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riding4fun
05-29-2007, 07:58 PM
Does anybody know when the updated version of the OKO carbs will be out. I am not interested in doing the work on it myself.

I have a Keihin on the way but the kids will be in the ITP Quadcross series in CA. They have a stock class, I just don't if they will let him run with the Keihin. Just covering my bases just in case.

Nichols Atvs
05-29-2007, 08:13 PM
A new shipment of carbs is due in any time will see if there on time i need a few. You can send it to drr and they will drill it for you if you want.

bulldogfallon
05-29-2007, 08:23 PM
I don't think the mod is a fix all or is right for everyone...

I used the .029 bit on both openings and have better success than modding with the bigger bit...

It allowed us to run stock jetting 103MJ and 42 Pilot with just drilling the 2 openings a little bigger on our 50


w/o the carb mod I ran a 90MJ w/ a 38 pilot on the 50 and a 95MJ w/40 Pilot on our 70 in FL

GNCC GROVE
05-31-2007, 09:30 AM
our 70 needs the carb mod. it's an oko 21
We live in Pa and are running the stock filter w/ the cage removed. main jet is a 103.
what size should i drill and what size jets do i need?
where can i get these jets?
thanks for the help

bulldogfallon
05-31-2007, 10:07 AM
I use the .029 drill bit on both holes....you can always go bigger...


The stock main jet may work with the .029 mod on both holes...

It does on our 50.....

I may be able to confirm that tonight.....I have a 70 that I went to the small mod from the big drill bit mod, but didn't have enough time to jet it last night...

bulldogfallon
05-31-2007, 10:08 AM
Originally posted by GNCC GROVE
our 70 needs the carb mod. it's an oko 21
We live in Pa and are running the stock filter w/ the cage removed. main jet is a 103.
what size should i drill and what size jets do i need?
where can i get these jets?
thanks for the help


They are Keihin style jets....

W/o the mod the 103 is a little rich for us in FL.

If you don't do the mod try a 40 pilot with a 95-98 Main Jet

If you try to mod only use the small bit at first and give the stock 103 MJ a try....

sldhd700
05-31-2007, 10:34 AM
Hey Ridin4fun
You can send your carb up to Mountain High Motorsports in Salt Lake City and they can do the Mod for you. I took mine over other day and it took them about 10 minutes to work it over. Give them a call ask for Dean or Rich. From where you are it you could probably have them back in two days. This mod seems to have worked for me. Iwas having problems with this bike loading up on the line. I think this may have cured it well find out tomorrow night.

Shayden Housley#39

bulldogfallon
05-31-2007, 12:05 PM
I have done the mod and am not sold on it....After many hours of testing I wouldn't do the mod on the DRR website

There are other factors that may not have been provided..

Like compression and other mods which will effect the results of this mod.

I rec'd a PM mentioning this from one of the people who originally did the mod before everyone else, so you should go small and then drill out the openings up if you think you can get more power by increasing the opening.

sldhd700
05-31-2007, 01:48 PM
Bulldog

I agree with you on gradually drilling larger to get more power. Rich and I discussed this and this setup drilled larger may work well for us in Utah because of elevation. We are at about 5000ft here and air density is different than lower elevation.

ecmini1
05-31-2007, 09:37 PM
Im not sold on the mod 100% either and was a little concerned when it came out. I see that bulldog is finding this out there is more to just trying to get the carb correct on these bikes. You can dump all kind of fuel and air in a machine but it has to be able to use it. Bulldog is finding this out and has come along way and I love tech talking with him. These bike need more compression then we can back in to tuning the carb. Untill this happens play with the carb all you want. Its only go to drive you crazy.

kenjolly
06-03-2007, 01:34 PM
Just my 2 cents, you better check with the track or series your running before you do the carb fix. Our track lastnight called it a modification, but even then nobody got DQ but they did run much better than us.

An honest 2nd is better than cheating and 1st

ecmini1
06-03-2007, 05:44 PM
Originally posted by kenjolly
Just my 2 cents, you better check with the track or series your running before you do the carb fix. Our track lastnight called it a modification, but even then nobody got DQ but they did run much better than us.

An honest 2nd is better than cheating and 1st


Your correct.

Thats funny how they think this is a mod. its just fixing what the factory screwed up on. (OKO)

riding4fun
06-04-2007, 06:56 AM
I put the Keihin on the 50 and no more problems.
The only concern that I have is getting a smaller intake boot. I'm going to put a Keihin on the 90 as well.

This is considered a mod by putting a smaller carb on it to make it run like it's supposed to. O well, the ITP Quadcross series said it was ok.

