starting jet size

[x-man]

Okay guys I know it is a lot of questions about getting getting and what kind of pipe n im sry but I just got the FMF jet kit in the mail and the springs and washers I know what to do with the springs but the two washers is 1 for in between the head and the flange and the other for in between the flange and the pipe ? And the second question is the jet kit comes with the needle and for jets I'm sure that I have to change the needle butt it comes with a 2:20 210 350 + 360 I run a Pure Stock blaster now with the Gold Series pipe and silencer uni air filter with no lid what jet should I start with the 2:20 because there is a stage 1 and a stage 2 butt the instructions that came with the kit are kind of hard to understand if you think I need different size jets please let me know thank u

 

[Larry's Shee]

Proof positive that jet kits aren't worth a crap, sorry to say. Would thought FMF would be clos(er) Probably not FMF kit
Stock jetting is 210 or 220 depending on the year.
Have never seen anyone with a 350-360 on anything.
Send that "KIT" back.

Google FMF , should come up with " Rider Support" enter make, model, year READ ALL THE INFORMATION !!!! As to air box, temp bla, bla, bla.

Bottom line is 260 is a starting point. Add / subtract for your setup, which if you list it we can get you a lot closer.

 

[x-man]

Proof positive that jet kits aren't worth a crap, sorry to say. Would thought FMF would be clos(er) Probably not FMF kit
Stock jetting is 210 or 220 depending on the year.
Have never seen anyone with a 350-360 on anything.
Send that "KIT" back.

Google FMF , should come up with " Rider Support" enter make, model, year READ ALL THE INFORMATION !!!! As to air box, temp bla, bla, bla.

Bottom line is 260 is a starting point. Add / subtract for your setup, which if you list it we can get you a lot closer.

just grate a big problem is that i dont no what year it is n what about the springs n washers?

 

[x-man]

Proof positive that jet kits aren't worth a crap, sorry to say. Would thought FMF would be clos(er) Probably not FMF kit
Stock jetting is 210 or 220 depending on the year.
Have never seen anyone with a 350-360 on anything.
Send that "KIT" back.

Google FMF , should come up with " Rider Support" enter make, model, year READ ALL THE INFORMATION !!!! As to air box, temp bla, bla, bla.

Bottom line is 260 is a starting point. Add / subtract for your setup, which if you list it we can get you a lot closer.

o n am i looking to get a needle too? im not really sure how they are sized im going to order 260 throw 300 dose that seam like a good start?

 

[x-man]

Proof positive that jet kits aren't worth a crap, sorry to say. Would thought FMF would be clos(er) Probably not FMF kit
Stock jetting is 210 or 220 depending on the year.
Have never seen anyone with a 350-360 on anything.
Send that "KIT" back.

Google FMF , should come up with " Rider Support" enter make, model, year READ ALL THE INFORMATION !!!! As to air box, temp bla, bla, bla.

Bottom line is 260 is a starting point. Add / subtract for your setup, which if you list it we can get you a lot closer.

im really really not trying to blow this up wit a bunch of threads but i just want to the fmf site n i went throw it n it sed the 260 like u sed but its crazy the box the paperwork all look exactly the same thats crazy sutch a rip off that sucks thanks tho

 

[Larry's Shee]

So was it an FMF "kit" ?

Apparently you didn't get the hint.
List your type of air filter, snorkle/lid (or not) any porting, elevation and temperature.
Like I mentioned, we'll get you close, have to plug chop/read to confirm . ALWAYS Start big and work your way down.
With stock carb have never seen anyone with other than stock pilot jet or stock needle, so you are good there.

 

[Larry's Shee]

BTW, in case you don't know, you have to rejet for the winter weather if it changes more than 20-30 degrees.
Colder air has more oxygen which would make summer jetting lean which WILL melt your piston

 

[x-man]

BTW, in case you don't know, you have to rejet for the winter weather if it changes more than 20-30 degrees.
Colder air has more oxygen which would make summer jetting lean which WILL melt your piston

well right now its all stock jetting n yes i put all that in i want to the fmf rider saport n thats the number it gave me also iv bin looking at the box n everything it dose look real so yesterday i messagedthe seller to see what they had to say as fare as winter weather i figured id have to re jet but id like to get to the point where i no what id have in for summer or winter n just chop n check o what about those flange washers do u no if thats where they both go 1 in between head n flange n 2 between flange n piep?

