jetting question

The bike is a 82 wr430. mikuni carb. Elevation is about 1100 ft. I was tuning the low speed jet and If I turn the air screw in all the way there is no change in the engine rpm. I have to turn the screw out about 2 turns to hear any rpm change. It has a 50 pilot jet. Would the jetting be too lean or rich?

hows the starting??? remember on an air screw out adds air= leaner

too rich...IF you are having problems..50 is pretty damn big as these bikes are usually too rich down low stock.

What condition is the carb slide, if rpm starts rising at 2 and continues past 3 then your too rich on the pilot but you need the engine warm for a true reading.if the slide is worn it lets air past and gives a false reading making the mixture leaner than normal.

The slide looks good. The bike starts good too. I was just adjusting the air screw and the idle would go down after around 2 turns out. It wouldn't change going all the way in. The plug looked pretty clean too.

Sounds lean then, interesting way to test jetting on smellofdeath site by removing the main.try new pilot at 52+ might be partially blocked pilot.could not get my mikuni vm jetted correctly due to condition.binned mikuni which was at 60 pilot and still lean new keihin is now 40.if you have a spare bowl drain plug drill it and put in a clear hose as an easy way to check float level and empty bowl when changing jets.

I run a 45 at sea level, I would guess a 50 at 1100ft is too rich, try a 45.

Try a 45 pilot but you may have to go to a 40.

I have a hard time hearing the difference in rpm. I just purchased a hand held tach.

I found out I'm losing my hearing. I can't hear what everyone says. I hear online. Lol

I went to a 45 and it runs bad now. I'm going back to the 50. maybe a 55 if I can find one.

50-55 man you gotta have sumpin hinky go'n on that is huge for a pilot jet

Troy, The bike runs pretty good with the 50. With the 45 it bogs just off idle. It has some sort of aftermarket reed valve. No markings on the housing. The housing has a rough finish to it.

air leak???? your reed valve would almost have to be a Mossberger u sure nothings got crud in it i think you hafta have some really thick air like 50 degrees and waay below sea level to really need a pilot that big i bet thats close to as big as they get saw a 500 main jet once .... that was a big hole

It had an air leak from behind the flange with the crank seal behind the mag. It was running real lean from that. I fixed that. Not sure how long is was leaking as I was chasing jetting because of it running lean. The way I found it was the bike ran real bad at a CC I went to. When I got home it wouldn't start and it flooded. Gas ran from the mag cover and i found the loose screws on the flange. I think my main is a 440. I could try a different carb and see what happens.

did you replace the seal or just tighten the screws?

The seal is new. It has a 440 main. The next smaller main I could find locally was a 400. That was too lean. The slide is a 2.0. I have a carb with a 2.5 slide. I've never tried changing slides. What difference would I notice with different slides?

50 is rich for sea level and even richer as you go up in altitude. 45 is stock and its rich with the stock 2.0 slide, if you are lean with a 45 you have some other issue, most likely another air leak.

Leak down test would be my recommendation although it is a lengthy tedious process stripping the bike and making up the kit.

So what is the best way to do a leak down test? I need to block the exhaust and intake? What is a test pressure to use?

6 PSI FOR 20 MINS TRY TO HOLD A VACUUM TO THE LITTLE SO N SO'S CAN BE SNEAKY AND HARD TO FIND

REMEMBER YOUR LIKELY DEALING WITH 33+ YEAR OLD SEALS AND GASKETS MIGHT DO SOME EXPLORATORY SURGERY LOOK FOR NEARLY TOAST BEARING GEARS AND CLUTCH STUFF