Slow jet is too small?
Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
Perhaps the oring in the a/f mixture screw is not sealing or is missing.Have you checked the
Slide diaphragm for holes? These carbs are generally very long life other than gumming up and rubber wearing.
Slide diaphragm for holes? These carbs are generally very long life other than gumming up and rubber wearing.
Last edited by RidemyEVO; Jun 19, 2012 at 01:36 PM.
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
And if there was a hole in the diaphragm, the slider wouldn't work or worked badly - no problems registered there.
As far as gumming up - it is possible I guess for those additional tiny holes/canals besides the idle port. I tried to blow compressed air when the slow jet was out - it seemed to come out from all those holes. Could it still be gummed up inside? How would I clean it then?
Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
I;m thinking the order is the way you said. When I rebuild a carb I will leave it submerged in Kleen Flo carb cleaner overnit and blow it out, I make sure I remove all rubber and plastic parts.
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
Well, the slider is actually pretty loose - I rechecked 
So, shimming the needle about 0.1" up, and screw out 4 turns, finally started getting me somewhere... I'm totally going for Mikuni, and maybe meanwhile slappin in a 50 jet :/
Now I'm worried that I did some damage on the brand new engine - the oil tmp didn't really go more than 200, but it was building up fast, and the heads felt overheated... Did less than a 100mi like that tho - what do you think?
So, shimming the needle about 0.1" up, and screw out 4 turns, finally started getting me somewhere... I'm totally going for Mikuni, and maybe meanwhile slappin in a 50 jet :/Now I'm worried that I did some damage on the brand new engine - the oil tmp didn't really go more than 200, but it was building up fast, and the heads felt overheated... Did less than a 100mi like that tho - what do you think?
Road Captain
Joined: Jun 2012
Posts: 533
Likes: 2
From: Virginia
This is indeed a possibility, especially if at any time during previous idle-mixture adjustments the mixture screw was turned in too far and the tiny brass tip of the mixture needle got broken off and is stuck in the orifice.
Road Master
Joined: Jan 2008
Posts: 1,187
Likes: 8
From: Montgomery, AL
Did you try and spray around the intake manifold seals just for ***** and grins for a leak? They may be new but maybe a fly got in there or something. There is no way you need a 48 or 50 to get a stock motor running. You talk about shimming the needle..are there any part numbers on it? First you said the carb was new and then rebuilt? As for your slide and spring does it look like maybe the spring was cut at sometime to make it "supposedly" work better? When I redid my carb I used the step by step on nightrider site. I also used some 2000 grit paper on the slide to remove impurities. You should not need enrichener on hot start. Just trying to help.
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
No no, the carb is old, form a severely overheated engine (I think for a reason). I was saying that I don't see a point of rebuilding it - would get a new mikuni instead... Good point about the spring - I have another one (lighter than stock) to compare with. But the slider as I said feels loose, I can even see significant wear on it's "wings". I'll be probably putting 50 in anyways, just to make it start and feel alright and to bring the plug color to normal, and then will be looking for mikuni anyways 
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Joe Kucinski
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Putting in the larger jet may make up slightly for an obvious deficency you have somewhere in your low speed circuit. Take a look at your factory manual. They have some pictures/diagram of the fuel flow through the various circuits in the CV. When you blow out the passages make sure you blow in the opposite direction as the fuel flow. That way if there are any solids in there you stand a better chance of blowing it out. WE soak our carbs in carb cleaner for 2-4 hours, then we rinse them out and blow dry them. Next it's into a metal gallon paiont can with two quarts of lacquer thinner. It will set in there overnight and then we blow it out again and rinse. This will pretty much take care of any blockage you might have. Hope this helps.
John
John
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Road Captain
Joined: Nov 2007
Posts: 517
Likes: 6
From: Ottawa, ON
Thanks so much Gents for your input!
So far I was able to "stabilize the situation" - runs alright, plug color is almost normal, very rarely stumbles at idle, somewhat difficult to start and no idle at all when cold. I still highly suspect the worn out slider. But I can live w that for the time being - already ordered a Mikuni kit
My friends are laughing at me - "how could I put an old carb on a brand new enige" :/
So far I was able to "stabilize the situation" - runs alright, plug color is almost normal, very rarely stumbles at idle, somewhat difficult to start and no idle at all when cold. I still highly suspect the worn out slider. But I can live w that for the time being - already ordered a Mikuni kit
My friends are laughing at me - "how could I put an old carb on a brand new enige" :/