# Rejetting After 3" Snorkle Installation



## NMKawierider (Apr 11, 2009)

This thread is mostly for all the carbed Brute owners but all you guys with carbed machines are welcome to post here.

A while back we went to the 3" air box snorkel because most everyone had to jet-down when they installed the 2" due to the additional restrictions. 

However, there have been a few that report they did have to make some jet change after installing the 3" after all. Some had reasons that include cutting out the air box port to make it larger, or additional bends that others didn't make , turning the 90 or 45 forward into the wind, some also added full pipes and CDIs along with engine mods. These are understandable. 

However, a few folks did have to re-jet that made no other changes or mods after installing the 3" snorkel. This is what we are looking to understand better.

Lets do the poll and post-up your experience. Lets hear your entire snorkel story and include any extras you might have done....and the elevation where you live and how much you had to go...either way.


----------



## wcs61 (Jun 7, 2011)

Interesting poll for me. I have to go to the 3" soon and this will help if I encounter problems. Right now I have glowing tail pipes and hopefully I can find someone with an exhaust gas tester before making the change and re-test afterwards. I'll be watching this one.

Should be linked to the 2 or 3" thread.


----------



## ozziestprime (Mar 16, 2010)

if your pipes are glowing your already to lean, moving up to a 3" will increase the airflow and thus lean the motor even more. your gonna have to move to larger jets., this will enriching the air fuel mix. and lower the temps. just keep cleaning and checking your plugs this is the best indicator of fuel mix.


----------



## redneckrancher420 (Jul 5, 2011)

My friend dis a 3" center and hmf exhaust and had to rejet. Was getting too much air. He should have pics up here of it. Hes southernbrute750


----------



## wcs61 (Jun 7, 2011)

ozziestprime said:


> if your pipes are glowing your already to lean, moving up to a 3" will increase the airflow and thus lean the motor even more. your gonna have to move to larger jets., this will enriching the air fuel mix. and lower the temps. just keep cleaning and checking your plugs this is the best indicator of fuel mix.


 and others here think different. I thought lean already but the Guru's say different so I'll have to experiment with snorkels.


----------



## southernbrute750 (Jul 5, 2011)

Did the 3" snorkle on my 05 brute and was getting entirly way to much air. Only other mods to affect this was my HMF untility exhaust. once it was all said and done i had to cover half or a little more than half of the intake in order for the bike to go anything higher than idle. my elevation is right at sea level or maybe 10 -20 being in southern louisiana.


----------



## southernbrute750 (Jul 5, 2011)

Any body else have anything pertaining to this matter? im really interested as to what everyone had to do or didnt have to do when they did a 3" snork as NMK said.


----------



## dirtydog (Nov 11, 2009)

I have the mimb set up and stock everything else . Did a stage 1 dynojet kit just like the instructions say and I'm happy for sure. Follow the directions exactly. I am in the northwest panhandle of florida and it said different settings for different levels. Don't just put in the jets though . U have to do the needles.


----------



## wyo58 (May 13, 2011)

wcs61 said:


> and others here think different. I thought lean already but the Guru's say different so I'll have to experiment with snorkels.


Two questions wcs:
1. does the power commander remove the factory timming retard at speeds lower than 10 mph?
2. Is it backfiring out the exhaust? or out the intake possibly?

Also where are most people connecting thier snorks to the factory airbox?


----------



## wyo58 (May 13, 2011)

Maybe the key to this is what exactly people are doing to thier stock air-boxes. Meaning are they connecting the 2or3" directly to the factory opening or are they modifying the factory opening to fit the snork pipes. It would sure make sense that leaving the factory opening alone and connecting the 3" to it should cause zero problems with air/fuel ratio's. I can see where the 2" would cause some problems because it's smaller than the stock factory opening in the air-box.


----------



## southernbrute750 (Jul 5, 2011)

wyo58 said:


> Maybe the key to this is what exactly people are doing to thier stock air-boxes. Meaning are they connecting the 2or3" directly to the factory opening or are they modifying the factory opening to fit the snork pipes. It would sure make sense that leaving the factory opening alone and connecting the 3" to it should cause zero problems with air/fuel ratio's. I can see where the 2" would cause some problems because it's smaller than the stock factory opening in the air-box.


