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Dan Turner

Still trying to get my junk dialed

8 posts in this topic

I just got my carbs back from XRs Only (87 w/ dual carbs) I had them rebuild them for me. I had 128 jets in them before, and they put 122s back in there. I have no idea what clip they put the needles in. The bike has a slight miss at idle, and occasionally the idle speeds up for a bit, then slows back down. When sitting idleing in the garage for just about 2 minutes or so, the head pipe is glowing pink, getting real hot. When I rev it up, it will shoot flames past the spark arrestor on decel.

Any ideas?? I'm getting tired of working on this thing...just wanna ride.

Dan

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That's the pilot circuit that is missing. Try richening them...sounds like you need at least a 1 jet size up change.

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Thanks for the reply, Tim.

This is what is confusing me...the hot pipe seems like a lean condition, but the flames out the back seem like too much fuel. Should I put my old 128s back in, or go buy 124s, 126s? What's the right way to adjust the pilot? Right now, it's 1-1/2 turns out.

Thanks again, Dan

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I just re-read that post, you meant the pilot jet didn't you? I have no idea what is in there or what should be in there. I have to take the carbs out again to get to that right?

Dan

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I can get the bowls off my 83 with out a problem. So He should be able to get the pilot out without removing the carbs. The pilot in the later dual carbed ones I think was a 42. You can look it up on Bikebandit.com. You can get larger pilots from Sudco. com for your bike. I think they offer up to a 50. My 83 has a 55 stock with an option for a 58 but only Honda offers it.

I'd suggest you close up the air screw a bit. These carbs have an air screw instead of a fuel screw. Adjusting the air screw is a little different than a fuel screw. After setting a decent idle speed (not too fast, not super slow) start to adjust the air screw. Dial it out until you reach the highest RPM at idle keep going past for about a quarter turn to make sure you've got it at its highest point,make a mental note how many turns out from all the way in you are, then go back in until it slows,again mental note, then back out to the highest point and stop. That ought to be it.

Rule of Thumb:If it idles best at less than 1/2 a turn, it needs a bigger pilot. If you get pasted 2 turns out where its best, you need a smaller one.

One thing though...the glowing header isn't new or even a symptom of a problem. They all glow the header a little. Especially if the motor and or header is new.

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It seems like it idled the highest with the air screw all the way in. I'll see if I can get a bigger one in there. Thanks

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Dan, please let us know when you get this problem resolved. I've been riding XRs for 20 yrs. and I have never seen fire out the exhaust. :applause:

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Are you sure you dont have an intake leak somewhere? And the second carb is seating all the way to closed? The second carb doesnt have an idle circuit in it, so if its open a hair at idle its going to lean the thing out.

Is it easy to start?

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