Just my .02

QuadJunkies
06-04-2007, 11:11 AM
Originally posted by bulldogfallon
I don't think the mod is a fix all or is right for everyone...


100% agreed

After a few motor failures, we wouldnt ever mess with that specific carb again.
We also have switched to the Keihin and are much happier.

drr5
06-04-2007, 12:17 PM
hey ken i guess you didnt catch what he said , its stock appearing from here on . thats why that had been brought up sat night ,so i guess its time to go to work on these bikes i hope to have one soon.

kenjolly
06-04-2007, 12:22 PM
no i got it, i just didnt want anyone else that might run a stock class run into the same problem.

i will be doing a few things in the next to weeks,just putting a parts list together.

lets get together and make these things run like they can.

drr wizard
06-04-2007, 01:09 PM
you guys are giving up to quick on the OKO, it is tricky to tune but it can make very good power, but I understand of lot people don't have the time or patience to tinker for hours on the carb so a kehin is a good choice.
drr wizard

kenjolly
06-04-2007, 01:47 PM
dont leave me hangin, i havent done anything to the 21oko yet. but as bad as we got outrun sat i need to.

racerdad199
06-04-2007, 02:27 PM
Is the keihin considered a modification? On the DRR website under the 90LTD it says either oko or keihin. Is the keihin that much better of a carb?

dirttrack86
06-05-2007, 05:36 PM
Does anyone make a boot that adapts down to the Keihin?

bulldogfallon
06-05-2007, 07:38 PM
Originally posted by drr5
hey ken i guess you didnt catch what he said , its stock appearing from here on . thats why that had been brought up sat night ,so i guess its time to go to work on these bikes i hope to have one soon.


Make sure you pass the word along that stock appearing means no aftermarket parts that are apparent(at that is my understanding of the term)

Ex--Metrakit cylinder, head, Uni Filters etc


Please get one as the 70cc class could use more riders.....

It could become as big as the 90cc class one day

I know both Austad and Cheater have liquid cooled 70s in stock ready to go.

If you want an air cooled version I have a 70cc kit to convert an air cooled 50 to an air cooled 70...everything else on the quad is the same...carb, jetting, rollers etc....

bulldogfallon
06-05-2007, 07:40 PM
Originally posted by dirttrack86
Does anyone make a boot that adapts down to the Keihin?


I think the stock OKO boot can be clamped to fit the Keihin....it worked for me and I know of others that have done it as well

Just clamp it tight!!!

bulldogfallon
06-05-2007, 07:45 PM
Originally posted by racerdad199
Is the keihin considered a modification? On the DRR website under the 90LTD it says either oko or keihin. Is the keihin that much better of a carb?


If you change it from the way you bought it then it is modified (unless local rules state otherwise)

A ltd would run in the modified class at most tracks anyway

A LTD is a stock DRX90 that is tweaked (in the U.S.) for out of the box convenience

Keihin is more user friendly, but theOKO can be good once you become one with it :) :)

She can be moody, but once you tame her your quad will run nicely

I prefer to use the .029 bit on both openings, which in most cases makes the stock jetting much closer to accurate.

dirttrack86
06-05-2007, 07:57 PM
I have the Keihin dc20 and the neck is much smaller than the OKO. Does Keihin even make a 21mm carb?

dirttrack86
06-05-2007, 08:05 PM
Sorry, I mean a Keihin PE20. I just went to the web sight and they don't list a 21mm. 20 or 22, but no 21.

bulldogfallon
06-05-2007, 08:28 PM
That is the carb I am talking about.....It is about 3-4 mm smaller than the OKO, but the boot will clamp on to the carb...

I don't want to take responsibility if it causes an issue, but I have had others tell me to just clamp it tight

I tried it and it worked for me....Just did it to test the Keihin carb for a few minutes

kenjolly
06-06-2007, 05:33 AM
Well after getting to bed about midnight my 70cc idles now, but now it has a bigger flat spot off the line. on the other hand it runs great once it on the main jet(102). i drilled each hole out to .032.

any ideas

the inside of these carbs need a lot of work very rough,the slide on mine is showing alot of wear already.

drr5
06-06-2007, 11:24 AM
ken it will take more than the carb drilling to outrun the bike in question, but not impossible;)

kenjolly
06-06-2007, 11:28 AM
we can get together this weekend and talk about getting some go fast parts.

drr5
06-06-2007, 12:24 PM
are you going to moroso?

kenjolly
06-06-2007, 12:56 PM
yes.im stay at the holiday inn express in juno. i should know everything about oko carbs after staying there. call me if your going sat 559-2466