Go more on the screws or needles?

[Guest]

Sorry fellas. I'm back with more silliness.

OK. The bike runs strong, smooth, and creamy, Buuuut.....................

After a 10 minuit ride down the highway at 75-80 MPH, (6500-7000rpm), the bike seems to idle like it's ritch or loaded up at the stop at the end of the ramp. It responds to slight throttle, (taking off from a stop), as if were loaded up, but once I get going, (get my feet on the pegs), it runs fine and the idle gets a little nicer with every stop, but still not quite right. I't won't stall, but it idles kind of "chuggy", not "purry".

It won't do this if I ride on secondary roads where I'm only going like 40-50 MPH, (4000-5000 rpm), at these speeds it idles nice and "purry" at stops and responds to slight throttle nicely. Only after I get her turning, (reving), a bit does it act less than perfect.

The factory settings on the low screws are in the neighborhood of 2.5-2.75 turns out. I currently have mine at 4.25 and the plugs are ok but a little leaner than I'd like. Not bad by any means, just a touch lean. Light grey to white centers and ground strap with a charcoal outer ring,(complete turn for you technical guys). These are not plug chop readings, they are simply overall, check em' after a ride readings so there is low and high color mixing, idle washing, etc.

My question is should I shim my unadjustable needles and close the screws a bit or just keep turning the screws? I'm approaching double the factory settings, hence my concern.

To head off the guys who will ask about the valves etc, Valves are adjusted, carbs are synched, Dyna 3 ohm greenie coils, coil relay mod, new stator and E-Sport r/r, stock airbox & filter, stock exhaust with the exception of the centers knocked out.

I appologize in advance for my known babbling and thanks in advance for the help.

Don

[Dave8338]

I would shim the needles, were it me. Where you are at with the mixture screws, you are maxed out. The next thing your going to find is a missing screw as it vibrated out during your ride. My .02

Paper or foam filter?

[Steve]

Sorry fellas. ... These are not plug chop readings, they are simply overall, check em' after a ride readings so there is low and high color mixing, idle washing, etc.

There is not really any "mixing" going on there. Whatever color was on there from the main circuit or the needle circuit while riding down the road was replaced by the pilot circuit when you started idling through town up to your parking spot.

You really need to do proper plug chops to see how the different circuits are doing.

You seem to be rather meticulous about everything else, why skimp on this?

.

[don]

Thanks fellas.

I know proper chops are required for correct settings, and I know my 2-barrel carbs are a little different than the usual ones, but they all do the same thing. I was just hoping someone had experienced the same kind of thing and could simply say ... oh yes, shim ... or ... just keep turning the screws.

I kind of had a notion I was putting myself in this position because I had the bike running nice, the way I wanted it, and then I had to go punch the pipes out, get the greenies in, and put the coil relay in. I'm sure I'm approaching the limits of the stock jets with a little more exhaust going out and a little more fire in the hole.

Guess I'll have to find a nice stretch of road to do some chops. I just hate to set the tank on the pavement or the dirt to get the plugs out. Oh well.....whine, whine, whine...........

[Nessism]

If the bike seems rich at low speed I'd turn in the screws a turn or so and try again. Shimming the needles works if the bike feels like its running out of gas (lean) but I wouldn't bother for the condition mentioned. You can't judge the idle circuit by looking at the plugs so I'd disregard that.

[don]

Besides the look of the plugs, another reason I've kept turning the screws out is this anannoying, slight, teeny, weeny, little, itty, bitty, hessitation with miniscule throttle increase. Like when you just barely turn the handle to keep your speed up going up a slight grade. I'm talking about flexing your hand kind of throttle increase, not actually turning the handle. If I simply turn the handle to increase my speed, all is well in the world. Turning the screws out helpped this, but I'm way out on them now. My thinking is if I turn them in a little and pick the needles up a bit I'll get enough fuel in there without having the screws so far out, with the added bonus of getting a little color on the plugs. (fuel=a little cooler air cooled engine in hot weather).

As mentioned, I think I'll just have to do some chops to see what's going on.

Ness,
The loaded up condition only happens after a run at higher revs. By the look of the plugs, I think I may be lean at higher throttle positions and getting a little warm, hence the ritch condition at the reduced revs.

If I run it at less than highway revs, everything is good. I can go for hours.

[Nessism]

Classic signs of a rich idle mixture is a low chugging idle after the bike is fully up to temperature. Leaning the mixture screws should help this condition. If the bike hesitates at speed that's a different matter, most likely lifting the needle a smig will take care of that.

