'plug diagnosis'. When the ol' girl is up & running I'll give that a go with a new pair of plugs (I have an abundance of D8HAs & D8HSs due to a purchasing oversight!).

But, I have to say, I've never seen the plug body anything other than considerably darker than the electrodes -- Bosch surface-discharge plugs notwithstanding. The logical part of my grey matter tells me that it's because of the mass difference, whereby the body doesn't reach the temp of the electrodes and insulator and, therefore, takes no part in the creating of the spark or combustion process.

[Hotshoe]

Thanks Davo, I've never heard of using the chop method for anything but WFO... that opens up a whole new carb tuning technique for me.

The heat sink effect on the plug body makes sense as far as why it's darker Steve. For general plug reading, I've always thought that an excessively sooty base ring indicated a rich low end that can be adjusted somewhat with the carb air screw.

[56_oval]

It's basicall whatever throttle opening you hold for 15-20 seconds, pull in the clutch, and kill the engine. It can be done at idle, 1/4, 1/2, 3/4 and wfo.

Davo

I've always done something similar. But I was taught to actually kill the engine with the clutch (stall it) to get a good reading. I don't know if that's necessary, it's just what I was taught.

[clarenceada]

By that I mean tuning by ear.

I've never had much luck reading carbs; might as well be a pot of tea for all the good, looking at a bunch of smudge marks on the end of a plug does me.

But now you give me 15 min. alone with the patient, and couple of large screw drivers and a dowel and as long as she runs good enough to idle and rev up; I get a lot more on the condition of the engine from just listening to it (sort of like a raising a kid).

Now most of what I've learned over the years has been on single cylinder engines, be they Honda, Kaw or other Japanese bikes, plus garden tractors, etc. The Twin cylinder is a little harder to pick up on things like piston slap, and broken rings, cause of the cylinders making "twin" noises but it can be done; single's are just a little easier.

For listening to gear and chain noises, need a quiet muffler or attache long plastic drain hoses from an rv with tin foil inbetween them, get her to idle and just listen at different places on the engine and picture in your mind what is on the other side of the casing. (may help to have an open spare engine next to it so you can see what is going on inside; or maybe an open repair manuel) and what kind of sound you should be getting if everything is OK.

For the top end, idling and then excellerating, listening for the spit of a bad intake valve or the bark or a burnt exhaust valve. Then if you can run the bike all the usual "tuning" noises can be heard, from hick-up when too lean, to flatness when too rich.

Of course you see the problem; people hear (and feel) differently, so it's not something you can teach to people. It's sort of like music---you can either hold a tune or you can't--- My dad had the technique; I remember him standing beside his over-the-road truck diesel engine and say " I think the 3rd main bearing is getting ready to go" and not believing he knew what he was talking about---forgot about it till he tore it done about a month later and sure enough the bearing was about to go.

On Saturday morning at 11:00 on PBS radio locally there is a program that a lot of you have probably heard called "Car talk" with click and clack the motcerali brothers who every other show they have people that call up and ask mechanical questions about noises coming from there car. So they have these women trying to make mechanical noises and it's very comical if not helpful.

Am I not seeing oil on the rings of the plugs, could that possibly be whats getting on the porcelain?



Clarence

[e3steve]

Hey Clarence, this image might be of help: