# pilot jets?



## dirtydog (Nov 11, 2009)

Has anyone actually put bigger pilot jets in their carbs on a 750 . When u buy jet kits none come with different pilots . If u have put them in did they help and where do u get them ? A part number would be a blessing


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## NMKawierider (Apr 11, 2009)

When I put my CDI in I had to go from #38s to #40s and shim the needles like most people. I get mine from PJ motorsports. I believe they are N424-74C-40


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## dirtydog (Nov 11, 2009)

That's awesome man ! I know I can count on you guys . These local bike shops here acted like they couldn't get them for me and I brought one in for them th look at. Did it help with the heat at idle any?


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## NMKawierider (Apr 11, 2009)

dirtydog said:


> That's awesome man ! I know I can count on you guys . These local bike shops here acted like they couldn't get them for me and I brought one in for them th look at. Did it help with the heat at idle any?


Mine realy never had a heat problem. Mostly it gets rid of the leaning problems most have at or near transition between the slow curcut and the main system.


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## dirtydog (Nov 11, 2009)

For sure . I was just wondering as an added benefit did it run a little cooler. Getting down some trails where there is a lot of stop and go. But for sure they r lean from the factory and when u bump the mains up its a bigger transition. I've actually got a buddy that has a wierd drop off at exactly 20 holding steady. And we were wondering if that could be it


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## brute574 (Aug 10, 2011)

dirtydog said:


> That's awesome man ! I know I can count on you guys . These local bike shops here acted like they couldn't get them for me and I brought one in for them th look at. Did it help with the heat at idle any?


 Idle is Controled by your Air Screws, not Pilot jets.


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## dirtydog (Nov 11, 2009)

and if the pilot is bigger u can adjust a bigger range right?


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## NMKawierider (Apr 11, 2009)

brute574 said:


> Idle is Controled by your Air Screws, not Pilot jets.


Right, the slow/pilot circut feeds the a/f control circut as well as the intermeadiate up to transition so don't expect the idle mix to change. The screw does that.


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## brute574 (Aug 10, 2011)

dirtydog said:


> and if the pilot is bigger u can adjust a bigger range right?


 Bigger is just more Fuel. The 20 MPH Thing could be to much or not enough fuel from the Pilot, but the Needles might be off too.


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## dirtydog (Nov 11, 2009)

It is wierd cause the 20 mph thing is happening with three different cdi boxes and 3 different jet settings and multiple settings on the needles . Do u think that is about the transition point ? So a bigger pilot no matter what won't affect idle? That is screw settings alone?


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## wyo58 (May 13, 2011)

I'm pretty sure that bigger jets will effect the idle mixture but not as much as the idle mixture screws will. In other words you could get your pilot jets so large that the idle mixture screws will not be able to compensate the mixture. How far out are your idle mixture screws?


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## dirtydog (Nov 11, 2009)

On this brute 2.5 with 46 front jet 48 rear jet . Full muzzy k and n filter mimb snorkels and 4th notch on the needles


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## wyo58 (May 13, 2011)

I doubt your atv would benefit from larger pilot jets at all. Your friends with the dead spot at around 20 mph, it's tough to say because it depends completely where that is on his throttle. Like 574 said could be pilots or needles. Might want to make certain his carbs are clean as well, some of his passages could be gumed up too.


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## dirtydog (Nov 11, 2009)

We have had them completely apart even the choke cables. Its really throwing us for a loop though . It runs perfect all the way up and down and you can stay steady at any speed just not 20. The transition really was what we were betting on


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## NMKawierider (Apr 11, 2009)

dirtydog said:


> On this brute 2.5 with 46 front jet 48 rear jet . Full muzzy k and n filter mimb snorkels and 4th notch on the needles


I assume you mean 146 and 148 on the jets. I'm kinda supprized on the main jet sizes with the Muzzy. Usualy you have to jet up for that but those are below the originals which were 152/158s. Do you have the 2" snorkle?

On the pilots, I will say even though it shouldn't have made be adjust mu a/fs, it did...but only from 2.50 to 2.25 turns out. And, I did try the 42s but it was too much and it lost power at transition.


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## dirtydog (Nov 11, 2009)

Yeah 2inch snorkels . The guy he bought the bike from had 134 front 138 rear on third notch and 2 turns . Way too lean we tried 160 and 165 and it wouldn't work at all couldn't go up the street. It runs really strong right now just has that dead spot


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## J2! (May 8, 2010)

Does he have dynojet needles in it ?? You referred to notches so I'm assuming they are dynojets. If so, get you some factory needles to put in it. The dynojet needles are junk. Just throwing this out there to try and help, but it sounds like the problem is within the needles.


