Proper jetting?

[Jre720]

On my 05 I'm running a fmf gold series header with a power core 2 pipe .. br8es spark plug 270 main jet stock pilot jet k&n air filter freshly cleaned and oiled have 8 one inch holes in my air box lid and my air screw is roughly 2 1/4 turns out ..I had it at 1 3/4 but when I drilled the holes it was bogging so I pulled it out a little more bike runs mint although I have fouled 2 plugs after 2 rides on each but my question is ...should I be running the br9es instead of the 8? What's the difference

 

[Blaaster]

Stay with the recommended B8es, the 9 will foul more.

The difference in heat ranges of plugs is that the hotter the plug the less heat gets transferred to the head keeping the electrodes at a temperature where the plug will self clean.

If the heat range is too cold the plug will foul.

If the heat range is too hot the electrodes may glow red hot, cause pre ignition and burn a hole in the piston.

You may Ike to try adjusting the idle speed as follows.

Idle adjusting.
Set float level, make sure that all jets are clean and fuel flows freely from the float bowl drain
when the screw is cracked open.
Start with air screw 1.5 turns out.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor responds.
Re adjust idle screw for desired idle .
if the air screw ends up being more than 2 1/2 turns out the pi;]lot is too big.
if the air screw is less than 1/2 a turn out the pilot is too small

You should do a plug chop to confirm the jetting.

You should also do an air leak test the see if the crank seals are not leaking oil into the crankcase.

 

[Jre720]

Thanks I will stay with the 8s then..as far as jets and float when I rebuilt the motor back in January I got a stock carb rebuild kit along with a. Brand new 270 main and put all them in..the jets are clean ...and as far as tranny fluid i have not done a leakdown but however I am not burning any the eye glass is full and to be honest my bike when warmed up doesn't really smoke at all so I know it's not burning , idle seems to be pretty spot on however it does die out on choke sometimes and idle a little low while warming up even not on choke ....guess I will seat them both and start out at stock specs and work it out from there

 

[Jre720]

So I took air screw out cleaned it and did as you said, ended up leaving it at just about 2 turns out seems to be revving better and more responsive while riding , think I can safely say I got the bike dialed in, now just need to change my tie rod ends and that should be a done deal

 

[Tooloose]

Br8 is

On my 05 I'm running a fmf gold series header with a power core 2 pipe .. br8es spark plug 270 main jet stock pilot jet k&n air filter freshly cleaned and oiled have 8 one inch holes in my air box lid and my air screw is roughly 2 1/4 turns out ..I had it at 1 3/4 but when I drilled the holes it was bogging so I pulled it out a little more bike runs mint although I have fouled 2 plugs after 2 rides on each but my question is ...should I be running the br9es instead of the 8? What's the difference

hotter than a br9 if anything maybe a br7. The lower the number the hotter the plug !

 

[Awk08]

have you plug chopped to confirm the 270 main ?
http://www.blasterforum.com/threads/how-to-plug-chop.53237/

needle clip position ?

jets in the kits are sometimes not genuine mikuni jets and not flow the same.

 

[Jre720]

I bought an oem moose carb rebuild kit, then afterward bought a genuine mikuni 270 main jet needle clip is in the middle slot and I have not plug chopped, bike seems to be dialed in mint though

 

[Awk08]

Plug chop to confirm. 270 is on the light side for your mods, depending on elevation and temps.
We run a 290 here with similar mods.

 

[Blaaster]

Br8 is

hotter than a br9 if anything maybe a br7. The lower the number the hotter the plug !

Do not use a 7 rated plug , you may create pre ignition and could burn a hole in the piston.

 

[Jre720]

Plug chop to confirm. 270 is on the light side for your mods, depending on elevation and temps.
We run a 290 here with similar mods.

I will have to do a plug chop then you are right ...I live in New York I'm not quite sure how to check my elevation? I know that sounds dumb lol but should I get a 290 and see if it is better?

