OMR,
Thank you for your reply.

So the jet sizes should be ok to start with at sea level?

 

You have an over-rev design exhaust and 190 is a good place to start.
Never hurts to have an assortment of main jets 185 - 200


OMR

 

Well I just received my dynojet kit today so I have jets up to 200 so I should be good.
I just want to try make sure I have everything I need when I take it out . It is a three hour drive for me to ride.
If you have any more input on my set up I would appreciate it. Pros's -con's or any other improvements that could be done.

Thanks again.

 

I have finally figured out how to run with the lid-off.
I had to rebalance the negative pressure in the emulsion tube.
Works great with my modified emulsion tube, I will tests with stock next.
It appears that turbulence is only responsible for 20% of high speed lean out.
With a 200 DJ main, I can black out the plugs and with needle in 6th groove, flood the motor out. Never could I do this in the past.

Runs bests now in 4th groove and 190 main. Hope to be able to share more details after testing stock emulsion tube.

Hope to tests new feature to control turbulence next.

It only took me 1 1/2 years to figure it out. What else does an oldman have to do anyway.

Freez pushes me alittle, but thats when I do the bests work.
Freez's dyno charts showed me an idea. With him being at high altitude, I was able to calculate a new theory and dam it worked.

My son could not believe what we did to make it work.
We will tests with lid-on to see which is bests, but right now the lid-off just jumped ahead.

OMR

 

Bmp

 

Any update?

 

Winter has came too early, raining in southern WI has made the fields too wet lately.
Made a large scaryfast type turbulence reducer, that is mounted between filter and inlet tube to carb. Took out for short run last night, but all we did was spin the tires, too much water in half frozen ground.
Need to do some high speed runs to also tests the stock needle and emulsion tube.
Hopefully this coming weekend I will finish this project.
OMR

 

Weather and I am going into the hospital thursday for my second surgery this year,
looks like I may not finish my jet kit for awhile. It actually works great, but I needed alittle more testing to see if the turbulent reducer really helped on top end.

Lets review why the stock carb runs lean at high rpm's with lid off:

The factory built the DS to meet emission and speed regulations.
For many years all builders hated cv carbs because they needed negative pressure created by a closed air box to help slide and fuel controll in the carb.

So how do we out smart all the above.
First, improve the exhaust system.
Second, rebalance the carb to match the motor needs - stock carb mods.
Third, control the negative pressure inside the carb, not in the airbox. - this is new.
Air going threw the venturi generates negative pressure, slide rises and fuel is drawn up the needle jet. Before fuel can rise quickly it needs to be atomized, thus the emulsion tube adds air to the fuel. Where does the air come from, threw the air jet on the right front of carb air intake. Side where throttle cable is mounted. Other side jet is for the pilot jet system.
But what happens when you allow outside air to enter the venturi area of a carb that has not been threw a tapered oriface?
It now becomes a air bleed. It now reduces the negative pressure in the venturi and has rpm's rise it starts to lose its ability to draw fuel up fast enough to match the air reqirements. Fuel mixture starts to run lean.
The air bleeds control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal."
How do we adjust for this condition. Install a smaller air bleed to richen the high rpm mixture by bleeding off less signal.

The fix:
The main air jet in the DS is a number 120.
The main air jet in a Quest or Traxter is a number 40
Part number 707200187
120 is actually a .037" hole.
40 is a .022" hole

The 40 still supplies all the air needs for the emulsion tube, but maintains the negative pressure to supply the needed fuel for high rpm's with the lid off.

For times that we are riding with the lid-on, jet accordingly, but there is added power at high rpm's also.

With the air snorkel removed from the front of carb, when looking straight into the carb venturi, the air jet is at the 3 o'clock position. Same side as the throttle cable. You will need a small screwdriver to remove the jet. Cost is around $8.00
When reinstalling, do not overtighten, small threads.
This will richen the mainjet by about 3 jet sizes and not allow the top end to lean out.

Getting late for this oldman, I better get some sleep.

Please say a pray for me, so that my surgery goes well and I can continue visiting you DS folks.

OMR

 

Good luck Omr.....I just did your carb mods 2day....4 1/8th in holes and all....It seems to run better we will see 2morrow....I am running no air box but 2day I took off my direct mount k&n and installed the intake tube and a uni filter. I have it rigged so the tube cannot collapse. I plugged the hole in the tube. But the hole from the side of the carb is still open. It seems to run good. Is this gonna hurt performance if i dont filter the hole from the passenger side of the carb. I read where you said to run a fliter, but i could not find one 2day so i left it open. ???

Also i have a aftermarket needle and i have it on the third slot. I have stock exhaust, but i will be getting a tip or a hmf slip on very soon. Will this be ok? I am in ok. and about 1500ft. I am still running the stock cdi also but i checked on a big gun 2day and its only about 120 so i may get that at the same time. Does that sound like a good idea?


Sorry to pump you full of info, i am sure you have enough on your plate right now. I am sure that you are very appreciated for your sharing of this wonderful experience. I know I sure am. But the guys I ride with may not after I bust their nuts. Thanx

 

Good luck omr and thanks for the posts.