DJ jetting and K&N tuning issues
02-10-2010, 06:11 PM
#1
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DJ jetting and K&N tuning issues
Finally had time to get the SH on a dyno and get some AF ratio read outs.
I knew I was down on power, and had a hole in the mid range... but I did not know how bad it was till today.
This is for my 1998 SuperHawk,
ALT 866 ft
OEM exhaust, K&N air filter, DJ jetting kit, 180/185 needle clip #4 position Fuel mixture on 2.5 turns out. Pair valve removed, passages blocked, carbs synced yesterday, leakdown at 4% .
As you can see from the dyno results today it’s lean almost everywhere and has a huge hole in the middle range power wise.
What you think? Where would you go from here?
Thanks in advance for the help.
Erik
[/QUOTE]
I knew I was down on power, and had a hole in the mid range... but I did not know how bad it was till today.
This is for my 1998 SuperHawk,
ALT 866 ft
OEM exhaust, K&N air filter, DJ jetting kit, 180/185 needle clip #4 position Fuel mixture on 2.5 turns out. Pair valve removed, passages blocked, carbs synced yesterday, leakdown at 4% .
As you can see from the dyno results today it’s lean almost everywhere and has a huge hole in the middle range power wise.
What you think? Where would you go from here?
Thanks in advance for the help.
Erik
[/QUOTE]
02-10-2010, 06:39 PM
#3
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Where would I start, not to be a *** but with a Factory kit (Well I ended up with a HRC kit) and a stock air filter.
While some here have had good results with that set up and I hope they can help get it to work for you. I spent around 2 yrs messing with that set up (except I had slip-ons) and could never get it to work right.
Got a HRC kit, talked to the Moriwaki guys and was told to run a stock filter, no more problems.
While some here have had good results with that set up and I hope they can help get it to work for you. I spent around 2 yrs messing with that set up (except I had slip-ons) and could never get it to work right.
Got a HRC kit, talked to the Moriwaki guys and was told to run a stock filter, no more problems.
02-10-2010, 06:51 PM
#4
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Hence this thread.
02-10-2010, 06:59 PM
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Where would I start, not to be a *** but with a Factory kit (Well I ended up with a HRC kit) and a stock air filter.
While some here have had good results with that set up and I hope they can help get it to work for you. I spent around 2 yrs messing with that set up (except I had slip-ons) and could never get it to work right.
Got a HRC kit, talked to the Moriwaki guys and was told to run a stock filter, no more problems.
While some here have had good results with that set up and I hope they can help get it to work for you. I spent around 2 yrs messing with that set up (except I had slip-ons) and could never get it to work right.
Got a HRC kit, talked to the Moriwaki guys and was told to run a stock filter, no more problems.
I can clean up the lean across the range at WOT with a larger main front and rear,, 190 / 195, and clip 5 should help the steady throttle issues. If I can not get this working.... I'll go to a stock filter and Factory Pro jet kit.
02-10-2010, 07:18 PM
#7
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Because that is the exhaust system that is on my bike,, would be kind of silly to tune my bike for the exhaust system on yours 
...yes baffles de baffled. but IMHO that is a sound only deal.. very little if any additional flow. The restriction is header all the way to muffler tip...
But yes, the baffles have been drilled
...yes baffles de baffled. but IMHO that is a sound only deal.. very little if any additional flow. The restriction is header all the way to muffler tip...
But yes, the baffles have been drilled
Last edited by E.Marquez; 02-10-2010 at 07:20 PM.
02-10-2010, 08:38 PM
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Because that is the exhaust system that is on my bike,, would be kind of silly to tune my bike for the exhaust system on yours
...yes baffles de baffled. but IMHO that is a sound only deal.. very little if any additional flow. The restriction is header all the way to muffler tip...
But yes, the baffles have been drilled
...yes baffles de baffled. but IMHO that is a sound only deal.. very little if any additional flow. The restriction is header all the way to muffler tip...
