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Dynojet Stage III...

  • Thread starter Thread starter keman
  • Start date Start date
K

keman

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I have searched and read EVERYTHING I can find on this site and several others...

I read in an older post about removing the bowl vent tubes when installing a dynojet stage III kit, but I do not see anything about that in the instructions.

Carbs are spotless (full clean etc. per the carb tutorial). Mains are DJ 155, Kerker4>1, Emgo pods, No air leaks, valves are adjusted and in spec...

Dynojet installed by the instructions. Idle mix out 4.5 (really??) drilled slides, installed air correctors, clip on 3rd slot...

Backfires through carbs at idle.... ARRRGH!!! What am I missing?


SCHOOL ME, for I am lost.
 
That's got to be a typo. Try the screws at 2.5 or three turns out.
They're too rich if it's popping through the carb.
And yes, if you're running pods, pull the tubes off the bowl vents. It isn't in the instructions, but it helps.
Make sure your float levels are set correctly. This is very very important.
Did you try the bike before changing the air corrector? Sometimes they're needed but many times not, unless the kit specifically stated for YOUR model that they needed changed, I'd put the stock ones back and try those first.
Making those too small will make the bike run a lil richer than it should.
I recall the directions stating that they aren't always needed, but I've never installed a kit on your model GS.
 
I thought 4.5 was ugly wrong too, but the PDF on the site shows it too.

As for the correctors, I did use them, Per instructions. .

The floats are set right I adjusted them while I had the carbs apart. Two were WAY off, but I made sure there were no bits of fluff or debris in the inlet seats, adjusted and double checked all the measurements.

The carbs were soaked, scrubbed, poked through all the tiny holes with a dental brush pic or wire, sprayed through with carb spray, and canned air, then rinsed in the sink with Dawn soap, and blown out with air again. Every jet, screw, new o-rings, and moving part got a very light touch of tri-flow oil. I was very thorough, and took my time.

I'll pull the vent tubes.

I will turn the mix back to 2.5 and go from there. Even tho' I have been through these carbs and know the parts, I still feel clueless.


FYI, I have replaced intake manifolds and O-rings, done the coil relay mod, stator direct wire, new R/R, replaced almost every bullet connector with shielded blade style, replaced oil pan gasket and checked the pick-up,... one piece at a time, Soon she'll have more new parts than old...
 
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update

update

Well, mix screws back to 2.5 turns out. Still poping back through the carbs. ..pops while reving from the pipes too... ran it a little hot trying to dual it in. At least all for pipes looked evenly red!


Did I mention I hate working on carbs! I need to find someone local who has a vac sync I can use to properly sync.
 
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REMOVE THE EMGO'S AND GO FOR A RIDE.
these filters are mis-shaped and small.
(28 bucks to the door...you get what you pay for).
and...all my instruction for the GS's say to remove the vent tubes.
get the bike running rite and then get a set of offset ovals from APE..60 bucks or so.
 
Ya, I know, I cheaped out... did not have the cash for the apes. Vent tubes are off. took them off before I went back to 2.5 on the mix screws..

If it would not be too rich, I would put the air box back on. Its it possible since I used the smallest main (DJ155) that i may be able to run the air box?
 
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Sounds like the same suggested setup for my 82 850 except 165 mains per instructions.

I started out with the screws 4.5 turns but ended up around 3 turns out. They're not all the same and I lost count. Start out at four or so and warm up the bike and turn em slowly clockwise till you hear an idle change and stop, turn it back counter clockwise about a 8th a turn.
I tried running it with em all turned 4.5 out turns but the plugs were black.
I think DJ give you this number as a starting point.

I run 165DJ main. Had the clip on the third grove but have recently changed to second notch to lean it out a bit. Not had a chance to ride it much since.
I also run vent tubes and K&N filters.
If I were you I would try the 165 mains and go from there.
How do your plugs look?
 