 

[Awk08]

I will have to do a plug chop then you are right ...I live in New York I'm not quite sure how to check my elevation? I know that sounds dumb lol but should I get a 290 and see if it is better?

google "(your town) elevation" it'll tell you

but I did it for you, as a moderator I can see where you are
wappingers falls elevation is..........154′
thats way lower elevation than my 1800' and will require richer jetting than the 290 we run here
plug chop to confirm, I could be wrong, I was once before

we usually suggest a range of jets and 6 pack of spark plugs to do the plug chops with

common jets for the FMF pipes and airbox/filter mods is 270 thru 310, elevation and current temps play a big role too
what jet works @ 1800' elevation and 80 degrees will fry stuff at sea level or 30 degrees.

it's just good insurance to learn and do the plug chops, unless you're very experienced and know what it should feel and sound like
a lean jetted bike will run like a scalded dog right up until it melts down.
better slightly rich and safe

 

[Jre720]

google "(your town) elevation" it'll tell you

but I did it for you, as a moderator I can see where you are
wappingers falls elevation is..........154′
thats way lower elevation than my 1800' and will require richer jetting than the 290 we run here
plug chop to confirm, I could be wrong, I was once before

we usually suggest a range of jets and 6 pack of spark plugs to do the plug chops with

common jets for the FMF pipes and airbox/filter mods is 270 thru 310, elevation and current temps play a big role too
what jet works @ 1800' elevation and 80 degrees will fry stuff at sea level or 30 degrees.

it's just good insurance to learn and do the plug chops, unless you're very experienced and know what it should feel and sound like
a lean jetted bike will run like a scalded dog right up until it melts down.
better slightly rich and safe

Thanks for all the help and looking that up for me, explains a lot, last summer I took my cr85 up state to the Andes mountains and blew my top end because it was running like crap and I had very little knowledge of carb tuning so I left it exactly how it was here home, once I blew up the top end I rebuilt it with my dad and that's what got me into all this stufff, everything happens for a reason


Back to this though what jet would you suggest me to try? I have two 4 packs of plugs so I deffinatly wana get this thing 100% even though it feels it right now I bet it could be better after you explained this to me, will plug chop probably Thursday because we're supposed to get a thunder storm tomorow, but should I order some more jets up to 310?

 

[Awk08]

should I order some more jets up to 310?

yes, and study that plug chop thread posted above, it must be done exactly as explained


when you took your bike up in the mountains, it would have ran richer @ that higher elevation, unless it was much cooler there ?
more than likely it had an airleak or worn piston/cylinder causing the boom

 

[Jre720]

Yea the piston was pretty worn when I pulled it , I will order jets tomorow .. so when I go back up state real soon what jet should I run up there and would I turn my air screw in more or out more? I don't want to get up there and it be running poorly

 

[Blaaster]

Idle adjusting.
Set float level, make sure that all jets are clean and fuel flows freely from the float bowl drain
when the screw is cracked open.
Start with air screw 1.5 turns out.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor responds.
Re adjust idle screw for desired idle .
if the air screw ends up being more than 2 1/2 turns out the pi;]lot is too big.
if the air screw is less than 1/2 a turn out the pilot is too small

 

[82cutty]

Make sure you get genuine Mikuni jets not the aftermarket crap . I'm at 400-500 feet in New York and ran a 310 at the time I had similar mods to you . That was slightly rich at temps from 65-80 . In the winter time I ran 330 at 30-45 degrees . I didn't take it out if it was colder than that . Remove your air box lid unless you are doing serious mudding and water puddles . Bikes are different so plug chops will need to be done

 

[Jre720]

Make sure you get genuine Mikuni jets not the aftermarket crap . I'm at 400-500 feet in New York and ran a 310 at the time I had similar mods to you . That was slightly rich at temps from 65-80 . In the winter time I ran 330 at 30-45 degrees . I didn't take it out if it was colder than that . Remove your air box lid unless you are doing serious mudding and water puddles . Bikes are different so plug chops will need to be done

I put holes in the air box because a couple parts of the trails there are stream crossings that I don't want any water getting in there, someone in NY reccomended to me the 270 but after talking on here I realize I need to go bigger even tho the bike runs mint, and of course always genuine parts never cheapies, I am going to get 280-330 and see what's is running the best for me want to get the most out of my motor and best performance

I'm thinking somewhere around 310 will be good but won't know until I get to it and plug chop

 

[Jre720]

Here is a little video of me giving it a 1-3 rip not full throttle or anything because I was snap chatting lol also no clutch shifts but how does it sound to you?