I am new to the 2 strokes and have read on jets but I am getting my cylinder back from KOR and don't want to chance messing it up. My bike has a fmf fatty and power core 2. I think boysen reeds and a k$n type filter with the lid on. I am at 2400 ft. and its in the 30-40's right now. It has a 230 main in it right now, don't know the pilot. What should I start with when I put it back together? I want to make sure I don't heat cycle it lean. What should I start with? I will plug chop after a couple tanks of gas. I think the 230 is too lean from what I have read. Thanks.
what jet to start with?
- Thread starter Jeff Bennett
- Start date
the main jets should have nothing to do with your heat cycles, as it only effects jetting above 3/4 throttle.
you should only be doing light 1/4 - 1/2 throttle blips to warm it up to temp for the heat cycles.
same goes for 10 years from now, light blips to warm it up, not full throttle stabs....ever !
so the 32.5 pilot and stock needle in the middle clip position will do for heat cycles
be sure to set your airscrew @ 1.5 turns out to start and try to tune it for high idle on that first heat cycle so it will idle good. (see airscrew/pilot tuning in carb section)
then after your heat cycles, at your elevation and current temps i'd buy 270 thru 310 mains
throw the 310 in there to "feel" safe during the heat cycles.
start large and work down with plug chops after you get your heat cycles done.
you should only be doing light 1/4 - 1/2 throttle blips to warm it up to temp for the heat cycles.
same goes for 10 years from now, light blips to warm it up, not full throttle stabs....ever !
so the 32.5 pilot and stock needle in the middle clip position will do for heat cycles
be sure to set your airscrew @ 1.5 turns out to start and try to tune it for high idle on that first heat cycle so it will idle good. (see airscrew/pilot tuning in carb section)
then after your heat cycles, at your elevation and current temps i'd buy 270 thru 310 mains
throw the 310 in there to "feel" safe during the heat cycles.
start large and work down with plug chops after you get your heat cycles done.
Do not attempt to do a WOT plug chop until you have run 2 tanks of fuel through at no more than 3/4 throttle.
I fear that with your mods a #310 main is going to be way too rich to plug chop.
I would be starting at a #290 for the break in and plug chop.
It may pay to investigate the pilot, it should be #32.5.
It is a good idea to perform a leak test after any rebuild to confirm that everything is air tight, common places to leak are reed Block and carby boot!
I fear that with your mods a #310 main is going to be way too rich to plug chop.
I would be starting at a #290 for the break in and plug chop.
It may pay to investigate the pilot, it should be #32.5.
It is a good idea to perform a leak test after any rebuild to confirm that everything is air tight, common places to leak are reed Block and carby boot!
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I always want to guess/bet what the final jet will be but I am afraid to post my guess as some might take it for gospel and destroy their motors.
yeah, I got a leak tester and as said would not plug chop until I ride a couple tanks through (Because I couldn't open it up until I run a couple tanks.) The reason I want it rich enough to start with is because I don't want to use the 230 just to heat cycle it because I want to ride it after I heat cycle. I would rather heat cycle and ride a couple tanks without taking the carb off again until I plug chop. I couldn't believe our Yamaha shop in beckely's biggest jet was a 238. Where is the best place to buy some jets?
just reread my post. I really meant didn't want to heat cycle it with the smaller jet, so I could ride it after. I wouldn't heat cycle wide open. I am new to 2 strokes though, so if it weren't for you guys, I wouldn't even leak test it or heat cycle it. 2 strokes are so different than 4 stroke.
just reread my post. I really meant didn't want to heat cycle it with the smaller jet, so I could ride it after. I wouldn't heat cycle wide open. I am new to 2 strokes though, so if it weren't for you guys, I wouldn't even leak test it or heat cycle it. 2 strokes are so different than 4 stroke.
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238? what carb do you have? Mikuni stack carbs are jetted 230, 240, 250... etc.
I use http://www.jetsrus.com/a_jet_kit_atv/yamaha_200_YFS200_blaster_1988-2006.htm for all my jetting needs.
