421 driveline baseline jetting

[Rossp]

I’m currently building a 421 driveline low port setup and I’m looking for a conservatively rich starting point for jetting. I will be running the cylinders as cast on pump gas, keihin pj 34mm, k and n 6” pods, slip pipes. What would you guys recommend for a starting point?

[hoppedupandcutdown]

Bill or Lane at Driveline can help you the best.

[Killacaviar]

On 10/31/2019 at 10:31 PM, Rossp said:

I’m currently building a 421 driveline low port setup and I’m looking for a conservatively rich starting point for jetting. I will be running the cylinders as cast on pump gas, keihin pj 34mm, k and n 6” pods, slip pipes. What would you guys recommend for a starting point?

talk to lane or bill they are alway and I mean always willing to help.
 

With that being said Every bike is different. I have a similar set up but with 35pwks. Lane told me to start at 165m and 52 pilot and work down with a dgh needle 
 

After plug chops and going back and forth with lane. I settle at 168m in one 170 main in the other and 50 pilot and 4th clip in a cel. 
 

it’s seems most of the guys on here run around a 155 m and a 45-50 pilot. 
 

my bike was totally different. If I were you I would start high ride it see where you stand and talk to lane when you need a little input as you dial it in. Mine took time. I went through 10 plugs until we felt the plugs looked comfortable with the jets i was using.
 

mine is a high port with slps.  It’s a fun motor your going to like it. Very enjoyable to ride especially with a stock swingarm. Wheelie machine...  good luck and be patient  

 

 

 

[Rossp]

I did speak to lane and my current jetting is really close to what he recommended. I was just looking for guys running similar setups. I’m a little richer than what lane recommended so I will stick where I’m at for breakin

[ClaudeMachining]

I did speak to lane and my current jetting is really close to what he recommended. I was just looking for guys running similar setups. I’m a little richer than what lane recommended so I will stick where I’m at for breakin

Start high (175) and work from there.

Each engine have his own soul. Stop asking about jetting with "similar" setup.

Again, start high and work from there. ALWAYS!!!!

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[Ayesully810]

claude, sounds like hes doing just that.  clearly he wont need a 175 main, thats just silly.  a CEL or CGL needle will work best, CGL is a tad leaner than the CEL.  

[Killacaviar]

Hey you never know about that 175... I’m pretty close lol. I started pulling everything apart thinking something was clearly wrong. After speaking to lane and double checking my work I was moving in the right direction with the 168 and a 170. Which according to lane and showing him my plugs it’s what the engine needed.

And if I remember correctly sully you were in the 140s on a “similar build”. It’s crazy how different each bike can be


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[Killacaviar]

I did speak to lane and my current jetting is really close to what he recommended. I was just looking for guys running similar setups. I’m a little richer than what lane recommended so I will stick where I’m at for breakin

Also lane recommended me starting at 165 and that was to lean for me...


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[ClaudeMachining]

See???? Simple rule for ALL your built.

 

I start at 180 with all my engine. I always want to know where is the "too rich" point.

 

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[Ayesully810]

good points, i redact my statement. 

[375hp banshees]

Imagine that

[trickedcarbine]

On 11/2/2019 at 11:26 PM, Killacaviar said:

talk to lane or bill they are alway and I mean always willing to help.
 

With that being said Every bike is different. I have a similar set up but with 35pwks. Lane told me to start at 165m and 52 pilot and work down with a dgh needle 
 

After plug chops and going back and forth with lane. I settle at 168m in one 170 main in the other and 50 pilot and 4th clip in a cel. 
 

it’s seems most of the guys on here run around a 155 m and a 45-50 pilot. 
 

my bike was totally different. If I were you I would start high ride it see where you stand and talk to lane when you need a little input as you dial it in. Mine took time. I went through 10 plugs until we felt the plugs looked comfortable with the jets i was using.
 

mine is a high port with slps.  It’s a fun motor your going to like it. Very enjoyable to ride especially with a stock swingarm. Wheelie machine...  good luck and be patient  

 

 

 

Why the SLP’s on Hi Port? 

[Killacaviar]

Why the SLP’s on Hi Port? 

Yes sir. Gives me flexibility. Runs great always on the pipe. And I have the option of getting shearers, or another drag pipe and changing the motor completely just with the pipe.

It was lanes recommendation. I’m super happy with it


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