82 1100EZ jetting

[singletrack]

So I finally am getting around to checking out the carbs on the 1100. Spring is around the corner!

I bought the bike late last year and it ran pretty good, very strong and even through the power band. The only thing is it pops quite a bit when you let off the throttle. I posted about it here and general consensus was the PO hadn't rejetted, despite aftermarket pipes (not sure who makes these, but they are high flow) and a K&N filter in stock airbox.

So after getting a look inside the carbs, I see stock needles and Mikuni 115 main jets (stock is 107.5). I didn't look at the pilot jet, can check that later if needed...I have the Dynojet kit and was planning on installing the needles and stage 1 jets (DJ 114) but now am thinking just keep the 115's. I've also read chef's comments about using 117.5's

Thoughts, comments, suggestions?

Thanks!

[BassCliff]

Hi,

As I have only a theoretical knowledge of the black art of carb jetting, I can offer general guidelines, not specifics. Raising the needles may take away the popping on deceleration. Generally you'll want to go up about 4 sizes on the main jets with pods and pipe. But plug chops will tell you if the jetting is correct. Read the spark plugs, they will tell the tale.


Thank you for your indulgence,

BassCliff

[posplayr]

So I finally am getting around to checking out the carbs on the 1100. Spring is around the corner!

I bought the bike late last year and it ran pretty good, very strong and even through the power band. The only thing is it pops quite a bit when you let off the throttle. I posted about it here and general consensus was the PO hadn't rejetted, despite aftermarket pipes (not sure who makes these, but they are high flow) and a K&N filter in stock airbox.

So after getting a look inside the carbs, I see stock needles and Mikuni 115 main jets (stock is 107.5). I didn't look at the pilot jet, can check that later if needed...I have the Dynojet kit and was planning on installing the needles and stage 1 jets (DJ 114) but now am thinking just keep the 115's. I've also read chef's comments about using 117.5's

Thoughts, comments, suggestions?

Thanks!

If stock is 107.5 Mikuni and you have 115 Mikuni, how do you figure it was not rejetted?

And so why would you not get some 117.5's?

BTW the DJ 114 is like a 104 Mikuni

Not sure what Bill said but I would put the 117.5's with Needle on the 3rd notch and see what it does (WOT to redline). The stock needles have a thick taper keeping the mixture too lean for more settings. That is why you need the DJ needles.

[singletrack]

Thanks gents.

@basscliff. Its a dark art to me too! I've been reading a lot, but I'd be lost without this site.

@posplayr sorry, I was't clear. I was guessing it hadn't been rejetted, but just learned it had been when I got the carbs off. I've been meaning to start this project for months, but am a bit intimidated by pulling the carbs apart. I'd even already bought the dynojet kit. Chef's comment was gleaned from other threads on rejetting stage 1 for my bike & setup.

Guess I should order up the 117.5's then.

One other question: the carbs ran well before (popping aside) and look great. Bowls are shiny clean no real visible residue. Should I dip them anyway? I have an o-ring set too...don't want to make extra work if its not necessary.

[posplayr]

Thanks gents.

@basscliff. Its a dark art to me too! I've been reading a lot, but I'd be lost without this site.

@posplayr sorry, I was't clear. I was guessing it hadn't been rejetted, but just learned it had been when I got the carbs off. I've been meaning to start this project for months, but am a bit intimidated by pulling the carbs apart. I'd even already bought the dynojet kit. Chef's comment was gleaned from other threads on rejetting stage 1 for my bike & setup.

Guess I should order up the 117.5's then.

One other question: the carbs ran well before (popping aside) and look great. Bowls are shiny clean no real visible residue. Should I dip them anyway? I have an o-ring set too...don't want to make extra work if its not necessary.

Is it popping on decell? That is idle mixture.

Are you jetting for pods or the K&N filter in the air box. The jetting is most sensitive to the air inlet and less so on the 4:1 exhaust (see Cliff's rule of thumb).

You could probably just do with a good spray down of some carburetor cleaner. Doesn't sound like any real problems now.

You could PM Chef with your specific bike (stock 34mm CV's right?,), I thought he had already answered you directly .

The DJ 132 are probably OK with 4:1/Pods stock motor 34mm CV's ; that would equivalent to 122 Mikuni.

The DJ 138 are better for a stock bike 4:1/pods hotter cam and 36mm CV's. That is equivalent to the 128 Mikuni's.

So moving up from 107 to 115 Mikuni is probably already rich enough unless you plan to remove the air box top or do pods. I would ask.

