OKO Carb Tech Update

[bulldogfallon]

DRR has posted an upgrade to get rid of that OKO bog...

http://www.drrinc.com/new_page_18.htm


DRR Wizard broke the news on another post so he gets the credit for the announcement

I had access to the forum so I figured I would post it

[forgiven]

Should we all do this? Is this just for the 50's?

Nice instructions btw :D

[bulldogfallon]

For all of the OKOs I believe....

The air screw opening is so small it is non existent.....The new hole is huge.....

I will have test results this weekend.....

[ecmini1]

Im wondering now if it does apply to the 24mm aswell.
This is great info. We usally run kehin anyway but good to know. This is another reason DRR is a great company always listening to the customers concerns and finding a solution.

Thanks Bulldog

[bulldogfallon]

On the 50s you may need to try a smaller main jet....

Every bike and area likes a little something different.

The 120 was the main jet for a 70cc quad with a high compression head.


All the credit for the info goes to DRR Wizard not me

[drr wizard]

Originally posted by bulldogfallon
For all of the OKOs I believe....

The air screw opening is so small it is non existent.....The new hole is huge.....

I will have test results this weekend.....

your right gary, the original hole is so small you would think it would not run at all, but the .029 drill bit is pretty dang small too. I have only had 1 of the 24 mm oko in the shop and it did not have this issue , so it may be only the 21mm that needs this mod. If anyone finds out some of the 24mm need mod please post. thanks

drr wizard

[forgiven]

With all the issues the 50's were having that sure sounded like a likely culprit, but I am curious if any starts playing with their 24. I am not adverse to getting more for a little drilling and PJ.

[Nichols Atvs]

i have a 24 I think needs to be drilled out it has a bad bog in mid range i just need to find some bits.

[ecmini1]

Thats more of a jeting issue in the mid range. Bog in question is out of the hole or off idle throttle responce.

[drr wizard]

CONVERSION HELPER; the bit sizes needed are #40 and #69 when you go to purchase
this will make your search for bits easier. I think ecmini is rihgt about the 24 , it sounds like your pilot jet is to small . If a larger pilot does not help it then investigate the pilot passage, it may need cleaning or drilling .
drr wizard

[dblacks]

Originally posted by Nichols Atvs
i have a 24 I think needs to be drilled out it has a bad bog in mid range i just need to find some bits.

correct me if I am wrong but the 90 is the one with 24 and the other 90's I have seen all needed jet changes to get rid of the mid range bog

[drr wizard]

yes the new 90cc comes with 24mm OKO , the pilot needs tuning in most cases.

[ecmini1]

The bikes are jetted rich DRR has no idea where they are sold so its set rich its up to your dealer to dial it in for you.
Altitude, humidity and temp plays a huge factor in the running of any machine. We are in FLA so my jetting is going to be diffrent than someone in N.Y. best way to get close is talk to the dealer or some one at the track and it should get you close.

[drr wizard]

If you want to check the 24mm and it needs drilling , drill the pilot to .059 instead of .029 like on the 21mm carb. for a 70cc with 21mm oko drill .045
drr wizard

[Nichols Atvs]

Originally posted by dblacks
correct me if I am wrong but the 90 is the one with 24 and the other 90's I have seen all needed jet changes to get rid of the mid range bog


gone up gone down nothing has changed in the performance
so were going to try drilling it out

[bulldogfallon]

I think it should also be mentioned what has been done to these quads beyond just the carb upgrade...



HC Heads and other mods may have been done as well

Let's make sure all mention the status of the mods so we can compare apples to apples



Some guys have bored out the pilot opening on the 50s to .059 as well


Any input on that?

I am still trying to tweak my 50 and it still has a little bog even with the .098 and .029 openings...

I am thinking of trying the .059 on the pilot side

Any thoughts?

[riding4fun]

Originally posted by drratvs
YES THIS A MOD YOU DO WANT TO DO TO THE 24 MM CARB. I DRILLEDOUT 2 LAST NIGHT AND I USED A .059 BIT ON THE PIOLET JET OPENING AND USED A 42 ON THE PIOLET AND A 125 ON THE MAIN AND OUT 2 TURNS ON THE AIR SCREW OND THE POWER ALL THE WAY THRU!!!!!!!!!!!

I did just as you did but now I can't keep it running. I am using a 115 main everything else is the same. It took forever for it to start and when it did it ran for a minute or two and bogged out like it was too lean. I have tried the mixture screw at 1, 1 1/2, 1 3/4 and 2 turns out.
Any suggestions.

[bulldogfallon]

Make sure you don't have anything clogging the carb up.....All those metals shavings can cause a problem if they are hiding somewhere

I had that happen with the brass from the main jet...I tightened it a bit too much and it left a small pc in the main jet that caused me some running issues

Change the plug?

[drr5]

i spent a whole day tunniing the 16 mm carb with a set of number drills ,but for all the work it runs perfect

[jetmedic]

Who is supplying the 120 main jet for the 50cc? Is this a recall from drr or are we on our own?

[drr wizard]

Originally posted by jetmedic
Who is supplying the 120 main jet for the 50cc? Is this a recall from drr or are we on our own?

I just called the dealer that sold it to me and he had it sent right out , no charge .
drr wizard

[Nichols Atvs]

drilled out a 24mm carb and used a 112 mainjet and 42 pilolet this thing ripps now .