# Rough running, need assitance for jetting.



## No_Substitue_For_A_Brute (May 4, 2011)

Hey guys I am needing some help with my jetting. I am new to MIMB but have to say I love the site. So here is what I've got. A used 2005 Brute Force 750, bought it with a full hmf penland pro exhaust (now added a quiet core), moose power module, I added 2" custom snorkels, 28" outlaws on ITP wheels. I am at 72' above sea level.

Currently Keihin 155 front main/ 160 rear main
stock pilot (38)
2 1/2 turns on A/F mix
2 washers under each needle, don't have a mic but they are 1/4" together.

The front plug looks white in center and edge is black, haven't pulled the rear one lately.

This is the closest I have gotten the bike to running right. At 0-1/4 it seems to run decent with no popping or such and is responsive, 1/4-3/4 it pops and shoots flames out the exhaust, doesn't have much power, pops on deceleration too, WOT seems to run good but doesn't get to top speed as quick as before it was jetted.

I would really appreciate any suggestions to help me make this thing run right again.


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## J2! (May 8, 2010)

It sounds like you are running lean. Stepping up to a 40 pilot will fix the popping on decel. I would step your mains up too about one or two sizes and see how it does. It may not be getting up to speed because it's starving for fuel. From 0 to1/4 throttle you are running mostly on the pilots, from 1/4 to wot it's running on the mains. You kinda confused me on the shims, they shouldn't be anywhere close to 1/4", that's ALOT. They should be a couple mm at the most. Do you have access to an LM1 or something to check your a/f ?? Check out Bootleggers guide to jetting on here, Alot of good info in that thread.


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## No_Substitue_For_A_Brute (May 4, 2011)

thanks for the input J2!. 

Here is my current setup.

Keihin 160 front main/ 165 rear main
stock pilot (38)
3 turns on A/F mix
1 washer under each needle, mic at .045"

She runs MUCH better now. Catwalks with no problem like a brute should. :arms:

I'm going to try and get two 40 pilots and put in it as its a little rough running at low speeds and still wants to pop on decel some.


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## brute for mud (Jul 15, 2010)

you deffinalty need bigger pilots any thing over 2 1/2 out not really doing much at all if anything at all


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## No_Substitue_For_A_Brute (May 4, 2011)

I ordered a couple #40 pilots today and will try them out. I'll let you guys know how it goes when I get them in. 

Thanks for the input guys!


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## No_Substitue_For_A_Brute (May 4, 2011)

So i got the #40 pilots in friday and got them installed. Took it for a ride yesterday and the popping on decel is definitely gone but at 0 - 1/4 it doesn't run smooth. I tried adjusting the A/F all the way from 1 turn to 3. At 3 its way too much and wants to pop and miss. 2 gets rid of the issues just doesnt run smooth. 1 turn out it pops and is really rough.

Not sure where exactly to go from here guys. I'm glad the pops gone but it cant be good for it to run so rough. Once you open it on up though past 1/4 all is well.

Thoughts/ideas?

thanks!


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## NMKawierider (Apr 11, 2009)

Might also check the carb boots between the carbs and the heads for splits around the edge of the clamps. Most 05 & 06s had this problem. Also, I was under the impression that the Moose only gave 3 degrees of advance where the Dynatek gave 5. Most of the pilot changes to #40 were with the Dynatek and not so much with the Moose..Might be bad info but it's in my head for some reason. :banghead: And yes, do not go over 40 thousands with the needle shims...and again, that number is for Dynatek CDIs and should be less with Moose...if the advance info is correct.


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## J2! (May 8, 2010)

Sounds like you might need to add one shim under your needles now.


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## Muddy Brute Force (Dec 17, 2008)

I agree with J2, add the second shim back to your needles and see if that doesn't cure your problems.


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## No_Substitue_For_A_Brute (May 4, 2011)

I finally had a chance to mess with this again yesterday. I added the second shim back to the needle and it ran MUCH worse. So I took both shims back out. It ran way lean then, pipe put out major heat real quick and it popped bad on decel again.

Not real sure where to go from here....Can't seem to find that perfect combo.


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## Muddy Brute Force (Dec 17, 2008)

No_Substitue_For_A_Brute said:


> I finally had a chance to mess with this again yesterday. I added the second shim back to the needle and it ran MUCH worse. So I took both shims back out. It ran way lean then, pipe put out major heat real quick and it popped bad on decel again.
> 
> Not real sure where to go from here....Can't seem to find that perfect combo.


What kind of washers are you useing for shims? You should be useing #4 brass washers that can be found @ just about any hardware store. I know that Lowes does carry them.


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## No_Substitue_For_A_Brute (May 4, 2011)

I had some small stainless steel washers around the house that I have been using. Mic out to be .045"


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## J2! (May 8, 2010)

That might be the problem.. From what you explained, one shim should have got you real close.


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## No_Substitue_For_A_Brute (May 4, 2011)

Muddy Brute Force said:


> What kind of washers are you useing for shims? You should be useing #4 brass washers that can be found @ just about any hardware store. I know that Lowes does carry them.





J2! said:


> That might be the problem.. From what you explained, one shim should have got you real close.


Ok I will try and get some #4 brass washers then and try them and report back. Thanks for the input guys I REALLY appreciate it. This thing is driving me crazy!


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## J2! (May 8, 2010)

I know how ya feel. These carbed bike can be a real pain sometimes, but when you get them right, WEEEEEEEEE !!!! LOL


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## No_Substitue_For_A_Brute (May 4, 2011)

Using the right washers made all the difference in the world! :woot: Runs great now all throughout the throttle range. I think the washers I was using were just big enough to hold the plastic claw piece up and left the needle loose to flutter at lower speeds until the slide moved up some.

Here is what I ended up with for a 2005 Brute 750i with Full HMF pipe and penland pro, with MIMB 2" center snorkels.

Keihin 160 front main/ 165 rear main
#40 pilots
2 turns out on A/F mix
1 #4 brass washer under each needle, mic at .025"

I think I spent about $30 total on my jets/shipping and washers. 

I do still have a small pop at low speeds but I believe two things are contributing to that. 1) moose power module - advanced timing 2) broken exhaust bolt in front cylinder causing exhaust leak.

I am not looking forward to that one. It's broke flush with the pipe flange. I took the pipe off and tried to get it out with some vice grips but it wouldn't come out. Other than drilling it and using an ease out anyone have some other suggestions? Looks like I would have to remove the whole front diff to be able to drill it.


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## Stogi (Feb 24, 2010)

The module will not cause the popping you have described. A loose, leaking head pipe will. Best bet would be to pull the head and let a machine shop extract the broken stud. Removing the head is a whole lot easier than pulling the diff anyway.


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