Ivan's Jet Ket with 2 Brothers and Fuel Mileage

[kokomosam]

Hello all,

I have a 2002 1200s with the Ivan's Jet Kit and a 2 brothers can and my tank range sucks.   Now this wasn't a big problem at first, but now that I am doing more touring this is getting to be a pain especially when riding with bikes with more then twice my range.  I got the bike with the Ivans' jet kit already on it, so I am not sure about exactly what was done to install it.

So the question is...

How hard / expensive would it be to make the carb's stock again?  I do have the stock exhaust.

Thanks

Sam

[PaulVS]

I have virtually the same setup as you on my '03... I only dropped about 2mpg.  I don't know that undoing it would accomplish much.

Did you have the bike before the jet kit/exhaust was put on?

[kokomosam]

I have virtually the same setup as you on my '03... I only dropped about 2mpg.  I don't know that undoing it would accomplish much.

Did you have the bike before the jet kit/exhaust was put on?

First of all let me comment on you sig.      I like it but I find it distracting from motorcycle trains of thought.

The bike had the jet kit/exhaust when I got it.

The idiot light comes on at around 140+ and I once got almost 160 out of it without actually running out of gas.  Is that what you are experiencing?

Sam

[PaulVS]

I get to about 125-135 before I have to switch to reserve.  Previously I would maybe get to 135-140 before reserve.

[Rocketjock]

My stage 1 and 2Bros dropped my milage signifigantly. Never figured out the mpg. but in kms. I used to get about 320 to a tank and now I get about 220. Plus I upped the pilot size to get smoother running at lower revvs. Not that the bike was not fast stock but I do have noticable more torque now. The other downside is I have buzzing loud noise in my helmet now that the best earplugs can't kill. I'm keeping it for one more season then I'll probably go back to stock. To do that I'll have to pull the carbs, replace the old jets, reset the screws to factory (3 1/2 turns), put the PAIRS system back on and of course the stock can. Not a huge job but worth it for sound comfort and fuel milage.

[kokomosam]

My stage 1 and 2Bros dropped my milage signifigantly. Never figured out the mpg. but in kms. I used to get about 320 to a tank and now I get about 220. Plus I upped the pilot size to get smoother running at lower revvs. Not that the bike was not fast stock but I do have noticable more torque now. The other downside is I have buzzing loud noise in my helmet now that the best earplugs can't kill. I'm keeping it for one more season then I'll probably go back to stock. To do that I'll have to pull the carbs, replace the old jets, reset the screws to factory (3 1/2 turns), put the PAIRS system back on and of course the stock can. Not a huge job but worth it for sound comfort and fuel milage.

I guess my concern here is doesn't the Ivan's kit involve some drilling?  Is it reversible?


Sam

[PaulVS]

The only drilling is to the airbox lid, which you can cover up with duct tape, or replace the lid for around $25.

The brass EPA-mandated "anti-tamper" caps over the A/F mixture screws are drilled out when the jet kit is installed....  but you want them out regardless of whether you have a jet kit or not.

Rocketjock... that's a huge drop in mileage.  I talked to Ivan and he said a 2-3 mpg drop (3-5 kpg) was the norm after installing his kit. 


If the bike is tuned right, you should only be losing about 25k per tankful at most. 

[PitterB4]

Yeah 140-160 doesn't sound bad at all.  Tank size is 5.3 gallons - which is what, probably ~5 gallons of usable capacity at most?    So from as full as practical to empty at 160 miles is 32mpg for a beastly powerful machine.  Sounds pretty reasonable.  With my mostly commuter riding, I'm only getting high-30s on my little 600 that's stock with the exception of a slipon and needle shims.  

[pmackie]

Your mileage sounds a little low, even for a jet kit, except when you are running really hard, then it sounds fine. In "cruise' mode, while touring, you should get 150-160 miles before you go onto reserve. Remember, the reserve will give you another 30-40 miles as well.

Before you convert completely back to stock, I would suggest you lean things out just a little, and see how it runs...
1. Adjust the air screws IN 1/4 to 1/2 turn
2. Pop the tops off the carbs and move the clips UP (dropping the needle DOWN) one clip, or if there are shims on the needles, remove one shim.

This will lean out the carb in the 1st 3/4 throttle, still leaving the larger main jets in place, for full throttle runs. With a little patience, you can do this with the carbs still in place.

3. Drop the main jets 1 size. - you will have to remove the carbs to do this.

These changes should make a measurable improvement in mileage, but WILL make the bike leaner, and it may not run as well as before.

[kokomosam]

Your mileage sounds a little low, even for a jet kit, except when you are running really hard, then it sounds fine. In "cruise' mode, while touring, you should get 150-160 miles before you go onto reserve. Remember, the reserve will give you another 30-40 miles as well.

Before you convert completely back to stock, I would suggest you lean things out just a little, and see how it runs...
1. Adjust the air screws IN 1/4 to 1/2 turn
2. Pop the tops off the carbs and move the clips UP (dropping the needle DOWN) one clip, or if there are shims on the needles, remove one shim.

This will lean out the carb in the 1st 3/4 throttle, still leaving the larger main jets in place, for full throttle runs. With a little patience, you can do this with the carbs still in place.

3. Drop the main jets 1 size. - you will have to remove the carbs to do this.

These changes should make a measurable improvement in mileage, but WILL make the bike leaner, and it may not run as well as before.

I am curious what you mean by not run as well...   With the kit in I get some deceleratoin popping from the exhaust and some hesitation/missing sometimes when coming off throttle to on throttle. 

thanks everyone for all the help.

Sam

[Red01]

I think what he's saying is if the bike was running fine now, and you leaned it out a little, it may not be so perfect.

Some decel popping is normal.  The OEM exhaust does a good job of quieting it in stock form.

I don't know what people are riding that are getting double the mileage between fill-ups, but even if you go back to bone-stock, you're not gonna get close to that much of an improvement.

My bike has ~4.0 gallons in the normal position and I'll hit reserve ~150-160 miles. (Holeshot Stage II & Holeshot 17" Street can - gets ~39mpg under my average conditions, I can eek more out, or thrash it hard and get worse.)  When it was bone stock, it might have went another 10-15 miles, since it got ~2-3 mpg better.

[Nitro]

I have a 97 with stock exhaust, and an unidentified (Dynojet?) jet kit installed, and stock gearing. I get around 150-160 miles before reserve. I average from 29 to 44 mpg, depending on how much around town driving I do. I don't think you'll get much more range by changing back. You may to better to change the gearing. Drop 2 or 3 teeth on the back sprocket and see how much that helps.

[redbandit12]

why do we buy big horsepower bikes and add pipes carb kits etc.... ?
i know why i got mine it sure ain't for the gas mileage! it's for smileage!!!!!!! tire smok'en wheelstand'en fun 

[mademiriam]

it's for smileage!!!!!!!

isn't that the truth! 

[PaulVS]

With the kit in I get some deceleratoin popping from the exhaust and some hesitation/missing sometimes when coming off throttle to on throttle. 

Sounds you may have some air/fuel problems that aren't related to the jet kit.  It may be gummed up carbs, bad plugs, dirty air filter, etc.