Dax RT Carb Idles High

Jasanabia

Jasanabia

New Member
I just installed the RT Carb form thatsdax.com, and its working great so far except for the idle. It starts out idling okay, but within a few seconds the engine revs higher and higher until its really loud. The idle screw is all the way out, and the throttle cable has slack. The slide is fully seated at the bottom position. My first thought was an air leak, so I picked up some Seal All and sealed the manifold to the engine and the carb to to manifold, this made no difference at all. Should I change the main jet? Leaner or richer? Thank you for any suggestions
 
Hey Jasan, take the top off and check this Frank and make sure everything is functioning right including the choke .when and she is running out of gas it will run really fast make sure your gas cap is venturing loosing your gas cap and run it and see what happens .is still nothing then jet down .get back with me and I'll turn you on where you can get jets.check to see if you have a5 or 6 millimeter they came both ways .
 
Thanks for the reply, the choke works fine, it clicks on and disengages off at full throttle like its supposed to. I don't think it's the gas cap because I've used the same one the kits come with since I got the bike, I haven't changed anything, and it's always been fine. I tried turning the gas valve off and riding it, and it seems to run better before it dies; this makes me think I should jet it leaner. The carb actually came with 5 jets plus one in it already. There's a 65,70,75,80, and 85. I believe the one in it is a 75, so I'll try the 70 tomorrow. I don't see why more or less air to gas could cause this, but I might as well try,
 
I sometimes have idle issues still.
When I first installed it, it was the cable, it has to be as slack as it can be.

btw, my jet is 0.65mm and that is perfect for me, I filled and drilled it myself with lead electronics solder and micro drill bits I bought on the net.

So yes about my ongoing issues,
Sometimes idles high, then goes low gradually, then it idles up and down at other times, idle needle is out as far as it can go, slide is all the way down, completely shut.
So, a couple days ago I drizzled contact cement on the intake pipe/carb junction (my spacer I used because my intake is a hand made extension is a piece of cereal box, suspect air leak of minor amount maybe)

Now, there are two other areas I suspect, the area where the choke lever is, I don't like it at all, it gives me concern, it's a vector for engine damaging dirt(but it is before the slide, so air from here is not part of the idle problem),
and the area behind the tightening screw, possible small air leak .
Havent figured the best solution for the choke lever yet, but going to do something about it. (tape for now?)

See the picture.

PS, it's one of my stock pictures, so you won't see glue (contact rubber cement) and I have not test drove it yet since sealing these spots, will update later.

Ps again! This is PS-ing me off!
I bought a wider intake, I had to widen the holes and the gasket too, I should blob some gasket maker on that area as I suspect the gasket may not be seating evenly.
I didn't know I would have to widen the holes, I thought these things were universal.
 

Attachments

  • intake1arrows.JPG
    intake1arrows.JPG
    667.8 KB · Views: 238
Last edited:
Well, what I did seems to have worked, I actually had to screw in my idle screw.
I didn't yet cover up the choke slit yet, I still want it to be functional, but yet resistant to dirt getting inside.
 
you need to get that cardboard are there and buy that sleeve for thats its only 2or3 bucks man come on dude. I'm telling you, no plastic sleeve, no deal and choke is on the airfilter side . it doesn't matter if sucks air by the choke. I had the same problem but I was running arrow motorized cycles read block indeed had the same symptoms so I should I just jeted down to 68 and it went away.what altitude are you at ?
 
Ok so I'll jet it down to 70 and add some Seal All behind the tightening screw. I'm using the plastic seal, ordered one with the carb and it came with one already in there plus 2 extra.
null_zpsab7df5a8.jpg

null_zps88d7f3cb.jpg

null_zpse4b5bb2c.jpg
 
Huffydavidson said:
you need to get that cardboard are there and buy that sleeve for thats its only 2or3 bucks man come on dude.
Click to expand...
I have the sleeve on, and the cardboard is working just fine. If you look carefully you can see my plastic sleeve.
(hint, behind tightening screw)

and choke is on the airfilter side . it doesn't matter if sucks air by the choke.
Click to expand...
Go back re-read my post, I already mentioned that.

what altitude are you at ?
Click to expand...
48 metres (157.5ft)

You had me going for a walk trying to find survey markers, found none.

Then I found this website
 
Last edited:
Jasanabia said:
Ok so I'll jet it down to 70 and add some Seal All behind the tightening screw.
Click to expand...
And make sure your home-made gasket is sealing good too, some permatex grey should ensure a good seal with that.

Just make sure you don't run too lean with your jet, good insurance is just a tad of 4 stroking, look up 4 stroking here or on youtube if you don't know what that is.
When I open mine up I get a bit of 4 stroking on acceleration, then it clears up. That's a good sign that it's getting enough lubrication and is not overheating, which is a bad thing.
 
I just went for a ride and there's a little bit of 4 stroking near wot, so I'll keep the jet for now and give it another try when the sealant cures
 
Last edited:
Mine sucked air at the clamp slice. You were right on the money that. So I installed 1/16"by 13/16" O-Ring in front of the sleeve. See I just machine in the third transfer port , David Rust's Reedblock kit. with your ring and no more air leak she idols right about 1600 rpm 1650rpm.s your ring set me back a whopping $0.39 .
 
Looks good. I am running one of these carbs and have found that the ultimate tool for tuning is one of these: https://www.treatland.tv/trail-tech-temperature-gauge-p/trail-tech-temp-gauge.htm
Its a little spendy but WELL worth the money. I have mine tuned so that it never hits 400 and just touches 385ish. Im also using a 69 jet ;))))) and a custom expansion exhaust, maniac intake, and ported motor. Now tuning my friends bikes that dont have temp gauges is like stabbing in the dark...
MOTO
 
So the idle speed is much better, I'm not sure if its because of the #70 jet or because I resealed the manifold when I changed the jet. When I first rode it today the idle seemed a bit higher and it was 4 stroking a lot, now after I rode it a couple miles there's no 4 stroking at all, and the idle is perfect. Does that sound right?
That thermometer would definitely be useful for tuning, certainly easier than checking the spark plug color
I'm also using an xpipe with no baffle, and the stock cylinder head is resurfaced on a milling machine for more compression, it wasn't even flat before!
I don't know if that matters for tuning , I've heard with a less restrictive muffler you run richer
 
You must log in or register to reply here.
Back
Top