I didn't mess with the stock opening. Just connected my 3" rubber 90 directly to the stock opening.


----------



## wyo58 (May 13, 2011)

I didn't mess with the stock opening. Just connected my 3" rubber 90 directly to the stock opening. 

That is really strange as I said in your picture posting, should have made almost zero difference in jetting. Oh well You have it going so live and learn.


----------



## southernbrute750 (Jul 5, 2011)

Yeah. That's the way I'm taking it Hahaha. I fi have to say I feel for my bike being carbed, throwing the 3 inch snorks on there and jetting made a pretty good difference in my throttle response.


----------



## wcs61 (Jun 7, 2011)

wyo58 said:


> Two questions wcs:
> 1. does the power commander remove the factory timming retard at speeds lower than 10 mph?
> 2. Is it backfiring out the exhaust? or out the intake possibly?
> 
> Also where are most people connecting thier snorks to the factory airbox?


As for the power commander, I haven't a clue. The previous owner installed it and I haven't researched it.

As for the hook-up I did not alter the air box at all. Here ia a photo taken during installation or re-running of the 2" snorkels. The previous owner had the side mounted snorkels and after breaking one it was time to de-Aeng. the thing.

http://i413.photobucket.com/albums/pp215/rolltide777/IMG_0504.jpg

Need to do something about that ugly arse exhaust pipe too!


----------



## wyo58 (May 13, 2011)

wcs looks like a good clean installation! Is it backfiring out the exhaust or the intake?


----------



## myst3ry (Mar 5, 2011)

my stuff is all in for this ( thanks VOGIE ) and i will update after i install everything ...

great thread nwk !!


----------



## NMKawierider (Apr 11, 2009)

This is all good information on this 3" snorkel stuff. Thanks guys. I think this will help lots of people. 

Like I said in another thread, looks like just adding the 3" is making some get more air. I wonder if making the air come around the stock deflector is harder for it then shooting straight in through a tube. Well, at least its not restricting it like the 2" was. Hay, anybody ever try a 2 1/2"?


----------



## wcs61 (Jun 7, 2011)

nmkawierider said:


> This is all good information on this 3" snorkel stuff. Thanks guys. I think this will help lots of people.
> 
> Like I said in another thread, looks like just adding the 3" is making some get more air. I wonder if making the air come around the stock deflector is harder for it then shooting straight in through a tube. Well, at least its not restricting it like the 2" was. Hay, anybody ever try a 2 1/2"?


 Yes there was a thread and when I asked the guy if he got the 2.5" at a pool supply business he never answered. Maybe it was on the other sites?


----------



## wcs61 (Jun 7, 2011)

wyo58 said:


> wcs looks like a good clean installation! Is it backfiring out the exhaust or the intake?


Give me a couple til monday and I'll see. Been gone for a month and can't recall for sure. I changed the snorkels shortly before comiong to work and when I noticed the glow i didn't ride it much. If it backfires it is was, as I recall, always from the exhaust.


----------



## wyo58 (May 13, 2011)

wcs61 said:


> Give me a couple til monday and I'll see. Been gone for a month and can't recall for sure. I changed the snorkels shortly before comiong to work and when I noticed the glow i didn't ride it much. If it backfires it is was, as I recall, always from the exhaust.


 
Ok np when you get a chance to ride it also when it's backfireing like off throttle or 1/4, 1/2, etc.


----------



## dman66 (Feb 20, 2011)

*3" snorkle*

OK guys,just throwing in my findings here. I am installing a 3" pvc intake. I purchased the drainage type pvc fittings in thinking that schedule 40 pvc pipe would fit into the drainage fittings - the sch.40 pipe and sch. 40 pvc fittings are larger than the 3" drainage pvc fittings.Also if you had bought a 3" rubber 90, the ends accept 3" pvc,but the inside of the rubber 90 is 2 1/2".As soon as I get some drainage pipe,I'll post back how she runs after the 3" center snorkle is installed.


----------



## killer666 (May 29, 2011)

if i do 3'' snorkels on my bike am i gonna have to re-jet again? i have full biggun dynatek cdi and 155f/160r and its running good. i really want to snorkel my bike but i really dont want to re-jet again.


