# 08 bf 650i jetting question



## conaan (Mar 4, 2010)

hi everyone ,newbie here.I've been lurking on here for a little while so I decided to join.I've got a 650i and i just put a hmf utility full system on and 2 in ch snorkels . I was wandering on what jets to use .I was told at my local dealer it had 138 and 142 mains in now, so i bought a 148 to put in one carb and move the 142 to the other. To make a long story short it has 155s in both carbs ,so now i am at a standstill.also what is a good baseline for the the air/fuel screws ? any info would be greatly appreciated. it also has a twin air filter.


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## 650Brute (Dec 18, 2008)

What is the bike doing?


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## conaan (Mar 4, 2010)

probably 70 % trails 30% mud


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## derk (Nov 24, 2009)

conaan i think he was asking what symptoms the bike was having as far as running conditions. If you have 138f 142r you should be very very close. I have 136f 140r, but your pipe probably flows a little better than mine so you may want to go one step up. The 155s that are in yours now are the stock kehlins(sp) so you're really at stock jetting right now, atleast on the main jets from what you've told us. Give us a little more info and we'll try our best to help you out.


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## conaan (Mar 4, 2010)

i haven't rode it since i put the pipe on. The 138 and 142 are stock jets in a 650 sra ,the 650i comes with 155 s in both carbs stock. I was just wanting some info on where to start .the 142 and 148 combo is for a 650 sra or prairie. all these jet numbers are kehein numbers not dynojet. I've got the carbs off so I was wanting to go ahead and change the jets and make whatever adjustments while i have them off.


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## derk (Nov 24, 2009)

Go with what dynojet says for the idle mixture/pilot as well as the vacuum slides. For the mains 136/140 or 140/144 should be about right. Dynojet says to put the same jets in front and rear, but i would go one step up in the rear to help keep the rear cylinder cool. Maybe Bootlegger can chime in, he's the carb wiz.


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## BIGPUN (Dec 20, 2008)

bootlegger told me 140 f & 144r and it works good


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## 650Brute (Dec 18, 2008)

138 f & 142 r, 2" Snorks, HMF, and I am spot on now.. I little hiccup on deceleration after a WOT run, but my plugs look great.


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## Bootlegger (Dec 18, 2008)

If you need any help jetting just PM me and I can help you out. Are you using a Dynojet kit? If not, I would get one...its a LOT easier then trying to mess with the kehein jets. Yours is the I model....correct? If so they will jet different than the SRA will.


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## DaveMK1 (Nov 8, 2009)

If you go to the HMF website they list the proper jets for your bike and exhaust combo. I installed a HMF swamp series and followed their jetting suggestions, I didnt have to mess with the mixture screws and the bike runs like a dream.


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## Bootlegger (Dec 18, 2008)

DaveMK1 said:


> If you go to the HMF website they list the proper jets for your bike and exhaust combo. I installed a HMF swamp series and followed their jetting suggestions, I didnt have to mess with the mixture screws and the bike runs like a dream.



They won't work well with snorkels.


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## 650Brute (Dec 18, 2008)

Bootlegger said:


> Yours is the I model....correct? If so they will jet different than the SRA will.


I just saw that in his post,... Oops.


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## conaan (Mar 4, 2010)

i fooled with it some today.i left the stock jets in put 1 shim under the front needle and 2 under the rear with the front screw 1 1/2 turns and the rear 2 turns out and it runs like a raped ape . no backfires or miss at any speed. I just cant figure out why the 650i has the same jets front and rear and none of the others do.


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## Bootlegger (Dec 18, 2008)

conaan said:


> i fooled with it some today.i left the stock jets in put 1 shim under the front needle and 2 under the rear with the front screw 1 1/2 turns and the rear 2 turns out and it runs like a raped ape . no backfires or miss at any speed. I just cant figure out why the 650i has the same jets front and rear and none of the others do.


Good Deal...most every bike is different on jetting....that is why. On the 650i the rear cylinder does not get as hot as the 750's.


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## AMR840 (Feb 15, 2010)

Bootlegger said:


> If you need any help jetting just PM me and I can help you out. Are you using a Dynojet kit? If not, I would get one...its a LOT easier then trying to mess with the kehein jets. Yours is the I model....correct? If so they will jet different than the SRA will.


