1150 airbox mod

[earlfor]

As with some other models, removal and installation of the carbs on the 1150 is not the most pleasant. The space is very limited. I have been thinking of measuring the airbox air intake area, and dividing that by 4 to get a required crossection needed per carb. Then install pod filters and make a mold for individual fiberglass airboxes to clamp over the pods, so the stock airflow is retained. The bike runs almost perfect now and is smooth as glass with plenty of hp, so there is no reason to upset an already balanced induction system. Its a maintenance issue, not a performance issue.

Removing the filter from the stock airbox would also have the advantage of providing a handy little storage box with lid. :-)

Anyone done this? Any thoughts?

Earl

[daveo]

I think you know better Earl, it's the air flow characteristics as well as the volume of air that you'll be messing with. I went to pods strictly for the maintenance aspect, and the unused airbox does make a fine storage compartment. Just go to pods and rejet, however you may want to check where the water from rain will run off into...on the EX for example, the water runs off the tank and right onto # 1 and 4 pods, on the EZ it's a non-issue, don't know squat about the 1150s. I just hated dealing with the airbox crap.

[kz]

Re: 1150 airbox mod

As with some other models, removal and installation of the carbs on the 1150 is not the most pleasant. The space is very limited. I have been thinking of measuring the airbox air intake area, and dividing that by 4 to get a required crossection needed per carb. Then install pod filters and make a mold for individual fiberglass airboxes to clamp over the pods, so the stock airflow is retained. The bike runs almost perfect now and is smooth as glass with plenty of hp, so there is no reason to upset an already balanced induction system. Its a maintenance issue, not a performance issue.

Removing the filter from the stock airbox would also have the advantage of providing a handy little storage box with lid. :-)

Anyone done this? Any thoughts?

Earl

Hi Earl,

If I remember correct your bike is running "as a turbine" and you don't want to make any major changes to the engine.

I would not have changed the Airbox on a stock engine, the stock airbox maybe is a little difficult to assamble and disassemble, but in my opinion it is defintly worth the effort, knowing that your bike then runs as it should.

You would also have to rejet the carbs.

The engine sound would also be a little bit louder.

The crankcaseventilation hose also would have to be placed out to the open. Crankcasegases smells!

On the other hand, a lot of people have done this mod and are happy with it..............

/Karl

[earlfor]

Re: 1150 airbox mod

I was thinking if I matched the air intake "resriction" to the original, no jetting changes would be needed. I had not considered that if would make the engine louder. The ventilation could be routed into a 4 way junction with a hose going to the box on each carb.

As it is now, I can adjust the valves and time the engine in less time than I can install the airbox with the proper fit. :-) :-)

Everytime I have to fit that airbox, I have to make at least three trips into the house to sit down, calm down and regain my composure. :-)

Earl

I would not have changed the Airbox on a stock engine, the stock airbox maybe is a little difficult to assamble and disassemble, but in my opinion it is defintly worth the effort, knowing that your bike then runs as it should.

You would also have to rejet the carbs.

The engine sound would also be a little bit louder.

The crankcaseventilation hose also would have to be placed out to the open. Crankcasegases smells!

On the other hand, a lot of people have done this mod and are happy with it..............

/Karl

[kz]

Hi Earl,

The engine is not that much louder, it's more like a sound change...

If you are prepered for the thing you have to take in count and think it's worth it, you will probably be happy with the change to pod filters.

[Jethro]

I puts me a handy-dandy storage compartment where that-thar airbox was-em!

It's a brand new 1 gallon portable gas tank that I cut the top off of. $2.79 at Auto-Zone. I haven't figured a way to make it watertight yet, but I don't really think I need to. I only put my cheap raingear and tools in there, so I no longer have to deal with the tank bag everytime I ride!

[Nerobro]

Earlfor, this is exactly what Ive been thinking of for my 550. I;m thinking a two parter that covers from the left and right.

You've used fiberglass before right? If not I have a few tips.

I do think that this "tuned restriction" would work well.

[Anonymous]

air box

earlfor I have been working on a air cleaner set up, with 90 degree pipes coming out from the carbs to the side with a baby weber carb K&N airfilter on each side of the bike, got enough power I just want the cool and different factor, I think the runner length will require minimal re jeting, oh yea the box is a pain, and last time I did it I scratched the frame paint and that made me decide its got to go!!