But yes, the baffles have been drilled
DJ, i've tuned 2 prior bikes of mine with their kits, i have noticed they have flat mid ranges. my last bike with the help of Ivan ( of Ivan kits ) and another rider friend reasoned that the diaphram springs were too stiff.
i talked to Dynojet and they could not tell me the spring rate ! wtf ?
since i'm in weights and measures i built a jig to calculate the stock spring vs. DJ spring. we all concluded that reducing the spring tension was the solution ( other than buying a Factory Pro or Ivans kit ).
best of luck in your tuning.
tim
02-11-2010, 06:25 AM
#11
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Yes I agree the OEM cans are more restrictive then a good aftermarket one, and while I do not have a flow bench to test an OEM can vice a baffleectomy one.. In my untrained in flow dynamics measuring mind, my observation is, over all flow is not significantly increased, just noise. (BTW, I built a flow observation device, and tested before an after, not scientifically, and it was not a flow bench.. but using a constant rate of flow from a shop vac and a calibrated ball and plastic tube (joking) I could see that additional flow was minimal.. How much? No idea as it was just a device to see if there WAS a difference, not a way of measuring. )
I ordered a Factory jet kit this morning.. and a stock filter, I’ll attempt one more jetting change and dyno run with the DJ kit, then toss it and start again….
Thanks all for the help….. lets see where this leads. ($80 a dyno session where ever it leads it better get there quick)
I ordered a Factory jet kit this morning.. and a stock filter, I’ll attempt one more jetting change and dyno run with the DJ kit, then toss it and start again….
Thanks all for the help….. lets see where this leads. ($80 a dyno session where ever it leads it better get there quick)
the stock cans imo are pretty restrictive.
DJ, i've tuned 2 prior bikes of mine with their kits, i have noticed they have flat mid ranges. my last bike with the help of Ivan ( of Ivan kits ) and another rider friend reasoned that the diaphram springs were too stiff.
i talked to Dynojet and they could not tell me the spring rate ! wtf ?
since i'm in weights and measures i built a jig to calculate the stock spring vs. DJ spring. we all concluded that reducing the spring tension was the solution ( other than buying a Factory Pro or Ivans kit ).
best of luck in your tuning.
tim
DJ, i've tuned 2 prior bikes of mine with their kits, i have noticed they have flat mid ranges. my last bike with the help of Ivan ( of Ivan kits ) and another rider friend reasoned that the diaphram springs were too stiff.
i talked to Dynojet and they could not tell me the spring rate ! wtf ?
since i'm in weights and measures i built a jig to calculate the stock spring vs. DJ spring. we all concluded that reducing the spring tension was the solution ( other than buying a Factory Pro or Ivans kit ).
best of luck in your tuning.
tim
02-11-2010, 06:49 AM
#12
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i'm suprised you didn't find a bigger difference. of course the difference would be greater as you go up the RPM range.
read about the factory jetkit tuning on this site & it will get you VERY close.
( as in don't use the #50 idle jets, keep the stock ones ). don't forget to epoxy closed the hole drilled in the slides.
i'm running Leo pipes #45 pilot / 2.75 turns out, 180/178 mains, stock filter.
tim
read about the factory jetkit tuning on this site & it will get you VERY close.
( as in don't use the #50 idle jets, keep the stock ones ). don't forget to epoxy closed the hole drilled in the slides.
i'm running Leo pipes #45 pilot / 2.75 turns out, 180/178 mains, stock filter.
tim
02-11-2010, 07:53 AM
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I'd get the OEM air filter and keep the DJ kit.
I've got the DJ kit, 175/180 mains, needles clipped fifth groove from the top and V&H slip ons. Perfect throttle response everywhere and no flat spot whatever.
You counted the needle grooves from the top, not the point right? Just asking 'cause I'm surprised you're running so lean with 180/185, a K&N and stock pipes. Or maybe air getting in somewhere besides through the filter element?
Only other thing I can think of would be that those cans are flowing more air than you give them credit for.
I've got the DJ kit, 175/180 mains, needles clipped fifth groove from the top and V&H slip ons. Perfect throttle response everywhere and no flat spot whatever.
You counted the needle grooves from the top, not the point right? Just asking 'cause I'm surprised you're running so lean with 180/185, a K&N and stock pipes. Or maybe air getting in somewhere besides through the filter element?