Bootlegger you are a very useful and knowledgeable person to site and helped many I'm sure.
My problem is the dynojet needles are junk when I've tried jetting with them. 
Could be my elevation I'm not sure. They did not work on my 03' 700 prairie or my 05 brute. I bought 2 kits and it was a waste of money. I found it was much easier to just shim needles and change jets. I know people like Fundy Dyno Ray love them also so just saying I can't get the needles right and may be a minority here but feel many feel the same as I do on the kits. 
As much as I try and wean myself from KR, I think it would be unaimous what I said if anyone asked about the dynojet kits. I use a A/F meter for jetting so just giving my experience and not trying to step on any toes believe me. Especially yours, could be I'm just at that elevation kits don't work.


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## Bootlegger (Dec 18, 2008)

AMR840 said:


> Bootlegger you are a very useful and knowledgeable person to site and helped many I'm sure.
> My problem is the dynojet needles are junk when I've tried jetting with them.
> Could be my elevation I'm not sure. They did not work on my 03' 700 prairie or my 05 brute. I bought 2 kits and it was a waste of money. I found it was much easier to just shim needles and change jets. I know people like Fundy Dyno Ray love them also so just saying I can't get the needles right and may be a minority here but feel many feel the same as I do on the kits.
> As much as I try and wean myself from KR, I think it would be unaimous what I said if anyone asked about the dynojet kits. I use a A/F meter for jetting so just giving my experience and not trying to step on any toes believe me. Especially yours, could be I'm just at that elevation kits don't work.


I agree on some bikes. I have had trouble with them on SRA bikes like the Praries and the Brute SRA more than any. Out of the Sixty plus Brute "I" models, I have had issues with the needles on about 7 or 8 of them. The ones I found the issue on was the Brutes that had to have a 144f and 148r size jets and up on. In the range of 134 to a 144 they work fine on....I just found it aggravating to have to buy a bunch of different size jets each time cause I have seen so many with the same mods use totally different jetting....but Yes, I do agree that some bikes have issues with Dynojet needles. In my situation its easier to get the Kit even if I have to go back to stock needles in a few cases. I use the new springs with the stock needles if I have to go back to them. I just did one this past week that I had to keep the stock needles....but it was a SRA Brute....and yes the elevation can change it. The bikes I have had to use the stock needles on seem to be the ones without the Dynotek CDI's. Cause you know they can cause the bike to have that misfire to them. No Biggie!

Since I do all the jetting at work I have ran into so weird stuff with these bikes. I jetted a 07 750 a few weeks ago that had the same size jets in it from the factory. First one of those I have ever seen...lol


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## AMR840 (Feb 15, 2010)

I'm sure it has to do my elevation and just never had the patience to use the little washers and get it right. The needle taper just seemed to steep.


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## Bootlegger (Dec 18, 2008)

AMR840 said:


> I'm sure it has to do my elevation and just never had the patience to use the little washers and get it right. The needle taper just seemed to steep.


I agree...it is kinda step but they have worked well for me most all the time. What is your elevation?


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## killer666 (May 29, 2011)

i am also new here and was woundering about jetting. i put a big gun exhaust, k&n,dynatek cdi,and dyna coils. the package came with dynojet jets stage 1, and was woundering what i should use for jets? i think my elevation is about 1500 feet. its not snorkeled or clutched. thank you


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## NMKawierider (Apr 11, 2009)

killer666 said:


> i am also new here and was woundering about jetting. i put a big gun exhaust, k&n,dynatek cdi,and dyna coils. the package came with dynojet jets stage 1, and was woundering what i should use for jets? i think my elevation is about 1500 feet. its not snorkeled or clutched. thank you


What machine do you have? I would be tempted to start about two sizes up from what Dynojet says for stock applications. JMO.


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## gusguy (Aug 18, 2009)

I need a little help also. 05 brute 750, 2" snorkel, dynatek. Just installed a big gun evo with a dynojet kit. 150f and 155r, needle on the fourth notch, a/f screws out 2 1/4. At 35 and over it falls on it's face untill you give it more throttle. Any advice?


