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Sputtering...


acfine

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I installed a NOSS head with 21cc domes and Boyesen dual stage pro series reeds this weekend. I'm running 300 main jets and 25 pilot, and the needle is in the stock position. I also have a K&N air filter as well as the K&N PowerLid. My question is after these mods, do I need to change the needle clip position?

 

Around the mid-range area, it's sputtering a bit, and then kicks in, but it's kicking in intermittently, which somwhat leads me to believe it could be in the twist throttle/throttle cable assembly. The cable itself is in pretty poor shape. I've ordered a new cable and am switching back to a thumb throttle, but wanted to know ya'lls thoughts about the carb situation.

 

Additional information, about 2 weeks ago I bit it hard, and really messed up my twist throttle, and it doesn't feel like it's operating properly, like for one, it doesn't feel like it's opening the carbs all of the way. When I took my breather off, should one of the sliders in the carb (the choke side carb) be a bit more open the the other at closed throttle position? And like a dumb-a**, I didn't look to see if they were opening all of the way while I was in there. :shoothead:

 

I just wasn't sure if the sputtering could be a result of my mods and keeping the needle clip in the stock position, or a bum throttle cable not opening the sliders all of the way.

 

Also, is there a break-in period for a new head and reeds?

 

I have attached 2 pics, hopefully you can see where the cable is in bad shape. It's where it comes out of the splitter and goes to the two carbs.

 

Any thoughts? :unsure:

 

Thanks in advance...

 

DSCF0053.jpg

 

DSCF0080.jpg

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4-6 sizes larger on the main.Adjust the air screws.

 

Just to make sure I understand this correctly, 340's to 360's on the mains? I've had a few guys tell me that they thought the 300's were a bit fat, but thst was also before the head and reeds install.

 

What are your approximate thoughts on the air crew? 2.5 turns out, or is it more of a feel thing, making small adjustments then testing?

 

Thanks again for the help,

Anthony

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No,I thought you pressed 3 by mistake instead of 2,,300's are a bit fat.

 

Question, and a it's not a smart ass question, but an honest question. Why do FMF and K&N send such big jets with their systems? Like 340's and 350's.

 

If 300's are fat, I can't imagine why they'd send even bigger ones.

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Question, and a it's not a smart ass question, but an honest question. Why do FMF and K&N send such big jets with their systems? Like 340's and 350's.

 

If 300's are fat, I can't imagine why they'd send even bigger ones.

 

Alot of things go into jetting(elevation and temperature) are acouple, and they may require you to run bigger mains.

Not to mention mods and engine work.The reason they send them is because you may need to go that big at some point.

 

Stock mains are 200 ,some dealers will install anywhere from 190-220.

300's are fat,but I dont know your elevation or temp,I thought you meant 200's not 300's :confused:

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I would recommend you get a K&N stage 3 jet kit with the sharper taper needles and run a 270 main with FMF fatties. You set the needle clip on the middle ring with this needle from the kit. If you are sticking with the stock needles you do need larger jets (290 i think, but i wouldn't swear by it since I went to aftermarket needles), but I wouldn't move the needle. I ran that setup for a long time. That was the best tune for my bike before changing the carbs, porting, etc.

 

And no, there is not break in time for heads and reeds. Just make sure and recheck the head torque after getting it hot and letting it cool off.

Edited by Tim Potteiger
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