Pilot jets?

[scrapvalue]

Which style pilot jets does the 1978 XS1100 use?
Is it the BS30/96's or the VM22/210?
The reason I ask is that the bike I am trying to get running properly has had a stumbling problem on take off and slow speed roll ons.
I have done every possible adjusment and the problem just won't go away.
Anyway, the manual says the stock pilot jet is a 42.5.
When I checked them, they are 45's.
What I have been able to find on line says that the BS30/96's are for CV carbs, but it looks like I have the VM22/210's according to the pics I find.
Anyway, any help would be greatly appreciated.

[DGXSER]

All of the 1100s XS and XJ use the BS30/96 pilot jets. 6 Holes total. The 78 came stock with 45 pilots.

[ManagerMike]

I had the same misinformation regarding the manual's statement for the pilot size. The 78 does indeed come with #45 pilots. BS30's that is.
If it helps at all, the manual is correct for the mains; 137.5

[scrapvalue]

O.k. I can understand the manual having the wrong size listed, but how the heck did they end up putting in the VM22/210's at the factory?
That is definetley what is in there.
The fact that they have less holes and the one on the end is a lot smaller then the BS30/96's makes me wonder if I should just order the right ones in the stock size or go up one size?
I'm so confused

By the way, the exhaust was all rusted out on the rear and the air box was trashed. So I cut the pipes of just behind the rear mount and have installed pod filters.
I am up to 145 mains, needle clip stock position and air screw 1 1/4 turns out.
Runs pretty good except for the low sped stumble.

[Larrym]

Mistaken Identity?

O.k. I can understand the manual having the wrong size listed, but how the heck did they end up putting in the VM22/210's at the factory?
That is definetley what is in there.

scrapvalue,



Assembly line work is very boring and the jets do appear similar from the outside....

[psycoreefer]

Just to clarify, as the picture above indicates, if the hole in the un-threaded end is very small then you've got the right type.

You can not go by the number of holes drilled in the "sides" of the jet to determine the type, only by the location of the metering hole.

I've seen 30/96 type jets stamped as the same "size" but with diffent numbers and combinations of side holes, I'm assuming its a manufacturing thing that isn't susposed to effect the actual flow of fuel.

[DAVINCI]

O.k. I can understand the manual having the wrong size listed, but how the heck did they end up putting in the VM22/210's at the factory?
That is definetley what is in there.
The fact that they have less holes and the one on the end is a lot smaller then the BS30/96's makes me wonder if I should just order the right ones in the stock size or go up one size?
I'm so confused

By the way, the exhaust was all rusted out on the rear and the air box was trashed. So I cut the pipes of just behind the rear mount and have installed pod filters.
I am up to 145 mains, needle clip stock position and air screw 1 1/4 turns out.
Runs pretty good except for the low sped stumble.

All the jet work in the world won't make up for open pipes. You'll never be able to tune it well without some kind of back pressure (muffler) on it.

[Larrym]

Release The Hounds!

All the jet work in the world won't make up for open pipes. You'll never be able to tune it well without some kind of back pressure (muffler) on it.

I concur. It's a jagged little pill to swallow for those that have no Muffs. Stumble....Choke...Slow to roll up to speed. Certainly a compromise in "Drivability".

But then again Wide-Open-Throttle may be all he wants/needs???

[scrapvalue]

Have ether of you have seen the inside of the stock exhaust where the rear foot begs mount, forward?
They are not "open" exhaust.
There are still internals and it is not very loud.
I have the bike running very good in all throttle positions except for the transfer from low to mid range.
Idle to 15 mph is good and from 25 to wide open is great.
If you have a helpful answer or an idea of how these carbs actually work,
please feel free to offer some help.
Otherwise, well you know.

[Larrym]

Have ether of you have seen the inside of the stock exhaust where the rear foot begs mount, forward?
They are not "open" exhaust.
There are still internals and it is not very loud.
I have the bike running very good in all throttle positions except for the transfer from low to mid range.
Idle to 15 mph is good and from 25 to wide open is great.
If you have a helpful answer or an idea of how these carbs actually work,
please feel free to offer some help.
Otherwise, well you know.

Scrapvalue,

No "offense" intended from my side here. Just trying to "assist" but having only "limited" info about your situation.

The "back-pressure/Tuning" issue is one that's been reported here before and a "search" of the site would show that those without sufficient back-pressure never did get that "hesitation" to go away. When you said you had cut your pipes this issue seemed important enough to bring to your attention. "Loud" is a subjective term and without measuring/knowing the back pressure? you might/might not have crossed the line.

I'm still "iffy" about whether the installed idle jets really are the vm or the bs type. You wording about the number and size of holes leaves me confused. That was important enough for me to post that illustration as an aid to help you tell the difference.

I do have a notion or two about how these carbs work. I'm also willing to impart some of that knowledge.

I am however on the fence right now as far as whether I should in this situation.

[petejw]

try opening ur mixture screws up a bit more
and see how they go.

[DAVINCI]

Have ether of you have seen the inside of the stock exhaust where the rear foot begs mount, forward?
They are not "open" exhaust.
There are still internals and it is not very loud.
I have the bike running very good in all throttle positions except for the transfer from low to mid range.
Idle to 15 mph is good and from 25 to wide open is great.
If you have a helpful answer or an idea of how these carbs actually work,
please feel free to offer some help.
Otherwise, well you know.

Well if the vast experience and real-world knowledge offered for free here is not good enough, you could always take it to a shop and pay for the work to correct your hack job.

[WMarshy]

Sounds to me like you need a carb sync to start (using the proper tools, not "by ear"). When's the last time the timing chain was adjusted? Believe it or not, those two things eliminated my hesitation. Granted I have stock exhaust and stock airbox, your outcome may vary but, those things are necessary. Second, get a color tune to set your low end mixture correctly. If your any good at reading plugs you can get close to where you need to be. Having short pipes like that is one of the biggest contributers to your problem, along with pods. Drive-ability suffers, no way to get around that. Add ambient temperature variables into the mix and be prepared to have a very good running bike one day and a crappy one the next day/month...

[DGXSER]

Hey ScrapValue,

First, we are just taking the bits and pieces of your bike you share with us and trying to help you find the answer your looking for. No one is intentionally acusing you of any wrong doing or trying to offend you.

Now as to the jets, I am certain, absolutely positive, that if you use the VM style jets, you will most definitely fight with getting those carbs to perform until you run out of steam and never get them quite right. You will want the BS30/96 style pilot jets. You asked if you shoud go with factory jet sizes or not, well, that exhaust issue is a BIG determining factor in that answer.

And yep, I have seen the innerds of these exhaust, I had one that was worthless and cut it all open to see just how it was configured. Basically, it is ALOT like a three pass shell and tube heat exchanger. The exhaust gasses hit a plate and are forced to go through some tubes the full length of the muffler to the back end of the muffler, where there is another plate so the gasses have to go through a few more shorter tubes into the middle chamber of the muffler and then allowed to go out that short middle tube to leave the muffler.

Cutting the muffler off halfway is only half the story, did you also move that baffle plate and the shorter tubes up? OR just left it open with that first baffle plate back in there and just the existing tubes? In the latter case it would basically be straight exhaust.

[LuckyEddie]

Check this

Scrapvalue,

Check this thread that I had a while back. What you are looking for is post #26. http://www.xs11.com/forum/showthread.php?t=23240&page=2