Pods and exhaust nightmare

[Theknickpruitt]

Just an update, I took off the carbs and put in some different jets. They are 155 now. I got them in a jet kit from 6 sigma. Put the carbs back on and after some priming the bike runs. It is idles at 3000 rpm. Its road worthy but I don't think it's 100% yet. It seems to struggle a bit when taking off in 1st gear. Do you think this is something that I can fix with the valves on top of the carbs with a flathead or do I need to open them back up?

[Tom R]

It should idle between 1 - 1.1k so your far from 100%. Can you lower the idle with the adjustment screw between the #2 and 3 carbs? I don't know if sigma uses Mikuni jets, so I can't comment on sizes, but did you install a new needle?
As Rich and myself said in earlier posts, your going to drive yourself crazy with this until you establish a baseline - which is much easier to do with the stock airbox.

[RichDesmond]

Just an update, I took off the carbs and put in some different jets. They are 155 now. I got them in a jet kit from 6 sigma. Put the carbs back on and after some priming the bike runs. It is idles at 3000 rpm. Its road worthy but I don't think it's 100% yet. It seems to struggle a bit when taking off in 1st gear. Do you think this is something that I can fix with the valves on top of the carbs with a flathead or do I need to open them back up?

You are going to have to take them off again. It won't be the last time.
As I said earlier, it takes both a number of iterations and some understanding of how the different circuits work and interact. The less understanding you have now, the more iterations it's going to take, because you have to gain that knowledge.

[TxGSrider]

A few years back I bought a 6 sigma kit for an ATV. It came with "RD" jets (which I have used before without any problems), some washers for the needle, and a drill bit to remove the idle mixture screw. The main jets they provided weren't close to the size I needed and it ran worse than the stock set up. I ended up buying a Dynojet kit and it worked great.

It sounds like you may have a vacuum leak or some pilot jet issues.

[Steve]

Do you think this is something that I can fix with the valves on top of the carbs with a flathead or do I need to open them back up?

I am trying to picture what "valves on top of the carbs" you have.

I have seen MANY sets of carbs on these bikes, but have never seen valves on top.

I know it's too late now, but you should have gotten the bike running properly in the stock configuration. If, for some reason, that was not good enough for you (performance, looks, whatever), THEN you could make your changes, but only make ONE change at a time. If you like the results, you will KNOW that that change was worth it. If it makes it worse, you will know what NOT to do next time.

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[Theknickpruitt]

[QUOTE=Steve;2410553]I am trying to picture what "valves on top of the carbs" you have.

I have seen MANY sets of carbs on these bikes, but have never seen valves on top.

I know it's too late now, but you should have gotten the bike running properly in the stock configuration. If, for some reason, that was not good enough for you (performance, looks, whatever), THEN you could make your changes, but only make ONE change at a time. If you like the results, you will KNOW that that change was worth it. If it makes it worse, you will know what NOT to do next time.


So the valves are on each carb, you can use a flathead screwdriver to make small adjustments to each carb of you don't know what I am talking about by now you might need more help then me, or maybe it was a hint of condescension.

to the second part, it was running stock before I started to modify. I am doing this because I have always wanted to do a scrambler type build. I really like a clean simple look. I have tackled and mastered the electrical by tearing out the old harness and installing an Munit. I'm doing the same thing with carbs now. I am not opposed to taking a long time to get it right and learning as I go.

[RichDesmond]

I am trying to picture what "valves on top of the carbs" you have.

I have seen MANY sets of carbs on these bikes, but have never seen valves on top.

I know it's too late now, but you should have gotten the bike running properly in the stock configuration. If, for some reason, that was not good enough for you (performance, looks, whatever), THEN you could make your changes, but only make ONE change at a time. If you like the results, you will KNOW that that change was worth it. If it makes it worse, you will know what NOT to do next time.

So the valves are on each carb, you can use a flathead screwdriver to make small adjustments to each carb of you don't know what I am talking about by now you might need more help then me, or maybe it was a hint of condescension.

to the second part, it was running stock before I started to modify. I am doing this because I have always wanted to do a scrambler type build. I really like a clean simple look. I have tackled and mastered the electrical by tearing out the old harness and installing an Munit. I'm doing the same thing with carbs now. I am not opposed to taking a long time to get it right and learning as I go.

There are no valves on top of the carburetors.
Discussing things on a forum is more difficult than doing it in person, and because of that language needs to be precise. Otherwise even very knowledgable people (like Steve) aren't going to know what the hell you're talking about.
You need more info and knowledge than is reasonable to expect from a forum discussion. Search the web for articles on carb tuning bikes with pods. A couple of of full days researching will give you enough to get started.
Even an experienced person may have to pull the carbs 5-6 times (or more!) to get it really right. Starting from a low knowledge base you can expect at least double that.

[cowboyup3371]

So I moved onto the exhaust and Carbs. They have be recently rebuilt. Had to find some new used carbs. I tore out the air filter box and put on some K&N filters. I obviously learned there were some adjustments needed. Since then I also put on a 4 into one exhaust. I could not get it to start up after that. I then raised the needles up to the last knotch. I am able to start with the choke all the way up and have to hold it that way. It will not Idle on its own. Please help, I feel lost in the sauce.

Just an update, I took off the carbs and put in some different jets. They are 155 now. I got them in a jet kit from 6 sigma. Put the carbs back on and after some priming the bike runs. It is idles at 3000 rpm. Its road worthy but I don't think it's 100% yet. It seems to struggle a bit when taking off in 1st gear. Do you think this is something that I can fix with the valves on top of the carbs with a flathead or do I need to open them back up?

I am trying to picture what "valves on top of the carbs" you have.