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I'm really not a fan of pods, sure they look kool, but I have really not heard much good about them. Only reason I put them on was because the guy at Dynojet said they were needed.
 
st.3 takes pods.
st.1 takes air box.
the difference is usually the main size and the mixture setting.
with the 850 being geared on the low side...
the couple st.3 i have done on them...you could really feel a "seat of the pants" difference.
but....the bikes was probably somewhat lean from the 4-1 pipes and factory jetting.
before and after was quite noticeable w/ the st.3.
 
I would have done stage 1, if they made one for the 80 GS850G. Stage III is the only kit available.

Just for S&G, I am going to test putting the air box back on and try it. If it blacks the plugs in the idle circuit, I will have to wait till I get the funds for a good set of pods.


As the bike sits, DJ155 mains, mix screws 2.5 turns out, emgo pods, bench sync'd.

Pops through carbs at idle, pops through exhaust on rev in neutral. Still in the learning curve here, I hate carbs.
 
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It's a bit frustrating. I can tell bolt sizes by sight and touch, rebuild most engines with nothing but the right tools and a spec sheet. Im a fairly cocky mechanic, often hand torquing a bolt by feel, then betting on it with friends only to collect when they put a torque wrench on it.

Carbs just make me feel like a total newbie! Rebuilding them, cleaning them, that was easy. Tuning them just escapes me. I should know this stuff. I have owned many GS bikes. I had my best friend as a carb savant for anything to do with the fuel systems. I did his electrical, he did my carbs. Hell, the day he left us I was changing the r/r on one of his bikes.
 
That link for GSZone........the pods shown only go back to 1980 which implies CV carbs on a GS1000. Are there any which will fit the VM26s? (I have a '79) I've hated the idea of $150 for K&Ns.....
 
That link for GSZone........the pods shown only go back to 1980 which implies CV carbs on a GS1000. Are there any which will fit the VM26s? (I have a '79) I've hated the idea of $150 for K&Ns.....

check the os diameter of your carbs. 54mm is quite common. K&N might list this in the product definition for your bike. If you have 54mm bells, you can use filters for just about any of the bs32 carbs.
 
bs32's take the same filter as most all the GS CV's...32/34/36 mm.
the same filter for the miks RS34/36/38/40mm.
2-1/4" opening roughly.
 
I'm roadracing a GS1000 with a Stage 3 kit, velocity stacks and racing baffle in the V&H 4 into 1. It's running too lean and I'm using the 138 main jets that came with the Stage 3. They also included a set of 142s.

The Stage 3 instructions say that the kit is made for K&N pod filters.

Question: Would it be better to replace the velocity stacks with K&N pod filters and try the 142 mains, or experiment with larger than 142 mains?

Thanks!
 
Velocity stacks have no filtration at all- but optimum air flow. If you are running lean with them on, I can't imagine installing K&Ns would help. I would go to the larger jets.
 
So, I bit the bullet and dug into my rapidly dwindling savings to purchase my very own Morgan Carbtune, and a Colortune. Got the screwdriver/nut carb tool while I was at it. I have figured out that no matter who tells me how to do it, I am inept at tuning carbs.

I have learned, that good tools can make all the difference in the world. Especially if they make an otherwise confusing project less confusing.

Is it bad that it was cheaper to buy these tools out of England? With shipping, I saved more than 30.00 on the three tools and shipping combined.
 
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If jetted correctly for pods..your carbs will run fine with NO filters. Period.
K..you're too lean. If you're using pods, even with a stock exhaust you need full stage three.
We can sit and argue about the backpressure difference between an aftermarket header and the stock exhaust but to keep it as simple as possible, a stock system, theoretically, will flow as much or more air as a baffled street header system. You got two pipes with a estimated diameter of, what, 1.5"? 2"? Vs one with an estimated diameter, even on the big boy full race yosh I had at maybe 3"? Sure there will be some backpressure and scavenging differences yada yada. But there's more effect to the carbs from pods than a pipe, which is why some guys have gotten away with shimming and bumping the mains with just a pipe and the stock box and filter....

Try the bigger main, screws three turns, stock pilots, clip in the second slot from the bottom...it might be a little wet and fat, but the clip can be leaned easily.
 
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