How lean to go ?

[Roidfingers]

I've put on some modified oem exhausts. Basically cut just aft of the collector and installed a 4 x 15 in turn down. When I had my cobra 6 into 6 on the bike I had to reset the mixture screw to 2 1/4 out to stop the popping. That I assume is caused by running to rich. ( from what I understand from other threads). That worked fine and had no popping. Iinstalled the exhaust as mentioned above and have rode and reseated my exhaust nuts 3 times. I then turned the mixture screw out another 1/2 turn. This helped a lot on the popping. Only get it on decal. I would like to stop it completely. Should I turn it out some more?

Will this harm the motor at all?  Thanks in advance.

[pancho]

Hey Roid,,  To answer you question, no, opening the pilot screw too much will not harm the motor,, it will make the mixture too rich at idle and right off idle but will cause no harm. It won't hurt to experiment with settings to find what works best for your exhaust, but not sure if it will get rid of popping on deceleration. If you smell gas when idling, they are certainly too far out.

[Roidfingers]

Pacho, thank you for your reply. I am now at 2 3/4 out. I do see at initial start up a puff of smoke from exhaust. But immediately goes away. I got down and smelled the exhaust and no gas smell at idle. I may try 1/4 turn more but don't think I'd go more than that. Would be afraid it might fall out. Not sure how many turns it takes. Ever heard of anyone running 3 turns out?

[pancho]

To get my bike to run as perfectly as possible with Cobra pipes, most of my pilot screws are about 2 1/2 out, with two of them close to three out. I adjusted each separately for minimal missing and maximum RPM at idle.

[Patrick]

With such an open exhaust I'd doubt you could get rid of all the decel popping. But, its sure worth a try.

[Roidfingers]

Yea it's open. Here it is mocked up before the weld.

[big poppa pump]

To get my bike to run as perfectly as possible with Cobra pipes, most of my pilot screws are about 2 1/2 out, with two of them close to three out. I adjusted each separately for minimal missing and maximum RPM at idle.

What size jets do you have? Do you have an OEM or K&N filter?

[Paladin528]

The popping is caused by too LEAN an mixture. turn them out from the stock setting until ou no longer get the popping.  if that fails install #38 slow jets and set the screws back to stock and start again

[pancho]

To get my bike to run as perfectly as possible with Cobra pipes, most of my pilot screws are about 2 1/2 out, with two of them close to three out. I adjusted each separately for minimal missing and maximum RPM at idle.

What size jets do you have? Do you have an OEM or K&N filter?

I'm running 35s and 100s with stock air filter BPP, the bike is running as good overall from idle to WOT as I think it can with CObra pipes and modified baffles,, I'd like to get a stock exhaust for further experimenting.

Roid, I forgot to mention that if you are trying to get good tune on the pilot circuit, you must have the air (carb sync) as close as you can get it first.

[Roidfingers]

Far as I know, stock jets and no K&N. Whats my best options>?? Also I don't understand what Pilot circuit is?

[big poppa pump]

To get my bike to run as perfectly as possible with Cobra pipes, most of my pilot screws are about 2 1/2 out, with two of them close to three out. I adjusted each separately for minimal missing and maximum RPM at idle.

I'm running 38's and 100's on my black Hotrod with a K&N filter and the pilots set at 2 turns and no baffles. Carb sync is almost perfect (thanks to the Digisync) and there is absolutely no popping even at decel. Bike idles perfectly at cold start and the acceleration is fantastic from idle to WOT, however I have a weird issue where the idle starts fluctuating (no surge) if I've been riding for a while and the engine is hot. I'm probably going to be experimenting with the needles next week. I have OEM needles with the IS carb springs right now, but I am going to switch the OEM needles with the Dynojet needles with the E-clip at the 3rd notch from the top.

[pancho]

Far as I know, stock jets and no K&N. Whats my best options>?? Also I don't understand what Pilot circuit is?

That's the "mixture screw" you have been adjusting ,,,  try to insure the carb sync is close to correct first to get good results from that adjustment.   That's a radical looking exhaust system Roid, must be pretty LOUD.

"I'm running 38's and 100's on my black Hotrod with a K&N filter and the pilots set at 2 turns and no baffles."   

Hmmm,, while I believe what I heard the S&S guy say in a video,, that you "can't fix an exhaust problem with carburetor mods", I may get a set of 38s and give them a try while waiting on that other bike with stock pipes to show up .  Be interested to hear if the needles help with the idle "fluctuating" ,, is it speeding up when hot?

