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Couple Of Jetting Q's!


stu

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i need to get the jetting sorted on my shee but im not confident at all! is it ok to just keep using slightly bigger jets till the shee bogs down, then use one size smaller?? ive heard many people say this is the easiest way to rejet but want to make sure im not goin to cause any damage! also, what position do i want the needles in whilst im jetiin the carbs?? will it matter enormously if i leave the air filter off when jetting as my filter set up is a bitch to get on and off!!

 

cheers for any help, i really need to get her sorted :huh:

 

stu :dance:

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i need to get the jetting sorted on my shee but im not confident at all!  is it ok to just keep using slightly bigger jets till the shee bogs down, then use one size smaller??  ive heard many people say this is the easiest way to rejet but want to make sure im not goin to cause any damage!    also, what position do i want the needles in whilst im jetiin the carbs??  will it matter enormously if i leave the air filter off when jetting as my filter set up is a bitch to get on and off!!

 

cheers for any help, i really need to get her sorted :huh:

 

stu :dance:

That sounds about right to me. If you know it's real lean I would go up a couple sizes at a time though. I've read in some guides to jet up until it bogs, than back down a size and that sounds good. Most people will tell you the only way to know for sure is to check the plugs (can't help you with that, I know I'm rich and still can't read anything on the plugs). As for the filter, as long as you're doing your runs on road or something without dust that should be fine, but keep in mind that once you put that filter back on you'll probably have to go down another size on the mains.

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i need to get the jetting sorted on my shee but im not confident at all!  is it ok to just keep using slightly bigger jets till the shee bogs down, then use one size smaller??  ive heard many people say this is the easiest way to rejet but want to make sure im not goin to cause any damage!    also, what position do i want the needles in whilst im jetiin the carbs??  will it matter enormously if i leave the air filter off when jetting as my filter set up is a bitch to get on and off!!

ok, first thing, we need a list of mods to have any idea where your needle (or any other jets) should be. If you have any aftmkt pipes at all, go for the 4th position from the top/blunt end.

 

Second, like Krmit said, your jetting is not going to be the same with and without the filter, becuase you'll be getting more air, so if you jet her right w/o the filter, you'll be rich when it goes back on.

 

Third, you can't hurt anything if your too rich, so going up on the mains till she richens up to the point of bogging then backing it off will be fine. Worst that can happen is shee smokes and you foul a plug, no big whoop.

 

Fourth, if you check your plugs on a WOT run and they're really light colored or white, then go up more than a slight amount, go up say two or three until you see some color then slow it down a bit. If, in the process, shee begins to bog, check your plugs to see if they're wet, they should be.

 

Fifth (and final), the ONLY way to correctly check the main is a Wide Open Throttle run in 5th or 6th. If you put a main size in and go cruising around the yard, you ain't doin shit. So, put the main in, get out on the road or something and run the shit out of it WOT and see what shee does. If you check the plugs, kill it while the throttle is still pinned and then coast to a stop and check them, that is the accurate way.

 

Try it out, and get back to us.

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There's actually different theorys behind that and it depends on who you talk to. I do just because i've heard some people say you have to, I don't necessarily believe it, but it can't hurt so screw it. Some say it's alright to let off after you kill it.

 

In the reply above, I was merely stating that he needed to make sure he held the throttle wide open until he killed it, not run WOT then back down to an idle or something like that then kill it.

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the mods ive got that affect the jetting is:

 

k&n w/outerware

keihin pwk 35mm's

pyramid reeds and cages

mx port

pistons

dmc alien pipes

coolhead w/ about 20.5 domes

 

at the moment the mains are 185 and its not bogging so maybe i should bump it all the way up to 195's and see what shee runs like then???

 

im at about sea level and its usaully between 10 - 15 degrees centigrade

 

 

cheers

stu

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have you checked your plugs? It's fine to bump up till shee bogs. Try the 195 and see if shee bogs, if not, go higher, until she does and back off a size. If you don't know how to check plugs, there is so much info on it, check this forum a page back or two and search if need be. There's a picture of what it should look like a page back.

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ive read up on jetting quite a bit. BenBB's jetting page has helped me enormously when i finally managed to read all 17 pages!!!! if u need help on jetting there is nothing that BenBB doesnt cover in that text. a perfect jetting resource..... cheers Ben :cheers:

 

im goin to order a couple more jets tomorrow when i get up and see how shee runs with them

 

stu

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ive read up on jetting quite a bit.  BenBB's jetting page has helped me enormously when i finally managed to read all 17 pages!!!!  if u need help on jetting there is nothing that BenBB doesnt cover in that text.  a perfect jetting resource.....  cheers Ben :cheers:

 

im goin to order a couple more jets tomorrow when i get up and see how shee runs with them

 

stu

yeah, benbb's site is very informative. good luck with getting 'er fixed up. ;)

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I agree, 185's are too big... I run 158 mains w/ 35mm pwks w/ a stroker motor....READ your plugs,,,you can be wayy to rich as well as too lean....YOUR PLUGS WILL TELL ALL........

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I'd make sure to put the air filter on for each jetting test because even a good flowing filter will restrict the air flow some and cause you to be rich once you put it back on if you have it jetted correctly with no air filter. Maybe a large K&N settup would be the same as no filter, but I doubt it.

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