 

[x-man]

BTW, in case you don't know, you have to rejet for the winter weather if it changes more than 20-30 degrees.
Colder air has more oxygen which would make summer jetting lean which WILL melt your piston

So listen to this I just got the reply from the company I bought the jet kit from apparently it is FMF and their explanation is that they use custom Jets and that they don't have stock numbers so what I said back was is there a chart or so that I can no what the numbers jets you sent are equivalent to I don't know but I'm going to go up to my local shop and order or buy 260 through 300 Main Jets and see where that gets me I don't know what I would be putting in based on their numbers because like I said I went to there site and typed in the information and the number came up with was a 260 Main Jet so I'm confused and I'm just going to order them through my shop

 

[Larry's Shee]

So listen to this I just got the reply from the company I bought the jet kit from apparently it is FMF and their explanation is that they use custom Jets and that they don't have stock numbers so what I said back was is there a chart or so that I can no what the numbers jets you sent are equivalent to I don't know but I'm going to go up to my local shop and order or buy 260 through 300 Main Jets and see where that gets me I don't know what I would be putting in based on their numbers because like I said I went to there site and typed in the information and the number came up with was a 260 Main Jet so I'm confused and I'm just going to order them through my shop

GOOD ANSWER !!!!​

Ya start with the 300 and work your way down. Don't worry about the smoke ring being exactly 2mm or med brown. Little wider or little bit darker won't hurt. Better a bit rich then lean.

When you start with the 300 and it is blubberie wide open, or won't clean out, you won't have to chop that plug, unless you really want to see what it looks like. Put the next size smaller in and try again.

When an engine is running lean it rev up really easily, or as I call it "Zinggy"

Little FYI as an engine goes from rich to "Perfect" jetting power increases moderately rapid and exhaust temperature increases slowly. When you get to the lean side of perfect power falls off very slowly, however exhaust and piston temperature skyrockets.
That's why air leaks usually aren't caught in time. You don't notice the drop in power.

Ya, I'd try to get a refund on those jets. Just sounds way to sketchy to me. IIRC, there is only like.005" difference between jet sizes.
Not worth the risk on unknown parts. For future reference Carb Parts Warehouse, Sudco, Jets are Us sell genuine Mikuni jets, besides the stealership. Maybe Ken O'CONNOR has them also.

 

[x-man]

GOOD ANSWER !!!!​

Ya start with the 300 and work your way down. Don't worry about the smoke ring being exactly 2mm or med brown. Little wider or little bit darker won't hurt. Better a bit rich then lean.

When you start with the 300 and it is blubberie wide open, or won't clean out, you won't have to chop that plug, unless you really want to see what it looks like. Put the next size smaller in and try again.

When an engine is running lean it rev up really easily, or as I call it "Zinggy"

Little FYI as an engine goes from rich to "Perfect" jetting power increases moderately rapid and exhaust temperature increases slowly. When you get to the lean side of perfect power falls off very slowly, however exhaust and piston temperature skyrockets.
That's why air leaks usually aren't caught in time. You don't notice the drop in power.

Ya, I'd try to get a refund on those jets. Just sounds way to sketchy to me. IIRC, there is only like.005" difference between jet sizes.
Not worth the risk on unknown parts. For future reference Carb Parts Warehouse, Sudco, Jets are Us sell genuine Mikuni jets, besides the stealership. Maybe Ken O'CONNOR has them also.

Little update I just got another message from seller he implied that he was FMF direct but the new message says to the question is there a chart or a guide for an equivalency he says sorry not sure try FMF Direct so I guess I was wrong it's not FMF

 

[x-man]

GOOD ANSWER !!!!​

Ya start with the 300 and work your way down. Don't worry about the smoke ring being exactly 2mm or med brown. Little wider or little bit darker won't hurt. Better a bit rich then lean.

When you start with the 300 and it is blubberie wide open, or won't clean out, you won't have to chop that plug, unless you really want to see what it looks like. Put the next size smaller in and try again.

When an engine is running lean it rev up really easily, or as I call it "Zinggy"

Little FYI as an engine goes from rich to "Perfect" jetting power increases moderately rapid and exhaust temperature increases slowly. When you get to the lean side of perfect power falls off very slowly, however exhaust and piston temperature skyrockets.
That's why air leaks usually aren't caught in time. You don't notice the drop in power.

Ya, I'd try to get a refund on those jets. Just sounds way to sketchy to me. IIRC, there is only like.005" difference between jet sizes.
Not worth the risk on unknown parts. For future reference Carb Parts Warehouse, Sudco, Jets are Us sell genuine Mikuni jets, besides the stealership. Maybe Ken O'CONNOR has them also.

So you're saying that I should start with a 300 and if it doesn't go or seem to go to full power I should go a size down I assume that I would start with the 260 and work my way up thats not the right way to do it?? n are you saying that I really don't need to worry about plug chop???

 

[x-man]

so i want to jets are us n i can order a "kit" lol but it comes with 320 300 280 270 260 250 n 240 n alin head bolts for the carb bowl i think its odd they dont give u a 290 but i can ether order that or order the 300 through 260 that would come out to 31 plus shipping i presume n the kit is 28 + what do u think?

