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Carb Bowl Fuel Level

Posted: Mon Dec 15, 2014 2:05 pm
by rkmason
Seem to have one non-functional carb (#3) that I'm trying to diagnose. FYI, all four carbs were rebuilt using the full Randakk Kit. I pulled the carb rack off the bike being careful to keep it upright so I could inspect the #3 carb bowl fuel. Can anyone tell me if this appears to be the correct bowl fuel level? The fuel level is just over .5" down from the carb bowl rim. So far nothing else is obviously amiss with this carb.

Also, I noticed that the little spring-loaded contact button built into the #3 carb float needle was stuck in the extended position. I got it loose, but it now hangs up in the fully compressed position. I have the #3 carb needle soaking in acetone right now. Would a stuck needle button contribute to functional issues with this carb? Thx

Re: Carb Bowl Fuel Level

Posted: Tue Dec 16, 2014 8:45 am
by RBGERSON
No not right the fluid level should be just below the lip of the bowl not .5" below. you need a need float needle..only buy OEM!!! Easier check is to drain the bowl while on the bike an measure the output shoild be about 1 1/2 oz. if my memory is correct. all four carbs should be the same.

Re: Carb Bowl Fuel Level

Posted: Tue Dec 16, 2014 8:59 am
by 4wred
I've read other posts on this and guy's fill up the bowls on the bench via a I V bottle.Did you do this before reinstall on bike?That way you could verify before you put them back on bike.When I finally get around to a total rebuild on my carbs I want to do that.

Re: Carb Bowl Fuel Level

Posted: Thu Dec 18, 2014 1:29 pm
by rkmason
I have measured the fuel volume in the carb bowls, and all four measure within 5 - 10% of a nominal 1.5oz each. So no issue with bowl fuel level; now looks like I'll be pulling out the slow jets on two of my problem carbs.

FIXED

Posted: Fri Dec 19, 2014 11:01 pm
by rkmason
So it turns out I had two carbs (#2 and #3) with plugged up slow jets. I had completely rebuilt all four carbs but did not attempt to remove the pressed-in slow jets because the removal process sounded risky. After exhausting all the other possibilities for fixes I decided the slow jets had to come out now for a thorough cleaning. Used the #2 Easy Out jet removal technique which works very well provided you drill a 7/64" pilot hole about 1/8" deep in the jet body to allow the nose of the easy out to bite into the brass jet. I ran a countersink around the edge of the 7/64" drilled pilot hole to make sure there were no brass chips waiting to come loose and cause another problem later.

The .013" central jet hole was 100% plugged on both carbs which kept cyls #2 and #3 from working at all. There was no contamination on the backside of the jet; the emulsion tube holes and downstream passages were all clear.

It runs a lot smoother now on 4 cyls than it did on 2....

Re: Carb Bowl Fuel Level

Posted: Sat Dec 20, 2014 7:57 am
by RBGERSON
Not to rain on your parade BUT!! drilling even the end of a jet changes it's draw..not good may seem to work OK but will not run as intended.

Re: Carb Bowl Fuel Level

Posted: Sat Dec 20, 2014 11:31 am
by rkmason
RBGERSON wrote:Not to rain on your parade BUT!! drilling even the end of a jet changes it's draw..not good may seem to work OK but will not run as intended.
Yes, I have seen the comments here about the effects of jet modifications; that is why I chose not to remove the slow jets when I was doing the initial carb rebuilds. If I could have removed these jets without drilling them first I would've done it, but the #2 easy out requires a 7/64" hole to engage properly and I wanted to maximize my chances to get the jets out. So these two slow jets now have a stepped lead-in hole.

I'll deal with the slight consequences of my slow jet modifications; all four cylinders firing vs only two firing is also what was intended.

Re: Carb Bowl Fuel Level

Posted: Sat Dec 20, 2014 6:11 pm
by RBGERSON
FYI you can use a sheet metal screw that fits, lightly screw in and pull gently

Re: Carb Bowl Fuel Level

Posted: Sat Dec 20, 2014 11:12 pm
by WingAdmin
rkmason wrote:
RBGERSON wrote:Not to rain on your parade BUT!! drilling even the end of a jet changes it's draw..not good may seem to work OK but will not run as intended.
Yes, I have seen the comments here about the effects of jet modifications; that is why I chose not to remove the slow jets when I was doing the initial carb rebuilds. If I could have removed these jets without drilling them first I would've done it, but the #2 easy out requires a 7/64" hole to engage properly and I wanted to maximize my chances to get the jets out. So these two slow jets now have a stepped lead-in hole.

I'll deal with the slight consequences of my slow jet modifications; all four cylinders firing vs only two firing is also what was intended.
You could put a correct diameter rod/wire (the back end of a drill bit perhaps) into the jet, and put a light coat of J-B Weld on the end around it, to try to fill in what you countersunk. Then pull it out before the J-B Weld fully cures.

Re: Carb Bowl Fuel Level

Posted: Sun Dec 21, 2014 10:26 am
by rkmason
I'm going to run it as-is for now and see how it works. If I notice anything obviously different in the operation of cyls #2 and #3 vs #1 and #4 I may do something about it then. Is there any known source for these pressed-in slow jets, new or salvage?