Only other thing I can think of would be that those cans are flowing more air than you give them credit for.
Last edited by RK1; 02-11-2010 at 08:02 AM.
02-11-2010, 08:49 AM
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Carb sync fitting extensions sealed, air box air tight, carbs tight in manifolds,, I dont think I'm leaking air into the intake.. tried the old propane test and got nothing so i think I'm ok there.
Why it's running so lean?? not sure, other then, it is, the dyno proves that, I have double checked my jetting notes this morning, pulled the carbs to be sure.. what I have noted, is what is in the bike...
I may just toss the K&N. I good friend, that is not only a master Tech, but truly a tuning expert, reminded me that as old as the R & D on the DJ kit is, chances are it was developed prior to a K&N air filter becoming available, as such, regardless of what one might read, it is probable designed around a standard flowing OEM filter. This notion matches what others have found when using the K&N.
Step one,,, install a stock air filter.
Why it's running so lean?? not sure, other then, it is, the dyno proves that, I have double checked my jetting notes this morning, pulled the carbs to be sure.. what I have noted, is what is in the bike...
I may just toss the K&N. I good friend, that is not only a master Tech, but truly a tuning expert, reminded me that as old as the R & D on the DJ kit is, chances are it was developed prior to a K&N air filter becoming available, as such, regardless of what one might read, it is probable designed around a standard flowing OEM filter. This notion matches what others have found when using the K&N.
Step one,,, install a stock air filter.
02-11-2010, 09:34 AM
#17
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The K&N is the culprit responsible for the hole... Get a stock filter in there and the hole will even out some... Makes the job of getting the setup much easier...
The K&N is matched to an aftermarket exhaust to begin with, and the OEM one's are a very bad match for it... And yes, de-baffling it makes a significant difference on flow... (I measured) still not enough for a K&N though...
The only benefit of a K&N is that it's cleanable... It's got no justification as a performance upgrade unless you modify the whole engine along with it...
The K&N is matched to an aftermarket exhaust to begin with, and the OEM one's are a very bad match for it... And yes, de-baffling it makes a significant difference on flow... (I measured) still not enough for a K&N though...
The only benefit of a K&N is that it's cleanable... It's got no justification as a performance upgrade unless you modify the whole engine along with it...
02-11-2010, 09:47 AM
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The K&N is the culprit responsible for the hole... Get a stock filter in there and the hole will even out some... Makes the job of getting the setup much easier...
The K&N is matched to an aftermarket exhaust to begin with, and the OEM one's are a very bad match for it... And yes, de-baffling it makes a significant difference on flow... (I measured) still not enough for a K&N though...
The only benefit of a K&N is that it's cleanable... It's got no justification as a performance upgrade unless you modify the whole engine along with it...
The K&N is matched to an aftermarket exhaust to begin with, and the OEM one's are a very bad match for it... And yes, de-baffling it makes a significant difference on flow... (I measured) still not enough for a K&N though...
The only benefit of a K&N is that it's cleanable... It's got no justification as a performance upgrade unless you modify the whole engine along with it...
02-11-2010, 12:33 PM
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02-11-2010, 02:08 PM
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I have an idea, and a plan.. But I’m smart enough to know, others have experience as well.. And I’m not ashamed to neither ask for help nor use others success.
I appreciate the opinions of others and suggestions thus far. Nothing earth shattering, but how would I know that unless I asked, and folks took the time to answer.
I appreciate the opinions of others and suggestions thus far. Nothing earth shattering, but how would I know that unless I asked, and folks took the time to answer.
02-11-2010, 06:15 PM
#23
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I have an idea, and a plan.. But I’m smart enough to know, others have experience as well.. And I’m not ashamed to neither ask for help nor use others success.
I appreciate the opinions of others and suggestions thus far. Nothing earth shattering, but how would I know that unless I asked, and folks took the time to answer.