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## NMKawierider (Apr 11, 2009)

J2! said:


> Does he have dynojet needles in it ?? If so get you some factory needles to put in it. The dynojet needles are junk. Just throwing this out there to try and help, but it sounds like the problem is within the needles. You referred to notches so I'm assuming they are dynojets.


There's a thought...they are junk for sure.


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## dirtydog (Nov 11, 2009)

Yeah they r dynojet needles. How would you use the stock ones and change the flow


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## NMKawierider (Apr 11, 2009)

dirtydog said:


> Yeah they r dynojet needles. How would you use the stock ones and change the flow


Well, you shim them...with washers up to 40-thousands. If you get a set, the fronts and backs are different. One other thought, the DJ springs are very light and with snorkles, the vacuum levels increase quit a bit making the CV slide ver fast...maybe too fast to maintain asperation and it may have a bad flat spot...kinda like a carbed car with a bad excelerator pump..

You might just try the stock needles and springs. Might be what the doctor ordered.


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## dirtydog (Nov 11, 2009)

I will look into that for sure man. I've got a dj kit in mine and don't have any issues . I did see the dj springs are shorter and thicker though . Even though we set the needles at multiple settings with the same results?


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## dirtydog (Nov 11, 2009)

I thought that was why the holes were drilled in the slides


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## NMKawierider (Apr 11, 2009)

dirtydog said:


> I thought that was why the holes were drilled in the slides


Yeah...so thay can react faster..with less vacuum, lighter springs and shorter needles. They didn't take into account the restriction the snorkles have. They just wanted the best dyno results. I took my kit back out..can't do anything about that extra hole but its not doing anything bad for me.


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## J2! (May 8, 2010)

dirtydog said:


> Yeah they r dynojet needles. How would you use the stock ones and change the flow


the stock ones have a different taper to them, they fit better.


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## dirtydog (Nov 11, 2009)

So are there any differnt amounts you guys are shimming them to get different results. And without the c clips they don't ever hang up?


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## NMKawierider (Apr 11, 2009)

dirtydog said:


> So are there any differnt amounts you guys are shimming them to get different results. And without the c clips they don't ever hang up?


No issues. Go right to .0040. There is a post on washers to use you can get from lowes... I just machined some out of some brass stock. If you have the complete DJ kit it does come with some .0020 washers for their needles.


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## J2! (May 8, 2010)

I believe they are #4 brass washers from lowes..


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## dirtydog (Nov 11, 2009)

cool . i will stop by there today . im gonna start working on this thing right now im off today and ill let u guys know what i find


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## dirtydog (Nov 11, 2009)

Well I tried every combo of jets and needle settings u can . I can make the dead spot change a little but it is there none the less. The only way I made it go away was drive it up the street with the lid off the air box . Any thoughts on this ?


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## NMKawierider (Apr 11, 2009)

It actualy ran past 1/3 throttle with the lid off? Un real...Most Brutes would be so lean it would stop about there.

There was only one other carbed Brute I know of that could do that but it was because he went up like 6 jet sizes from stock. You are not quire there but you must be getting extra fuel from somewhere. You....might just have a leaking choke plunger...or two or the cable adjustment is too tight...or they got twisted once when the carbs were off.


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## J2! (May 8, 2010)

Do you have the 3" snorkle everyone talks about ?? Go down a size or two on the mains and see how it does.


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## dirtydog (Nov 11, 2009)

Just the 2 inch snorks . Chokes r good for sure. With the lid off I had it at 140 f 142 r and 4th notch at 2 turns af screws. It was lean but as long as I didn't just peg the throttle it drove fine


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## dirtydog (Nov 11, 2009)

I tried every jet setting that comes in the kit other than the 130s . The best feeling set up I found was 146 f and 148 r. 4th notch 2 turns on af screws.


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## dirtydog (Nov 11, 2009)

I can't understand how this thing runs on almost any setting you can think of but mine wouldn't run right after I put the snorkel on .


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## NMKawierider (Apr 11, 2009)

Maybe its time....to go to the 3" snorkle...


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## dirtydog (Nov 11, 2009)

wow !!!!! let me start by saying thanks for all the advice. this brute was bought with 10 hrs on a rebuild and 350 total miles on it. it had some chatter we figured the valves were off some. we checked the valves and the intake valves were touching plus 3/4 over tight . the exhaust valves were about 20 thousands out supposed to be 8 k. and the intake were supposed to be 4 k . well surely after all this the chatter should be gone. no. just as loud . its internal. in the chain system. its throwing off the cam timing is where we are. this was done at a dealership. they may actually stand behind it.


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