----------



## southernbrute750 (Jul 5, 2011)

As of right now its kindest hit or miss with the jetting. It seems as though us guys down here in the south closer to sea level have to re jet. Then people at higher elevations are having less issues with it. That's the only thing I can honestly think of. Only thing you can do is give it a shot. If you have your needles close with your cdi and exhaust, you may only have to do some very fine tunning.


----------



## killer666 (May 29, 2011)

actually i think i had the worst time jetting because of what i did and im at about 3000ft elevation. i had to put a 750 jet kit in but thats not a big deal. so basicaly its gonna be trial and error


----------



## REDBRUTE1 (Oct 30, 2010)

I have the same jet setup 155/160 and 2" snorkles,my bike topped out at 80 Km/h . with your mods and 3" snorkle I think you will be fine


----------



## dman66 (Feb 20, 2011)

*3" snorkles*

If you want to test the 3" snorkle set up out,without installing the actual snorkles,just take a 3" rubber 90,install it on the stock intake without the 3" piping,and run the bike to see how she does with jetting.I'm at 158/160 main jets {kehin},and the bike pulls great.


----------



## killer666 (May 29, 2011)

thanks dman thats a great idea im gonna try that


----------



## southernbrute750 (Jul 5, 2011)

dman66 said:


> If you want to test the 3" snorkle set up out,without installing the actual snorkles,just take a 3" rubber 90,install it on the stock intake without the 3" piping,and run the bike to see how she does with jetting.I'm at 158/160 main jets {kehin},and the bike pulls great.


Also have to take in consideration of the amount of bends off the 3" rubber 90*. The that alone will alone more "free flow" compared to running your snorkles up and out


----------



## Astaelan (Jul 24, 2011)

Okay, thought I'd post my experiences, even though I'm running 2". So far I've found too many factors to consider, elevation is bigger than I thought. First the machine, I got it used, with a muzzy, the previous owner said he didn't need to rejet, once I got the machine home I could tell it wasn't running quite right, the smell and hesitation, and some backfiring. Now, I did the snorkels much the same as the MIMB, with one difference, instead of a 3" 90* rubber, I used a 3" to 2", and used 3 90's instead of a 90 and 45. Which, compared to MIMB, means I restrict the flow even more. After doing this, my bike runs a lot better, and now it's just a little bit fuel starved (if I cover half the intake snorkel, it takes off the start with less hesitation, but it's still there, I need to increase fuel maybe 1 size, I backfire a lot less, mostly when letting off the throttle quickly on a long, faster stretch).
All this said, I'm still running on stock jets, but I ride at 3000 feet, where most people are closer to sea level, or below 2000 I think. The air is much richer closer to sea level, until you start looking into humidity factors right at sea level. I am planning to take my machine in to rejet for a little more fuel, but that aside, as far as I can tell, too much air has been my problem even at higher altitudes where the air is thinner... It seems to me like using 3" here, or lower altitudes would pretty much force you into rejetting, simply too much air. Now I realize the original airbox has a 3 inch intake, but I wouldn't be able to wrap my head around going to 3" and then having to face it forward to force air in, unless the machine was already rejetted for other reasons prior.

Since I don't run 3", I won't vote on the poll, but I would say that you'd pretty much have to rejet going to 3" anywhere below.... probably around 5000 feet, give or take? If you want some real numbers to work with, google "air density versus altitude". From 0 to about 7000 feet, there is close to a third drop in air density, it's pretty significant.


----------



## dman66 (Feb 20, 2011)

*3" snorkles*

Completed the 3" center intake snorkle made from 3" thin wall drainage pvc. After running the bike I found that at about 1/4 to 1/2 throttle,I have a hesitation. Time to play with reshimming the needles. I have factory needles NFKK/NFKL with # 40 pilots at 2 3/4 turns out on A/F screws,and Kehing main jets at 158 f/160r. With just the 3" rubber 90 installed the bike ran perfect,after adding the additional pipe,the bike developed the 1/4 - 1/2 throttle hesitation. Back to the drawing board with checking for air problems.


----------



## NMKawierider (Apr 11, 2009)

Interesting. Do you think its a lean stumble or a rich issue? That range is where they transition from the slow/pilot system to the mains. Wonder how she would act with the choke on just a touch.


