Jetting an 1100

[earlfor]

I think I will see if I can match up the jet diameter with something I already have that is marked. The largest jet I have on hand is a 125, so if what is in the bike is bigger than that, I probably have a needle problem. If its much smaller than that, I'll expect a jet and needle problem.

The bike is pretty quick now even without proper fuel flow and will likely do a 50 mph, roll on wheelie. I may scare myself when its really right. :-)

Earl
P.S. You know you would mess with me anytime you thought you could get away with it. LOL

I swear Earl. I wouldn't mess with ya'! Check any jetting chart or Suzuki carb info and it will tell you the same thing.
I would definitely suspect the mains in your case but only because they're unmarked. A bore kit will effect the mid-range a lot.

[earlfor]

This just occured to me. Some may find it interesting. I took some know values and played with my calculator. This is main jetting for stock bikes with stock pipes and airbox with the exception of Lukes 1229.

Luke 1229cc mainjet 135 ..............1229/135=9.10

Earl 1150E mainjet 120 ..............1150/120=9.58

stock 1100E mainjet 115 ...............1100/115=9.56


Taking that indexing and applying it to my 1197 .............

1197/9.58= 124.94
1197/9.56=125.2
1197/9.10=131.5

Knowing Luke is racing a bit and probably more to the rich side and knowing that stock suzuki has traditionally been to the lean side, I estimate the optimum jet size as midway between those numbers.

That would be 128.22 so, 127.5 or 130 should work well.

This also coincides with rphilipps post, which was..................
quote...
Won't be much help, but with 1148 pistons, stock air box with lid removed, and V & H pipe, 127.5 worked real well....unquote.

and

agrees with Karl Z on the use of 130 jets.

Earl

P.S. If this works out OK, then Keith and I can continue our needle debate. :-) :-)

[KEITH KRAUSE]

Debate? :? What debate? I see you're not convinced, which is OK.
I wouldn't give out bad info Earl unless there was an honest mistake or someone wasn't accurately describing their problem. If a larger main jet does cure your problem, it's only because those unmarked mains are unusually small. At the throttle position you describe when the problem hits, the bike is solidly on the jet needle. You may need larger mains, but you need to raise the needle too.
I still think you can rig up a timed flow test and figure out what your mystery mains are.

[earlfor]

I'm only messing with you Keith. :-) I know you dont give out bad info.
I suspect the mains are undersize and either way, I expect I will need to raise the needles. If I find the mains are way undersize, raising the needles may not be necessary. I take books such as Clymer, etc. as a starting point and general appraisal of the situation. They point in the right direction, but are not always accurate for every situation.
The great thing about this forum is the information and feedback. I now know what jets some have found to work with various displacements and set up. Combining the various viewpoints allows me to make a more accurate decision of how best to solve the problem. Instead of doing this a dozen times searching for the right combination, I think I will get it right in one try. :-) 130 mains and raise the needle one notch. :-) At worst, I will have to do it twice if I need to go two on the needles.

Just a little side into............. I found that for mikuni round main jets as used in CV carbs. the jet sizes are described as percentages of 1 millimeter. So, a #35 jet is .35 mm. A #100 jet is 1 mm. A #130 jet is
1.3 mm. (1mm= .0395 inches) (a #200 jet would give 4 times the flow of a #100 jet)

For VM carbs which use the hex jets, the size designates % of flow, not the diameter of the opening. So, a #200 jet is twice the flow or area of a #100 jet.

Therefore, if someone is asking about jet sizes because they have changed their exhaust to a 4 into 1 and intake to pods, it is necessary to know if they have CV or VM carbs. The two types of jets do not use the same indexing system.

Earl

Debate? :? What debate? I see you're not convinced, which is OK.
I wouldn't give out bad info Earl unless there was an honest mistake or someone wasn't accurately describing their problem. If a larger main jet does cure your problem, it's only because those unmarked mains are unusually small. At the throttle position you describe when the problem hits, the bike is solidly on the jet needle. You may need larger mains, but you need to raise the needle too.
I still think you can rig up a timed flow test and figure out what your mystery mains are.

[earlfor]

Well, I got the 1100 out for a long test run and the plugs are burning a nice medium brown, oil temp has come down and the bike no longer expansion/heat crackles after shutdown. The combination of #130 mains and
and raising the needles 3mm seems to be about right. Gas milage is about 40 mpg which is probably decent for an 1197cc kit.

Thanks all, I really appreciate the help.

Earl

[KEITH KRAUSE]

That's good!
Just want to add: Mikuni jets are rated by the cc's that will flow through in 1 minute. A 130 Mikuni jet will flow 130 cc's in 1 minute.
DJ jets, are sized by the size of the hole. A 130 DJ jet is 1.30mm.
A DJ 138 jet is about the same flow as a 130 Mikuni jet.
I'm not sure about your jet comment Earl...Mikuni VM carbs use round jets.

[Anonymous]

Seems like Mikuni has a strange way of sizing their jets. If the jet were screwed in the bottom of a full 55 gal. barrel, it would flow a lot more cc per min. than the same size jet screwed in the bottom of a full 12oz. Coke can. I guess it would be too much to ask, but why wouldn't they all measure them the same.

[earlfor]

OH NO!!!! Not ANOTHER carb debate. LOL :-) :-) In my CV carb GS's keith, the mainjets are round. In my VM carb'd 750, the main jets were hex headed. The jet body itself is round, but the end are hex headed. They cannot be removed with a screwdriver because there is no slot. You have to use a wrench. I can send you one if you dont believe me. :-) :-)
(I'll even send you a wrench if you need one hehehehehe)

Earl

That's good!
Just want to add: Mikuni jets are rated by the cc's that will flow through in 1 minute. A 130 Mikuni jet will flow 130 cc's in 1 minute.
DJ jets, are sized by the size of the hole. A 130 DJ jet is 1.30mm.
A DJ 138 jet is about the same flow as a 130 Mikuni jet.
I'm not sure about your jet comment Earl...Mikuni VM carbs use round jets.

[KEITH KRAUSE]

OH NO!!!! Not ANOTHER carb debate. LOL :-) :-) In my CV carb GS's keith, the mainjets are round. In my VM carb'd 750, the main jets were hex headed. The jet body itself is round, but the end are hex headed. They cannot be removed with a screwdriver because there is no slot. You have to use a wrench. I can send you one if you dont believe me. :-) :-)
(I'll even send you a wrench if you need one hehehehehe)

Earl

That's good!
Just want to add: Mikuni jets are rated by the cc's that will flow through in 1 minute. A 130 Mikuni jet will flow 130 cc's in 1 minute.
DJ jets, are sized by the size of the hole. A 130 DJ jet is 1.30mm.
A DJ 138 jet is about the same flow as a 130 Mikuni jet.
I'm not sure about your jet comment Earl...Mikuni VM carbs use round jets.

What's a wrench?? :?

[Jethro]

What's a wrench??

It's a guy that insists shafts are better than chains!