ThatsDax rt High Performance Carburetor

Got my RT carb today, rode 3 km just trying to get it started, but it doesnt want to, I cant figure it out. It fired once, after about 1km without the choke on, then never again (with or without). Am I running it too lean? With my NT carb I figure I was running it fairly lean with a 0.6mm jet, I'm using a 0.65mm in the RT, however it was 20 degrees C running the NT, now its averaging around -5 C, should I go even bigger? say 70 or 75? I tried switching spark plugs so... yeah

EDIT: I shortened it cuz my ride to work was waiting, however the NT carb was having troubles starting and even running (but the key is it DID run) and I think the cold dense air has something to do with it. Keep in mind the original jet with the NT was a 0.7mm and it caused four stroking. in +25C weather. I have yet to check for a spark because its ridiculously difficult to check for a spark in the day, while riding the bike, and I cant get the plug off (my 13/16 socket went missing). I tried disconnecting the killswitch and made sure the white wire wasnt shorting out. So... I'm at a loss... Rode the bike literally just before switching the cylinder to a mostly stock (mild porting done) and installed the new carb, using Permetex Copper as a gasket (as I didnt have any non-40mm gaskets)
 
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If you do have spark, start with the stock rt jet, make sure your bowl is full and your getting gas to bowl. Check for air leaks at manifold and carb to intake ( plastic ring ). Check for air leaks at new cylinder top to bottom. Check spark plug gap (making sure something did not go awry on cylinder swap and your piston slammed your gap shut)

Most engines really love cool dense air once there warmed up. I don't think thats the problem. It should start and run reasonably well with stock jet. Get it started and then you will know which way you wanna play with jets. Good Luck! Making sure there is gas in bowl will save your lungs.
 
changed to a 75 jet, and now bike will start after riding and holding the throttle WOT for about 3 seconds (with the choke on), after which it'll rev out of control for about 2 seconds (choke clicked off), then die, where I have to repeat the process. So I'm willing to bet there's an air leak... Most likely at the manifold (I didnt have a gasket so I used a 3mm bead of permetex copper and let it sit for 22 hours, made sure to circle both bolts and the port), but perhaps at the carb as well (I dont have an o-ring but I never had an issue without one before)
 
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Get the o-ring and a tube of "Seal All" for that spacer. Just because the carb can't move does not mean it can't leak. As normal, this is just my experience, trials and tribulations, respectfully.
 
yeah, I'll grab an o-ring, but by spacer, you mean the automotive hose? or the manifold to jug because I didnt have an actual gasket? either way I can get an O-ring for the carb, just getting the manifold checked out could be problematic
 
How are you attaching carburetor to engine? Are you using stock intake? I'm talking about the plastic spacer inside rt where it slides on to intake and then clamps.
 
ohhhhh okay, yeah its on an automotive hose with a copper pipe with the OD the same size as the OD of the intake manifold, and two hose clamps clamp it down I'll check the carb seal though, unfortunately I dont have any allen keys to take the stupid thing off (I borrowed one to put it on). Everything else is a phillips screw, the intake clamp is a hex key...
 
I actually took a pic early yesterday. I'm not sure where I can get Seal All though, I imagine from your description its a jelly-like substance. But having never heard of it I'm just not sure where to find it, but I imagine a good place to start would be Part Source

EDIT: just looked it up, looks like I can grab some at Home Hardware
 

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Is the carburetor installed inside the tubing or on top of the tubing?

You have to remove the 19mm plastic insert from inside the carburetor and slide it onto the intake, then install the carburetor. There is an O-ring inside the carburetor outlet that seals the intake to the carburetor when you slide the carburetor onto the intake.

Here's more information on how to remove and install 19mm insert: http://www.dragonfly75.com/motorbike/SHA.html

Good Luck,

Chris
 
did that, same issue, thankfully a friend took me to canadian tire where I grabbed an O-ring (which didnt fit, sadly), and Seal-all. Seal-all'ed the manifold to jug, bike ran and didnt die, but revved like crazy. Seal-all'ed the carb outlet, bike ran flawlessly. Awesome (I removed the permetex I was originally using as a gasket), now I just gotta re-jet it down again to eliminate the four stroking, and it'll be running again :) Thanks for the advice, guys. Sadly I can hear ringing from my motor at idle and it's not a vibrating exhaust, my assumption is in all the crazy revving, a bearing's about to give. So I'll order a GT5-A jug (and port it right this time), new bearings, and do it all properly
 
hey wats up guys. i have a slight problem with my rt carb, i cant tight the thing enough to stay on the intake manifold! this problem is driving me nuts! what can i do to make it seal? ive got some gasket sealer how bout that?:-||
 
thats odd, it should have a plastic insert that should grip the manifold quite well, mine held tight (so tight I can actually flip the bike over just twisting the carb), only issue was it was leaking air so I sealed it with some Seal-all. You'll need to fashion a shim if you dont have one, or return it.
 
I don't see any problem with using a small amount of goop to resolve a sealing problem, but the spacer must be in position.
Shim stock would be my choice if it was just too loose, then I'd use a little bit of goopy stuff.

RTV red would be my choice of products.

Good luck
rc
 
that sounds like an excellent idea rc. what kind of material should i use? and also how thick should i get it? u know i actually did use an piece of aluminum can and that held alright but it still didnt satisfy me, within an hour of run time the carb broke anyway. i retured the carb a little over two week and i still havent heard back from dax but ill call tomorrow to see whats the status.
 
so here i am tuggin along and all of sudden my bike loses all it power. its dark and hard to see but with the flashlight on my phone i discovered that the black plastic top on the rt carb was cracked in half. this is my SECOND rt carburetor that has broken. im not impressed with the quality of these carbs at all. instead of spend of spending the money on a third carb when its only the plastic top piece. is there unless that i can make or use to replace it? im very crafty and creative with this stuff so any suggestions would be great. or even if any you might have a spare top piece i could buy off you that would be even better.
 
Genisisonyx29 said:
so here i am tuggin along and all of sudden my bike loses all it power. its dark and hard to see but with the flashlight on my phone i discovered that the black plastic top on the rt carb was cracked in half. this is my SECOND rt carburetor that has broken. im not impressed with the quality of these carbs at all. instead of spend of spending the money on a third carb when its only the plastic top piece. is there unless that i can make or use to replace it? im very crafty and creative with this stuff so any suggestions would be great. or even if any you might have a spare top piece i could buy off you that would be even better.
Click to expand...

you can find rebuild parts for that carb on RSE website
 
geoldr said:
Yeah it does. I have an RT carb and the SBP throttle. You just have to remove the little hook thing that the cable goes into from the RT carb, and replace it from one with the NT
Click to expand...

Any pics on this?I have the SBP HD Throttle too, and just purchased a RT Carb. I don't wanna go back to the stock Plastic Throttle so any help would be great on a Cable for the Rt Carb to work with the SBP HD Throttle.
 
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