new build 1075 w/29 smoothbores - idling questions

I've had issues with VM29's not coming down off idle with the air screws set around 1/4 turn out. Usually I would just go up one size on pilot and get a better idle at around 1 1/4 turns out.

Jeff.Saunders wrote:

I've had issues with VM29's not coming down off idle with the air screws set around 1/4 turn out. Usually I would just go up one size on pilot and get a better idle at around 1 1/4 turns out.

Never ran into that myself..... anything's possible I think location has a lot to do with it. I jetted a bike here that ran just fine but when it went up to your area it was lean.... Must be all that good air coming off the lake :laugh:

air quality may be part of it. I've noticed the hanging idle issue more on hot days when the bike had been running for a good while.

The particular bike I had issues with was a 30,000 mile 77 kz1000a - stock engine, but 4-1 pipe and K&N pod filters. Running 120 mains, 17.5 pilots with the air screw about 1/4 turn out would work when the bike was freshly started. But after a ride it just would not come down. I swapped the pilot jets to 20's and backed the air screw out to around 1 1/4 and the bike idled fine.

Larry - one thing I've never really understood about the air screws on the 29's is the hole drilled through the screw from side to side feeding the hole in the tip. When you set the air screws all the same, then look down the air passageway some of the holes are inline with the gallery, some are not. Intuitively this seems wrong. Have you ever experimented with air flow through that circuit on the carbs - and messed with alignment of the air screw?

Took the air screws down to a 1/4 turn out, played with the idle screw, but things are still running a little high. I still have to find the time to check the float levels and try the timing again. I will let you know how things come out.

I have a 1075 with 29s also, like the other guys said your jetting is in the ball park. I ended up with 22.5 pilots, it wouldn't run smoothly off throttle with smaller pilots, but it idled fine with 17.5 or 20 pilots.

I would the check the mechanical linkages too.

Make sure the throttle pull cable moves freely and is not set too tight - also make sure it does not pull the slides open slightly when the wheel is at full lock.

Look inside the bore and make sure that the slides close all the way when you back off the idle screw. If the carbs have been synched with the slides too high up in the bores they may not drop down far enough to get the idle where you want it.

Thanks Dutchz, The high is now in the low 30's here in Ohio so it makes working on things a little harder. I may up to 22.5 like you say and see how things run.

PS - love your bike, it is a classic look and you have done a great job on the build.
jim

Thanks Jim! Let us know what you find... after you defrost :laugh:

lewisj, it's nice to know there are other Kaw enthusiasts in central Ohio. I live in Plain City. There's a pretty good wrench named Bruce Sauer in Reynoldsburg if you get stuck. He's a pretty good guy. You're right, these Ohio winters suck. Time to work on your projects to pass the time.

lewisj wrote:

Thanks Dutchz, The high is now in the low 30's here in Ohio so it makes working on things a little harder. I may up to 22.5 like you say and see how things run.

PS - love your bike, it is a classic look and you have done a great job on the build.
jim

If it's 30deg outside and the bike is the same temp, it's not going to work right. It will run real shitty. It's way too lean. Should do what jeff did and tune it in a warm garage. That air temp will mess with you to the point of no return. Just went through this in the last couple of weeks when the weather got cold. I'll bet I was the only one in Fargo that was riding a motorcyle with the snow falling and below zero temp. Cuz I got NADS. And one very small brain to go with it. Just make sure you didn't or someone else didnt adjust the slides so they don't come down. It should not quit when you move the timing plate, something weird there.

Gman,You have a great wrench in your backyard. John Walton, in Plain City was named the Drag Bike Mechanic of the Year in 1994. He built my bottom end, welded crank, backcut tranny and degreed my cams. Very nice guy and reasonable. Let me know if you need his number.
Jim

Nads, Looks like it's time to turn on the heater. Thanks for the insight!