I have seen MANY sets of carbs on these bikes, but have never seen valves on top.

I know it's too late now, but you should have gotten the bike running properly in the stock configuration. If, for some reason, that was not good enough for you (performance, looks, whatever), THEN you could make your changes, but only make ONE change at a time. If you like the results, you will KNOW that that change was worth it. If it makes it worse, you will know what NOT to do next time.

.

So the valves are on each carb, you can use a flathead screwdriver to make small adjustments to each carb of you don't know what I am talking about by now you might need more help then me, or maybe it was a hint of condescension.

to the second part, it was running stock before I started to modify. I am doing this because I have always wanted to do a scrambler type build. I really like a clean simple look. I have tackled and mastered the electrical by tearing out the old harness and installing an Munit. I'm doing the same thing with carbs now. I am not opposed to taking a long time to get it right and learning as I go.

It's interesting how the story changes here a bit and with a lot of attitude from you Pruitt but no answers to the questions. I can't see how you would have had it running well stock if you had to buy used carbs and then tore out the airbox replacing it with pods. Did you properly dip the used carbs before putting them back on and did you test everything with the airbox on first?

I think you mean the idle mixture screws but those are not valves and that is what is throwing others off. It will be best for you to either include pictures of what you are looking at or use the actual words to describe the various parts.

Also, where are you located as maybe someone is close enough to assist?

[mmattockx]

I know how they achieved the success...spending money a lot of time, and wasted efforts. All of which I have no interest in just for some "cool look" factor. I like to ride way more than i like getting tied down to a exercise of take on..take off..guess what size jet to use next...etc etc.

You can test which way to go with the choke while running down the road. I didn't spend much money, just three sets of main jets (I think it was) and my time. Pods aren't cheap, though. Just for interest sake, I had a look back in my tuning notebook and I had the carbs off and apart 7 times in the initial jetting sessions, then once more last year when I switched to APE pods to raise the needles one notch to kill a slight lean surge I picked up with the better flowing APE filters.

Calling them a filter always seemed optimistic to me. More like a gravel strainer deluxe.

I would say this is slightly pessimistic, but they certainly do not filter like the OEM set up does. They also make more power than the OEM set up does, so you have to give something to get something.

Pods can be made to work well, but it takes a lot of iterations and it's imperative that you truly understand how carbs work and how the different circuits interact.
If you don't have experience and that understanding you'll be far, far better off putting the airbox back on.

Words to live by.

Just an update, I took off the carbs and put in some different jets. They are 155 now. I got them in a jet kit from 6 sigma. Put the carbs back on and after some priming the bike runs. It is idles at 3000 rpm. Its road worthy but I don't think it's 100% yet. It seems to struggle a bit when taking off in 1st gear. Do you think this is something that I can fix with the valves on top of the carbs with a flathead or do I need to open them back up?

The 'valves' are called mixture screws and they only affect the idle mixture. You will most certainly be opening your carbs up again. To do this correctly you must be methodical and careful, not making changes randomly in hopes of getting lucky and finding a combination that works OK.

The way I test for rich/lean is as follows:

Mark the throttle openings on your throttle housing with tape. Mark the openings in 1/8 increments. The various carb circuits are controlled by the amount of throttle opening you have, not the engine revs or road speed. The pilot circuit covers idle-~1/4, needles ~1/4-1/2 and main jet above 1/2. There is overlap between them but this is close enough for tuning purposes. Unless you know you are slobbering rich on the 155 I would go a size or two bigger to be sure you aren't lean at full throttle.

Now go out on a quiet back road where you can run highway speeds and change speeds, etc. without screwing anyone else up. Get into 3rd or 4th gear so it will pull for a while without revving off the tach. Then slow down and let the revs drop to 3000rpm or so. Open the throttle to 1/8 and hold it there. Once the engine has been pulling for a few seconds and everything has settled down to a steady state pull the choke and see what happens. If it pulls better you are lean, if it bogs badly you are rich, if it bogs slightly you are close to right. Do this for each carb circuit, preferably a few times to get some consistent readings. This will tell you which direction you need to be going with your jetting.

Some jet kits tell you to sort the main jet first, then the others, but that is backwards, IMO. The lower circuits affect the ones above them, but not the other way around. So I sort the idle mixture first, then the needle, then the mains.

You still have not told us what your jetting is, if you are using the Sigma needle, what groove it is in and where your mixture screws are set. We need to know that if you want useful assistance in sorting your bike out.

I am trying to picture what "valves on top of the carbs" you have.

I expect those are the mixture screws.


Mark

[GS1150Pilot]

Great wisdom here; I hope the OP is paying attention.

[RichDesmond]

...Some jet kits tell you to sort the main jet first, then the others, but that is backwards, IMO. The lower circuits affect the ones above them, but not the other way around. So I sort the idle mixture first, then the needle, then the mains...

Yep. And the further off you are to start with the more important this is.

[Steve]

Some jet kits tell you to sort the main jet first, then the others, but that is backwards, IMO. The lower circuits affect the ones above them, but not the other way around. So I sort the idle mixture first, then the needle, then the mains.

I tend to agree with you, Mark. After all, how can you get out there and test the main jets if you can't use the pilots to get you idling and out to the test area?

.

[mmattockx]

I tend to agree with you, Mark. After all, how can you get out there and test the main jets if you can't use the pilots to get you idling and out to the test area?

.

Indeed. You don't even need a main jet in to get the pilots working, you can putter around at low throttle openings just fine without the mains but it will bog terribly if you start to get up on the needles and fuel starts dumping in.


Mark

[GS1150Pilot]

Did the OP bail?