Random jetting question ?

Many years ago when I had a KH400 I used to run the middle cylinder slightly richer than the outer two (can't remember the details but i think it was 1 notch on the needle and 1 jet size bigger on the main, the plug colour was always a nice even brown across all three cylinders. Has anyone ever tried this with the inner 2 cylinders on a 4 as they run hotter

The inner two run hotter but I've never thought about different jetting.  In thinking about it I can't see any reason to add more gas to them.  Would it not just richen the mixture?  

Richer runs cooler - leaner runs hotter so in theory it helps to even the cylinder temperatures

ZRX1200 came from the factory with slightly richer jetting on 2 & 3.

Ok, but I'm not sure why even temperature is desirable.  The center two cylinders should naturally be hotter because they have less air flow cooling available to them.  I would think the correct fuel/air mixture would be more important.  

I found it interesting that you had nice plug colour across the three cylinders despite running a richer mix on the center one.

When it was running hotter on the centre cylinder the plug was lighter than the outer two, it's interesting that KHI went down the same route with the ZRX. Ultimately I just threw it out there as a talking point to see what other people's views where, I'm certainly not advising people to go down this route but it is "food for thought" 

ZR7 & ZR7S have different carb needles in #2&3 than 1&4.
Not sure what the change is off hand but must have a similar effect, making 2&3 a little richer.

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When it was running hotter on the centre cylinder the plug was lighter than the outer two, it's interesting that KHI went down the same route with the ZRX. Ultimately I just threw it out there as a talking point to see what other people's views where, I'm certainly not advising people to go down this route but it is "food for thought" 

That's exactly how I took it.  I'm not being argumentive.  Just trying to understand the issue from an engineering point of view.

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When it was running hotter on the centre cylinder the plug was lighter than the outer two, it's interesting that KHI went down the same route with the ZRX. Ultimately I just threw it out there as a talking point to see what other people's views where, I'm certainly not advising people to go down this route but it is "food for thought" 

That's exactly how I took it.  I'm not being argumentive.  Just trying to understand the issue from an engineering point of view.

HRM - my response wasn't intended to be defensive, the "written word" can be easily misinterpreted at times - Ultimately I'm short, fat and ginger, it would be too stressful for me to sensitive 

Cooling the center cylinder on the triples was always problematic and I reckon the additional lubrication was also needed there. However, I have no idea why Kawasaki would see a need to do so on a modern water cooled engine. By the way, the ZRX1100 did not have this feature.

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Cooling the center cylinder on the triples was always problematic and I reckon the additional lubrication was also needed there. However, I have no idea why Kawasaki would see a need to do so on a modern water cooled engine. By the way, the ZRX1100 did not have this feature.

 

Agreed, it's interesting looking at rstnick's post that Kawasaki seem to have dablled with this on several models. You are right in so much as I don't see the need on a water cooled motor as all cylinders share the water jacket so should theoretically be at a similar temperature

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wrote:

wrote:

When it was running hotter on the centre cylinder the plug was lighter than the outer two, it's interesting that KHI went down the same route with the ZRX. Ultimately I just threw it out there as a talking point to see what other people's views where, I'm certainly not advising people to go down this route but it is "food for thought" 

That's exactly how I took it.  I'm not being argumentive.  Just trying to understand the issue from an engineering point of view.

HRM - my response wasn't intended to be defensive, the "written word" can be easily misinterpreted at times - Ultimately I'm short, fat and ginger, it would be too stressful for me to sensitive 

It's all good!  So.....a tinge of the ginge!  My son is similarly infected!  As for me...I've lost my ginge.  Lost all my hair to be more precise.