[don]

I guess I've said the exact same thing in my inherently long winded way.

What you have just said is exactly what I think is going on. Just wasn't 100% on how to prove or disprove it so I can fix it.

I think at lower rpms the ritch idle is an ok bandaid, but once I get her going for a bit, the slightly lean condition is heating the engine up a little and causing the idle mixture to be too ritch for that temp. If I raise the needles, that would ritchen the higher rpms a little and keep the engine cooler at whitch point I may be able to lean out the low section a smidge.

That's my thought. Agree.....dissagree.....?

[Dave8338]

Please revert to post suggestion #1

OR you can continue on and see what happens

Been there...done that...on machines that produces in excess of 800HP

Yeah...I'm speaking out of my arse...

And please...let us know what you find...

Paper OR foam filter?

[don]

Factory paper filter.

It's raining here today so it's a perfect time to do the shimmy shuffle. I won't be able to ride it to get the screws backed down proper. I'm thinking 1/4 - 1/2 turn in, (lean), to start.

The washers I found ammount to a .020" change in needle length. If I use one less washer, that changes to .040-.050. Not sure how mutch is a little or enough. Lack of experience with these. I know what 1/4 turn on the screws does, but I don't know what .020 or .100 will do on the needles.

An experienced suggestion will be humblly recieved............

[tkent02]

Somehow something isn't right, apparently you have a stock intake and exhaust, stock engine, so the original carburetor setup should be very close. Raise the needle a tad maybe, tweak the mixture screws 1/2 turn or so should do it. You have something else somewhere causing a problem. Float levels, clogged passages, something.

But go with very small increments of change on the needle, it doesn't take much. It's easy to get in a second time and go a little more if needed. Once you go too far it may be harder to figure out what to do next.

[don]

Here are some plug pix. The darker one is before the relay coil mod and me knocking out the centers of the exhaust pipes. The other 2 are where I'm at now.

And again, not plug chop, I just took them out after a ride for a look see

http://i510.photobucket.com/albums/s350/donmod/DSC00079.jpg

http://i510.photobucket.com/albums/s350/donmod/DSC00130.jpg

http://i510.photobucket.com/albums/s350/donmod/DSC00128.jpg

[don]

PS

The dark spot on the base of the strap on #1 was a blob of anti-sieze when I bumped the plug against the hole putting it in.

[posplayr]

I guess I've said the exact same thing in my inherently long winded way.

What you have just said is exactly what I think is going on. Just wasn't 100% on how to prove or disprove it so I can fix it.

I think at lower rpms the ritch idle is an ok bandaid, but once I get her going for a bit, the slightly lean condition is heating the engine up a little and causing the idle mixture to be too ritch for that temp. If I raise the needles, that would ritchen the higher rpms a little and keep the engine cooler at whitch point I may be able to lean out the low section a smidge.

That's my thought. Agree.....dissagree.....?

You would normally raise the needle as they came lean from the factory.

how much you reco Ed?

If that works driving around then set the idle mixture screws for best idle speed and be done.

The coil mod and green coils should not effect the jetting unless you want to chase your tail because of poor ignition

[don]

OK. Just got done doing the needles. The factory shim measured at exactly .100". The washers I put in are .020" each so I put 4 in = .080" = a change of .020". ( Just to be sure, I measured a stack of 4 and they do indeed measure .080"). I also turned all of the screws in,(lean), 1/4 turn.

I started it up and it did so like it did before. Choke to get it started, then just use the throttle without the choke and keep it around 1500 - 2000 rpm for about 20 sec, then let it idle untill the idle comes up to 1000 rpm. Just came inside for a quick snack. I'm going to fire it up in the shed, (raining), let it warm up a bit and adjust the screws for best idle. Won't be able to ride till the rain stops.

TKENT02,

Ican't be 100% sure, but I'm pretty sure all is well with everything/else. I believe knocking out the centers of the stock pipes has had the biggest effect on why it seems to want more fuel. By doing so I have taken out the diversion/restriction toward the silencing material/perferated exhaust holes and replaced that diversion/obstruction with a clear .875" or so avenue for the exhaust to flow through freely in each side.

Basicly I've added whatever cfm at exhaust pressure will flow through a .875" orafice to each side of the exhaust system.

Even though the intake has not been modified, due to the stock pipes being so restrictive, the reduction in " back preassure" has increased the scavenging effect of the exhaust which in turn will also increase the vacuum at the intake through the ovelap in the cam when both valves are open at the same time.

Just my thought.

Man I get ramblly and technical and overthinking and overcomplicated and....... "this one time at band camp".............