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jetting help


stacman450

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ok heres what ive got

 

HJR mx/hardcore port, stock stroke, stock carbs, VF3's, Pro Circuit pipes, stock air box. and +5 timing. (per kevin at hjr). milled head .30.

 

300 mains, 25 pilots. needle in 3 clip. air screws out 1.5 turns. im about 1500-1800 above sea level.. its 30 degrees here.

 

having hard time idling. its a brand new top end. so i need this to be right.. also it seems to miss if i give it a little throttle, but fine when i rev it a little more..

 

any input would be appreciated.. thanks you Merry Christmas..

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ok heres what ive got

 

HJR mx/hardcore port, stock stroke, stock carbs, VF3's, Pro Circuit pipes, stock air box. and +5 timing. (per kevin at hjr). milled head .30.

 

300 mains, 25 pilots. needle in 3 clip. air screws out 1.5 turns. im about 1500-1800 above sea level.. its 30 degrees here.

 

having hard time idling. its a brand new top end. so i need this to be right.. also it seems to miss if i give it a little throttle, but fine when i rev it a little more..

 

any input would be appreciated.. thanks you Merry Christmas..

 

Wow.... 300mains on stock carbs with port work? Woo wee... Keep your eye's on them plugs sounds like a recipe for melt down. My bike set ups with No airbox and just T-5 V-3's and +4 timing pump gas run 310 main jets. I'm not sure who HJR is or the type of work they do so i'm going to keep this post neutral they just might of just misunderstood your set up or something. Let me ask what needles you running and fuel?

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well i never asked anything to kevin at herr juggs. i had 250's on stock with just pipes, not 2 months ago..

 

it seems rich right now smoking really good. so you guys think i need to go up even more?

 

its been a few years since ive jjetted anything.. keep the opinions coming... thanks

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well i never asked anything to kevin at herr juggs. i had 250's on stock with just pipes, not 2 months ago..

 

it seems rich right now smoking really good. so you guys think i need to go up even more?

 

its been a few years since ive jjetted anything.. keep the opinions coming... thanks

 

stacman450

 

Still waiting on that needle bud is it stock or after market? Do you have the lid on or off on the air box?

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I would start rich at 340 main and work down if neccessary but its cold rite now.def 27.5 pilots 1 turn out to start needle 4th clip from blunt end.340 might be spot on in this weather but might need 320 in summer

 

X2. Start at 340's and see where your at. I'm running stock carbs with an agressive dune port and I run 310's in the summer weather......but I'm also at 5000ft.

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while your there get yourself some 27.5 pilot jets. no doubt that is part of your problem......aftermarket pipes really do need a lil more fuel at the low end. you can get jets from most site sponsors along with ordering them on-line or even snowmobile shops will carry the mikuni hex head main jets. If youd like you could even call a site sponsor (im gonna suggest Jeff at FAST) and tell him your mods and what jets your running right now and he'll tell you what you need to be running.....

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while your there get yourself some 27.5 pilot jets. no doubt that is part of your problem......aftermarket pipes really do need a lil more fuel at the low end. you can get jets from most site sponsors along with ordering them on-line or even snowmobile shops will carry the mikuni hex head main jets. If youd like you could even call a site sponsor (im gonna suggest Jeff at FAST) and tell him your mods and what jets your running right now and he'll tell you what you need to be running.....

 

 

 

x2 on the 27.5 pilots

 

x2 on the 4th clip

 

x2 on calling jeff at F.A.S.T.

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there we go. yeah i misunderstood my bro... bigblock is my builder.. :D

 

any one know a good place to order jets for decent prices. my yamaha dealershit is a joke...

 

 

Ok Cool got it. Thanks for that bigblock. Love your car in your avatar pic by the way too. I Got a 1968SS with a 6speed Manuel in the works Here's the pic of my motor just got the charger on it last week. I guess it's my Christmas present to my self lol... I so love them 68's Here's the pic of my baby's motor. I can't wait! It's been a 4 year build frame off car. it's a 383 stroker with a little push. Build it to run on 91 octane building it to be a road race style car. Leaving the drag racing on the quads lol...

 

100_1935.jpg

 

Now back to the subject i didn't want to get off course here lol....

 

My suggestion for jetting ported with airbox no lid

 

I'd suggest a 360m I know it's cold where your at as well elevation also recall it's a fresh ported top end. the idle issue can be lack of fuel possibly cause so cold where your at. but work with this and your idle screws.

 

Run your set up like this with airbox lid off it will be safe from the mud or get a outerwear lid cover. Don't choke out your Horse power. OuterwearsAirboxCover.jpg

360m

27.5 pilots a/s at 1- to 1-1/2 out to start

Needle clip *2nd from bottom* on the stock needle and i suggest keep the stock needle too they work the best on smaller bore motors VS the dyno jet or toomey needles. if it seem a little fat in the mid then raise the clip one more 3rd from the bottom. This might happen due to elevation and weather. but at least the 2nd from the bottom will be a safe start as well.

 

Now if you were @ sea level in regular 75 degree weather I'd suggest 370-390's but the elevation play's a little with trying to get it dialed in where your at.

 

If it's hard to start that might be normal due to it being so cold there. A little break cleaner or carb cleaner is the trick. I never rode in super cold weather but i know when it's cold they can be a little tough to start. after the 1st initial start I'm sure it will be no problem.

 

Still do a plug check do to I'm taking a guess with what type of porting. Either way you'll be a lot closer then where your at with the 300's

 

For sure let us know how it turns out. Curious minds like to know I'm sure.

 

If you need the jets I have them in stock as well. Stay with genuine Mikuni jets too. I seen a lot of knock off china jets on e-bay and are not the same.

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just spoke with my builder.. he told me around 310 mains, 27.5 pilots, and middle clip.. with lid on if thats how i want it.. which it is.. sometimes muddy around here.. so ill start around there.. and also i have not even pulled out of garage. just start up to get idle going.. so not even been in main jet yet..

 

when i started to mess with this thing it was bone stock and i put PC"s on it. and jumped from 200 stock to 260s. prob a littl rich cause it was summer time.. but ill start around 320 or so and if needed work down..

 

I hate jetting this sum biatches :shootself:

 

and btw.. bigblock's camaro is a slow POS.. :yank:

 

just playin bro ITS BAAAAD!!!!! :whoa:

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