Dyno Jet Tuning Question - Update

[2fs2ns]

Ok guys, I got my kit in the mail today and couldn't wait.  Me and my brother tore into it...

The bike has been rejetted, it already had 105's in it.  They were stamped: "105k Factory"  We decided to just leave them in and not open my new ones.  


We used the tool to set the screws out 2 7/8 turns.   They were out ranging from 3 to 3.5 turns already.

Next, we took off the plastic covers and removed the needles, this is where I'm a little confused.  I wasn't expecting to see the needle with the clip on it, I hadn't seen that in pictures, is that stock?  I don't see how adding a second shim would be that different from just moving that clip to the the next slot?


This all brings up another concern.  I believe my bike was running too rich.  If you started it in the garage it was really potent exhaust, smelled very much like fuel, not exhaust.  Won't adding a shim make my mix richer?  I am not by ANY means very carb smart, it's just what makes sense to me right now...am I right?  Should I just go with it like the paper says to  

We're stopping there for now, tomorrow we'll shim it and reinstall.  Thanks so much for all the help guys!  Hope I didn't wake you Ron!

[2fs2ns]

[roboto65]

Thats not what you wanted to see that is a Cobra kit same one I have in mine when I got her you will notice a couple holes in the plastic slide also the stock needles are not cheap at 25 a piece and don't even ask about the slides   but all is not lost mine runs great just have to open the Idle jets abour 2 and 3/4 or 3 somewhere in there is good depending on the pipe and filter config  ...  My advice put it back the way it was and adjust the Idle jets and maybe sync but thats debateable toI would not add any shims at least we did not when we did mine at Mootmag 3...

[Greg Cothern]

Yeppers as Allen said that is the Dyno-Jet kit!!!  The thing I dont like is that they want the slides drilled to allow the diaphragm slides to receed quicker.  
The Dave Dodge jet/shim kit does not alter parts.  The 2 7/8 turns out should be pretty close with V & H pipes, might have to tweak them a bit to around 3 1/8 turns.
Give it a try with RPM's around say 6K let the gearing pull the RPM's down during deceleration, listen for popping in the exhuast.  If no popping and throttle response is crisp then RIDE!  If it decel pops then open the pilots an 1/8 turn more until it stops the pop.

[2fs2ns]

Ok, was afraid of that, but I'll roll with it.

So does turning out the screw lean it, or make it richer?  Just so I know...

[Gloveberg]

Makes it richer.

[2fs2ns]

So is the Dyno-Jet kit really that bad aside from having to drill the slides?  

Or is that the only down side?  Can I ever expect to get it running smooth?

As it was, it popped continuously coming down from 6k rpms, and sometimes if you were just cruising along at 30mph or so, no gas, but not decelling either.

I did find a great writeup of the Dyno Jet install, lots of good pictures for those of us that are visual learners...
http://www.shotsnapped.com/public/carburetor/index.php

He recommends going out about 3 turns, but he also says the retainer clip should be on the 3rd groove from the top, mine is on the 2nd.

[Greg Cothern]

Yeah the biggest drawback of the Dyno-jet kit is drilling the slides, that is just something I dont agree with.
Other than that they do pretty well, I would try the clip in the 3rd slot leave your pilot jets where you have them.  Ride it and see how it reacts, if you have good crisp quick throttle response and no or very little decel popping then you are good to go!
If the throttle response is slow and it bogs down low then it is a bit rich and I would think about turning in the pilot screws a 1/4 of a turn and test.

[MagnaMan]

Here's some information from another Magna Forum regarding the dyno-jet kit:

The actual DymoJet kit worked fine in my bike. The Cobra kit is made by DynoJet, and is similar, but doesn't run well with multiple mods. The only way to tell if the carbs have this type of jet kit installed, is to get the needles out of the slides. The Honda needles are fixed, and have no grooves or clips for adjustments. If the needles are adjustable, you have either the DJ kit or the Cobra kit. The only way to tell them apart is by the main jets. The Cobra kit will have "98" or "100" mains, where as the DJ will have "100", "104", or "108" mains. Besides the main jets, the main difference between the kits is the absence of new slide springs from Cobra. I believe this is the reason for it's poor performance. If you find the "100" jets assume you have the Cobra kit, and see if you can order the springs and "104", "108" mains from DJ. HONDA/KEHNIN JETS ARE NUMBERED DIFFERENTLY, AND WILL REQUIRE EXPERIMENTATION TO GET RIGHT. If you have the bigger jets, just set your pilots to 2 3/4 turns from lightly seated, and resynch the carbs. If you have V&H exhaust or drag pipes (or live in colder climes), set your pilots to 3 turns. These kits are touchy on startup. Too much choke tends to flood the engine. Start on 1/2 choke, then adjust until 2000 rpm +/- is achieved. I would recommend a K&N filter and a DYNA ignition module set to curve 4 or 5 as additional mods.

Here are the links to the DJ and Cobra kits. There is a parts list in each.

http://www.dynojet.com/pdf/1167.pdf

http://www.cobrausa.com/pdf/92-1164.pdf

If this guy is correct about the jet sizes then yours aren't exactly matching up.  Allen probably has the Cobra version of the kit because that's the kind of pipes his bike came with.  But he might be able to step in here and let you know what size his jets are and what settings he uses for his pilot screws.

[2fs2ns]

Yup, you're right.  The DJ kit comes with 108's, and that's what that guy has that I linked to.  

Just need to start messing with it I guess.

[roboto65]

I really cannot remember what size the jets are we left it alone and adjusted the Idle jet screws and that solved it all. So what I would do is leave it where it is and adjust the screws and see if that cures it... If not well then go in and lower the clip one slot and try that.....

[2fs2ns]

Ok, update...

Moved the clip to the 3rd groove, screws are about 2 7/8 turns out.

Bike idles good.
Small bog on throttle up.
Midgrange 2.5-4k rpm's is smooth, that flat spot is gone.
No problems up into higher rpms.
Lots of popping on engine decel still.  If I run up to 8k and let it come down it starts popping around 4.5k.

So some progress, flat spot is gone.  Still have popping, and that initial bog isn't a preferred feature.

Any suggestions?

[Greg Cothern]

Since the pilot adjustment is easier open it a 1/8 turn more and see if that takes away your decel popping.
What do you have the idle RPM set at??  And what air filter are you running?  If you dont have a K&N might put on in this will lean the entire range a bit will help with the bog some, and if you do open the pilot jets another 1/8 turn.

[ronmag]

Dan I am glad you are making some progress. Don't know
about that kit so I can't help. I think you keep tweeking from
where you are you will get there. You didn't wake me last night
I am glad you called, that is what we are here for! I was just shutting
down my puter when you called.           ronmag

[2fs2ns]

I'll check the idle rpm, I didn't notice what the actual rpm was.

No K&N, kinda been debating it, haven't heard good things in the automotive world about them, so it's kinda made me leary to put one on the bike.

On that note, the filter should be changed regardless, it's dirty, thaty *may* help some.

I'll mess with it some more tomorrow night.  Thanks again guys!