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## killer666 (May 29, 2011)

its an 08 650i, nothing done to the engine and i dont know the factory jet sizes. the largest jet that dynojet sends is 148. thank you


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## killer666 (May 29, 2011)

*still not right*

i just finished jetting after all the other stuff i put on and it still not running perfect. if i go 0 to full throttle it's good but from 35mph and jam on it it pauses then goes. as well when i burp it it hasitates. and from full throttle when i let off it pops on deceleration. i got a shop to do it and they followed dynojet specs and put 140 jets in. i have searched mimb and found some answers but nothing specific. please help. thank you very much


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## No_Substitue_For_A_Brute (May 4, 2011)

killer666 said:


> i just finished jetting after all the other stuff i put on and it still not running perfect. if i go 0 to full throttle it's good but from 35mph and jam on it it pauses then goes. as well when i burp it it hasitates. and from full throttle when i let off it pops on deceleration. i got a shop to do it and they followed dynojet specs and put 140 jets in. i have searched mimb and found some answers but nothing specific. please help. thank you very much


If you can tell us exactly what year, model, and type your bike is and all mods you have on it we may can help a little better. Things we need to know about the bike: snorkeled? exhaust? if so is it full or slip on? Aftermarket CDI? What jet kit are you using? All these will give a good place to start.

What is the current carb set up? What jets main and pilot, what needle setting?

How does the bike run now in regards to throttle positions
1/8 -1/4 ?
1/4 - 3/4 ?
3/4 - WOT ?

With all this we should be able to help you out.


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## killer666 (May 29, 2011)

*still not right*

it's a 2008 650i with a k&n,full big gun exhaust,dyna coils, and dynatek cdi,and a dynojet stage 1 kit. it seems to work good when i go smoothly through 1/8-1/4-3/4-wot but from any of these positions and hit it hard it pauses then goes good, and when i let off it pops not loud but puck puck puck puck. and thank you for responding so quick


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## No_Substitue_For_A_Brute (May 4, 2011)

killer666 said:


> it's a 2008 650i with a k&n,full big gun exhaust,dyna coils, and dynatek cdi,and a dynojet stage 1 kit. it seems to work good when i go smoothly through 1/8-1/4-3/4-wot but from any of these positions and hit it hard it pauses then goes good, and when i let off it pops not loud but puck puck puck puck. and thank you for responding so quick


What size jets are in it right now? The dyna CID is going to cause a small miss at low end. If its pausing on acceleration i would say its lean on the low to mid range. I might try putting a #40 pilot in it if you haven't already. That should help the pop on decel and maybe the responsiveness. Other thing to try would be moving the clip down one notch to richen it up.


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## killer666 (May 29, 2011)

the shop i took it to followed the dynojet instrutions and put the 140 jets in front and back. im not to sure the size of the pilot. i will try to and move the clip down one notch and see what happens. thank you


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## No_Substitue_For_A_Brute (May 4, 2011)

killer666 said:


> the shop i took it to followed the dynojet instrutions and put the 140 jets in front and back. im not to sure the size of the pilot. i will try to and move the clip down one notch and see what happens. thank you


long as it is not snorkeled that should be close. Find out the pilot and clip locations and we can work it from there. That rear jet should prolly be a little bigger than the front one to keep it from running too lean.


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## killer666 (May 29, 2011)

i will take it back to the shop and get them to put a size bigger jet in the rear and move the clip one notch. its not snorkeled, yet, but maybe not we'll see. again thank you very much


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## killer666 (May 29, 2011)

*carb picture?*

i was going to move my clips on my needles but where are they? i would like to know before i start tearing my bike apart, if i have to tear it apart. i looked at my manual but there are many needles and i dont have a clue. a picture of what i need to do would help so so much, and wortha thousand words. i checked the jetting guide pic and it really dont help me.


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## killer666 (May 29, 2011)

*now too rich????*

so i just moved the clips on my needles down 1 notch and its now too rich, i think? it idles good and revs good but when i try to go it hesitates, and if i try to give it more it bogs out. doesnt stall. so im assuming i need to re-jet and move the clip back a notch or 2. i currently have 140 size jets in front and rear. and why do most people go a bigger jet in the rear then the front?


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