The needle does not affect WOT, so if the bike pulls to red line now with the 115 Mikuni, (and plugs look good) then leave it there.

if you read here you start by getting the main correct. It might be that you are already close enough there.

http://www.factorypro.com/tech/carbtun.html

[chef1366]

I'd install the Dynojet kit via the instructions. I don't use the main jets in their kits since my engines require a bigger jet.
I'd bring out the idle mixture screw to stop the popping

[posplayr]

I'd install the Dynojet kit via the instructions. I don't use the main jets in their kits since my engines require a bigger jet.
I'd bring out the idle mixture screw to stop the popping

So what mains for a Stock EZ, 4:1 and K&N airfilter with stock box/cover?

[chef1366]

So what mains for a Stock EZ, 4:1 and K&N airfilter with stock box/cover?

I'd go with the 117.5s

[posplayr]

I'd go with the 117.5s

he already has some 115's so a quick plug chop would be easy before ordering them.

[singletrack]

Thanks again folks, very helpful. I was able to find the mikuni 117.5's online for $14 shipped, so I think I'll just order em. We have 3 feet of snow still on the ground and I'm going away for a week, so hopefully they'll be here by the time I get back. Then I can take my time getting the bike back together and pray for warm weather.

Cheers!

[Johnny Drummond]

Hi single track, I fitted a GSX1100EZ engine and carbs of '84 vintage into my GS1000 chassis a couple of years ago and had to re-jet for pods from scratch( the GS airbox doesn't have enough room to fit the rubbers to the back of the carbs as it was a slide carb model engine originally) so I remembered that some 2-stroke racers I knew in the late '70s early '80s always said to jet rich to begin with.I started with145 main jets and just worked by trail and error to the 117.5' you have ordered.The bike goes really well and at least you had the advice from various people here, I just winged it!, although I did have a mile long straight road outside my house in a rural(that our local police can't even find) area to use as a test strip!!.It also says something about me-although what I'm not sure that I could come in from a run and strip, change jets and be out again in under 40 minutes.All the best with the work, and here's a photo of the finished bike.Johnny

[posplayr]

Hi single track, I fitted a GSX1100EZ engine and carbs of '84 vintage into my GS1000 chassis a couple of years ago and had to re-jet for pods from scratch( the GS airbox doesn't have enough room to fit the rubbers to the back of the carbs as it was a slide carb model engine originally) so I remembered that some 2-stroke racers I knew in the late '70s early '80s always said to jet rich to begin with.I started with145 main jets and just worked by trail and error to the 117.5' you have ordered.The bike goes really well and at least you had the advice from various people here, I just winged it!, although I did have a mile long straight road outside my house in a rural(that our local police can't even find) area to use as a test strip!!.It also says something about me-although what I'm not sure that I could come in from a run and strip, change jets and be out again in under 40 minutes.All the best with the work, and here's a photo of the finished bike.Johnny

Hi Johnny,
Pods make a big difference relative to the air box so I'm wondering if your 117's might be a bit lean. I have been up in the 145 area but that is usually 1166cc, bigger cams and 36mm carbs. Of course may be some other factors.
Jim

117

[singletrack]

Hi single track, I fitted a GSX1100EZ engine and carbs of '84 vintage into my GS1000 chassis a couple of years ago and had to re-jet for pods from scratch( the GS airbox doesn't have enough room to fit the rubbers to the back of the carbs as it was a slide carb model engine originally) so I remembered that some 2-stroke racers I knew in the late '70s early '80s always said to jet rich to begin with.I started with145 main jets and just worked by trail and error to the 117.5' you have ordered.The bike goes really well and at least you had the advice from various people here, I just winged it!, although I did have a mile long straight road outside my house in a rural(that our local police can't even find) area to use as a test strip!!.It also says something about me-although what I'm not sure that I could come in from a run and strip, change jets and be out again in under 40 minutes.All the best with the work, and here's a photo of the finished bike.Johnny

Gotta love these engines, eh? I wish I had a strip like yours...not a lot of straight roads in my area without COPS.

[Johnny Drummond]

Hi Jim, if I was using a performance exhaust as well as the pods I would agree but the exhaust is from a company in England called Motad.They are a straight replacement for the standard system that rots within about 5-6 years over here because of the constant damp weather and salt on the roads, I don't think are marketed over in the states(but I could be wrong!)also it's not even for the GSX-it is for a GS but it fits straight on it was used because that is all I had, and I can't afford the $4-500 for a new system!.
Our road is great, but what gets people is the first 4 houses are numbered accordingly then you come up the 500 yards to our house and we are number 56! the only disadvantage with the straight is that it has a series of ripples running across it about mid way-really not fun to run over at over 100mph as the bike behaves like a dog that has just got out of a pond!.Johnny