Dyno Jet Jet-Kit Is Crap! AFR Dyno Results;

[JungleJustice]

OK, so the pilot-jets that are in there are 170s... The ones in the DynoJet kit are DH160s.. Weird - smaller air-jets are going to help lean it out!? In my mind the smaller air-jets mean less air to fuel and that means richer running!? No - I'm already running in the 8s and 9s...

OR -

Do they somehow feed the vacuum-draw on fuel and by reducing their size, you are effectively reducing the amount of fuel pulled through - thereby leaning it out!?

 

[Guest]

OK, so the pilot-jets that are in there are 170s... The ones in the DynoJet kit are DH160s.. Weird - smaller air-jets are going to help lean it out!? In my m,ind the sdmaller air-jets mean less air to fuel and that means richer running!? No - I'm already running in the 8s and 9s...

OR -

Do they somehow feed the vacuum-draw on fuel and by reducing their size, you are effectively reducing the amount of fuel pulled through - thereby leaning it out!?

Those are pilot air jets. The pilot jets are under the rubber cap in the float bowl.
Don't mess with that jet.
I gave you good advice.

 

[BassCliff]

Hi,

Mikuni and DJ use different different numbering schemes when sizing their jets. Mikuni's sizes are based on the volume of fuel passed per minute, i.e. 125 cc of fuel per minute. DynoJet uses the actual diameter of the opening in the jet, i.e. 130 mm. There are conversion charts available online or you can download Mr. salty-monk's conversion spreadsheet from my website.


Thank you for your indulgence,

BassCliff

 

[crazypaint]

dk how the 160 leans it out but it dose. i had to lean out the bottom end on my bike i put the 160 in it and it made a big difference on the bottom. mine use to load up and run like complete s*** then i put thos in and ran better on the bottom end then had to play with the air screws a little

 

[JungleJustice]

Guys, thanks SO much for all of your help!

Chef, I don't doubt for ONE MINUTE that you are giving me good advice; it is just somewhat important to me that I understand what I am doing and that I try to make it work with what I have here and that I get the bike on the road and see where we are again! Wait a second - there are the mains, the idle-jets, the pilot jets (air-jets) and then the needle. Something I missed!?
I don't have access to the Mikuni 117.5 mains - I have the DJ 110s, the 114s (that are in there now), the 132s and then the 138s that they also sent to me in the kit! I do have the needles 4th from the bottoms - 3rd from the tops. The pilot-jets now in there are 170s - DJ sent me 160s. You recommend 45s!? Are we talking the same thing here!? Verified float-levels at 21.4mm to 23.4mm - all exact at 22.2-22.7mm. Carbs are rebuilt – new o-rings etc!

For the record; I probably have something like 500 hours on various car dynos tuning several different fully-programmable, stand-alone engine management systems (me personally – on the laptop – moving timing and fuel and measuring peak-hold horsepower, mapping for drive-ability, part-throttle, cursing, idle, cold-start, back-off modes, WOT etc, so I think that I understand things from the air-in/air-out perspective and from the AFR-perspective. I re-read the DJ instructions and yes – there, clear as daylight - it gives the OPTION of installing the DH160 pilot-jets "in order to lean-out the bottom-end" IF the bike starts up WITHOUT the choke (reason we did not do them - it DOESN'T start without the choke...!)

Also, on the troubleshooting questionnaire that sparki posted, there is a diagram that clearly shows the rpm / load-range of the air-jet / pilot jets to impact the ranges that I am having problems with!

Perhaps I'll do those 160s and see? Still puzzled by the thought that SMALLER air-jets will lean it out!? Are we talking the same thing here - air-jets / pilot-jets...?

 

[posplayr]

do step #1 first. You should be using a main no smaller than stock

Mikuni 117.5 mains - I have the DJ 110s, the 114s (that are in there now),

A DJ 110/114 is like a 90/95 Mikuni

Bill is telling you to run a 117.5 mikuni You are way off on the main. Best to buy some or go pods and 4:1 and step up to the 132 dj


If you are way rich on a 110 dj I suspect there is something wrong with the carb. Get this straight first.