----------



## dman66 (Feb 20, 2011)

*3" snorkle*

With the 3" center snorkle,I tried to reshimm the needles - first I had one shimm on each needle from the start. Then I tried two shimms - then tried three shimms. Did'nt go to well. I did try turning on the choke,and the idle went up in rpms,and the lean stumble cleared up.Should I try larger #42 pilots, larger mains,or trysomething else?


----------



## NMKawierider (Apr 11, 2009)

dman66 said:


> With the 3" center snorkle,I tried to reshimm the needles - first I had one shimm on each needle from the start. Then I tried two shimms - then tried three shimms. Did'nt go to well. I did try turning on the choke,and the idle went up in rpms,and the lean stumble cleared up.Should I try larger #42 pilots, larger mains,or trysomething else?


What do you have for pilots now? I once tried 42s but they were too much.


----------



## nathen53 (Jun 13, 2011)

Just finished the 3" snorks and it runs good but it seems to be flooded when I first try to start it not sure if it's the new dynatek or what


----------



## dman66 (Feb 20, 2011)

*3" snorks*

NMK,I currently have # 40 pilots installed,so thats why I was thinking to go to # 42 pilots? nathen53,need more info on how your carbs are set up - what size pilots,wheres your A/F screws set at,main jet type and sizes,what needles are in,and what mods you have to engine,what size snorkles? nathen53 have you checked you chokes on each carb to insure they're not stuck on,and have you checked your valves and or plugs lately?


----------



## nathen53 (Jun 13, 2011)

dman66 said:


> NMK,I currently have # 40 pilots installed,so thats why I was thinking to go to # 42 pilots? nathen53,need more info on how your carbs are set up - what size pilots,wheres your A/F screws set at,main jet type and sizes,what needles are in,and what mods you have to engine,what size snorkles? nathen53 have you checked you chokes on each carb to insure they're not stuck on,and have you checked your valves and or plugs lately?


I don know what I have in my carbs guy I bought it from said it had been jetted when he snorkeled it 2" but it didn't run good. I just changed it to 3" today and runs good just hard to start it not the valves or choke cable and all I have I a hmf slip on could it be the the carb vent lines I changed the size of the line to a smaller one to run it to the pod?


----------



## dman66 (Feb 20, 2011)

*3"*

nathen53,try covering 1/2 of your intake snorkle,then try starting the quad.see if that helps you out.If it does,chances are that theres too much air with the 3" intake - I imagine you have the chokes partially on when starting the engine when engine is cold start up.ith the 2" intake,your bike had to be jetted lower in main jets.


----------



## dman66 (Feb 20, 2011)

*3"*

UPDATE PROGRES: OK,Today I took off my needle shimms,and just put back one shimm on each needle,and retried the 3" intake.Well the throttle is still breaking up at 1/4 - 1/2 throttle with 3" center intake.Now,I took off the 3" intake snorkle and just left the now 22 1/2 deg. rubber 90,and she runs great. So I think maybe with the snorkle attatched,that the engine could be loosing vaccum - I don't know? Any suggestions on this,cause I'm ready to go back to 2" intake.Off the air box factory opening,I have the rubber 3" 90 - now 22 1/2 deg.,a thin wall 3" street 90,thin wall 3" 45,8" straight up thin wall 3" pipe,3" rubber coupler, then 3" thin wall street 90. 

UPDATE PROGRESS #2: Today I installed #42 pilots,on each carb and set each air/fuel screw at 2 turns out - ran the bike - the stutter between 1/4 -1/2 throttle is better.Then I adjusted A/F screw to 2 1/2 turns out,and now have two washers under each needle - the stutter is almost gone.If I put on the 3" rubber coupler with a 90 on top the air/fuel ratio starts going south,so I may just stick a street 45 on top of the 3" intake upright tube.For now,I think I'll adjut A/F screws out to 3 turns and live with it,but I think #44 pilots could be in the near future. Rejetting is looking brighter though - thank god..........


----------



## subforeman (Jan 2, 2010)

just did the 3 inch snorkel on my '06 carb 750 and i did not have to rejet. i did have to reduce the end of the snorkel down just a little. everything is completely stock excpet for a UNI filter and HMF slip on. Bike runs like a top!