[Dink]

Earl dont do it!!! The easy way to remove and install carbs on an 1150 is to take the cylinder head side boots off. I can remove and re-install mine in a half hour.
Dink

[earlfor]

Y'know Dink, sometimes I amaze myself with my lack of problem solving ability. :-) :-) That solution is too simple. LOL I never would have thought of just removing the boots on the other side. heh heh heh We will give'er a go that way. Thank you sir. :-)

The bike runs too well for me to want to change induction properties. Its taken me 3 years to learn to properly tune the 1150 to where its smoother than a swiss watch. I dont want to start over.

Earl

Earl dont do it!!! The easy way to remove and install carbs on an 1150 is to take the cylinder head side boots off. I can remove and re-install mine in a half hour.
Dink

[kz]

Earl dont do it!!! The easy way to remove and install carbs on an 1150 is to take the cylinder head side boots off. I can remove and re-install mine in a half hour.
Dink

Hi Dink, I agree and disagree..

First I agree with "Earl dont do it!!! " and "I can remove and re-install mine in a half hour."

but in my opinion it's not easier to remove the carbs if you take the head side boots off.

I tried both methods and came to the conclusion than loosening the boots at the carb side is the easiest way.

BTW:

Earl if you do this mod and for some reason not are satisfied with it, it's not that hard to convert it back, so follow your inner feeling if you want to invest in the pod-filters.

[mike J]

The bike runs too well for me to want to change induction properties. Its taken me 3 years to learn to properly tune the 1150 to where its smoother than a swiss watch. I dont want to start over.

Earl


Earl, so care to share some of your secrets here? I want my bike to run fast but I also want that swiss watch effect too. Mike J

[earlfor]

My only reason for considering pod filters is to make carb removal and installation easier. If I can not modify the pods so no jetting or tuning changes are needed, I would not consider using them.

Earl

Earl if you do this mod and for some reason not are satisfied with it, it's not that hard to convert it back, so follow your inner feeling if you want to invest in the pod-filters.

[earlfor]

Mike, there are no secrets. I dont think I do anything everyone else isnt doing. The only difference may be in how picky I am when working on the 1150. I admit to being rather anal where my bike is concerned. :-) For example, my carb synch is spot on the line across the board. Twist the throttle, and all four carbs draw vacuum exactly the same whether increasing or decreasing. The four bubbles move as if they are one bubble. The voltage drop between my battery terminals and the coils is less than 1/4 volt. Both coil input leads show precisely the same voltage. (the cylinder pairs are not going to run the same if the coils are operating on different voltage levels) My coil resistances are the same. The exhaust headers all warm at the same rate and to the same temp. The exhaust pulses at the mufflers are balanced between the two sides. I set my valves to 3.5 /1000. Not between 3 and 5. I set ignition timing spot on.
My valve timing is precisely on the marks. I have high output accel coils and use a .040 plug gap on the stock D9ES. I also have a Dyna 2000 ignition and have modified the timing characteristics. I'm set to 12 deg of advance initially and from 1100 rpm to 4500 rpm, it feeds in another 20 deg for a full advance of 32 deg. I'm running 25 cm hg of vacuum at 1800 rpm. Stock main jetting is #120 on the 1,4 carbs and 122.5 on the 2,3 carbs. I run 122.5 mains on all four carbs.

When I synch carbs, besides the vacuum guages, I feel the frame and watch the mirrors. You can feel and hear it smooth out when everything comes together.

Be picky. :-)

Earl

Earl, so care to share some of your secrets here? I want my bike to run fast but I also want that swiss watch effect too. Mike J

[Anonymous]

Earl, as much as I admire your analness with setting up a bike ( in this regard I will follow you ), I cant understand your problems with removing carbs.
I just unscrew the bolts holding an airbox, make connection between both parts of box loose, pull an airbox back as much as possilble ( after unscrewing boots between carbs and a box ) and have enough space to yank carbs from the side of the bike.
I dont have to much problem with putting them back either.
I have to admitt, I bought a set of new boots ( between carbs and a head) four years ago.

Adam M.