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

• <B>[SIZE=+1]

  • [SIZE=+1]1. Top end (full throttle / 7.5k to redline -[/SIZE]

  [/SIZE][SIZE=+1]

  • 
    
    
    Best Main Jet must be selected before starting step 2 (needle height)!
    
    • • [SIZE=+1]Select Best Main Jet [/SIZE]
    • To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the hardest pull at high rpm.
      • If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.

  
  

  • • • If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
        • In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!
          
          
          

          • Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.

  [/SIZE]</B>

 

[sparki]

without wishing to labour the point.... but why not just contact DYNOJET and explain the issues you are having :idea:

 

[posplayr]

without wishing to labour the point.... but why not just contact DYNOJET and explain the issues you are having :idea:

well he could do that but there is probably 100 times the collective experience tuning GS1100E's on this website v.s. DJ.

Bill has rebuild/setp many of these carbs and can just tell you what the setup should be (in fact he did) and get very close especially if it is a stock motor.

This is a stock engine and the if the smallest dj mains are running rich there is a gas leak in the carb (I'm guessing) ; calling DJ will not fix that.

 

[JungleJustice]

My point exactly...

So, we put the DH160s in and removed the 170s that were in there, re-verified the float-levels and reinstalled.

She runs much better! Smooth and pulls strong! We also synched the carbs - they were pretty far out of whack!

I'll get to the dyno and see where things are at now!

Thanks for the help guys!

 

[posplayr]

My point exactly...

So, we put the DH160s in and removed the 170s that were in there, re-verified the float-levels and reinstalled.

She runs much better! Smooth and pulls strong! We also synched the carbs - they were pretty far out of whack!

I'll get to the dyno and see where things are at now!

Thanks for the help guys!

Did you ever get any updates to the AFR's?

 

[JungleJustice]

Nope - I have to get back to the dyno with this machine! (Just got done doing the two 2-stroke V4 bikes on the CarbCon dyno in Kirkland a few weeks ago to get them dialed in a bit more!) The Suzi has been running pretty good, so I haven't felt the need, but I DO want to go and verify it soon - a few minor hiccups here and there...

 

[1948man]

So is the consensus that smaller Pilot-Air jets do indeed lean out the mixture? How does that work? Do the pilot air jets influence how much fuel is sucked into the mixture? I'm dyno-jetting my 1100 2 valve and have stock 170 pilot air jets.

 

[1948man]

Bumpity Bump

 

[posplayr]

So is the consensus that smaller Pilot-Air jets do indeed lean out the mixture? How does that work? Do the pilot air jets influence how much fuel is sucked into the mixture? I'm dyno-jetting my 1100 2 valve and have stock 170 pilot air jets.

Have you read your manual? I woudl gather a bigger air jet would make things leaner ; but the manual would know for sure.

 

[blowerbike]

i love the misinformed title of this thread

 

[Billy Ricks]

Yeah, it's news to me.

 

[1948man]

I'm happy with Dynojet. I don't think the answer to the question is in my manual. I thought it was kind of a general question about carburetors. Dynojet sends 160 pilot air jets to "lean out the bottom end" for 16 valve gs 1100's from '80 to '85. Those bikes come stock with 180 pilot air jets. The original poster thought it was counter-intuitive that smaller jets would result in a mixture with more air in the air/fuel ratio. Crazypaint agreed the smaller pilot air jets resulted in a leaner condition. I was just wondering if there is any agreement on this. It seems counter-intuitive to me also but I was hoping somebody understood the theory of how this works.
Edit: By manual I was assuming my Gs 1100 gl owner's manual. The Dynojet paperwork states the smaller jet produces a leaner condition.

 

[Katarat]

http://jockeyjournal.com/forum/showthread.php?t=64769&highlight=dynojet Mikuni to dynojet chart

 

[1948man]

If I read the chart correctly, the 160 dynojet equals a 150 Mikuni so that makes it even more smaller than the stock 180 jet. Yet the smaller jet (by 30?) yields more air in the mixture?

 

[Guest]

I don't think the pilot air jets are different