----------



## gusguy (Aug 18, 2009)

Just got done with the 3" and now on the jetting. Running 146f and 150r dyno jet with three shims on the needles. It rips pretty good except for when you hit it from a stop. It stumbles really bad and then takes off hard. I thought a stumble like that was from lean needles but mine are pretty good thru the midrange. Can any one tell me what makes it do this. Stock motor with a twin air and full big gun


----------



## NMKawierider (Apr 11, 2009)

gusguy said:


> Just got done with the 3" and now on the jetting. Running 146f and 150r dyno jet with three shims on the needles. It rips pretty good except for when you hit it from a stop. It stumbles really bad and then takes off hard. I thought a stumble like that was from lean needles but mine are pretty good thru the midrange. Can any one tell me what makes it do this. Stock motor with a twin air and full big gun


Vacuum drops so fast it leans. Kinda like a carbed car with a bad excelerator pump. The slow circut probably could use a #40 pilot. Might also make sure the float levels at correct and the A/F screws are around 2.5 turns out as well.


----------



## gusguy (Aug 18, 2009)

I'll give the 40's a try. I backed the a/f screws out to 3.5 to get rid of some popping around 12-15 mph. Where's the best/quickest place to get pilot jets from. Closest kawi dealer is 3 hr away


----------



## NMKawierider (Apr 11, 2009)

gusguy said:


> I'll give the 40's a try. I backed the a/f screws out to 3.5 to get rid of some popping around 12-15 mph. Where's the best/quickest place to get pilot jets from. Closest kawi dealer is 3 hr away


Lots of places but I get mine from PJmotorsports.


----------



## gusguy (Aug 18, 2009)

Well after getting pushed aside for lack of patience I'm back at it now. I tried everything from stock pilots to the 45's and couldn't get rid of a bad stumble. Today I tried putting the dynojet needles back in on the 5th notch and that got rid of my stumble. I'm a little worried about running lean in the mid range cause of the cold dense air. Is there a way to richen up the dj needles past the 5th notch. Can I throw a shim under the needle?

Also don't know if this means anything to anyone but when I ran it without the snorkel and the airbox wide open on the front it ran great. When I put the snorkel on it would run it lean. This is with a 4" riser and a 45 on top. Didn't make sense. Maybe some one can explain it


----------



## NMKawierider (Apr 11, 2009)

gusguy said:


> Well after getting pushed aside for lack of patience I'm back at it now. I tried everything from stock pilots to the 45's and couldn't get rid of a bad stumble. Today I tried putting the dynojet needles back in on the 5th notch and that got rid of my stumble. I'm a little worried about running lean in the mid range cause of the cold dense air. Is there a way to richen up the dj needles past the 5th notch. Can I throw a shim under the needle?


You can shim any needle bit once you have it all the way up and need more, its better to go up a size on main jet and set the pin back down.


----------



## Nick_08 (May 29, 2013)

2005 with twin air filter, stock exhaust, moose module, snorkels are setup exactly as on this forum...

Rubber 90>sewer pipe>90*>45* and up. 

I was getting to much air (resulting in hesitation) if I stabbed the throttle from a stop or light roll. Added a pvc drain gate and fixed the problem. Runs great now.


----------



## pmk6181 (Apr 2, 2013)

*Brute backfires when stuck*

Good Afternoon,

I have been reading through the forums and trying to get some help with my 07 Bruteforce 750 with snorkels (3inch intake). I have been unable to locate the answer to my question.

Problem- 

Quads running rich. Lots of carb all over brand new plugs after 1 use. So of course I will look at the at A/F screw but my next question baffles me. When stuck in the mud I get a really bad backfire ( sounds like a shotgun going off). This only happens when I'm stuck and need a lot of throttle. Any advice would be much appreciated..

Paul.


----------



## NMKawierider (Apr 11, 2009)

pmk6181 said:


> Good Afternoon,
> 
> I have been reading through the forums and trying to get some help with my 07 Bruteforce 750 with snorkels (3inch intake). I have been unable to locate the answer to my question.
> 
> ...


Probably dumping so much fuel pinned it builds up and explodes in the pipe. If everything else is stock then the stock main jet size should be a good starting point. The A/Fs only control idle mix. All 750s with carbs came with #152s in front and #158s in the rear with #38 pilots. If yours has these, then I suggest you check/set your float level. DO check the valve lash first though.