[Roidfingers]

I don't think it's as loud as my cobras with no baffles. But I'm in front of the exhaust. It's doesn't have the lower growl of the cobras, little higher pitch. Not sure I like it. But want to get everything set right before I determine that. It makes the engine look so much bigger. Not that it needs any help.

[big poppa pump]

Hmmm,, while I believe what I heard the S&S guy say in a video,, that you "can't fix an exhaust problem with carburetor mods", I may get a set of 38s and give them a try while waiting on that other bike with stock pipes to show up .  Be interested to hear if the needles help with the idle "fluctuating" ,, is it speeding up when hot?

Not speeding up, the other way around, it goes down and comes back to the proper idle speed. That's what makes it weird. Most of the issues I've read on the forums relate to the bike surging where the idle speeds up. I'm thinking with the open exhausts, the bike is still running a little lean. I had it set at 1-3/4 turns before increasing it to 2 turns. The idle fluctuation has actually improved after increasing it to 2 turns. So rather than mess around with the pilots, I will use the dynojet needles to enrich the mixture.

[pancho]

The other thing could be vacuum leaks on the intakes that are sealing up as things expand from the heat, only have a couple of places that could cause that.

[CajunRider]

I'm not sure how accurate this is, but I have been told that 3 turns on the mixture equals (approximately, anyway) one size on the pilot jet.

So, 3 turns out with 35's would be similar to 0 or 1/2 turn out with 38's.  I'm not a fan of going more than 3 turns out... it starts to worry me.

Using this, I tuned my Triumph (over the course of a few weeks/months).
- Starting at two turns on factory pilots, major backfiring.
- Turned out 1/2 turn... better, but still backfiring.
- Went another 1/2... better, but still backfiring.

- Didn't want to go past 3 turns, so I upped the Pilots, started again a 1/2 turn out...
- settled on 1 1/2 turns now, no more backfire (any only need choke on days below 50 deg. F.).
 

[Paladin528]

There is a long drawn out procedure in the manual for setting the screws properly.  It takes a while to get it right.

[big poppa pump]

Finally figured out the idle fluctuation. The airbox boot on carb #1 was not properly seated. The boot was kinked up at the rear and there was a very slight gap leading to a leak. Surprised how I missed this.

[98valk]

there will always be some popping, when getting off the throttle to closed throttle, it will go lean, nature of carbs. if u go pig rich then popping will go away. u will have to change oil sooner due to excess fuel getting past the rings which when doing that is washing the oil film off of the cylinder walls which equals high wear.
Why do u think HDs with open pipes don't pop and need to be rebuilt so soon?

[RDKLL]

Nice tire and nice exhaust....it does make the engine huge

[pancho]

Finally figured out the idle fluctuation. The airbox boot on carb #1 was not properly seated. The boot was kinked up at the rear and there was a very slight gap leading to a leak. Surprised how I missed this.

I guess it can happen to the most careful of us,, good that you have it solved. A couple of these around the house come in handy for such jobs..   

http://www.ebay.com/itm/New-Dental-Mirror-Dentist-Handle-Tool-for-Teeth-Mouth-Cleaning-Inspection-/262524185045?hash=item3d1fa929d5:g:QtQAAOSwyDxXhzjjdo

you still feel the need for the Dynojet needles?

[big poppa pump]

Finally figured out the idle fluctuation. The airbox boot on carb #1 was not properly seated. The boot was kinked up at the rear and there was a very slight gap leading to a leak. Surprised how I missed this.

I guess it can happen to the most careful of us,, good that you have it solved. A couple of these around the house come in handy for such jobs..   

http://www.ebay.com/itm/New-Dental-Mirror-Dentist-Handle-Tool-for-Teeth-Mouth-Cleaning-Inspection-/262524185045?hash=item3d1fa929d5:g:QtQAAOSwyDxXhzjjdo

you still feel the need for the Dynojet needles?

Yep, have one of those mirrors. Harbor Freight to the rescue.

I did switch out the OEM needles for Dynojet needles and have my E-clip at the 3rd notch. With my pilots at 2 turns with #38 jets, there is a very faint odor of richness. Spark plugs look really good. I'm going to try this out for about a week and keep an eye on the mileage. If mileage goes down, I will keep #1 & #2 at the 3rd notch and move the e-clip on the others up to the 2nd notch.