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Discussion Starter · #1 ·
Hi all I followed the directions that I found here on rebuilding my Carburetor and I tried to start the bike today WOW it started and ran. You guys rock. Nex issue the bike starts and runs but the idle is rough and dies when you try to rev engine. I know it is a adjustment some where. Please help.

John Brown
86 Rebel 250
Brought on a whim

:Thanx:
 

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The only adjustments on the carb are the mixture screw and idle screw. The mixture screw should have been set to it's initial setting of 2.75 turns out from lightly seated when you put the carb back together then fine tuned after it's running. If you did set the mixture screw when you reassembled the carb I'd say your problem is still a dirty carb. Particularly the accelerator pump passageways. It's not uncommon for a dirty carb to require a couple of cleanings before it's right. Did you clean the carb using Chem-Dip? Did you use an air compressor to blow out all the passageways in the carb, float bowl, and accelerator pump bowl?
 

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Discussion Starter · #3 ·
The only adjustments on the carb are the mixture screw and idle screw. The mixture screw should have been set to it's initial setting of 2.75 turns out from lightly seated when you put the carb back together then fine tuned after it's running. If you did set the mixture screw when you reassembled the carb I'd say your problem is still a dirty carb. Particularly the accelerator pump passageways. It's not uncommon for a dirty carb to require a couple of cleanings before it's right. Did you clean the carb using Chem-Dip? Did you use an air compressor to blow out all the passageways in the carb, float bowl, and accelerator pump bowl?
I used the Chem Dip and let the parts soak for 2 days and was careful to blow it out real good. I have a feeling it is the mixture screw because I tried putting it back using the amount of turns it took to take it out. Do I have to take it all apart to do this adjustment? Thanks for your reply

John Brown
86 Rebel 250
 

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If the limiter tab is still on the head of the idle adjustment screw, you'll either need to remove and partially disassemble the carb or file off the tab. Some members have reported problems with the screw vibrating out with the tab removed.
 

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If it still has the limiter cap on it the float bowl will have to be removed to turn it all the way in unless you can get the cap off. I've heard it can be removed by applying heat to it but I haven't tried it so I can't confirm that. Some people have cut the tab off of the cap or notched the stop on the bowl. Don't try to pry the cap off. The screw has a tiny neck that is easily broken off, then you have a whole new problem.
 

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Discussion Starter · #6 ·
If it still has the limiter cap on it the float bowl will have to be removed to turn it all the way in unless you can get the cap off. I've heard it can be removed by applying heat to it but I haven't tried it so I can't confirm that. Some people have cut the tab off of the cap or notched the stop on the bowl. Don't try to pry the cap off. The screw has a tiny neck that is easily broken off, then you have a whole new problem.
I don't need any new problems so I guess I will take the float bowl off. So I need to seat it and then back it off 2 1/2 turns?
 

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I just checked the manual and the initial setting for the pilot screw is 2 1/4 turns out. I was thinking about the second gen carbs that should be set to 2 3/4 turn out.
 

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If the limiter tab is still on the head of the idle adjustment screw, you'll either need to remove and partially disassemble the carb or file off the tab. Some members have reported problems with the screw vibrating out with the tab removed.
Do you suppose this "vibrating loose" issue is probably a missing/worn out O ring issue? Never had this problem and my screws seem to fit quite snug. :confused:
 

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Spark plug gaps

Had similar problem not too long ago here, and it ended up being resolved by pulling and re-gapping my spark plugs. Please check those plugs, might not be them but they are easy to pull, check and put back in.
 

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I'd clean the carb again. Sometimes (often?) it takes multiple wash cycles to get all the gunk out. When I did mine, it took 6 tries before it ran right. Nothing to be proud of, but there it is. Until I got it right, the bike would die when I touched the throttle, just like yours.
 

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Discussion Starter · #12 ·
Had similar problem not too long ago here, and it ended up being resolved by pulling and re-gapping my spark plugs. Please check those plugs, might not be them but they are easy to pull, check and put back in.
Thanks you are right whole lot earier than pulling the Carb. Do you know what the gap should be?

John Brown
86 Rebel 250

:Thanx:
 

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Discussion Starter · #13 ·
I will clean the Carb again this weekend and check plugs. I pulled the bowl off last night and reset the mixture screw and it helped a little. To me the mixture screw seems very loose don't know if I am missing something or what

John Brown
86 Rebel 250
Learning as I go
 

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Make sure there is an o-ring/washer in the hole. ;)
 

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Thanks you are right whole lot earier than pulling the Carb. Do you know what the gap should be?

John Brown
86 Rebel 250

:Thanx:
0.6-0.7 mm or 0.024-0.027 inch, right out of my Hayens Service and Repair Manual, page 1-1. I have a brass disk that lives on my bike keys for gapping spark plugs, think I picked several of them up, many years ago at some auto parts place, know I gave #2 son one, who has lost it and keys, years ago.
 

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Discussion Starter · #16 ·
Make sure there is an o-ring/washer in the hole. ;)
I believe that is my problem. I am not seeing any washers O rings or springs. Is that correct 2 washers a O ring and Spring? I am guessing that I will have a heck of a time finding them.

John Brown
86 Rebel 250
What did I get myself into
 

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It is an O ring then a washer and then the spring. The limiter cap can be removed with a little heat, as it is only Loctite that holds it on the brass adjuster. I too have never seen one vibrate out on any carb that has had all the parts correctly installed on the adjuster. On the larger 4 cylinders motors it is rare to find the locking tabs still intact on the carbs.

The carb still is dirty by the symptoms you have described. Yet if you are missing those parts off the adjuster for the air mixture, that will also have an effect on your running motor.
 

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You might find those tiny washers at Radio Shack, I did at the one in Jacksonville IL, take that long skinny screw and that easy to loose spring when you go for fitting them.
 

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Discussion Starter · #20 ·
Well I ordered the parts for the carb so now goes the waiting game. Next item will be Front Brake master cylinder, the one on there is ruined in my opinion, been setting out without cap for years. I got a rebuild kit but no idea how to disassemble it, anybody got tips? I do thank each and every one of you who have commented.

:Thanx:

John Brown
86 Rebel 250
 
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