125 jet

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Old Jan 25, 2006 | 01:31 AM
  #1  
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Default 125 jet



the left plug is with a 120 jet with stock exhaust. After I drilled the pipe, I had a lean surge on the freeway.

the right plug is with a 125 jet and drilled exhaust. It still looks very lean and I peak at 80mph instead of 85mph.

I'm off to get the next size up jet. Comments?
 
Old Jan 25, 2006 | 01:57 AM
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Default RE: 125 jet

What is your vote: 128 or 130
 
Old Jan 25, 2006 | 02:11 AM
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Default RE: 125 jet

128 my bet ,but not enough go 130. if you start with 130 you could always go down to 128. LOL damned if you do damned if you dont[sm=alcoholic.gif]
 
Old Jan 25, 2006 | 05:04 AM
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Default RE: 125 jet

Get the N1TC needle, collar, and circlip while your at the dealer. That'll give you some more fine tuning options.

I have not had a chance to do a plug check yet (I'm out of town at the moment) but mine has no lean surge with the 122 jet, high flow snorkle, and 1/2" hole in the first plate. I may try the 125 just for grins if I get a chance.
 
Old Jan 25, 2006 | 01:18 PM
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Default RE: 125 jet

The best part is your gas mileage probably hasn't changed significantly! The bike is running stronger, so less throttle position is required.

 
Old Jan 25, 2006 | 04:41 PM
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ORIGINAL: bmwhd

Get the N1TC needle, collar, and circlip while your at the dealer. That'll give you some more fine tuning options.

I have not had a chance to do a plug check yet (I'm out of town at the moment) but mine has no lean surge with the 122 jet, high flow snorkle, and 1/2" hole in the first plate. I may try the 125 just for grins if I get a chance.
I haven't run the 128 yet, but on the 125 yerterday, I still had a little surge and the power was dropping off at 8000rpm. The only difference between us I can figure right now is temp and elevation. I'am at sea level, you?
 
Old Jan 25, 2006 | 05:41 PM
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Default RE: 125 jet

I'm a few hunderd feet above sea level. With an after market exhaust and header (both from FSW) I tried the 132, but it was too rich -- turned my plug pitch black. I'm currently running a 128 and so far it seems right -- but I haven't checked the plug yet. I was actually thinking of trying a 125 for kicks, but hearing your post I think I'll just stick with the 128.

By the way, can anyone explain what a "lean surge" is???
 
Old Jan 25, 2006 | 06:47 PM
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Default RE: 125 jet

a16tony,

The way you're doing it takes a whole lot of time. But it is one of the more accurate ways of jetting the bike.

The other way is on a dyno with a sniffer up the exhaust. You can get it spot on then.

The way I used to do it was take it to the track. Watch your mph on each pass. Keep increasing jet size until your mph does not increase any more. Drop down one size. Should be perfect.

 
Old Jan 25, 2006 | 06:52 PM
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ORIGINAL: Marty

a16tony,

The way you're doing it takes a whole lot of time. But it is one of the more accurate ways of jetting the bike.

The other way is on a dyno with a sniffer up the exhaust. You can get it spot on then.

The way I used to do it was take it to the track. Watch your mph on each pass. Keep increasing jet size until your mph does not increase any more. Drop down one size. Should be perfect.

My track is INTERSTATE # 5. [sm=icon_rock.gif]Same idea though
 
Old Jan 25, 2006 | 06:56 PM
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ORIGINAL: NavKLX

I'm a few hunderd feet above sea level. With an after market exhaust and header (both from FSW) I tried the 132, but it was too rich -- turned my plug pitch black. I'm currently running a 128 and so far it seems right -- but I haven't checked the plug yet. I was actually thinking of trying a 125 for kicks, but hearing your post I think I'll just stick with the 128.

By the way, can anyone explain what a "lean surge" is???
If your cruising at a steady speed and the bike feels like it's starting to run out of gas or has a slight miss. In most cases you won't notice during acceleration.
 



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