I appreciate the opinions of others and suggestions thus far. Nothing earth shattering, but how would I know that unless I asked, and folks took the time to answer.
theres no shame in learning bud
ive asked my fair share of questions and trust me most of mine are stupid, haha. i do enjoy reading these posts as im getting close to having my bike tuned with a similar setup to yours
02-16-2010, 08:32 AM
#25
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I know what you mean on this one. I fought and fought with my hawk. I just did not have the bottom end or midrange I knew it should. Top end great.
Devil slip-ons, stk header, BMC race filter, Factory pro jet kit.
I fought and fought this thing. I could get it to run good but just did not have the bark off the bottom. I know some folks are having success with their K&N filters. They are getting some top end, but I wonder if they are losing in bottom end or midrange. I talked around and it seems as if even factory race teams use the stock filters, RC51s, CBRs.......Reliable source?
So I tried the stock filter. Works great!
Others have the same results.
Devil slip-ons, stk header, BMC race filter, Factory pro jet kit.
I fought and fought this thing. I could get it to run good but just did not have the bark off the bottom. I know some folks are having success with their K&N filters. They are getting some top end, but I wonder if they are losing in bottom end or midrange. I talked around and it seems as if even factory race teams use the stock filters, RC51s, CBRs.......Reliable source?
So I tried the stock filter. Works great!
Others have the same results.
02-16-2010, 11:22 AM
#26
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I know what you mean on this one. I fought and fought with my hawk. I just did not have the bottom end or midrange I knew it should. Top end great.
Devil slip-ons, stk header, BMC race filter, Factory pro jet kit.
I fought and fought this thing. I could get it to run good but just did not have the bark off the bottom. I know some folks are having success with their K&N filters. They are getting some top end, but I wonder if they are losing in bottom end or midrange. I talked around and it seems as if even factory race teams use the stock filters, RC51s, CBRs.......Reliable source?
So I tried the stock filter. Works great!
Others have the same results.
Devil slip-ons, stk header, BMC race filter, Factory pro jet kit.
I fought and fought this thing. I could get it to run good but just did not have the bark off the bottom. I know some folks are having success with their K&N filters. They are getting some top end, but I wonder if they are losing in bottom end or midrange. I talked around and it seems as if even factory race teams use the stock filters, RC51s, CBRs.......Reliable source?
So I tried the stock filter. Works great!
Others have the same results.
Went on the web and read that the folks who built 150 h.p. VTRs in the '90s, Erion Racing in the U.S. and Revolution Racing in UK reported the same thing. They had tried every aftermarket filter available. NONE made more power than the OEM. And EVERY aftermarket made the bike run shittier on less than full throttle.
If you already have a VTR with aftermarket filter and it runs goods? Thank your lucky stars.
If you are considering buying one and tuning a bike to an aftermarket filter?
You are a fool.
02-16-2010, 12:10 PM
#29
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Not sure what to make of the data you posted, Wicky.
Appears adding race cans, jets and a K&N netted you 2.4 peak HP over "STD". I'll assume "STD" means OEM cans, jets and air filter?
It's not unusual to pick up 2-5 HP by adding race baffle cans and doing nothing else whatever. I have no idea what, if anything, the K&N added to (or subtracted from!) your 2.4 HP gain.
Appears adding race cans, jets and a K&N netted you 2.4 peak HP over "STD". I'll assume "STD" means OEM cans, jets and air filter?
It's not unusual to pick up 2-5 HP by adding race baffle cans and doing nothing else whatever. I have no idea what, if anything, the K&N added to (or subtracted from!) your 2.4 HP gain.
02-16-2010, 12:26 PM
#30
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Not sure what to make of the data you posted, Wicky.
Appears adding race cans, jets and a K&N netted you 2.4 peak HP over "STD". I'll assume "STD" means OEM cans, jets and air filter?
It's not unusual to pick up 2-5 HP by adding race baffle cans and doing nothing else whatever. I have no idea what, if anything, the K&N added to (or subtracted from!) your 2.4 HP gain.
Appears adding race cans, jets and a K&N netted you 2.4 peak HP over "STD". I'll assume "STD" means OEM cans, jets and air filter?
It's not unusual to pick up 2-5 HP by adding race baffle cans and doing nothing else whatever. I have no idea what, if anything, the K&N added to (or subtracted from!) your 2.4 HP gain.
