351 with stock carb - a detailed review
#31
04-18-2017, 07:49 PM
Well, ordinarily you would have "struck a nerve" by referencing the spreadsheet, all the setups that "work ok", etc etc.. But I'm past that now..
The spreadsheet serves a good purpose. It will give guidance to those that need a "good working" setup - and my dyno testing proves that "good working" setups include main jets as small as DJ132's.. Bryan is correct that the performance needles and lower clip positions can create a "good running" KLX with a main jet that is way too small - but top end power(perhaps even engine health), is greatly reduced
I do not want a "good working" setup - I want the most HP and TRQ I can possibly get from my bike - and I found the setup that does that.(With what we currently have to work with in the way of needle choices..)
It just so happens that what I found is waay off from all the "good working" hand-me-down setups that have been used for years now.. And, in a way, that's too bad. But, in another way, that's really good as everyone running a setup "from the herd" can now find biggy power with minimal alterations, if they want to run lidless..
You choose dyno data (mine/Houstons4/etc) or dogma (the spreadsheet).. Dyno butts and plug chops, as it turns out, will cost you the HP and TRQ you've paid good money for..
Any 250 running a DJ128 or DJ132 had certainly better also be running the lid on the airbox. I don't have data for 351's. No one does. But feeding it the same as you'd feed a 250 has never made any sense to me..
The spreadsheet serves a good purpose. It will give guidance to those that need a "good working" setup - and my dyno testing proves that "good working" setups include main jets as small as DJ132's.. Bryan is correct that the performance needles and lower clip positions can create a "good running" KLX with a main jet that is way too small - but top end power(perhaps even engine health), is greatly reduced
I do not want a "good working" setup - I want the most HP and TRQ I can possibly get from my bike - and I found the setup that does that.(With what we currently have to work with in the way of needle choices..)
It just so happens that what I found is waay off from all the "good working" hand-me-down setups that have been used for years now.. And, in a way, that's too bad. But, in another way, that's really good as everyone running a setup "from the herd" can now find biggy power with minimal alterations, if they want to run lidless..
You choose dyno data (mine/Houstons4/etc) or dogma (the spreadsheet).. Dyno butts and plug chops, as it turns out, will cost you the HP and TRQ you've paid good money for..
Any 250 running a DJ128 or DJ132 had certainly better also be running the lid on the airbox. I don't have data for 351's. No one does. But feeding it the same as you'd feed a 250 has never made any sense to me..
#32
04-19-2017, 06:32 PM
One quick question for anyone that may know. When I was putting my carb back on, I happened to look into the fuel hose and saw something foreign. I started picking at it and pulled out a tiny crushed fuel filter. Is this stock? I can't see a manufacturer putting a scrappy little filter right up against the carb fuel intake.
#33
04-19-2017, 06:54 PM
One quick question for anyone that may know. When I was putting my carb back on, I happened to look into the fuel hose and saw something foreign. I started picking at it and pulled out a tiny crushed fuel filter. Is this stock? I can't see a manufacturer putting a scrappy little filter right up against the carb fuel intake.
#34
04-19-2017, 07:09 PM
One quick question for anyone that may know. When I was putting my carb back on, I happened to look into the fuel hose and saw something foreign. I started picking at it and pulled out a tiny crushed fuel filter. Is this stock? I can't see a manufacturer putting a scrappy little filter right up against the carb fuel intake.
#37
04-20-2017, 08:23 PM
BTW, bryan, your choice of "DJ140/3N lidless" certainly should properly fuel your 351 below 7K RPM. That setup overfuels a similarly modded 250cc KLX below 7K and underfuels it above..
Also, you need to be using the stock slide spring whether your slide is drilled or not.. I assume you've verified that the lift hole/port has been drilled to 7/64th ?
Also, you need to be using the stock slide spring whether your slide is drilled or not.. I assume you've verified that the lift hole/port has been drilled to 7/64th ?
Last edited by Klxster; 04-20-2017 at 08:28 PM.
#38
04-20-2017, 09:03 PM
I'm guessing you're right. I can't verify above 7k right now. I'm taking it easy for break in. When I had the lid off of the carb, I stuck the 7/64 down through and it is drilled. I chose the stiffer of the 2 springs to put in it. The difference was miniscule, but noticeable. For the break in period, the 140 is kicking butt. If I'm at 2200 and go to WOT, the bike pulls like an angry mule until I let off the gas. Can't wait to get out and really give it hell on the road. I have a 146 on the way also, I may jump up to that. My goal is to have it running optimally with the clip on the 2nd notch. I may be wrong, but I feel that if I have to go to the first notch, then I'm over fueling at some point. I think the 144 or 146 will put me right in that area.