----------



## bruteman88 (Jul 3, 2013)

I need help with mine. It's an 07 750 and it does fine at low speeds but when you get up to 30 or so it hesitates and sputters and all sorts of stuff. But when I turn the snorkel kit around using ram air then it will get up to 40 until it starts to sputter. Some people say its because my stock exhaust was cut off at the end so there is just a huge hole in the end of it and it may not have e bought back pressure. Would getting the HMF pipe and HMF rejeting kit fix all this?

---------- Post added at 08:03 PM ---------- Previous post was at 08:02 PM ----------

And it's only a 2" snorkel


----------



## NMKawierider (Apr 11, 2009)

bruteman88 said:


> I need help with mine. It's an 07 750 and it does fine at low speeds but when you get up to 30 or so it hesitates and sputters and all sorts of stuff. But when I turn the snorkel kit around using ram air then it will get up to 40 until it starts to sputter. Some people say its because my stock exhaust was cut off at the end so there is just a huge hole in the end of it and it may not have e bought back pressure. Would getting the HMF pipe and HMF rejeting kit fix all this?
> 
> ---------- Post added at 08:03 PM ---------- Previous post was at 08:02 PM ----------
> 
> And it's only a 2" snorkel


Unfortunately these are designed to have a balance of intake restriction and exhaust back pressure. Can't just cut the pipe off and let it open-discharge without having issues like complete loss of savaging. 

If it were me...I would at least get a slip-on..HMF if you like..then get rid of the 2" setup for a 3", then see about jetting if needed. If you keep the 2", plan on coming down 1 size or two on the mains and for sure get a good airfilter. Uni or Twinair are great filters.


----------



## bruteman88 (Jul 3, 2013)

NMKawierider said:


> Unfortunately these are designed to have a balance of intake restriction and exhaust back pressure. Can't just cut the pipe off and let it open-discharge without having issues like complete loss of savaging.
> 
> If it were me...I would at least get a slip-on..HMF if you like..then get rid of the 2" setup for a 3", then see about jetting if needed. If you keep the 2", plan on coming down 1 size or two on the mains and for sure get a good airfilter. Uni or Twinair are great filters.


So your saying that its not getting enough air? And what do you mean complete loss of savaging?

---------- Post added at 08:30 PM ---------- Previous post was at 08:19 PM ----------

And I'm pretty sure it still has the stock air filter

---------- Post added at 08:31 PM ---------- Previous post was at 08:30 PM ----------

But I didn't install the 2" setup so I have no idea how to change it all out with 3. Plus isn't this thread about problems with 3" setup? Just really confused. And what would no back pressure really do?


----------



## dman66 (Feb 20, 2011)

Put a stock or aftermarket muffler back on it,then check to see if it needs jetting. 2" intake snorkles will rob power at mid to WOT,THATS WHY MOST INSTALL THE 3" INTAKE SNORKLE.More than likely the 2" intake and jetting is way off. Install a good muffler,pull the carbs and record the jets in each carb.then we can help more.


----------



## NMKawierider (Apr 11, 2009)

dman66 said:


> Put a stock or aftermarket muffler back on it,then check to see if it needs jetting. 2" intake snorkles will rob power at mid to WOT,THATS WHY MOST INSTALL THE 3" INTAKE SNORKLE.More than likely the 2" intake and jetting is way off. Install a good muffler,pull the carbs and record the jets in each carb.then we can help more.


:rockn:


----------



## pmk6181 (Apr 2, 2013)

I'm fairly mechanically inclined and was comfortable jetting if need but could you please explain where and what the valve lash is?

Much appreciated


----------



## dman66 (Feb 20, 2011)

There's videos on you tube on this topic of how to check/ adjust your valves - just do a search on this site on valve adjustment - it's been posted and lots of threads on this . Here's the link.....http://www.mudinmyblood.net/forum/67-engine-exhaust/17172-adjusting-valves-video-camokvf700.html


----------



## DavidC65 (Aug 2, 2019)

Bruteman88, are you in Atlanta? If so can you email me at [email protected]?


----------



## NMKawierider (Apr 11, 2009)

DavidC65 said:


> Bruteman88, are you in Atlanta? If so can you email me at [email protected]?


The last time he even logged-in was 2013so don't hold your breath


----------

