E: Engine Measuring & Changing Float Level In 289 Carb

[CarlHungness]

I have a fitting made up that will go into the space occupied by the 1BA bolt in the arm that holds the float bowl. It is a 90
degree affair I'm hoping will fit in between the front cylinder fins and the carb, and pretty sure I can take out the battery in the
rear to install it.
Having never measured the float level previously I need some assistance. One post says the "float level at the top edge of the float
measured at the edge away from the needle and seat should be .080" below the top edge of the float." So do I hook up my line, take off the top of the float bowl and try to measure .080"? Another says 'ensure the clear tube is against the banjo nut, not the float bowl. If the level is somewhere in the middle to upper part of the top band of the banjo, it passes the test."
So, suggestions solicited.
I''ll replace the needles, do my best to check the floats and start over once again if necessary.

 

[greg brillus]

Carl the correct level is set so it is just bellow the pilot mixture screw......at or just bellow the base of the thread........Check it several times by turning off the fuel tap........lower the clear tube thus draining the fuel into a container, then raise the tube alongside the pilot screw and test again.......Make sure the bike is upright before carrying out this test........do it on both carbs........If it is out a little, you can simply rotate the carb on its flange/clip fitting......if it is out a lot, then we will further our discussions.

 

[CarlHungness]

Carl the correct level is set so it is just bellow the pilot mixture screw......at or just bellow the base of the thread........Check it several times by turning off the fuel tap........lower the clear tube thus draining the fuel into a container, then raise the tube alongside the pilot screw and test again.......Make sure the bike is upright before carrying out this test........do it on both carbs........If it is out a little, you can simply rotate the carb on its flange/clip fitting......if it is out a lot, then we will further our discussions.

Thanks Greg. I have new jets, will order new needles. It SEEMS to me that the times I've had it started, except with the old B-TH still in place, it is either running out of fuel or the ATD is slipping. When I got it started with the B-TH it ran extremely rough. With the Lucas it died after 30-60 seconds and could not re-start with either one. Will check the ATD tomorrow and hopefully know something. Don't know what else I can do to the carbs (that have served well for 20 odd years).

 

[Chris Launders]

Carl the .080 measurement is for Concentrics, (the give away is "the side opposite the needle and seat") not your carbs, as Gregg says it should be just below the pilot mixture screw thread on your carbs.

 

[lee_812d]

Stating the obvious probably, I guess we are hoping to see the fuel level too low here because if it was too high it would continue to pour out of that overflow hole.
Another check would be if the fuel cap vent is blocked, but I can't see that would impact so soon after starting.

 

[CarlHungness]

Carl the .080 measurement is for Concentrics, (the give away is "the side opposite the needle and seat") not your carbs, as Gregg says it should be just below the pilot mixture screw thread on your carbs.

Thanks..I ran Concentrics for a few years when I got the bike, lousy fuel mileage. Found I had the original
289's and installed them and no problems for years. Now though, it seems like it is running out of fuel
when I do get it to start for a few seconds. Will check float levels tomorrow, broke KS spring, the end of
it..so waiting for a replacement. Timed it at 8 BTDC with ears on ATD closed, no luck. Have gone back to
35 degrees fully advanced and will try that again.

 

[lee_812d]

When it is set at 35 degrees fully advanced, if you then measure with the ATD ears fully closed, does that give around 4 degrees BTDC?

 

[CarlHungness]

When it is set at 35 degrees fully advanced, if you then measure with the ATD ears fully closed, does that give around 4 degrees BTDC?

I think you are asking if the points open at 4 degrees BTDC with the ATD closed, and the quick answer is yes. I didn't use my light to check it (yet) but have my degree wheel in, rolled it toward TDC and could see the 'shoe' j-u--s-t
before my 35 degree pencil mark, which has been there for years (actually it was at 39 degrees previously with the
B-TH) but after installing the two mags, one sure knows just-about-where the points are going to open by looking
at the outer ring and its attendant bump. I'll re-check before buttoning it all up once again. Have had the timing chest
pipes off 9-10 times lately, so I'm quick at doing it all now.

 

[Gary Gittleson]

I'm having trouble understanding this answer. When setting for full advance (35 or 39 or whatever), the ATD has to be in full advance. It sounds like you are setting with the ATD closed but using the full-advanced setting.

Also, you referred to the compression numerous times and mentioned that after a rebuild, the valves were found to be hitting the pistons and that the remedy was to install a compression plate. That's all that was done to correct this? Without further attention to the valves, might they not be bent from hitting the pistons and now leaking? I have no experience with compression plates, but I don't think they should have so strong an affect. I don't remember if you did a leak-down test but if not, maybe it's time to do so.

 

[CarlHungness]

I open the ears on the ATD, wedge my 5/16' bolt in, set the points to open at 35 degrees while holding
the armature with the earth brush removed and a finger tightened bolt.
Valves, seats, etc. were all checked, replaced and on and on while doing the compression plates. Later
another set of pistons were installed along with another complete head job done perfectly by Glenn
Bewley, and the bike has run over 30,000 miles with no hiccups.
I DID set the ATD closed, at six degrees last week, first time I've ever set it with the ears closed.
Leak down test shows, near as I can tell, about half a percentage and the compression feels just
as normal, it's not at all easy to kick over, never has been.
There is no possibility I have set the ATD with the ears closed at 35 degrees, ever..or before that at
39 degrees with my B-TH Gary.
Ironically, back when the pistons were just kissing (0ne) rear valve, the bike ran great and I only
noticed the problem when I cracked a couple of rockers in row. Jean didn't check it with plastilene
and it could not have been very far off at all or it wouldn't have run as well as it did.