Last edited by bryan632; 04-20-2017 at 09:04 PM. Reason: Spelling
#39
04-20-2017, 09:08 PM
Another quick question for the masses. Has anyone tried changing the needle jet (emulsion tube) on these for a more proper mid range? Not sure if that would even help. Then again it may open up options for different needles.
#40
04-20-2017, 10:45 PM
"My goal is to have it running optimally with the clip on the 2nd notch. I may be wrong, but I feel that if I have to go to the first notch, then I'm over fueling at some point. "
Well, yes, you are wrong. With enough reading of my posts and threads, you'll see that as I gained knowledge - with dyno tests and research - the relationship between the needle, clip setting, main jet, and slide spring, became "revealed".. As it turns out, it is a carefully crafted combination that will best fuel the low/mid in the 13's:1 and the top end at 12.5-13 :1 ..... Since we have only the stock, DJ, and N1TC needles to work with, we are very limited as to our options for getting the fueling correct. Even worse is the fact that none of the needles were designed to fuel your bike, my bike, or any similar modded KLX's - If given half a change (I.E. using lower clip settings, DJ springs, etc..) they all will overfuel the midrange when combined with a main jet appropriate for fueling the top end. This is the world you and I live in at this point..
Understand that there is practically no difference in the low/mid fueling between DJ140/3N and DJ144/1N .. But DJ144 adds significant HP in the top end over the DJ140..
To summarize, you and I are using the wrong needles - needles that are not meant to fuel our bikes - but I found a way to get them to "act acceptably" - 1N, stock spring, stock lift port.
Understand that 1N is the top notch and leanest possible setting for the DJ needles.
Your idea of the DJ146 makes a lot of sense to me as a starting point - go with 1N, stock spring, and you'll have exactly what I've been running in my KLX300R for several years now with great success.
Since you aren't going to Dyno test, you'll have to determine if a DJ148 or even DJ150 produces a better "experience"..
There was one company offering their own emulsion tube with their carb kits, maybe it was FactoryPro.. Just know that the AFR your bike is forced to run with is a combination/compromise of the interoperation between the emulsion tube, Main Air Jet, Needle, Needle jet, main jet, and to a slightly lesser extent, the fuel bowl level... Once you know this stuff, you do what I did, find the easiest way to properly fuel with what we have readily available..lol I did try to fool with the MAJ for a while, as our bikes' MAJ is waay too big for performance use. That damned huge, non replaceable, MAJ is the reason we have to run such large main jets to get the top end fueled properly with lidless high performance KLX's..
Well, yes, you are wrong. With enough reading of my posts and threads, you'll see that as I gained knowledge - with dyno tests and research - the relationship between the needle, clip setting, main jet, and slide spring, became "revealed".. As it turns out, it is a carefully crafted combination that will best fuel the low/mid in the 13's:1 and the top end at 12.5-13 :1 ..... Since we have only the stock, DJ, and N1TC needles to work with, we are very limited as to our options for getting the fueling correct. Even worse is the fact that none of the needles were designed to fuel your bike, my bike, or any similar modded KLX's - If given half a change (I.E. using lower clip settings, DJ springs, etc..) they all will overfuel the midrange when combined with a main jet appropriate for fueling the top end. This is the world you and I live in at this point..
Understand that there is practically no difference in the low/mid fueling between DJ140/3N and DJ144/1N .. But DJ144 adds significant HP in the top end over the DJ140..
To summarize, you and I are using the wrong needles - needles that are not meant to fuel our bikes - but I found a way to get them to "act acceptably" - 1N, stock spring, stock lift port.
Understand that 1N is the top notch and leanest possible setting for the DJ needles.
Your idea of the DJ146 makes a lot of sense to me as a starting point - go with 1N, stock spring, and you'll have exactly what I've been running in my KLX300R for several years now with great success.
Since you aren't going to Dyno test, you'll have to determine if a DJ148 or even DJ150 produces a better "experience"..
There was one company offering their own emulsion tube with their carb kits, maybe it was FactoryPro.. Just know that the AFR your bike is forced to run with is a combination/compromise of the interoperation between the emulsion tube, Main Air Jet, Needle, Needle jet, main jet, and to a slightly lesser extent, the fuel bowl level... Once you know this stuff, you do what I did, find the easiest way to properly fuel with what we have readily available..lol I did try to fool with the MAJ for a while, as our bikes' MAJ is waay too big for performance use. That damned huge, non replaceable, MAJ is the reason we have to run such large main jets to get the top end fueled properly with lidless high performance KLX's..
Last edited by Klxster; 04-20-2017 at 11:09 PM.