ThatsDax rt High Performance Carburetor

Hate to be the first bummer report here on the RT but mine will not work no matter what I have done to it. I am a maintenance mechanic and have been for over 30 years and work on all types of internal combustion engines. That said, I have fiddled for 2 weeks on it to no avail. I modified the choke to be remote operated so I cannot return it. I do not recommend this carb from my experience. The fuel bowl had to be sealed...leaks. The fuel inlet around the filter had to be sealed...leaks. I have no air leaks....tested with starting fluid, the fastest and easiest way to find air leaks...none. I also bought a new gas tank cap from Dax..would not allow fuel to flow because the venting is messed up on it. Got the carb to run on the 75 jet finally but could only go 1/3 the speed of my CNS, with lots of pedalling to keep it at that speed. I have a second complete set of ignition components and have changed them all one at a time to test the outcome...no change. This particular carb was probably not tested at the factory, just manufactured and shipped. Quite a few chinese manufacturers do business this way. It cuts costs. This is all my fault because I went the cheap route instead of paying for a quality dellorto or mikuni. I had to put my CNS back on, now at least I can ride again. Like the guy on the first page of this thread who doesn't want to go faster, you can have my RT and go alot slower..hehehe.

Sorry to hear about your troubles, man I put mine on and not one leak, although I tighten all the screws first. You must have got one of the rare bummers. Just as a long shot call Duane at DAX and see what he says.

Thanks for the kind words Tim. I am not going to ask him to take it back because I modified it first, my bad. I cut off the choke lock and then drilled a hole in the choke handle to install my cable. It worked out sweet with the stainless steel bracket I made to hold the cable. Just a lemon carb. I was very jacked up about installing it because of all the rave reviews, but doodoo happens and I am ok with it. Just going to chalk it up as experience and save for that Mikuni 16mm round slide that is just under $100.

I tried out the #80 jet today. It was not good. If I gave it any throttle at all it just four stroked. I figured this can't be from the jet, it only affects mid to wot. I checked things over and when I touched the spark plug wire it came out of the cdi box. Ah Ha, this must be it. Reinstalled it and same results. Cleaned out some burrs in the intake tube, same results. Changed spark plug, same results. i was beginning to think that I had finally screwed with it long enough to REALLY screwed up something. Changed back to the #70 jet in desperation and now it's running just like before all this started. Good except for four stroking past 3/4 throttle unless I'm going up hill then it purrs like a kitten at wot. Does that sound like I need to try the bigger #65 jet? If I get another #70 I might try drilling to a #68 but I got to stick with my only #70 for now. I'm open to suggestions as I really don't know which way to go.

I wish I had insight for you, Perry. But all I got was crap results any which way I went and have no good 1st hand knowledge as to what might be the answer. I understand how it works with the center tube and it's 2 holes and how the square slide exposes the top large hole at about 3/4 throttle on up. I scratch built a small carb for a scale motor I made based on the same principle, vortex being larger as the slide is opened more so the hole has to be larger hence the jet needs to be correct for your atmospheric pressure and on and on. Take your jet out and inspect the inner tube that is below it, or above depending on how you look at it, as closely as you can making sure there is no blockage in the small lower hole or the larger upper hole. One thing I forgot to mention in my 1st post was the very small amount of metal particles and shavings I found inside my carb. Most chinese equipment of any kind I have ever had to open up, and I mean any kind, has had shavings or even sand from the casting process inside. It costs money to clean things up and test run them. I had no super high expectations as to my motor kit when I bought it and installed it. I have been happily surprised at the abilities my motor has for what it is and what I paid. But a carb is a bit of a more advanced piece of equipment compaired to the motor it is installed on. I spent about 30 minutes looking at the entire inside of mine for defects but found nothing obvious. Your carb may have a clue inside, just look closely. Bout all I can recommend. Best of luck to you.

Did one more thing that seems to have made it run a little better. When I installed my NGK B6HS spark plug I went with the gap it had. I just checked it and it was around .024. I re-gapped to .030 and it seems to have less 4 stroking. Could just be my wishful thinking too.

I just got my DAX carb in and man its awesome, It was bogging and 4stroking amighty at first, So to see if it was to rich I ran it WOT and closed the fuel line and a few seconds later I got this massive surge of power for about 10seconds. So I put the #70 and it runs great it could still be leaner but I think its fine for now, Its certainly better the CNS and the NT. So my rating for the DAX 1-10 I think I'll give it a 10

Good for you, Texhun. I am sure I just got a lemon, one of few in a large production carb. Keep it runnin and try to keep the bugs off your big grin

Thanks I'm gonna order smaller jets tonight so we'll see if it gets better I'll keep you posted.

4 stroking on a two stroke ? Could someone explain to me just what this means. It has to be the most stupid thing i have ever heard.

NormO said:

4 stroking on a two stroke ? Could someone explain to me just what this means. It has to be the most stupid thing i have ever heard.

Click to expand...

You got it Norm!
It's a stoopid burbling sound, caused by dumping too much fuel in there.
So much, that it does not fire every stroke!
...and a throttle chop will show you a black, wet sparkplug.
The engine stumbles and stammers... has trouble getting rpm.
Get the proper jet in there and the engine comes to life!

It's almost as bad as running with the choke on, all the time.

Hope that 'splains it well enough for you...
rc

I gotta try one of these rt's...
Ratchetbirds, you wanna dump your lemon?

NormO said:

It has to be the most stupid thing i have ever heard.

Click to expand...

It happens all the time to new kits that have not been properly tuned.

Here's a video on the subject:
What is "four stroking" ? - YouTube

Great video link, GN!

Thanks for explaining guys. I'll let everyone return back to the subject at hand.

I tried to using my rt with the high performance intake from dax and it doesn't fit well. The pipe is too small, the stock was a little bigger. Still with the stock intake It doesn't seem like it gets tight on the pipe, still moveable. If it wasn't for the bike frame being so close I would have lost my carb last night going to work, it fried back and forth the whole way, electric tape is my quick fix till I can think of something.

Thanx for that video GearNut. A picture with sound is worth 2 million words. Thank you for the offer Rusty, but it will sit on my wall of shame for a while to remind me of several things I did wrong. Modifing it before using it being the worst of my offenses. I am a lil thick headed that way and need reminders now that I am getting older. I also want to save it for a future project with a different motor on a test-run stand that I can modify and test run easily. Maybe by then I will have solved the mystery to my carb. Personally I would say you have a very good chance of getting a good RT right from Dax, so please don't let me be the reason you don't try one. They are very affordable and if you don't modify it first and it doesn't work I am sure you will be taken care of. Dax has a great reputation.

...Do you have a collection, like Burt Munro? 'Offerings to the gods of speed'?


Yes, all else fails, I'll get one from DAX. Can't recall when I didn't hear nice things abt him.

Best
rc

Hehehe, sadly my collection of the stupider things I have done can be read in the scars on my body. Total reminder when I look in the mirror, but I still forget. The wife and I run a parrot rescue and I get a lil too close sometimes with birds who don't trust me yet and WHAM, another scar LOL.

So I got replacement parts for the Dax carb from treatland over the weekend. The Type 2 Shim (21-19mm) + the intake gasket are HUGE winners. Finally cured my air leak blues...

Now waiting on some new jets to see what I can do about this 4-stroking.