I use http://www.jetsrus.com/a_jet_kit_atv/yamaha_200_YFS200_blaster_1988-2006.htm for all my jetting needs.
I just asked him for like a 280 for a blaster and he said the biggest jet he had was a 238. I thought they went in 5's. I figure he was talking about the biggest jet he had for anything. Its the only Yamaha shop within 60 miles from here too.
you've jetted how many blasters with an FMF at his current altitude and temperature ?
oh thats right.....NONE.
I've jetted 3, built and maintain them, all run great with 290 main in the summer 60-90's F temps @ 1800 - 2400' elevation.
and a 300 for 40-50's F degree fall temps.
for his current 30-40 degree temps at a similar altitude, I suggested larger to start to be on the safe side.
I never give a 2+1+2 =? chinese arithmetic guess either.
This math isn't written in stone ...ANYWHERE !
every bike is different, and the pipe is the biggest factor in jetting, not filter, airbox lid, or premix.
Jeff I run in to that at my Stealership too. A lot of them don't know jets well. I had to bring in a Mikuni Jet from my Blaster and show him so he had a visual to compare to. He didn't have much selection either. Also don't buy a kit they never have what you actually need. Order exactly what you want. in this case I agree with Awk get a 270 - 310. never know when you end up riding at a different elevation and need that extra jet up or down.
Awk why did you quote me? I don't use the hard fast math rule. Last season I had to field chop 6 times as my rides were always at different elevations. I even ended up at 9200 feet at one point. ended up happy with a 240 on the blasterpiece. I had em all charted out so I could just jet and go next season. Sold that bike and now I have to do it again next season as I will have 2 wildly different machines going with.
I carry extra plugs and a big selection of Jets on every ride.
Awk why did you quote me? I don't use the hard fast math rule. Last season I had to field chop 6 times as my rides were always at different elevations. I even ended up at 9200 feet at one point. ended up happy with a 240 on the blasterpiece. I had em all charted out so I could just jet and go next season. Sold that bike and now I have to do it again next season as I will have 2 wildly different machines going with.
I carry extra plugs and a big selection of Jets on every ride.
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Thanks guys. Do you have any particular place to order from that you know is good. I know on my streetbikes, if it is not genuine mikuni that they have problems. The holes wont be where they are supposed to and such. That's what I was thinking also was to get like 270-310 and have them. Its gets nice and warm here in the summer but cold in the winter and I like to ride in snow. Of course I have the Kodiak for the snow but I bet the blaster would be fun!
qouted you because i was agreeing with you agreeing with me
the chinese arithmatic was thrown in as a general warning to others not to follow it.
not that you use it
sorry for the confusion.
btw..I've used http://www.carbparts.com/index.html
when my dealer didn't have pilots or needles i needed.
It seems such a shame that a staff member has to resort to Facebook tactics to attempt to discredit another staff member.
You should be ashamed of your self, airing your dirty washing in public!
Feel free to have a feud with me, but please keep it from public view.
There is no place on BF for this kind of crap.
I don't know anything about facebook, never had one and never will.
your jetting advice is bunk and someone is going to fry their piston.
you have ZERO experience jetting at our US. temps or altitudes.
for me to sit back and allow you to spew it in every thread on here would be the real crime.
maybe stick to giving advice on what you actually have experience with (which is limited at best)
instead of disagreeing with the direct personal experience advice I had already given in this thread ?
keep posting that 2+1+2 = 260 main jetting rubbish you've been, and i'll keep pointing out your errors.
it's my duty to my fellow members here, token staff member or not.
boy thats original ha ?
this has to do with you giving horrible jetting advice, not some larry-john-jim-bob qoute about me
This is the post that sparked the argument.
There is no way that an engine with the mods and environment specified needs a #310 main jet.
No matter where in the world you are, US, Asia, Oceania, or Timbuctoo, the oxygen content of the atmosphere is identical.
Is the US so different that it requires special jetting practices than the rest of the world.