 

[Larry's Shee]

No !! You ALWAYS Start BIG and work your way down !! If you started at the lean side you could melt your piston before you get to 6th gear. Ya, it can happen that quick!!
As to plug chop, I meant that you might not have to cut the plug when you do the 300. More of a learning experience for you.
You still do everything else for a plug chop, warm up, full throttle pull, kill engine, inspect or "chop" threads off.
It will give you experience on how it is when it's rich and what a rich plug looks like.

Problem with that kit is you will never need the 240, 250 and it doesn't have a 290.
I would order 270-300 maybe 310
You have a Uni filter and no lid, so that bumps it up one size. Unless you ride at 2,000 feet above sea level you won't need the 260

 

[x-man]

No !! You ALWAYS Start BIG and work your way down !! If you started at the lean side you could melt your piston before you get to 6th gear. Ya, it can happen that quick!!
As to plug chop, I meant that you might not have to cut the plug when you do the 300. More of a learning experience for you.
You still do everything else for a plug chop, warm up, full throttle pull, kill engine, inspect or "chop" threads off.
It will give you experience on how it is when it's rich and what a rich plug looks like.

Problem with that kit is you will never need the 240, 250 and it doesn't have a 290.
I would order 270-300 maybe 310
You have a Uni filter and no lid, so that bumps it up one size. Unless you ride at 2,000 feet above sea level you won't need the 260

hmm ok ok so tell me if I'm getting this right I'm going to pull the carb change the main jet start at 300 make sure everything is clean put the carb back in do the springs rubber washer tighten down the exhaust started let it warm up on a nice straight piece of road once I think it's warmed up go as fast as I can through 1st to V hit the kill switch hold the clutch and roll to a stop pull the plug and see what it looks like??? Also after I tighten down everything and replace the carb and I take it and let it warm up and my listening very carefully to how it runs right and idols and then I just how it goes through 1st to 5th doing the warm up and that listening to it running and how it's running that's how I judge it and this may be a dumb question I chop the plug after I run it and pull it right I don't chop it before I put it in and start it and just to give me an idea what's the best way to cut the threads

 

[x-man]

hmm ok ok so tell me if I'm getting this right I'm going to pull the carb change the main jet start at 300 make sure everything is clean put the carb back in do the springs rubber washer tighten down the exhaust started let it warm up on a nice straight piece of road once I think it's warmed up go as fast as I can through 1st to V hit the kill switch hold the clutch and roll to a stop pull the plug and see what it looks like??? Also after I tighten down everything and replace the carb and I take it and let it warm up and my listening very carefully to how it runs right and idols and then I just how it goes through 1st to 5th doing the warm up and that listening to it running and how it's running that's how I judge it and this may be a dumb question I chop the plug after I run it and pull it right I don't chop it before I put it in and start it and just to give me an idea what's the best way to cut the threads

Oh and I guess I didn't think of it but yeah that does make total sense that you should start bigger and go lower da

 

[Phoenix81]

Not trying to hijack the thread, just wanted to thank everyone for all the information. I have learned a ton on just this thread alone. So thanks ya'll.

 

[x-man]

Not trying to hijack the thread, just wanted to thank everyone for all the information. I have learned a ton on just this thread alone. So thanks ya'll.

well thats him not me im lerning myself i mean i know alot but not about carbs but deff thanks so fare but still not there yet plz dont leave me now

 

[Larry's Shee]

Go to carburetor sub-forum in engine forum.
There is a sticky thread titled "How to plug chop" tells you how to do it.
Make sure carb and air filter are clean. And float is set.

Would have thought others would have chimed in by now. Oh well.

Disregard what I said before about the 300 jet. Just do the chop in a normal way.
Pay attention to the directions on how to do it correctly. It is a one time shot on a NEW plug. No idling, letting off for curves. One hard, FULL throttle"drag race" pull. The object is to make the engine work hard. If you don't have quite enough room, drag the brakes a bit.

 

[nick20555]

Look at the sticky on how to plug chop but one thing I know you didn't mention was changing your plugs out for a fresh one after its warm.

I'd start with a fresh plug if it were me (at less than $2 a piece I change plugs like a I change underwear lol). Get it started and warm. Ride it around real quick and slam it full throttle with the 300 main in. If it blubbers up and doesn't clean out then you know that's way too big. Throw the 290 in. If it isn't blubbery or you aren't sure if its blubbery then continue with your plug chop. While its warm and you have a straight stretch in front of you, turn quad off and put a brand new plug in (should have a plug and tools to change plug in your pocket). If you are trying to find a way to not touch the motor while putting in the new plug because its too hot to touch then you know its warm. Start it up and immediately do your "drag race" style full throttle pull through all the gears and leaving it pinned the whole time until 15 seconds have passed. Pull clutch and kill the motor and let it roll to a stop. Take your brand new plug you only did a 15 second WOT pull with and take it back with you (put the other plug you had for the warm up back in). Once you get back, chop the thread off your WOT pull plug. Inspect the smoke ring on whats left. Take a picture and post it here. People will tell you how it looks.